Moisture content measuring device

Abstract

To provide a moisture content measuring device that can prevent a conduction failure caused by rust between a crushing roller and an electrode terminal.SOLUTION: When grain which is the harvest is being crushed between circumferential surfaces of crushing rollers 17, 18, a current for measurement is supplied to an electrode terminal 45 from a measurement circuit 61, and a signal corresponding to an electrical resistance value between the electrode terminals 45, 46 is output from the measurement circuit 61. When rust is generated in a localized area where the roller electrodes 32, 35 come into contact with the electrode terminals 45, 46 and conductivity between the crushing rollers 17, 18 and the electrode terminals 45, 46 decreases, the electrical resistance value between the electrode terminals 45, 46 increases. When the electrical resistance value acquired from the output signal of the measurement circuit 61 is an abnormal value, an abnormality resolution current larger than the current for measurement is supplied from an external constant current source 66 to the electrode terminal 45 to cause the abnormality resolution current to flow between the electrode terminals 45, 46.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a moisture content measuring device that is mounted on a harvester such as a combine harvester to measure the moisture content of crops harvested by the harvester. [Background technology]

[0002] For example, a combine harvester is a harvesting machine that harvests grains such as rice and wheat. In a combine harvester, crops planted in a field are harvested by a harvesting device, and the harvested crops are transported from the harvesting device to a thresher, where the grains are removed from the stalks. The removed grains are transported from the thresher to a discharge section located at the top of a grain tank, and are then discharged from the discharge section into the grain tank and collected.

[0003] Some combine harvesters are equipped with an electrical resistance moisture measuring device (moisture meter) in a grain tank to measure the moisture content of grains. The moisture measuring device is placed in a position where it can receive grains discharged from the discharge section. The moisture measuring device is equipped with a pair of crushing rollers, and electrode terminals for measuring the electrical resistance between the electrode rollers are provided in contact with the shafts of each crushing roller. Grains received in the moisture measuring device are caught between the circumferential surfaces of the crushing rollers as the crushing rollers rotate, and are crushed between the circumferential surfaces of the crushing rollers. With the crushed grains sandwiched between the circumferential surfaces of the crushing rollers, the electrical resistance between the crushing rollers is measured, and the moisture content of the grains is determined from the electrical resistance value (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6451513 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it was discovered that conventional moisture content measuring devices tend to rust at the contact points between the crushing roller shaft and the electrode terminals. When this rust occurs, poor electrical continuity occurs between the crushing roller and the electrode terminals, making it impossible to accurately measure the electrical resistance between the crushing rollers.

[0006] An object of the present invention is to provide a moisture content measuring device that can prevent poor electrical conduction caused by rust between the crushing roller and the electrode terminal. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, one aspect of the present invention provides a moisture content measuring device that is mounted on a harvester and measures the moisture content of a crop harvested by the harvester, and includes a pair of crushing rollers whose circumferential surfaces are arranged close to each other and that crush the crop between their circumferential surfaces as they rotate, roller electrodes attached to one end surface of each of the crushing rollers, electrode terminals in contact with each of the roller electrodes, a measurement circuit that supplies a measurement current to the electrode terminals when the crop is being crushed between the circumferential surface of one crushing roller and the circumferential surface of the other crushing roller, and outputs a signal corresponding to the electrical resistance value between one electrode terminal and the other electrode terminal, and a control device, and the control device performs an acquisition process that acquires the electrical resistance value from the signal output by the measurement circuit, a judgment process that determines whether the electrical resistance value acquired in the acquisition process is an abnormal value, and a current process that, if the judgment process determines that the electrical resistance value is an abnormal value, passes an abnormality-resolving current greater than the measurement current between one electrode terminal and the other electrode terminal.

[0008] With this configuration, when the harvested product is being crushed between the circumferential surface of the crushing roller and the circumferential surface of the other crushing roller, a measurement current is supplied from the measurement circuit to the electrode terminals, and a signal corresponding to the electrical resistance between the electrode terminals is output from the measurement circuit. When rust develops at the contact points between the roller electrodes and the electrode terminals, reducing electrical continuity between the crushing roller and the electrode terminals, the electrical resistance between the electrode terminals increases. Therefore, if the electrical resistance value obtained from the output signal of the measurement circuit is abnormal, an abnormality-resolving current greater than the measurement current is passed between the electrode terminals. This generates an arc between the roller electrodes and the electrode terminals, and the cleaning effect of the arc destroys the rust (oxide film). As a result, electrical continuity failure due to rust between the crushing roller and the electrode terminals can be prevented, and the electrical resistance between the crushing roller and the other crushing roller can be accurately measured. This ultimately allows for accurate measurement of the moisture content of the harvested product being crushed between the crushing roller and the other crushing roller.

[0009] Another aspect of the present invention provides a moisture content measuring device that is mounted on a harvester and measures the moisture content of the harvested product harvested by the harvester, and includes a pair of crushing rollers whose circumferential surfaces are arranged close to each other and that crush the harvested product between their circumferential surfaces as they rotate, electrode terminals in contact with each of the crushing rollers, a measurement circuit that supplies a measurement current to the electrode terminals when the harvested product is being crushed between the circumferential surface of one crushing roller and the circumferential surface of the other crushing roller, and outputs a signal corresponding to the electrical resistance value between one electrode terminal and the other electrode terminal, and a control device.The control device performs an acquisition process that acquires the electrical resistance value from the signal output by the measurement circuit, a judgment process that determines whether the electrical resistance value acquired in the acquisition process is an abnormal value, and a current process that, if the judgment process determines that the electrical resistance value is an abnormal value, passes an abnormality-resolving current greater than the measurement current between one electrode terminal and the other electrode terminal.

[0010] With this configuration, when the harvested product is being crushed between the circumferential surface of one crushing roller and the circumferential surface of the other crushing roller, a measurement current is supplied from the measurement circuit to the electrode terminals, and a signal corresponding to the electrical resistance between the one electrode terminal and the other electrode terminal is output from the measurement circuit. If rust develops at the contact points between the crushing roller and the electrode terminals, reducing electrical continuity between the crushing roller and the electrode terminals, the electrical resistance between the one electrode terminal and the other electrode terminal increases. Therefore, if the electrical resistance value obtained from the output signal of the measurement circuit is abnormal, an abnormality-resolving current greater than the measurement current is passed between the one electrode terminal and the other electrode terminal. This generates an arc between the crushing roller and the electrode terminal, and the cleaning effect of the arc destroys the rust (oxide film). As a result, poor electrical continuity due to rust between the crushing roller and the electrode terminals can be prevented, and the electrical resistance between the one crushing roller and the other crushing roller can be accurately measured. This ultimately allows for accurate measurement of the moisture content of the harvested product being crushed between the one crushing roller and the other crushing roller.

[0011] The control device may (automatically) execute current processing in response to the determination that the electrical resistance value is an abnormal value in the determination processing.

[0012] In addition, the control device may execute an abnormality notification process to notify of an abnormality in response to the judgment process determining that the electrical resistance value is an abnormal value, and after the abnormality notification process, may execute current processing in response to an instruction to execute current processing being input from outside.

[0013] If the harvester is provided with an operation panel (meter panel) for displaying and inputting information, an abnormality may be notified by the display on the operation panel, and an instruction to perform current processing may be input from the operation panel to the control device by operating the operation panel.

[0014] The control device may execute a series of processes from the acquisition process to the current process a predetermined number of times, then execute the acquisition process and the judgment process, and if the final judgment process determines that the electrical resistance value is an abnormal value, execute a replacement notification process to notify the user that the electrode terminal needs to be replaced.

[0015] After the current processing, the control device may re-execute the acquisition processing and the determination processing, and if the re-executed determination processing determines that the electrical resistance value is an abnormal value, may re-execute the current processing.

[0016] By repeating the current treatment, the electrical continuity between the crushing roller and the electrode terminal can be restored to a good state, and poor electrical continuity due to rust between the crushing roller and the electrode terminal can be prevented.

[0017] The control device may perform the current processing a predetermined number of times, and then re-execute the acquisition processing and the judgment processing, and if the re-executed judgment processing determines that the electrical resistance value is an abnormal value, execute a replacement notification processing to notify the user that the electrode terminal needs to be replaced.

[0018] If the electrical resistance value is still abnormal even after the current processing has been repeated a predetermined number of times, the user of the harvester can be prompted to replace the electrode terminal by being notified of the need to replace the electrode terminal.

[0019] A moisture content measuring device according to yet another aspect of the present invention is a moisture content measuring device that is mounted on a harvester and measures the moisture content of a crop harvested by the harvester, and includes a pair of crushing rollers whose circumferential surfaces are arranged close to each other and which crush the crop between their circumferential surfaces as they rotate, roller electrodes attached to one end surface of each of the crushing rollers, electrode terminals in contact with each of the roller electrodes, a measuring circuit having an internal constant current source that is electrically connected to the electrode terminals via a first conductor and outputs a measurement current, an external constant current source that is electrically connected to the electrode terminals via a second conductor and outputs an abnormality resolution current that is larger than the measurement current, a first switch that is attached to the first conductor and switches between disconnection and connection of the first conductor by opening and closing, and a second switch that is attached to the second conductor and switches between disconnection and connection of the second conductor by opening and closing. The device includes a second switch that switches between disconnection and conduction, and a third switch that is provided on a third conductor that electrically connects one roller electrode and the other roller electrode and that switches between disconnection and conduction in the third conductor by opening and closing.The device has a measurement state in which, when the first switch is closed and the second and third switches are open and the harvested product is being crushed between the circumferential surface of one crushing roller and the circumferential surface of the other crushing roller, a measurement current is supplied from the internal constant current source to the electrode terminal and a signal corresponding to the electrical resistance value between the one electrode terminal and the other electrode terminal is output from the measurement circuit; and a current processing state in which the first switch is open and the second and third switches are closed and an abnormality resolution current is supplied from the external constant current source to the electrode terminal and the abnormality resolution current flows in the third conductor.

[0020] According to this configuration, in the measurement state, when the harvested crop is crushed between the circumferential surfaces of the crushing rollers, a measurement current is supplied from the internal constant current source of the measurement circuit to the electrode terminals, and a signal corresponding to the electrical resistance between the electrode terminals is output from the measurement circuit. In the measurement state, rust may form locally at the contact points between the roller electrodes and the electrode terminals, reducing electrical continuity between the crushing rollers and the electrode terminals. In the current treatment state, an abnormality resolution current is supplied from the external constant current source to the electrode terminals, and the abnormality resolution current flows through the third conductor connecting the roller electrodes. This generates an arc between the roller electrodes and the electrode terminals, and the cleaning effect of the arc destroys the rust (oxide coating). Therefore, by switching from the measurement state to the current treatment state at the appropriate time, electrical continuity problems due to rust between the crushing rollers and the electrode terminals can be prevented, and the electrical resistance between the crushing rollers and the electrode terminals can be accurately measured. As a result, the moisture content of the harvested product being crushed between one crushing roller and the other crushing roller can be measured with high accuracy.

[0021] Furthermore, a moisture content measuring device according to yet another aspect of the present invention is a moisture content measuring device that is mounted on a harvester and measures the moisture content of a crop harvested by the harvester, and includes a pair of crushing rollers whose peripheral surfaces are arranged close to each other and which crush the crop between their peripheral surfaces as they rotate, electrode terminals that contact each of the crushing rollers, a measuring circuit that is electrically connected to the electrode terminals via a first conductor and has an internal constant current source that outputs a measurement current, an external constant current source that is electrically connected to the electrode terminals via a second conductor and outputs an abnormality resolution current that is larger than the measurement current, a first switch that is provided on the first conductor and that switches between disconnection and continuity in the first conductor by opening and closing, and a second switch that is provided on the second conductor and that switches between disconnection and continuity in the second conductor by opening and closing. The device includes a second switch and a third switch provided on a third conductor electrically connecting one crushing roller and the other crushing roller, which switches between disconnection and conduction in the third conductor by opening and closing.The device has a measurement state in which, when the first switch is closed and the second and third switches are open and the harvested product is being crushed between the circumferential surface of one crushing roller and the circumferential surface of the other crushing roller, a measurement current is supplied from the internal constant current source to the electrode terminal and a signal corresponding to the electrical resistance between the one crushing roller and the other crushing roller is output from the measurement circuit; and a current processing state in which the first switch is open and the second and third switches are closed and an abnormality resolution current is supplied from the external constant current source to the electrode terminal and the abnormality resolution current flows in the third conductor.

[0022] According to this configuration, in the measurement state, when the harvested crop is crushed between the circumferential surfaces of the crushing rollers, a measurement current is supplied from the internal constant current source of the measurement circuit to the electrode terminals, and a signal corresponding to the electrical resistance between the electrode terminals is output from the measurement circuit. In the measurement state, rust may form at the contact points between the crushing rollers and the electrode terminals, reducing electrical continuity between the crushing rollers and the electrode terminals. In the current processing state, an abnormality resolution current is supplied from the external constant current source to the electrode terminals, and the abnormality resolution current flows through the third conductor electrically connecting the crushing rollers. This generates an arc between the crushing rollers and the electrode terminals, and the cleaning effect of the arc destroys the rust (oxide film). Therefore, by switching from the measurement state to the current processing state at the appropriate time, electrical continuity problems due to rust between the crushing rollers and the electrode terminals can be prevented, and the electrical resistance between the crushing rollers and the electrode terminals can be accurately measured. As a result, the moisture content of the harvested product being crushed between one crushing roller and the other crushing roller can be measured with high accuracy.

[0023] The moisture content measuring device may further include a control device that controls opening and closing of the first switch, the second switch, and the third switch.

[0024] The electrode terminal may include a current source terminal for supplying current between one crushing roller and the other crushing roller, and a detection terminal for detecting the potential difference between the one crushing roller and the other crushing roller. In other words, the measurement circuit may be configured to measure the electrical resistance value by a four-terminal method.

[0025] With this configuration, the electrical resistance value between one crushing roller and the other crushing roller can be measured more accurately than with a configuration that measures the electrical resistance value using the two-terminal method, and ultimately the moisture content of the harvested product being crushed between one crushing roller and the other crushing roller can be measured more accurately. [Effects of the Invention]

[0026] According to the present invention, poor electrical conductivity due to rust between the crushing rollers and the electrode terminals can be prevented, and therefore the electrical resistance between one crushing roller and the other crushing roller can be measured with high accuracy, and therefore the moisture content of the harvested product being crushed between the one crushing roller and the other crushing roller can be measured with high accuracy. [Brief explanation of the drawings]

[0027] [Figure 1] 1 is a right side view of a combine harvester equipped with a moisture content measuring device according to an embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view of a moisture content measuring device. [Figure 3] FIG. 2 is a front view of the moisture content measuring device. [Figure 4] FIG. 2 is a perspective view of the front lower portion of the roller unit as viewed from the front bottom. [Figure 5] FIG. 2 is a diagram illustrating the circuit configuration of the moisture content measuring device. [Figure 6] FIG. 2 is a block diagram showing the main parts of the electrical configuration of the combine harvester. [Figure 7] 10 is a flowchart showing the flow of abnormality resolution control. [Figure 8] 10 is a flowchart showing the flow of abnormality resolution control according to a modified example. [Figure 9] FIG. 10 is a side view of an electrode terminal according to a modified example. [Figure 10] FIG. 10 is a front view of a mounting base according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0028] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0029] <Overall configuration of the combine> FIG. 1 is a right side view of a combine harvester 1 on which a moisture content measuring device according to one embodiment of the present invention is mounted.

[0030] The combine 1 is an agricultural machine that harvests and threshes crops while traveling in a field, and is a harvester that harvests grains.

[0031] The combine harvester 1 employs a pair of left and right crawler traveling devices 2 as traveling devices capable of traveling over rough ground such as farm fields. A machine frame 3 is supported by the left and right crawler traveling devices 2, and power from an engine provided on the machine frame 3 is transmitted to the crawler traveling devices 2 via a transmission.

[0032] Additionally, a cabin 4, a threshing device 5, and a grain tank 6 are provided on the machine frame 3. A reaping device 7 that reaps crops is provided in front of the crawler traveling device 2 and the machine frame 3.

[0033] The cabin 4 is disposed on the front end of the vehicle frame 3. The cabin 4 provides a space for a user to board, and within this space, for example, a driver's seat where the user sits, operating levers that the user operates, etc. An openable door 8 is provided on the right side of the cabin 4, and the user can open the door 8 to enter the cabin 4.

[0034] The threshing device 5 is located to the left rear of the cabin 4. The grain tank 6 is located behind the cabin 4 and to the right of the threshing device 5. In the threshing device 5, the materials to be sorted obtained by threshing the crop are sorted and collected. The collected materials to be sorted (grains) are transported to the grain tank 6 and stored in the grain tank 6. An unloader 9 is connected to the grain tank 6, and the grains stored in the grain tank 6 can be discharged from the grain tank 6 to the outside of the machine by the unloader 9.

[0035] <Moisture content measuring device> FIG. 2 is a perspective view of the moisture content measuring device 11. As shown in FIG.

[0036] The grain tank 6 is provided with a moisture content measuring device 11 that measures the moisture content of the grain stored in the grain tank 6. Although not shown, the grain tank 6 also has a discharge section that discharges the grain transported from the threshing device 5. The discharge section is provided with rotating blades that rotate around an axis that extends in the vertical direction, and the grains transported to the discharge section are swept away by the rotating rotating blades. The moisture content measuring device 11 is placed in a position that can receive the grains discharged from the discharge section, for example, on the front inner wall surface of the grain tank 6.

[0037] In the following, the moisture content measuring device 11 is assumed to be arranged on the front inner wall surface of the grain tank 6, and the front-to-back, left-to-right and up-to-down directions of the moisture content measuring device 11 are assumed to be the same as the front-to-back, left-to-right and up-to-down directions of the combine 1.

[0038] The moisture content measuring device 11 includes a box-shaped housing 12. A roller unit 13 is provided inside the housing 12, and an opening 14 is formed in the rear surface of the housing 12 to expose the rear surface of the roller unit 13.

[0039] The roller unit 13 is provided with a rear case 15 having an open front face. A receiving opening 16 for receiving grains into the rear case 15 is formed on the rear face of the rear case 15.

[0040] A pair of crushing rollers 17, 18 are housed within the rear case 15. The crushing rollers 17, 18 are arranged side by side behind the receiving port 16 with their rotation axes extending in the front-to-rear direction. The crushing rollers 17, 18 are spaced apart at a distance corresponding to the size of the rice (unhulled rice), for example, a distance slightly smaller than the width of the rice (the length in the direction perpendicular to the longitudinal direction). The crushing rollers 17, 18 have a large number of minute irregularities formed on their peripheral surfaces. The left crushing roller 17 rotates clockwise and the right crushing roller 18 rotates counterclockwise by the power of a motor 82 (see Figure 6).

[0041] Some of the grains scattered from the discharge section inside the grain tank 6 reach the position of the housing 12 and are directly received into the housing 12 through the receiving port 16 of the housing 12. A guide member 19 is attached to the rear surface of the housing 12, and the grains that reach the guide member 19 flow over the guide member 19, drop from the guide member 19, and are received into the rear case 15 through the receiving port 16. The grains received into the rear case 15 through the receiving port 16 accumulate on the circumferential surfaces of the crushing rollers 17, 18. When the crushing rollers 17, 18 rotate, the grains are sandwiched between the circumferential surfaces of the crushing rollers 17, 18 and crushed.

[0042] FIG. 3 is a front view of the moisture content measuring device 11.

[0043] The roller unit 13 includes a plate-shaped front case 21. The front case 21 is provided to close the front of the rear case 15, and the rear case 15 and the front case 21 together provide a roller storage space for storing the crushing rollers 17 and 18.

[0044] FIG. 4 is a perspective view of the front lower portion of the roller unit 13 as viewed from the front and bottom.

[0045] Circular openings 22 and 23 are formed in the front case 21 on the axes of the crushing rollers 17 and 18, respectively. The crushing rollers 17 and 18 are integrally formed with roller shafts 25 and 26, respectively. A front end surface 27 of the roller shaft 25 and a front end surface 28 of the roller shaft 26 (see FIG. 9) are exposed forward from the openings 22 and 23, respectively.

[0046] A circular plate-shaped roller electrode 32 and a spacer 33 are replaceably attached to the front end surface 27 of the roller shaft 25 by a fixing screw 31. Specifically, the fixing screw 31 is inserted through the center of the stacked roller electrode 32 and spacer 33 from the roller electrode 32 side. A threaded hole is formed in the center of the front end surface 27 of the roller shaft 25, and the tip of the fixing screw 31 inserted through the roller electrode 32 and spacer 33 is screwed into the threaded hole. This fixes the roller electrode 32 and spacer 33 to the roller shaft 25 with the spacer 33 interposed between the front end surface 27 of the roller shaft 25 and the roller electrode 32. Because the spacer 33 is interposed between the front end surface 27 of the roller shaft 25 and the roller electrode 32, the roller electrode 32 is provided in a floating state above the front case 21 and is not in contact with the front case 21. When the fixing screw 31 is removed, the roller electrode 32 and spacer 33 are released from the roller shaft 25. Therefore, by removing the fixing screws 31, the roller electrode 32 and the spacer 33 can be removed from the roller shaft 25. Then, another roller electrode 32 and spacer 33 can be attached to the front end surface 27 of the roller shaft 25 using the fixing screws 31.

[0047] A circular plate-shaped roller electrode 35 and a spacer 36 are replaceably attached to the front end surface 27 of the roller shaft 26 with fixing screws 34. The attachment structure of the roller electrode 35 and the spacer 36 is similar to the attachment structure of the roller electrode 32 and the spacer 33, and therefore a description thereof will be omitted.

[0048] A terminal unit 41 is attached to the front case 21. The terminal unit 41 includes a mounting base 42, terminal holding members 43 and 44 attached to the mounting base 42, and electrode terminals 45 and 46 held by the terminal holding members 43 and 44, respectively.

[0049] The mounting base 42 has a generally rectangular plate shape. The mounting base 42 is disposed on the front surface of the front case 21 below the roller electrodes 32, 35 so as to extend longer in the left-right direction than in the up-down direction. The mounting base 42 is attached to the front case 21 with, for example, two fixing screws 37.

[0050] The terminal holding members 43, 44 are disposed on the front surface of the mounting base 42 at positions offset to the left of the centers of the roller electrodes 32, 35. The terminal holding members 43, 44 have the same configuration, and each of the terminal holding members 43, 44 includes a front holding plate 47 and a rear holding plate 48 that are overlapped from front to back.

[0051] The electrode terminals 45 and 46 have the same configuration. Here, the configuration of the electrode terminal 45 will be described, and a description of the configuration of the electrode terminal 46 will be omitted. In Figures 3 and 4, parts of the electrode terminal 46 that correspond to the parts of the electrode terminal 45 are given the same reference numerals as the parts of the electrode terminal 45.

[0052] The base end 51 of the electrode terminal 45 is shaped like a substantially rectangular plate. The electrode terminal 45 has two terminal arms 52, 53 extending from the base end 51 in the longitudinal direction of the base end 51. Approximately semicircular plate-shaped terminal contacts 54, 55 are provided to protrude from one surface of the tip end of the terminal arms 52, 53.

[0053] The electrode terminal 45 is positioned such that its base end 51 is sandwiched between the front holding plate 47 and the rear holding plate 48 of the terminal holding member 43, and its terminal contacts 54, 55 contact the roller electrode 32 at a position offset to the left of the center of the roller electrode 32 (the axis of rotation of the crushing roller 17). The front holding plate 47 and the rear holding plate 48 are attached to the mounting base 42 as an integrated unit by a fixing screw 56 that penetrates the terminal holding member 43 in the front-rear direction, and the base end 51 of the electrode terminal 45 is sandwiched between the front holding plate 47 and the rear holding plate 48.

[0054] The electrode terminal 46 is positioned such that its base end 51 is sandwiched between the front holding plate 47 and the rear holding plate 48 of the terminal holding member 44, and the terminal contacts 54, 55 are in contact with the roller electrode 35 at a position offset to the right with respect to the center of the roller electrode 35 (the axis of rotation of the crushing roller 18). The front holding plate 47 and the rear holding plate 48 are attached to the mounting base 42 as an integrated unit by a fixing screw 57 that penetrates the terminal holding member 43 in the front-rear direction, and the base end 51 of the electrode terminal 46 is sandwiched between the front holding plate 47 and the rear holding plate 48.

[0055] The roller electrodes 32, 35 and the electrode terminals 45, 46 are made of the same metal, while the crushing rollers 17, 18 are made of a different metal than the roller electrodes 32, 35 and the electrode terminals 45, 46. The spacers 33, 36 and the fixing screws 31, 34 may be made of the same metal as the roller electrodes 32, 35 and the electrode terminals 45, 46, or may be made of a different metal than the roller electrodes 32, 35 and the electrode terminals 45, 46. The spacers 33, 36 and the fixing screws 31, 34 may be made of the same metal as the crushing rollers 17, 18, or may be made of a different metal than the crushing rollers 17, 18. However, since the spacers 33, 36 and the fixing screws 31, 34 come into contact with the roller electrodes 32, 35, it is preferable that the spacers 33, 36 and the fixing screws 31, 34 be made of materials with natural potentials (ionization tendencies) similar to those of the roller electrodes 32, 35 and the electrode terminals 45, 46 to prevent galvanic corrosion. For example, the crushing rollers 17 and 18 are made of iron, the roller electrodes 32 and 35 and the electrode terminals 45 and 46 are made of copper, and the spacers 33 and 36 and the fixing screws 31 and 34 are made of stainless steel.

[0056] FIG. 5 is a diagram illustrating the circuit configuration of the moisture content measuring device 11. As shown in FIG.

[0057] The moisture content measuring device 11 is equipped with a measuring circuit 61. The measuring circuit 61 includes an internal constant current source 62 that outputs a measuring current. The measuring circuit 61 is connected to the electrode terminals 45, 46 via first conductors 63, 64, respectively. A first switch 65 is provided in the first conductor 63. Opening and closing the first switch 65 switches between disconnection and conduction in the first conductor 63. The first conductor 64 is connected to ground.

[0058] An external constant current source 66 is connected to the electrode terminal 45 via a second conductor 67. The external constant current source 66 is, for example, built into an ECU 81 (see FIG. 6 ), which will be described later. A second switch 68 is provided on the second conductor 67. Opening and closing the second switch 68 switches between disconnection and conduction in the second conductor 67.

[0059] Although not shown in FIGS. 3 and 4 , the moisture content measuring device 11 is also equipped with electrode terminals 71 and 72, as shown in FIG. 5 . The electrode terminals 71 and 72 have the same configuration as the electrode terminals 45 and 46 and include two terminal arms 73 and 74. The electrode terminal 71 is positioned so that terminal contacts provided at the ends of the terminal arms 73 and 74 contact the roller electrode 32 at a position offset to the right with respect to the center of the roller electrode 32 (the axis of rotation of the crushing roller 17). The electrode terminal 72 is positioned so that terminal contacts provided at the ends of the terminal arms 73 and 74 contact the roller electrode 35 at a position offset to the left with respect to the center of the roller electrode 35 (the axis of rotation of the crushing roller 18). One end and the other end of a third conducting wire 75 are connected to the electrode terminals 71 and 72, respectively. Thus, the electrode terminals 45 and 46 are electrically connected via the roller electrodes 32 and 35, the electrode terminals 71 and 72, and the third conducting wire 75. A third switch 76 is provided on the third conducting wire 75. When the third switch 76 is opened or closed, the third conducting wire 75 is switched between disconnection and conduction.

[0060] <Electrical configuration of combine> FIG. 6 is a block diagram showing the main parts of the electrical configuration of the combine harvester 1. As shown in FIG.

[0061] The combine harvester 1 is equipped with an ECU (Electronic Control Unit) 81. The ECU 81 includes a microcomputer (microcontroller), which includes, for example, a CPU, a nonvolatile memory such as a flash memory, and a volatile memory such as a DRAM (Dynamic Random Access Memory).

[0062] The ECU 81 controls a motor 82 provided in the moisture content measuring device 11 to switch between rotating and stopping the crushing rollers 17, 18. The ECU 81 also controls the opening and closing of the first switch 65, the second switch 68, and the third switch 76 of the measuring circuit 61.

[0063] By opening and closing the first switch 65, the second switch 68, and the third switch 76, the moisture content measuring device 11 switches between a measurement state in which a measurement current is supplied from the internal constant current source 62 of the measuring circuit 61 to the electrode terminal 45, and a current processing state in which an abnormality resolution current is supplied from the external constant current source 66 to the electrode terminal 45. That is, by closing the first switch 65 and opening the second switch 68 and the third switch 76, the internal constant current source 62 of the measuring circuit 61 and the electrode terminal 45 are electrically connected, and the moisture content measuring device 11 enters the measurement state in which a measurement current is supplied from the internal constant current source 62 to the electrode terminal 45. By opening the first switch 65 and closing the second switch 68 and the third switch 76, the moisture content measuring device 11 enters the current processing state in which an abnormality resolution current larger than the measurement current is supplied from the external constant current source 66 to the electrode terminal 45.

[0064] When measuring the moisture content of grains stored in the grain tank 6, the ECU 81 sets the moisture content measuring device 11 to a measurement state. When grains are being crushed between the circumferential surfaces of the crushing rollers 17, 18, a measurement current is supplied from the internal constant current source 62 of the measuring circuit 61 to the electrode terminal 45, causing a potential difference between the electrode terminals 45, 46, and a signal (voltage) corresponding to this potential difference is output from the measuring circuit 61. The larger the electrical resistance value between the electrode terminals 45, 46, the larger the potential difference between the electrode terminals 45, 46. Therefore, the signal output from the measuring circuit 61 is a signal corresponding to the electrical resistance value between the electrode terminals 45, 46. The ECU 81 acquires the electrical resistance value between the electrode terminals 45, 46 from the signal output by the measuring circuit 61. Furthermore, the ECU 81 uses a calibration curve to determine the moisture content of the grains crushed between the circumferential surfaces of the crushing rollers 17, 18 from the acquired electrical resistance value between the electrode terminals 45, 46.

[0065] An operation panel 83 is disposed in the cabin 4 at a position where it can be seen and operated by a user seated in the driver's seat. The operation panel 83 is, for example, a touch panel configured by overlaying a pressure-sensitive or capacitance-type transparent film switch on a display such as a liquid crystal display. Images of various information and operation buttons are displayed on the operation panel 83 under the control of the ECU 81. When the user touches an operation button, an instruction corresponding to the type of operation button that was touched is received by the operation panel 83. When the operation panel 83 receives an instruction, a signal corresponding to the content of the instruction is input from the operation panel 83 to the ECU 81.

[0066] <Abnormality resolution control> FIG. 7 is a flowchart showing the flow of the abnormality resolution control.

[0067] For example, if rust occurs locally where the roller electrode 32 and the electrode terminal 45 come into contact, the conductivity between the crushing roller 17 and the electrode terminal 45 decreases, and the electrical resistance between the electrode terminals 45 and 46 increases. Also, if rust occurs locally where the roller electrode 35 and the electrode terminal 46 come into contact, the conductivity between the crushing roller 18 and the electrode terminal 46 decreases, and the electrical resistance between the electrode terminals 45 and 46 increases. If the electrical resistance between the electrode terminals 45 and 46 increases due to rust, the moisture content of the grain stored in the grain tank 6 cannot be determined accurately.

[0068] Therefore, in order to eliminate the abnormality caused by rust, the ECU 81 executes abnormality elimination control.

[0069] In the abnormality resolution control, the first switch 65 is closed, and the second switch 68 and the third switch 76 are opened (step S11), and the moisture content measuring device 11 is put into a measurement state.

[0070] Thereafter, the electrical resistance value between the electrode terminals 45, 46 is acquired from the signal output by the measurement circuit 61 (step S12: acquisition process). Then, it is determined whether the electrical resistance value between the electrode terminals 45, 46 exceeds a threshold value (step S13: determination process).

[0071] The acquisition of the electric resistance value (step S12) and the determination of whether the electric resistance value exceeds the threshold value (step S13) may be performed while the grains are being crushed between the circumferential surfaces of the crushing rollers 17, 18.

[0072] If the electrical resistance value between the electrode terminals 45, 46 does not exceed the threshold value (NO in step S13), an abnormality due to rust has not occurred, and therefore the abnormality resolution control is terminated.

[0073] If the electrical resistance between electrode terminals 45, 46 is an abnormal value exceeding the threshold value (YES in step S13), first switch 65 is opened, and second switch 68 and third switch 76 are closed (step S14), and moisture content measuring device 11 is switched from the measurement state to the current processing state. As a result, an abnormality resolution current larger than the measurement current is supplied from external constant current source 66 to electrode terminal 45 (step S15: current processing).

[0074] Furthermore, the count value N of the current processing number counter set in the volatile memory of the ECU 81 is incremented (+1) (step S16). The count value N is reset to 0, for example, when new electrode terminals 45, 46 are incorporated into the moisture content measuring device 11.

[0075] When a preset time has elapsed since the start of the supply of the abnormality resolution current, first switch 65 is closed, second switch 68 and third switch 76 are opened, and moisture content measuring device 11 is switched from the current processing state to the measurement state. Then, the electrical resistance value between electrode terminals 45, 46 is again acquired from the signal output by measurement circuit 61 (step S17: acquisition process). Then, it is determined again whether the electrical resistance value between electrode terminals 45, 46 exceeds the threshold value (step S13: determination process).

[0076] When an abnormality-resolving current is supplied from external constant current source 66 to electrode terminal 45, the abnormality-resolving current flows from electrode terminal 45 through roller electrode 32, electrode terminal 71, third conducting wire 75, electrode terminal 72, and roller electrode 35 to electrode terminal 46. This causes arcs to be generated between roller electrode 32 and electrode terminal 45 and between roller electrode 35 and electrode terminal 46, and the cleaning action of the arcs can destroy rust (oxide film) that has formed at the local contact points between roller electrode 32 and electrode terminal 45 and / or the local contact points between roller electrode 35 and electrode terminal 46.

[0077] If the electrical resistance value between the electrode terminals 45, 46 does not exceed the threshold value (NO in step S18), the supply of an abnormality resolution current to the electrode terminal 45 destroys the rust at the local contact point between the roller electrode 32 and the electrode terminal 45 and / or the local contact point between the roller electrode 35 and the electrode terminal 46, and the abnormality caused by rust is resolved, so the abnormality resolution control is terminated.

[0078] On the other hand, if the electrical resistance value between electrode terminals 45, 46 is still an abnormal value exceeding the threshold value even after an abnormality resolution current is supplied to electrode terminal 45 (YES in step S18), the rust abnormality has not been resolved. In this case, it is determined whether the count value N of the current processing number counter has reached a predetermined number (step S19). If the count value N has not reached the predetermined number (NO in step S19), the first switch 65 is opened, and the second switch 68 and the third switch 76 are closed (step S14), and the moisture content measuring device 11 is switched back from the measurement state to the current processing state. As a result, an abnormality resolution current larger than the measurement current is again supplied from the external constant current source 66 to the electrode terminal 45 (step S15).

[0079] In this way, the supply of the abnormality resolution current to the electrode terminal 45 is repeated until the electrical resistance value between the electrode terminals 45, 46 exceeds the threshold value (NO in step S18) or the count value N of the current processing number counter reaches a predetermined number (YES in step S19). By repeatedly supplying the abnormality resolution current, rust occurring in the local contact area between the roller electrode 32 and the electrode terminal 45 and / or the local contact area between the roller electrode 35 and the electrode terminal 46 can be destroyed, and good conduction can be restored between the crushing roller 17 and the electrode terminal 45 and between the crushing roller 18 and the electrode terminal 46.

[0080] When the count value N of the current processing number counter reaches a predetermined number (YES in step S19), a message is displayed on the operation panel 83 to notify the user that the electrode terminals 45, 46 need to be replaced (S20: replacement notification process), and the abnormality resolution control is terminated. By notifying the user that the electrode terminals 45, 46 need to be replaced, the user of the combine harvester 1 can be prompted to replace the electrode terminals 45, 46, etc.

[0081] Although it has been stated that replacement of the electrode terminals 45, 46 is to be notified, it may be necessary to replace other parts such as the roller electrodes 32, 35, and the parts that need to be replaced will be determined by the serviceman who performs maintenance on the combine 1. Therefore, instead of notifying the replacement of the electrode terminals 45, 46, it is also possible to notify the replacement of other parts of the moisture content measuring device 11, and these notifications are synonymous.

[0082] <Action and effect> As described above, when harvested grains are being crushed between the circumferential surfaces of the crushing rollers 17, 18, a measurement current is supplied from the measurement circuit 61 to the electrode terminal 45, and the measurement circuit 61 outputs a signal corresponding to the electrical resistance between the electrode terminals 45, 46. If rust occurs at the local contact points between the roller electrode 32 and the electrode terminal 45 and / or the roller electrode 35 and the electrode terminal 46, reducing the electrical continuity between the crushing roller 17 and the electrode terminal 45 and / or between the crushing roller 18 and the electrode terminal 46, the electrical resistance between the electrode terminals 45, 46 increases. Therefore, if the electrical resistance value obtained from the output signal of the measurement circuit 61 is abnormal, an abnormality-resolving current larger than the measurement current is supplied from the external constant current source 66 to the electrode terminal 45, causing the abnormality-resolving current to flow between the electrode terminals 45, 46. This generates an arc between the roller electrode 32 and the electrode terminal 45 and between the roller electrode 35 and the electrode terminal 46, and the cleaning action of the arc can destroy rust (oxide film) that may have formed at the local contact points between the roller electrode 32 and the electrode terminal 45 and / or the local contact points between the roller electrode 35 and the electrode terminal 46. This prevents poor conductivity due to rust between the crushing roller 17 and the electrode terminal 45 and between the crushing roller 18 and the electrode terminal 46, allowing for accurate measurement of the electrical resistance between the crushing rollers 17, 18. This in turn allows for accurate measurement of the moisture content of the grains being crushed between the circumferential surfaces of the crushing rollers 17, 18.

[0083] <Modification> Although one embodiment of the present invention has been described above, the present invention can be embodied in other forms.

[0084] For example, in the above-described embodiment, a configuration was adopted in which the roller electrode 32 and the spacer 33 are replaceably attached to the front end surface 27 of the roller shaft 25 of the crushing roller 17, and the terminal contacts 54, 55 of the electrode terminal 45 contact the roller electrode 32, and the roller electrode 35 and the spacer 36 are replaceably attached to the front end surface 28 of the roller shaft 26 of the crushing roller 18, and the terminal contacts 54, 55 of the electrode terminal 46 contact the roller electrode 35.

[0085] Alternatively, the roller electrodes 32, 35 and spacers 33, 36 may be omitted, and the terminal contacts 54, 55 of the electrode terminals 45, 46 may contact the front end surface 27 of the roller shaft 25 of the crushing roller 17 and the front end surface 28 of the roller shaft 26 of the crushing roller 18, respectively. In this configuration, an abnormality resolution current greater than the measurement current is supplied from the external constant current source 66 to the electrode terminal 45, causing the abnormality resolution current to flow between the electrode terminals 45, 46, generating arcs between the roller shaft 25 and the electrode terminal 45 and between the roller shaft 26 and the electrode terminal 46. The cleaning effect of the arcs can destroy rust (oxide film) that may have formed at the contact points between the roller shaft 25 and the electrode terminal 45 and / or the contact points between the roller shaft 26 and the electrode terminal 46.

[0086] In the abnormality resolution control shown in FIG. 7, if it is determined that the electrical resistance value between the electrode terminals 45, 46 is an abnormal value exceeding the threshold value (YES in step S13), the first switch 65 is immediately opened and the second switch 68 and the third switch 76 are closed (step S14), and the moisture content measuring device 11 is switched from the measurement state to the current processing state.

[0087] 8, if it is determined that the electrical resistance value between the electrode terminals 45, 46 is an abnormal value exceeding a threshold value (YES in step S13), a message indicating that an abnormality has occurred in the moisture content measuring device 11 may be displayed on the operation panel 83, thereby notifying the abnormality of the moisture content measuring device 11 (step S21). Then, when a user of the combine harvester 1 or the like operates the operation panel 83 to input an instruction to execute a process to resolve the abnormality, that is, a current process to supply an abnormality resolution current greater than the measurement current from the external constant current source 66 to the electrode terminal 45 (YES in step S22), the first switch 65 may be opened and the second switch 68 and the third switch 76 may be closed (step S14), and the moisture content measuring device 11 may be switched from the measurement state to the current processing state.

[0088] 9, the electrode terminals 45, 46 may have terminal arms 52, 53 that extend vertically and are bent midway so that terminal contacts 54, 55 at the tips thereof come into contact with the roller electrodes 32, 35.

[0089] Bending the electrode terminals 45, 46 increases the contact pressure between the terminal contacts 54, 55 and the roller electrodes 32, 35. As a result, rust can be prevented from forming at the local contact points between the roller electrodes 32, 35 and the terminal contacts 54, 55. Even if rust does form, it can be scraped off by the terminal contacts 54, 55 as the crushing rollers (roller electrodes 32, 35) rotate. This prevents poor conductivity due to rust from occurring between the crushing rollers 17, 18 and the electrode terminals 45, 46.

[0090] 10 , grooves 91 and 92 may be formed on the front surface of the mounting base 42 at the mounting positions of the terminal holding members 43 and 44, respectively. The groove 91 has wall surfaces 93 and 94 that face each other in the left-right direction and are spaced apart according to the left-right width of the terminal holding member 43. The groove 92 has wall surfaces 95 and 96 that face each other in the left-right direction and are spaced apart according to the left-right width of the terminal holding member 44. The terminal holding members 43 and 44 may then be fitted into the grooves 91 and 92, respectively.

[0091] If the electrode terminal 45 contacts the roller electrode 32 at a position offset to the left of the rotation axis of the crushing roller 17, and the electrode terminal 46 contacts the roller electrode 35 at a position offset to the left of the rotation axis of the crushing roller 18, the electrode terminals 45, 46 may wobble left and right when the crushing rollers 17, 18 rotate, which could cause unstable contact between the electrode terminals 45, 46 and the roller electrodes 32, 35. By arranging the terminal holding members 43, 44 between the wall surfaces 93, 94 of the groove 91 and between the wall surfaces 95, 96 of the groove 92, respectively, it is possible to prevent the electrode terminals 45, 46 from wobbling left and right when the crushing rollers 17, 18 rotate.

[0092] Although the combine harvester 1 has been taken up as an example of a harvester, the present invention is not limited to the combine harvester 1 and can also be applied to harvesters that harvest vegetables such as carrots, radishes, edamame beans, and cabbage.

[0093] In addition, various design modifications can be made to the above-described configuration within the scope of the claims. [Explanation of symbols]

[0094] 1: Combine (harvester) 11: Moisture content measuring device 17, 18: Crushing roller 32, 35: Roller electrodes 45,46: Electrode terminal 61: Measurement circuit 62: Internal constant current source 63: 1st conductor 65: First switch 66: External constant current source 67:Second conductor 68: Second switch 75: Third conductor 76: Third Switch 81: ECU (control unit)

Claims

1. A moisture content measuring device that is mounted on a harvester and measures the moisture content of a crop harvested by the harvester, a pair of crushing rollers whose peripheral surfaces are arranged close to each other and which crush the harvested product between their peripheral surfaces by rotation; a roller electrode attached to one end surface of each of the crushing rollers; an electrode terminal in contact with each of the roller electrodes; a measuring circuit that supplies a measuring current to the electrode terminals when the harvested product is being crushed between the peripheral surface of one of the crushing rollers and the peripheral surface of the other of the crushing rollers, and outputs a signal corresponding to the electrical resistance value between the one of the electrode terminals and the other of the electrode terminals; a control device; The control device an acquisition process of acquiring the electrical resistance value from a signal output by the measurement circuit; a determination process for determining whether the electrical resistance value acquired in the acquisition process is an abnormal value; If the judgment process determines that the electrical resistance value is abnormal, a current process is performed in which an abnormality resolution current greater than the measurement current is passed between one of the electrode terminals and the other of the electrode terminals.

2. A moisture content measuring device that is mounted on a harvester and measures the moisture content of a crop harvested by the harvester, a pair of crushing rollers whose peripheral surfaces are arranged close to each other and which crush the harvested product between their peripheral surfaces by rotation; an electrode terminal in contact with each of the crushing rollers; a measuring circuit that supplies a measuring current to the electrode terminals when the harvested product is being crushed between the peripheral surface of one of the crushing rollers and the peripheral surface of the other of the crushing rollers, and outputs a signal corresponding to the electrical resistance value between the one of the electrode terminals and the other of the electrode terminals; a control device; The control device an acquisition process of acquiring the electrical resistance value from a signal output by the measurement circuit; a determination process for determining whether the electrical resistance value acquired in the acquisition process is an abnormal value; If the judgment process determines that the electrical resistance value is abnormal, a current process is performed in which an abnormality resolution current greater than the measurement current is passed between one of the electrode terminals and the other of the electrode terminals.

3. The moisture content measuring device according to claim 1 , wherein the control device executes the current processing in response to the determination that the electrical resistance value is an abnormal value in the determination processing.

4. The control device In response to the determination that the electrical resistance value is an abnormal value in the determination process, an abnormality notification process is executed to notify the user of the abnormality; The moisture content measuring device according to claim 1 or 2, wherein the current processing is executed in response to an external instruction to execute the current processing after the abnormality notification processing.

5. The control device After the current processing, the acquisition processing and the determination processing are executed again; 3. The moisture content measuring device according to claim 1, wherein if the re-executed determination process determines that the electrical resistance value is an abnormal value, the current process is executed again.

6. The control device After the current processing is performed a predetermined number of times, the acquisition processing and the determination processing are performed again; 6. The moisture content measuring device according to claim 5, further comprising: a replacement notification process for notifying the user that the electrode terminal needs to be replaced if the re-executed determination process determines that the electrical resistance value is abnormal.

7. A moisture content measuring device that is mounted on a harvester and measures the moisture content of a crop harvested by the harvester, a pair of crushing rollers whose peripheral surfaces are arranged close to each other and which crush the harvested product between their peripheral surfaces by rotation; a roller electrode attached to one end surface of each of the crushing rollers; an electrode terminal in contact with each of the roller electrodes; a measurement circuit electrically connected to the electrode terminal via a first conducting wire and having an internal constant current source that outputs a measurement current; an external constant current source electrically connected to the electrode terminal via a second conducting wire and outputting an abnormality resolution current greater than the measurement current; a first switch provided on the first conducting wire, the first switch opening and closing to switch between disconnection and conduction of the first conducting wire; a second switch provided on the second conducting wire, the second switch opening and closing the second conducting wire to switch between disconnection and conduction; a third switch provided on a third conductor that electrically connects one of the roller electrodes and the other of the roller electrodes, the third switch switching between disconnection and conduction of the third conductor by opening and closing the third switch; a measurement state in which, when the first switch is closed, the second switch and the third switch are open, and the harvested product is being crushed between the circumferential surface of one of the crushing rollers and the circumferential surface of the other of the crushing rollers, the measurement current is supplied from the internal constant current source to the electrode terminals, and a signal corresponding to the electrical resistance value between one of the electrode terminals and the other of the electrode terminals is output from the measurement circuit; and a current processing state in which the first switch is open, the second switch and the third switch are closed, and the abnormality resolution current is supplied from the external constant current source to the electrode terminals, and the abnormality resolution current flows through the third conductor.

8. A moisture content measuring device that is mounted on a harvester and measures the moisture content of a crop harvested by the harvester, a pair of crushing rollers whose peripheral surfaces are arranged close to each other and which crush the harvested product between their peripheral surfaces by rotation; an electrode terminal in contact with each of the crushing rollers; a measurement circuit electrically connected to the electrode terminal via a first conducting wire and having an internal constant current source that outputs a measurement current; an external constant current source electrically connected to the electrode terminal via a second conducting wire and outputting an abnormality resolution current greater than the measurement current; a first switch provided on the first conducting wire, the first switch opening and closing to switch between disconnection and conduction of the first conducting wire; a second switch provided on the second conducting wire, the second switch opening and closing the second conducting wire to switch between disconnection and conduction; a third switch that is provided on a third conductor that electrically connects one of the crushing rollers to the other of the crushing rollers, and that switches between disconnection and conduction of the third conductor by opening and closing the third switch; a measurement state in which, when the first switch is closed, the second switch and the third switch are open, and the harvested product is being crushed between the circumferential surface of one of the crushing rollers and the circumferential surface of the other of the crushing rollers, the measurement current is supplied from the internal constant current source to the electrode terminal, and a signal corresponding to the electrical resistance value between the one of the crushing rollers and the other of the crushing rollers is output from the measurement circuit; and a current processing state in which the first switch is open, the second switch and the third switch are closed, and the abnormality resolution current is supplied from the external constant current source to the electrode terminal, and the abnormality resolution current flows through the third conductor.

9. The moisture content measuring device according to claim 7 or 8, further comprising a control device that controls opening and closing of the first switch, the second switch, and the third switch.

Images