Combine-harvester and control method of using combine-harvester

Abstract

To provide a combine-harvester configured to control a height of a reaping part, capable of preventing the reaping part from coming into contact with or thrusting into the ground, and preventing a reaping failure such as leaving some of a crop unreaped.SOLUTION: A combine-harvester includes: a reaping part liftably / lowerably provided on a traveling machine body; a reaping height detector for detecting a reaping height, the ground height of the reaping part; a height above machine-body detector for detecting a height above the machine body, the height of the reaping part above the traveling machine body; and a controller for controlling the height of the reaping part. The controller is configured to execute reaping height control for controlling the height of the reaping part such that the reaping height detected by the reaping height detector becomes a prescribed target value, and lifting / lowering range limit control for limiting a lifting / lowering range of the reaping part within prescribed ranges of a lifting amount and a lowering amount relative to a reaping reference height, the reference value of the height above the machine body, where the lifting / lowering range limit control is invalidated from start of the control until a traveling distance of the traveling machine body becomes a prescribed distance.SELECTED DRAWING: Figure 12

Description

[Technical field]

[0001] The present invention relates to a combine harvester having a height-adjustable cutting unit and a method for controlling a combine harvester. [Background technology]

[0002] Generally, a combine harvester is equipped with a reaping unit at the front of the traveling body and a threshing unit on the traveling body, and while traveling, the reaping unit harvests stalks and the threshing unit threshes the stalks. Conventionally, some combine harvesters have a reaping unit that can be raised and lowered relative to the traveling body and a cutting height detection device for controlling the cutting height (height above the ground), which is the height of the reaping unit from the ground (see, for example, Patent Document 1). In such a configuration, the operation of a lifting device such as a hydraulic cylinder that raises and lowers the reaping unit is controlled based on a detection signal from the cutting height detection device, and the cutting height is automatically controlled.

[0003] Patent Document 1 describes a control content for controlling the height of the cutting unit, in which, since the machine body is more likely to tilt forward and backward at the start of work than during normal cutting work, the cutting height detection device switches to a cutting height detection state at the start of work, and the lowering operation of the cutting unit is stopped for a predetermined period of time thereafter. According to such height control of the cutting unit, the lowering operation of the cutting unit is limited at the beginning of work, so that even if the machine body tilts forward and backward significantly, it is considered that the cutting unit can be prevented from contacting or plunging into the ground. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Jpn. Jpn. Published No. 61-7533 Summary of the Invention [Problem to be solved by the invention]

[0005] According to the height control of the cutting unit as disclosed in Patent Document 1, the lowering operation of the cutting unit is stopped for a predetermined period of time, which prevents the cutting unit from coming into contact with the ground. However, there is a concern that the target cutting height may not be reached during cutting work, resulting in cutting problems such as leaving some grass uncut.

[0006] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a combine and a control method for a combine that is configured to control the height of the cutting part, can prevent the cutting part from contacting or crashing into the ground, and can prevent cutting problems such as leaving some grass uncut. [Means for solving the problem]

[0007] The combine harvester of the present invention is a combine harvester comprising a cutting unit that is capable of being raised and lowered relative to a running machine body, a cutting height detection device for detecting the cutting height, which is the height of the cutting unit relative to the ground, a machine-body height detection device for detecting the machine-body height, which is the height of the cutting unit relative to the running machine body, and a control device for controlling the height of the cutting unit based on the detection signals of the cutting height detection device and the machine-body height detection device, wherein the control device performs cutting height control that controls the height of the cutting unit so that the cutting height detected by the cutting height detection device becomes a predetermined target value, and lifting range limit control that limits the lifting range of the cutting unit to within a range of predetermined rise and fall amounts relative to a cutting reference height, which is a reference value for the machine-body height detected by the machine-body height detection device, and the lifting range limit control is disabled from the start of control until the running machine body has traveled a predetermined distance or until a predetermined time has elapsed.

[0008] The combine harvester of the present invention is a combine harvester equipped with a cutting unit that is capable of being raised and lowered relative to a running body, a cutting height detection device for detecting the cutting height, which is the height of the cutting unit relative to the ground, a machine-to-body height detection device for detecting the machine-to-body height, which is the height of the cutting unit relative to the running body, and a control device for controlling the height of the cutting unit based on the detection signals of the cutting height detection device and the machine-to-body height detection device, wherein the control device performs cutting height control that controls the height of the cutting unit so that the cutting height detected by the cutting height detection device becomes a predetermined target value, and lifting range limit control that limits the lifting range of the cutting unit to within a range of predetermined upward and downward amounts relative to a cutting reference height, which is a reference value for the machine-to-body height detected by the machine-to-body height detection device, and the lifting range limit control is disabled from the start of control until the vehicle speed of the running body reaches a predetermined speed.

[0009] In a combine harvester according to another aspect of the present invention, the control device calculates the reference cutting height as an average value of the height relative to the machine body stored at each specified time period, and updates the calculated height at each specified time period.

[0010] The control method for a combine harvester of the present invention detects the cutting height, which is the height of the cutting part relative to the ground, and the machine-to-body height, which is the height of the cutting part relative to the running body, and controls the height of the cutting part based on the detected cutting height and machine-to-body height.The control method performs cutting height control, which controls the height of the cutting part so that the detected cutting height becomes a predetermined target value, and lifting range limiting control, which limits the lifting range of the cutting part to within a range of predetermined rise and fall amounts relative to a cutting reference height, which is a reference value for the machine-to-body height, and disables the lifting range limiting control from the start of control until the running body has traveled a predetermined distance or until a predetermined time has elapsed.

[0011] The control method for a combine harvester of the present invention detects the cutting height, which is the height of the cutting part relative to the ground, and the machine-to-body height, which is the height of the cutting part relative to the running body, and controls the height of the cutting part based on the detected cutting height and machine-to-body height.The control method performs cutting height control, which controls the height of the cutting part so that the detected cutting height becomes a predetermined target value, and lifting range limiting control, which limits the lifting range of the cutting part to within a range of predetermined upward and downward amounts relative to a cutting reference height, which is a reference value for the machine-to-body height, and disables the lifting range limiting control from the start of control until the vehicle speed of the running body reaches a predetermined speed.

[0012] A combine control method according to another aspect of the present invention is a combine control method in which the cutting reference height is calculated as an average value of the height relative to the machine body stored at each specified time period, and updated at each specified time period. Effect of the Invention

[0013] According to the present invention, it is possible to prevent the cutting part from contacting or crashing into the ground, and also to prevent the cutting part from leaving any grass uncut. [Brief description of the drawings]

[0014] [Figure 1] FIG. 2 is a left side view of a combine harvester according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a right side view of a combine harvester according to one embodiment of the present invention. [Diagram 3] FIG. 2 is a plan view showing the configuration of the reaping section of a combine harvester according to one embodiment of the present invention. [Figure 4] This is a left side view showing the configuration of a grass dividing section and a cutting height detection device according to one embodiment of the present invention. [Diagram 5] 1 is a left front perspective view showing a cutting height detection device and its support structure according to an embodiment of the present invention. FIG. [Figure 6] 1 is a left side view showing a cutting height detection device and its support structure according to an embodiment of the present invention. FIG. [Figure 7]1 is a right side view showing a cutting height detection device and its support structure according to an embodiment of the present invention. FIG. [Figure 8] 1 is a plan view of a cutting height detection device according to an embodiment of the present invention. [Figure 9] FIG. 2 is a front perspective view showing a sensor unit according to an embodiment of the present invention. [Figure 10] 2 is a block diagram showing a control configuration of a combine harvester according to one embodiment of the present invention. FIG. [Figure 11] FIG. 2 is a diagram showing an example of an operating unit for reaping work of a combine harvester according to one embodiment of the present invention. [Figure 12] 5A to 5C are diagrams illustrating an example of an operating state of an automatic mowing height switch and a mode display unit according to an embodiment of the present invention. [Figure 13] 5 is an explanatory diagram of lift range limit control according to an embodiment of the present invention. FIG. [Figure 14] FIG. 4 is an explanatory diagram of a first control mode of lifting and lowering control of a reaping unit according to one embodiment of the present invention. [Figure 15] FIG. 4 is an explanatory diagram for calculating and updating a standard mowing height according to one embodiment of the present invention. [Figure 16] FIG. 11 is an explanatory diagram of a second control mode of lifting and lowering control of the reaping unit according to one embodiment of the present invention. [Figure 17] FIG. 11 is an explanatory diagram of a third control mode of lifting and lowering control of the reaping unit according to one embodiment of the present invention. [Figure 18] 5 is a flowchart showing an example of processing related to a standard mowing height by a control device according to one embodiment of the present invention. [Figure 19] FIG. 11 is an explanatory diagram of a problem in controlling the lifting and lowering of a reaping unit. [Figure 20] FIG. 11 is an explanatory diagram of a problem in controlling the lifting and lowering of a reaping unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention has a cutting unit with a height adjustable, and in a configuration in which the height of the cutting unit is controlled based on a detection value of the cutting height, which is the height of the cutting unit, the control content is divided between control in the initial stage from the start of control and control thereafter, thereby preventing the cutting unit from contacting or crashing into the ground and preventing cutting problems such as leaving some grass uncut. An embodiment of the present invention will be described below.

[0016] [Overall configuration of the combine] The overall configuration of a combine harvester 1 according to this embodiment will be described with reference to Figures 1 and 2. In the following description, the left and right sides of the combine harvester 1 facing the front (left side in Figure 1) are the left and right sides of the combine harvester 1, respectively.

[0017] 1 and 2, the combine harvester 1 according to this embodiment includes a traveling section 2 configured as a crawler-type traveling device having a pair of left and right crawler sections 3, 3, and a traveling body 4 supported by the traveling section 2. The traveling body 4 includes a frame-shaped structural part of the vehicle body of the combine harvester 1. The combine harvester 1 includes an engine 11 mounted on the traveling body 4 as a drive source.

[0018] A reaping unit 5 is provided at the front of the traveling body 4, which harvests and collects stalks of rice, wheat, etc. in the field. A threshing unit 6 which threshes the stalks harvested by the reaping unit 5, and a grain tank 7 which stores the grains removed from the threshing unit 6 are provided side by side on the traveling body 4. The threshing unit 6 is located on the left side of the body, and the grain tank 7 is located on the right side of the body. The combine harvester 1 travels on the traveling unit 2 while harvesting stalks with the reaping unit 5 and threshing with the threshing unit 6.

[0019] Each crawler unit 3 constituting the traveling unit 2 has a track frame 3a extending in the front-rear direction below the traveling body 4, various rotating bodies such as a drive sprocket 3b supported by the track frame 3a, and a track 3c wound around these rotating bodies. The crawler unit 3 is driven by the power of the engine 11 transmitted to the drive sprocket 3b.

[0020] The reaping unit 5 is driven by driving force from the engine 11, harvests the stalks, and transports the harvested stalks to the threshing unit 6, etc. The reaping unit 5 is provided in front of the traveling body 4 across substantially the entire width of the combine harvester 1. The reaping unit 5 is provided so as to be able to rise and fall relative to the traveling body 4. Note that Fig. 2 shows the reaping unit 5 in a state where it has been lowered from the state shown in Fig. 1.

[0021] The threshing section 6 has a threshing drum 6a with a rotation axis extending in the front-to-rear direction, and a stump supplying device provided to the left of the threshing drum 6a. The stump supplying device holds the base of the stump cut by the reaping section 5 and transports the stump rearward in a lying position with the ear tip facing the threshing drum 6a. The stump supplying device includes a feed chain 6b wound around multiple sprockets with a rotation axis extending in the left-to-right direction, and a stump supplying clamping body 6c that cooperates with the feed chain 6b to clamp the base of the stump.

[0022] Below the threshing section 6 on the traveling machine body 4, a sorting section 8 is provided which sorts the material threshed by the threshing section 6. The sorting section 8 has a rocking sorting device 8a, a wind sorting device and a grain conveying device. The sorting section 8 rocks and sorts the material that has fallen from the threshing section 6 using the rocking sorting device 8a, and wind sorts the material after rocking and sorting using the wind sorting device. The sorting section 8 conveys grains from the material after wind sorting to the right towards the grain tank 7 using the grain conveying device, and blows straw dust, dust and the like backwards using the wind sorting device and discharges them outside the machine body. The grains conveyed by the grain conveying device towards the grain tank 7 are stored in the grain tank 7.

[0023] A discharge auger 9 is rotatably provided at the rear right end of the traveling body 4 as a grain discharge device that discharges grains from the grain tank 7 to the outside. The discharge auger 9 has a discharge port 9a at its tip, and discharges grains stored in the grain tank 7 from the discharge port 9a. The grains discharged from the discharge port 9a are dumped into the bed of a truck, a container, or the like.

[0024] On the traveling machine body 4, behind the threshing section 6, there is provided a straw waste processing section 10 which processes the straw waste after threshing by the threshing section 6. The straw waste processing section 10 has a straw waste conveying device 10a and a straw waste cutting device 10b. The straw waste conveying device 10a conveys the threshed stump (stump) by the threshing section 6 rearward and discharges it outside the machine body or conveys it to the straw waste cutting device 10b. The straw waste cutting device 10b cuts the stump transported from the straw waste conveying device 10a and discharges it outside the machine body.

[0025] On the traveling body 4, to the right of the reaping unit 5 and in front of the grain tank 7, there is provided a driver's unit 14 covered by a cabin 13. A handle unit 15 serving as a steering operation unit is provided in front of the driver's unit 14, and a driver's seat 16 is provided behind the handle unit 15. To the side of the driver's seat 16, there is provided a side operation unit 12 in which various operating tools including a main shift lever 17, and various operation units 300 such as dials and switches are arranged on a side column 19 (see FIG. 11).

[0026] A prime mover unit including an engine 11 is provided below the driving unit 14. The engine 11 is, for example, a diesel engine. The power of the engine 11 is transmitted to various devices provided in each part of the combine 1 via a transmission or the like.

[0027] The reaping unit 5 will be described with reference to Figures 1 to 3. The reaping unit 5 has a reaping support machine frame 20 as a reaping frame, and is configured by supporting a grass dividing board 21, a lifting device 22, a raking device 23, a cutting blade device 24, a stalk transport device 25, etc. on the reaping support machine frame 20. Each device of the reaping unit 5 operates by transmitting power from the engine 11.

[0028] The grass dividing board 21 is an example of a grass dividing body constituting the grass dividing section 50 of the cutting unit 5, and is provided at the front of the cutting unit 5. The grass dividing board 21 has a tapered shape and divides the culms growing in the field. The lifting device 22 is provided at the rear of the grass dividing board 21, and lifts up fallen culms by operating multiple tines 22a connected by a chain.

[0029] The raking device 23 is provided behind the lifting device 22, and includes a chain-driven conveying mechanism 23a and a rotary packer 23b, and raks in the stalks. In addition, in Fig. 3, only the components of the raking device 23 provided at the left end are shown, and the other components are omitted.

[0030] The cutting blade device 24 is a clipper-type device that cuts the base of the raised culms. The culm transport device 25 is a device that transports the culms that have been cut, and it joins multiple culms together, clamps and transports them upward and rearward, and delivers them to the starting end of the feed chain 6b of the threshing section 6 in a horizontally lying position.

[0031] As shown in Fig. 1, the reaping support machine frame 20 is supported by a support frame 26 arranged in a downwardly-descending manner on the front side of the traveling machine body 4. The support frame 26 is provided in approximately the center in the left-right direction of the machine body, and the reaping support machine frame 20 is provided on the front side of the support frame 26.

[0032] As shown in Fig. 3, the reaping support machine frame 20 has a horizontal frame 31 extending in the left-right direction of the machine body, and a plurality of grass dividing frames 32, 34 extending forward from the horizontal frame 31. The reaping support machine frame 20 is supported by the support frame 26 at the horizontal frame 31.

[0033] The horizontal frame 31 is a straight frame part made of square pipe-shaped members. The grass division frames 32, 34 are frame parts made of round pipe-shaped members, have a predetermined bent or curved shape, and extend in the front-rear direction in a plan view. The grass division frames 32, 34 are supported in a cantilevered manner by fixing and supporting their rear ends or rear parts to the horizontal frame 31.

[0034] The multiple grass dividing frames 32, 34 are arranged in parallel at a predetermined interval in the left-right direction. The number of grass dividing frames 32, 34 is one more than the number of mowing rows of the combine harvester 1. The combine harvester 1 in this embodiment is a six-row mower, and seven grass dividing frames 32, 34 are provided. Of the seven grass dividing frames 32, 34, the grass dividing frames 34 located second and sixth from the left respectively have different shapes from the other multiple (five) grass dividing frames 32.

[0035] A lifting device 22 is arranged between adjacent grass dividing frames 32, 34 on the left and right, and a total of six lifting devices 22 are provided. The lower part of the lifting device 22 is connected and supported to the front of each grass dividing frame 32, 34 via a support stay or the like (not shown). A grass dividing board 21 is also attached to the front of each grass dividing frame 32, 34. The multiple grass dividing boards 21 include two types of grass dividing boards 21, one relatively large and one relatively small, which are provided in a predetermined arrangement. In this embodiment, four relatively large grass dividing boards 21 and three relatively small grass dividing boards 21 are arranged alternately in the left-right direction.

[0036] The reaping unit 5 having the above-mentioned configuration is attached to the traveling machine body 4 so as to be rotatable about a predetermined rotation axis via a reaping lifting cylinder 18 (see FIG. 1) serving as a lifting device. In other words, the reaping unit 5 is provided so as to be able to be raised and lowered relative to the traveling machine body 4 by a rotational action due to the extension and contraction of the reaping lifting cylinder 18. The reaping lifting cylinder 18 is a hydraulic cylinder, and is provided between the traveling machine body 4 and the support frame 26. The rear end of the support frame 26 is supported rotatably about a left-right axis relative to the traveling machine body 4 as a rotation fulcrum for the lifting and lowering action of the reaping unit 5 by the reaping lifting cylinder 18.

[0037] As described above, the combine harvester 1 has the reaping unit 5 provided so as to be able to rise and fall relative to the traveling body 4. The combine harvester 1 is equipped with a cutting height detection device 40 and a control device 200 (see FIG. 10) in order to control the cutting height (height above the ground), which is the height of the reaping unit 5 from the ground 30. In this configuration, the control device 200 controls the operation of the reaping lifting cylinder 18, which lifts and lowers the reaping unit 5, based on a detection signal from the cutting height detection device 40, thereby automatically controlling the cutting height.

[0038] The operation of the cutting lift cylinder 18 is controlled by controlling the operation of a solenoid valve, which is a control valve. The control device 200 controls the cutting height by controlling the operation of the control valve of the cutting lift cylinder 18 based on a detection signal from the cutting height detection device 40.

[0039] The automatic control of the cutting height controls the operation of the control valve of the cutting lifting cylinder 18 so as to maintain the cutting height of the cutting unit 5 at a set value based on a detection signal from the cutting height detection device 40, and automatically controls the lifting and lowering of the cutting unit 5. In the automatic control of the cutting height, the control device 200 controls the height of the cutting unit 5 so that the cutting height detected by the cutting height detection device 40 becomes a preset target value (hereinafter referred to as the "target cutting height value").

[0040] In other words, when the detected cutting height is below the target cutting height value, the control device 200 raises the cutting unit 5, and when the detected cutting height is above the target cutting height value, the control device 200 lowers the cutting unit 5, thereby controlling the lifting and lowering of the cutting unit 5 so that the height of the cutting unit 5 is maintained at a height corresponding to the target cutting height value.

[0041] In addition, in the automatic control of the mowing height, the target mowing height value may be set as a value within a predetermined range (a value having a width). In this case, the control device 200 controls the elevation of the mowing unit 5 so that the height of the mowing unit 5 is maintained within the range of heights corresponding to the target mowing height value by raising the mowing unit 5 when the detected mowing height is below the lower limit of the target mowing height value and lowering the mowing unit 5 when the detected mowing height is above the upper limit of the target mowing height value.

[0042] The driving unit 14 is provided with an operating unit for adjusting the cutting height, and for example, during automatic control of the cutting height, control is performed that prioritizes adjustment of the cutting height by operating the operating unit for adjusting the cutting height. As an operating unit for adjusting the cutting height, a cutting lift lever 35 (see FIG. 10) for lifting and lowering the cutting unit 5 is provided.

[0043] According to the cutting lift lever 35, by manually operating the cutting lift lever 35, the operation of the control valve of the cutting lift cylinder 18 is controlled via the control device 200, and the cutting unit 5 is raised and lowered. By operating the cutting lift lever 35 from the neutral position to the upward side, the cutting lift cylinder 18 is controlled to extend, and the cutting unit 5 is raised. By operating the cutting lift lever 35 from the neutral position to the downward side, the cutting lift cylinder 18 is controlled to contract, and the cutting unit 5 is lowered. Note that the operating unit for adjusting the cutting height may be configured with an operating tool other than a lever, such as a switch operating unit (cutting lift switch).

[0044] In addition, the driving unit 14 is provided with a mowing autolift switch 36 for lifting the mowing unit 5 to a preset height position and a mowing autoset switch 37 for lowering the mowing unit 5 to a preset height position as operation units for operating the mowing unit 5. When the mowing autolift switch 36 is turned ON with the mowing clutch ON after the engine 11 is started, the mowing lift cylinder 18 is extended and the mowing unit 5 is automatically raised to a preset height position. When the mowing autoset switch 37 is turned ON with the mowing clutch ON after the engine 11 is started, the mowing unit 5 is automatically lowered to a preset height position with the mowing lift cylinder 18 being contracted. The mowing autolift switch 36 and the mowing autoset switch 37 are arranged, for example, as operation buttons on the main shift lever 17. During the raising and lowering of the cutting unit 5 by these switch operations, the raising and lowering operation of the cutting unit 5 by operating the cutting lift lever 35 takes priority. The cutting clutch is turned ON by operating a clutch operating tool such as a work clutch lever disposed in the driver unit 14.

[0045] In this embodiment, the cutting height detection device 40 is disposed behind the grass dividing boards 21A that are the second and sixth from the left among the seven grass dividing boards 21 (see FIG. 3). The grass dividing board 21A is supported by a grass dividing frame 34 that has a different shape from the other grass dividing frames 32. The grass dividing board 21A is the relatively smaller of the two types of grass dividing boards 21. Thus, the combine harvester 1 is equipped with two cutting height detection devices 40. However, the number of cutting height detection devices 40 equipped in the combine harvester 1 and the positions at which the cutting height detection devices 40 are provided are not limited. The cutting height detection device 40 may be provided, for example, in one location behind the leftmost or rightmost grass dividing board 21.

[0046] [Configuration of cutting height detection device] The configuration of the cutting height detection device 40 will be described with reference to Figures 4 to 9. As shown in Figures 4 to 9, the cutting height detection device 40 includes a device main body 41, a grounding body 42, a cutting height sensor 43 which is a sensor for detecting the cutting height, and a unit support 44 which is a member for supporting the device main body 41.

[0047] In the cutting height detection device 40, the device body 41, the grounding body 42, and the cutting height sensor 43 form an integrated sensor unit 45 (see FIG. 9), and this sensor unit 45 is supported so as to be rotatable about an axis in the left-right direction relative to the unit support body 44. The unit support body 44 is supported so as to be rotatable about an axis in the front-rear direction relative to the grass dividing section 50.

[0048] The height-of-cutting detection device 40 as a whole is supported rotatably about an axis in the front-to-rear direction relative to the grass dividing section 50, and the sensor unit 45 is supported rotatably about an axis in the left-to-right direction relative to the unit support body 44. Rotation of the height-of-cutting detection device 40 about its front-to-rear axis and rotation of the sensor unit 45 about its left-to-right axis are performed in response to an external force acting on the height-of-cutting detection device 40. Below, a state in which no external force is acting on the height-of-cutting detection device 40 is defined as a reference state, and the height-of-cutting detection device 40 in its basic reference state will be described.

[0049] In the sensor unit 45, the device main body 41 has a configuration in which various gears, springs, etc. are supported on predetermined shafts within a case 51 made of, for example, a metal casting. The case 51 has a left-right two-part structure consisting of a right case body 52 forming the main body of the case 51 and a left case body 53 covering the left side of the right case body 52 like a lid. The right case body 52 and the left case body 53 are fixed to each other by fixing bolts 55 at four points around the periphery of the case 51 in a side view. The case 51 has a roughly rectangular outer shape with the longitudinal direction being the front-rear direction (the left-right direction in FIG. 6) in a side view. The upper side of the case 51 has a mountain-like shape that is convex upward in a side view.

[0050] In the sensor unit 45, the grounding body 42 extends downward from the rear side of the rear end of the case 51. The cutting height sensor 43 is provided in a manner such that it is attached to the right side surface of the case 51.

[0051] The unit support 44 is a member in the form of a narrow plate-like member that is bent to have a predetermined shape in a plan view, and extends in the front-rear direction. As shown in Fig. 8, the unit support 44 has a first support 46 that mainly constitutes the left side of the unit support 44, and a second support 47 that mainly constitutes the right side of the unit support 44.

[0052] The unit support 44 has a left side surface portion 44a that is elongated in the front-rear direction, a front surface portion 44b that is formed so as to form a right angle from the front end portion of the left side surface portion 44a toward the right, and a right side surface portion 44c that is elongated in the front-rear direction and formed from the right end portion of the front surface portion 44b toward the rear. All of these surface portions that form the unit support 44 are vertical surface portions. In other words, the first support 46 and the second support 47 are both plate-like members that are bent to form a predetermined shape in a plan view, and the left side surface portion 44a, the front surface portion 44b, and the right side surface portion 44c are formed by these supports.

[0053] As shown in FIG. 8, the first support 46 has an outer wall surface portion 46a forming the left side surface portion 44a of the unit support 44, a front wall surface portion 46b forming a part of the front surface portion 44b of the unit support 44, and an inner wall surface portion 46c formed so as to form a right angle from the right end portion of the front wall surface portion 46b toward the rear. The first support 46 has a bent shape that is approximately "J" shaped in a plan view by the outer wall surface portion 46a, the front wall surface portion 46b, and the inner wall surface portion 46c. Also, as shown in FIG. 8, the second support 47 has a side wall surface portion 47a forming the right side surface portion 44c of the unit support 44, a front wall surface portion 47b forming a part of the front surface portion 44b of the unit support 44, and an inclined wall surface portion 47c formed at the corner portion formed by the side wall surface portion 47a and the front wall surface portion 47b and having a chamfered shape in a bottom view.

[0054] The left side surface portion 44a of the unit support 44 (the outer wall surface portion 46a of the first support 46) is a plate-like portion that is elongated in the front-rear direction and has a plate thickness direction in the left-right direction. The rear end portion of the left side surface portion 44a extends rearward beyond the rear end portion of the case 51 in the front-rear direction. The front surface portion 44b of the unit support 44 is a plate-like portion whose plate thickness direction is in the front-rear direction. The front surface portion 44b is formed by the front wall surface portion 46b of the first support 46 and the front wall surface portion 47b of the second support 47.

[0055] The first support 46 and the second support 47 are connected to each other by being fastened and fixed by a screw body 48 and a nut 49 that penetrate the overlapping portion between the front wall surface portions 46b, 47b. The screw body 48 has a threaded portion that protrudes forward from the front wall surface portion 47b of the second support 47, and the nut 49 is screwed into this protruding portion. The fixing portions by the screw body 48 are provided at two locations, one above and one below.

[0056] The right side surface portion 44c (side wall surface portion 47a of the second support 47) of the unit support 44 is a plate-like portion that is elongated in the front-rear direction with the plate thickness direction being in the left-right direction, and is provided so as to face the left-right direction relative to the left-right direction. The position of the rear end of the right side surface portion 44c in the front-rear direction is substantially the same as the rear end of the case 51.

[0057] The unit support 44 is open at the top and bottom, and has a shape that is approximately rectangular in plan view with the left side surface portion 44a, the front surface portion 44b, and the right side surface portion 44c, with the front and rear direction being the longitudinal direction. The left side surface portion 44a, the front surface portion 44b, and the right side surface portion 44c of the unit support 44 are positioned on the left side, the front side, and the right side of the sensor unit 45 (see FIG. 9), respectively, to form a peripheral wall portion that surrounds the sensor unit 45. That is, the sensor unit 45 is provided so that the entire sensor unit 45 is positioned in the space surrounded by the unit support 44 in plan view. The entire sensor unit 45 is positioned inside the unit support 44 in the front and rear directions and the left and right directions.

[0058] The components of the sensor unit 45 will be described below. The device body 41 is provided on a front fixed shaft 61, which is a first shaft, so as to be rotatable up and down. The front fixed shaft 61 is a support shaft whose axial direction is in the left-right direction, and supports the sensor unit 45 so as to be rotatable around a first axis P1 (see FIGS. 6 and 8).

[0059] The front fixed shaft 61 is located in the device body 41 near the front end of the case 51. The front fixed shaft 61 extends leftward from the inner wall surface portion 46c with the right end portion fixed to the inner wall surface portion 46c of the first support 46 via the support plate 56. The front fixed shaft 61 is a fixed shaft supported in a cantilever manner by the inner wall surface portion 46c. The support plate 56 is fixed at two points, upper and lower, by bolts 57 in a state where it overlaps the inside (left side) of the inner wall surface portion 46c. Note that the front fixed shaft 61 may be any shaft fixed to the unit support 44. The front fixed shaft 61 is supported so as to be rotatable relative to the case 51. That is, the case 51 is supported so as to be rotatable relative to the front fixed shaft 61.

[0060] In this way, the sensor unit 45 is provided so as to be vertically rotatable in a cantilevered state with the left-right direction as the axial direction relative to the front fixed shaft 61, which is a fixed shaft fixed to the unit support 44 (see arrow A1 in FIG. 6). That is, the unit support 44 supports the device body 41 of the sensor unit 45 by the front fixed shaft 61 so as to be vertically rotatable about the first axis P1.

[0061] With respect to the rotation of the sensor unit 45 around the first axis P1 relative to the unit support 44, the sensor unit 45 is biased in a downward rotation direction (clockwise direction as viewed from the left side) by a case return member, which is an elastic member such as a spring provided in the case 51. The case return member is, for example, a torsion spring having linear extensions at both ends of a coil-shaped main body. In this case, the case return member is provided in a state in which the front fixed shaft 61 penetrates the main body, one extension is engaged with the front fixed shaft 61 side and the other extension is engaged with the case 51 side, and applies a force that presses the case 51 downward toward the front fixed shaft 61 side. As a result, the sensor unit 45 is biased in a direction of downward rotation around the axis of the front fixed shaft 61.

[0062] A case return spring 58 for urging the sensor unit 45 in a downward rotation direction relative to the front fixed shaft 61 is provided on the portion of the front fixed shaft 61 protruding to the right from the case 51 (see FIG. 8). The case return spring 58 is a torsion spring having linear extensions 58a on both ends of a coil-shaped main body.

[0063] The case return spring 58 is provided with the front fixed shaft 61 penetrating the main body, one extension 58a inserted into and locked in a locking hole 52a (see FIG. 7) formed on the right side of the front part of the right case body 52 of the case 51, and the other extension 58a locked in a predetermined manner to the front surface 44b of the unit support 44, and exerts a force pressing the case 51 downward toward the front fixed shaft 61. As a result, the sensor unit 45 is urged in a direction to rotate downward around the axis of the front fixed shaft 61.

[0064] Meanwhile, with regard to rotation of the sensor unit 45 relative to the unit support 44, downward rotation of the sensor unit 45 is restricted to a standard position by a case stopper bolt 59 provided on the case 51. The case stopper bolt 59 is screwed from the left into the front-to-rear middle part of the upper edge of the left case body 53, with its head protruding from the left case body 53 to the left.

[0065] With this configuration, in the standard state, the head of the case stopper bolt 59 abuts against the upper edge of the left side surface portion 44a of the unit support 44, thereby preventing the sensor unit 45 from rotating downward relative to the unit support 44. Note that the locking portion of the sensor unit 45 with respect to the unit support 44 may be a protruding portion formed as a part of the left case body 53.

[0066] In this way, the sensor unit 45 is restricted from rotating downward from the reference state relative to the unit support 44 while being biased in the downward rotation direction with respect to rotation about the front fixed shaft 61. Therefore, when an external force from the ground 30 or the like acts on the sensor unit 45 to rotate the sensor unit 45 upward about the front fixed shaft 61, the sensor unit 45 rotates upward against the biasing forces of the case return member and the case return spring 58 in the case 51. When the action of the external force is released, the sensor unit 45 in the upward rotated state automatically rotates downward due to the biasing forces of the case return spring 58 and the like, and returns to the reference state position due to the locking action of the case stopper bolt 59 on the unit support 44.

[0067] The grounding body 42 is rotatably supported by a rear rotating shaft 62, which is a second shaft located behind the front fixed shaft 61 with respect to the device body 41. The rear rotating shaft 62 is a support shaft whose axial direction is in the left-right direction, and supports the grounding body 42 rotatably with respect to the case 51 of the device body 41 about the second axis P2.

[0068] The rear rotating shaft 62 is located near the rear end of the case 51, and is supported for relative rotation with respect to the case 51 via a bearing member such as a bush. The grounding body 42 is fixed to a portion of the rear rotating shaft 62 that protrudes to the right from the case 51. The grounding body 42 has a grounding body main body portion 42a that is a portion that extends downward from the device main body 41, and a support arm portion 42b that is a support portion for the rear rotating shaft 62. The grounding body main body portion 42a and the support arm portion 42b are both plate-like portions having a predetermined shape.

[0069] The grounding body main body 42a is a spatula-shaped portion that gradually widens downward in width (left-right dimension) from the top to the bottom. The support arm 42b extends from the upper end of the grounding body main body 42a, which is located immediately behind the case 51, to the right front side along the case 51 and is fixed to the rear rotating shaft 62. The right end of the rear rotating shaft 62 passes through the front part of the support arm 42b, and the support arm 42b is fastened and fixed to the rear rotating shaft 62 by a nut 68 or the like. A threaded portion is formed at the right end of the rear rotating shaft 62 into which the nut 68 is screwed.

[0070] In this manner, the grounding body 42 is fixed to the rear rotating shaft 62 and rotates integrally with the rear rotating shaft 62 about the second axis P2. The grounding body 42 is provided so as not to interfere with the case 51 within its rotation range. With regard to the rotational position of the grounding body 42, the position of the grounding body 42 in the cutting height detection device 40 in the reference state is defined as the reference position.

[0071] The ground contact body 42 rotates as follows relative to the device body 41 around the rear rotation shaft 62. That is, with the tip of the ground contacting the ground 30, the ground contact body 42 rotates (rotates backward) to move the tip side backward due to drag resistance (ground sliding resistance) from the ground 30 caused by the combine 1 moving forward (see arrow C1 in FIG. 6). On the other hand, the ground contact body 42 rotates (rotates forward) to move the tip side forward due to ground sliding resistance caused by the combine 1 moving backward (see arrow C2 in FIG. 6).

[0072] The cutting height sensor 43 is a sensor that detects the amount of rotation of the grounding body 42 about the rear rotating shaft 62. The cutting height sensor 43 is provided with respect to an intermediate rotating shaft 70, which is the third shaft provided in the cutting height detection device 40, and detects the amount of rotation of the grounding body 42 about the rear rotating shaft 62 from the amount of rotation of the intermediate rotating shaft 70.

[0073] The intermediate rotating shaft 70 is a support shaft whose axial direction is in the left-right direction, and is supported via a bearing member such as a bush to be relatively rotatable about a third axis P3 relative to the case 51 of the device body 41. The intermediate rotating shaft 70 is located midway between the front fixed shaft 61 and the rear rotating shaft 62 in the front-rear direction.

[0074] The cutting height sensor 43 is a rotary type potentiometer, and detects the rotational position of the grounding body 42 via the intermediate rotating shaft 70 and the rear rotating shaft 62. The cutting height sensor 43 is fixed to the right case body 52 at two points, one above and one below, with bolts 73 on the right side surface of the right case body 52 (see FIG. 7).

[0075] The cutting height sensor 43 is connected to the right end of the intermediate rotating shaft 70, and directly detects the rotational position of the intermediate rotating shaft 70 about the third axis P3, using the intermediate rotating shaft 70 as a detection axis. The cutting height sensor 43 has a main body 43a and a connector 43b to which a signal line is connected in the main body 43a. One end of a wire harness (not shown) serving as a signal line is connected to the connector 43b. The cutting height sensor 43 is connected to the control device 200 provided on the traveling machine body 4 side by the wire harness. Note that the cutting height sensor 43 may have a configuration in which a signal line is directly extended from the main body as a connection configuration to the control device 200.

[0076] The intermediate rotating shaft 70 rotates by receiving the rotational power of the rear rotating shaft 62 accompanying the rotation of the ground contact body 42. The intermediate rotating shaft 70 receives the rotational power of the rear rotating shaft 62 via gears or the like provided for each of the rear rotating shaft 62 and the intermediate rotating shaft 70. The rotation of the intermediate rotating shaft 70 is detected by the cutting height sensor 43. The ground contact body 42 uses a ground contact body returning member which is an elastic member such as a spring provided in the case 51, and is provided so that the ground contact body 42 is positioned at a predetermined reference position in the absence of the action of an external force with respect to the rotation around the rear rotating shaft 62 by setting the biasing force (torque) of the ground contact body returning member, the case returning member, etc.

[0077] In the height-of-cut detection device 40 having the above-described configuration, the grounding body 42 is arranged to rotate about the rear pivot shaft 62 with respect to the device body 41, which is in a state where rotation about the front fixed shaft 61 is stopped, when the grounding body 42 is located rearward of the reference position, for example, when the combine harvester 1 moves forward and the like, when the grounding body 42 is pressed from the front and rotates rearward from the reference position, the device body 41 does not rotate about the front fixed shaft 61, and only the grounding body 42 rotates about the rear pivot shaft 62 relative to the device body 41.

[0078] The cutting height sensor 43 detects the amount of rotation of the grounding body 42 backward from the reference position. That is, the rearward relative rotation of the grounding body 42 with respect to the device body 41 from a state in which the grounding body 42 is in the reference position is detected by the cutting height sensor 43 as the rotation for detecting the cutting height.

[0079] On the other hand, with regard to the relative rotation of the grounding body 42 with respect to the device body 41, the rotation of the grounding body 42 forward from the reference position is accompanied by the upward rotation of the case 51. That is, when the grounding body 42 rotates forward from the reference position, the device body 41 as a whole rotates upward about the front fixed shaft 61 in conjunction with the rotation of the grounding body 42. Here, when the grounding body 42 rotates forward from the reference position relative to the device body 41, the intermediate rotating shaft 70 does not rotate, and the cutting height sensor 43 does not detect the rotation of the intermediate rotating shaft 70.

[0080] As described above, the cutting height detection device 40 is configured so that the cutting height sensor 43 detects the amount of rotation of the grounding body 42 when the grounding body 42 is rotated rearward from the reference position relative to the device body 41.

[0081] By using the cutting height detection device 40 having the above-mentioned configuration, the combine harvester 1 detects the height (cutting height) of the cutting part 5 based on the detection signal from the cutting height sensor 43. As described above, the cutting height detection device 40 detects the rearward rotation of the ground contact body 42, and therefore detects the cutting height mainly when the body of the combine harvester 1 moves forward.

[0082] In the cutting height detection device 40, the cutting height sensor 43 detects the height of the grass dividing board 21 from the ground 30, i.e., the cutting height, by detecting the rotational position of the intermediate rotating shaft 70, which rotates in conjunction with the rotation of the grounding body 42. The detection signal of the cutting height sensor 43 is sent to the control device 200 by a wire harness. The control device 200 receives the detection signal from the cutting height sensor 43, and based on the detection signal, operates the cutting lifting cylinder 18 (see FIG. 1) to adjust the cutting height so as to hold the cutting height calculated from the detection result at a set value.

[0083] In a configuration in which the cutting height sensor 43 is attached to the outside of the case 51 of the device body 41, the device body 41 is provided with a sensor cover 170 that covers the cutting height sensor 43. The sensor cover 170 is fixed to the case 51 with a bolt 176.

[0084] [Support structure of cutting height detection device] The support structure of the cutting height detection device 40 will be described with reference to Figures 4 to 8. The cutting height detection device 40 is supported by the support structure of the unit support body 44 relative to the grass dividing section 50 so as to be rotatable so as to swing left and right about an axis O1 (see Figures 6 and 8) that runs along the front-rear direction.

[0085] As shown in Figures 4 to 8, the grass dividing section 50 includes a grass dividing frame 34 provided at the bottom of the cutting section 5, and a grass dividing board 21 provided in front of the grass dividing frame 34. Here, the grass dividing board 21 and grass dividing frame 34 related to supporting the cutting height detection device 40 are the grass dividing board 21A and grass dividing frame 34 located second and sixth from the left, respectively (see Figure 3).

[0086] The grass dividing frame 34 has, from the rear end side to the front end side, a rear inclined portion 101 which is a downward inclined portion at the front, an intermediate horizontal portion 102 which is a horizontal portion, and a front inclined portion 103 which is an upward inclined portion at the front which forms an obtuse angle with the intermediate horizontal portion 102. The intermediate horizontal portion 102 and the front inclined portion 103 form a curved corner portion 104. The grass dividing frame 34 has the rear end portion of the rear inclined portion 101 as its base end portion and the front end portion of the front inclined portion 103 as its tip end portion. The grass dividing frame 34 has the rear end portion of the rear inclined portion 101 positioned above the horizontal frame 31, and the rear inclined portion 101 is fixed to the horizontal frame 31 via a predetermined support member 105 fixed to the horizontal frame 31 (see FIG. 4).

[0087] The grass dividing board 21 has a grass dividing board main body 121 and a rib board section 122 provided on the rear side of the grass dividing board main body 121. The grass dividing board main body 121 is a plate-shaped member with the front side convex in a planar cross-sectional view, and has a pointed shape that gradually narrows from the rear side to the front side in a front view and a planar view. The grass dividing board main body 121 has a curved shape with the front side downward and the rear lower side convex in a side view. The rib board section 122 is a plate-shaped part with the board thickness direction in the left-right direction, and is provided as an integral part of the grass dividing board main body 121 on the rear side of the front board section of the grass dividing board main body 121. The configuration in which the rib board section 122 is provided on the grass dividing board main body 121 has an approximately left-right symmetrical shape.

[0088] The grass dividing section 50 also includes a hitch 125 as a grass dividing board support member provided on the rear side of the grass dividing board 21. The hitch 125 is a longitudinal plate-like member, and is provided with an upward-reaching slope so that its longitudinal direction follows the upward-reaching slope of the grass dividing board 21. The hitch 125 is fixed to the grass dividing frame 34 via a hitch support plate 124. The hitch support plate 124 is a plate-like member whose thickness direction is in the left-right direction, and is fixed to the front inclined portion 103 of the grass dividing frame 34 by welding or the like.

[0089] The hitch 125 is fastened to the hitch support plate 124 at two locations, front and rear, by bolts 127 and nuts 128, with the rear portion overlapping the hitch support plate 124 from the left side. A grass dividing board 21 is attached to the hitch 125. The grass dividing board 21 is fastened to the hitch 125 at two locations, front and rear, by bolts 141 and nuts 142, with the rear portion of the rib plate portion 122 overlapping the front portion of the hitch 125 from the right side. In this way, the hitch 125 is fixed to the grass dividing frame 34, thereby supporting the grass dividing board 21 in front of the grass dividing frame 34.

[0090] The cutting height detection device 40 is supported so as to be rotatable around a fore-aft axis relative to the grass dividing unit 50 having the above-mentioned configuration. The cutting height detection device 40 has a shaft support part 130 on its front side as a support part for the grass dividing unit 50, and is supported by this shaft support part 130 so as to be rotatable around a fore-aft axis O1 as a rotation axis.

[0091] The pivot support 130 is provided on the rear side of the grass dividing board 21. The pivot support 130 has a boss 132, which is a support provided on the rear side of the grass dividing board 21, and a support shaft 131 provided at the front end of the unit support 44 and supported by the boss 132. The pivot support 130 has a configuration in which the support shaft 131, which protrudes forward from the front wall surface 46b of the front surface 44b of the unit support 44, is supported by the boss 132 provided at the lower end of the hitch 125. In other words, the front end side of the cutting height detection device 40 is attached to the hitch 125 via the boss 132.

[0092] The support shaft portion 131 protrudes forward from the front wall surface portion 46b as an integral part of the unit support body 44, and its axis coincides with the axis line O1. The boss portion 132 is a hollow cylindrical portion with an open rear side, and is provided by fixing a cylindrical member to the lower end portion of the hitch 125. The support shaft portion 131 is rotatably supported by the boss portion 132 via a bearing member such as a bush with the front portion inserted into the boss portion 132, and is prevented from coming off from the boss portion 132 by a set screw 137 and a lock nut 138 (see FIG. 8).

[0093] In this way, the pivot support part 130 supports the support shaft part 131 provided on the front part of the unit support body 44 by the boss part 132 via the hitch 125 to the grass dividing board 21. As a result, the pivot support part 130 supports the front side of the cutting height detection device 40 rotatably with the front-to-rear direction as the rotation axis relative to the grass dividing part 50. The cutting height detection device 40 is supported in a cantilever manner relative to the grass dividing part 50 by the pivot support part 130.

[0094] As described above, the cutting height detection device 40 supports the unit support 44 so that it can rotate around the front-to-rear axis O1 relative to the grass dividing section 50, thereby supporting the sensor unit 45 supported by the unit support 44 so that it can swing left and right.

[0095] The cutting height detection device 40 is elastically positioned so as to be located at a predetermined neutral position with respect to rotation about an axis in the front-rear direction by a return spring 147 provided on the shaft support portion 130. The return spring 147 is a so-called torsion spring, and the coil-shaped portion passes through the rear portion of the boss portion 132 and is engaged with a locking pin 148 that protrudes forward from the front wall surface portion 46b above the boss portion 132.

[0096] The return spring 147 has extensions 147a at both ends positioned on the left and right sides of the locking pin 148, and the extensions 147a hold the locking pin 148 from both the left and right sides with elastic force. The return spring 147 also has extensions 147a positioned on both the left and right sides of the lower part of the hitch 125 located above the locking pin 148, and the left and right extensions 147a hold the hitch 125 with elastic force.

[0097] According to this configuration, when an external force of a predetermined magnitude or greater that rotates height-of-cutting detection device 40 about axis O1 acts on height-of-cutting detection device 40, height-of-cutting detection device 40 rotates against the elastic force of return spring 147 with one extension portion 147a pressed by locking pin 148 in accordance with the direction of rotation and the other extension portion 147a locked to hitch 125. Then, when the external force is no longer acting, height-of-cutting detection device 40 returns to the neutral position due to the elastic force of return spring 147.

[0098] [Mowing height detection device operation] The operation of the cutting height detection device 40 will now be described. During normal operation by the combine harvester 1, that is, when the machine body is in forward motion, the cutting height is controlled based on the cutting height detection value by the cutting height detection device 40 so that the cutting height is maintained at a set value. The cutting height is detected when the rotation position of the grounding body 42 relative to the device body 41 is rearward of the reference position.

[0099] When the machine body moves forward, the ground contact body 42, which slides with its tip in contact with the ground 30, rotates rearward from a reference position about the rear rotating shaft 62 relative to the case 51 of the device body 41 due to ground sliding resistance (see arrow C1 in FIG. 6). The ground contact body 42 rotates integrally with the rear rotating shaft 62 about the second axis P2, and the rotation of the rear rotating shaft 62 is transmitted to the intermediate rotating shaft 70 via gears or the like. The rotation of the intermediate rotating shaft 70 is detected by the cutting height sensor 43, and the cutting height is detected based on the amount of rotation of the intermediate rotating shaft 70.

[0100] Furthermore, if a lateral external force acts on height-of-cutting detection device 40, for example when the machine is steered with grounding body 42 on the ground, height-of-cutting detection device 40 will rotate about axis O1 in the front-rear direction by pivot support 130 and escape. When the lateral external force acting on height-of-cutting detection device 40 is no longer acting, the biasing structure of return spring 147 and locking pin 148 will return height-of-cutting detection device 40 to a predetermined neutral position.

[0101] [Combine control configuration] The control configuration of the combine harvester 1 will be described with reference to FIG. 10. As shown in FIG. 10, the combine harvester 1 includes a control device 200. The control device 200 controls each part of the combine harvester 1 based on input signals from various sensors and the like included in the combine harvester 1. The control device 200 includes a central processing unit (CPU) as an arithmetic processing device that executes various arithmetic processing and control, storage devices such as random access memory (RAM) and read only memory (ROM), input / output devices (input / output circuits) such as an input / output interface for data input / output, and peripheral circuits such as a clock circuit, all connected via a bus or the like. The CPU of the control device 200 performs arithmetic processing according to various programs stored in the ROM or the like.

[0102] 10, the combine harvester 1 has, as components electrically connected to the input device (input circuit) of the control device 200, in addition to the cutting height sensor 43 of the cutting height detection device 40, a vehicle speed sensor 201, a cutting height adjustment dial 202 as a cutting height target value setting operation unit, an automatic cutting height switch 205, a machine body height sensor 203, and a grain stalk detection sensor 204. The control device 200 receives input signals from these sensors, switches, etc., and generates control signals based on these signals.

[0103] The machine-body height sensor 203 is provided on a shaft support that supports the reaping unit 5 rotatably around a predetermined rotation axis along the left-right direction relative to the traveling machine body 4. The machine-body height sensor 203 is a machine-body position sensor for detecting the machine-body height (machine height), which is the height of the reaping unit 5 relative to the traveling machine body 4. The machine-body height sensor 203 is, for example, a rotary potentiometer, and detects the rotation position of the reaping unit 5 via the rotation axis of the reaping unit 5 relative to the traveling machine body 4.

[0104] The vehicle speed sensor 201 is a sensor that detects the vehicle speed, which is the traveling speed of the combine harvester 1 (traveling body 4). The control device 200 receives an input of a detection signal from the vehicle speed sensor 201 and detects the vehicle speed. The control device 200 controls the vehicle speed based on the detection signal from the vehicle speed sensor 201. The control device 200 is configured to calculate the traveling distance of the combine harvester 1 based on the detection information from the vehicle speed sensor 201 and time elapsed information.

[0105] The combine harvester 1 has a traveling HST for changing the traveling speed as the driving unit 220 related to the vehicle speed. Here, the "HST" is a hydraulic stepless transmission that employs a system in which hydraulic pressure generated by driving a hydraulic pump is converted again into rotational force by a hydraulic motor. The HST has a variable displacement pump and motor that are fluidly connected to each other, solenoid valves corresponding to the pump and motor, respectively, and an output shaft. In the HST, the pump is adjusted and driven (traveling drive adjustment) via the solenoid valve for the pump while receiving power from the engine 11, and the drive of the motor by the adjustment drive is transmitted to the output shaft.

[0106] The output shaft of the HST for traveling is interlocked with a transmission mechanism for transmitting driving force to the left and right crawler units 3, 3 that constitute the traveling unit 2. This transmission mechanism is configured including a planetary gear group and has left and right output shafts that transmit driving force to the drive sprockets 3b of the left and right crawler units 3.

[0107] The control device 200 receives a detection signal regarding the forward / rearward rotation operation position (operation amount) of the main shift lever 17, generates control information based on the detection signal, and controls the drive of the drive unit 220 based on the generated control information. The operation amount of the main shift lever 17 is detected by, for example, a rotary encoder or a rotary potentiometer. The control device 200 controls the drive of the pump and motor by controlling the solenoid valve for the HST, and controls the power transmission from the output shaft to the transmission mechanism.

[0108] In such a configuration, the vehicle speed sensor 201 detects, as the vehicle speed, for example, the rotation speed of the crawler unit 3 or the rotation speed of the output shaft of the HST used for traveling. The control device 200 controls the drive unit 220 so that the vehicle speed detected by the vehicle speed sensor 201 corresponds to a speed corresponding to manual operation of the main shift lever 17, etc.

[0109] The control device 200 controls the lifting and lowering of the cutting unit 5 by operating the cutting lift cylinder 18 so that the cutting height is maintained at the target cutting height value based on a detection signal from the cutting height sensor 43. The control device 200 controls the extension and contraction operation of the cutting lift cylinder 18 by controlling the operation of a solenoid valve 221 for hydraulic control of the cutting lift cylinder 18.

[0110] A mowing height target value used for controlling the elevation of the mowing unit 5 is set and stored in the control device 200. The mowing height target value is set in the control device 200 by a mowing height adjustment dial 202.

[0111] 11, the mowing height adjustment dial 202 is provided as one of a group of operation units 300 provided on the upper surface of the side column 19 in the side operation unit 12 provided on the left side of the driver's seat 16 in the driver's section 14, and is operated by an operator seated in the driver's seat 16. The mowing height adjustment dial 202 is an operation tool that adjusts the target mowing height value in stages, and is provided as a cylindrical protrusion (knob) that is rotated, and in this embodiment, it is configured so that the target mowing height value can be adjusted in five stages, for example, within a range of 10 to 50 mm.

[0112] As described above, the combine harvester 1 is equipped with the cutting unit 5 which is movable up and down relative to the running body 4, a cutting height detection device 40 for detecting the cutting height, which is the height of the cutting unit 5 relative to the ground, a body-to-body height sensor 203 as a body-to-body height detection device for detecting the body-to-body height, which is the height of the cutting unit 5 relative to the running body 4, and a control device 200 which controls the height of the cutting unit 5 based on the detection signals of the cutting height detection device 40 and the body-to-body height sensor 203.

[0113] [Lifting control of the harvesting unit] The lifting and lowering control of the reaping unit 5 performed by the control device 200 in the combine harvester 1 having the above configuration will be described. In the lifting and lowering control of the reaping unit 5 according to this embodiment, for example, of the detection signals of the two cutting height detection devices 40, the detection signal that detects the lower cutting height is used. However, the manner in which the two cutting height detection devices 40 are used is not particularly limited.

[0114] The control device 200 performs two types of control, a first type of control being a cutting height control, and a second type of control being a lifting range limiting control, as lifting and lowering control of the reaping unit 5. These controls are basically performed in parallel during the reaping operation by the combine harvester 1.

[0115] The mowing height control will now be described. The mowing height control is based on the detection signal of the mowing height detection device 40, and includes the automatic mowing height control described above. The control device 200 has, as control modes for the mowing height control, an automatic mowing height mode, which is a first control mode that performs the automatic control of the mowing height described above, and an automatic lift mode, which is a second control mode that controls the mowing unit 5 to rise to a fixed height under predetermined conditions. Hereinafter, the mowing height control that includes these two control modes and is based on the detection signal of the mowing height detection device 40 will be referred to as "automatic mowing height control."

[0116] The automatic mowing height mode of the automatic mowing height control is a mode in which the height of the mowing unit 5 is controlled so that the mowing height detected by the mowing height detection device 40 becomes a predetermined target value (mowing height target value), and the height of the mowing unit 5 is maintained at a constant height relative to the ground 30 during mowing work. The automatic lift mode of the automatic mowing height control is a mode in which, based on the mowing height detected by the mowing height detection device 40, the mowing unit 5 is raised to a constant height when the height of the mowing unit 5 becomes lower than the set height relative to the ground 30 during mowing work.

[0117] The automatic mowing height switch 205 functions as a mode changeover switch for switching between an automatic mowing height mode and an automatic lift mode in the automatic mowing height control. As shown in Fig. 11, the automatic mowing height switch 205 is disposed near the mowing height adjustment dial 202 as an operation part set with the mowing height adjustment dial 202 in the operation part group 300. In this embodiment, the automatic mowing height switch 205 is an operation part that is operated by pressing, and is disposed near the right side of the mowing height adjustment dial 202 (the lower side in Fig. 11).

[0118] A mode display unit 206 that indicates the current control mode is provided near the automatic mowing height switch 205. The mode display unit 206 has a first display unit 206a that displays the characters "Automatic Mowing Height" corresponding to the automatic mowing height mode, and a second display unit 206b that displays the characters "OK Lift" corresponding to the automatic lift mode. The first display unit 206a and the second display unit 206b are configured to be able to blink, and the display unit corresponding to the control mode selected by operating the automatic mowing height switch 205 is configured to light up. In addition, by operating the automatic mowing height switch 205, the automatic mowing height control is turned off by not selecting either the automatic mowing height mode or the automatic lift mode. When the automatic mowing height control is turned off, both the first display unit 206a and the second display unit 206b are turned off. In other words, by operating the automatic mowing height switch 205, three states are switched: an automatic mowing height mode state of the automatic mowing height control, an automatic lift mode state of the automatic mowing height control, and an off state of the automatic mowing height control.

[0119] When working in the automatic mowing height mode, with the engine 11 started, the automatic mowing height mode is selected by operating the automatic mowing height switch 205. When the automatic mowing height mode is selected, as shown in Fig. 12A, the first display unit 206a is lit and the second display unit 206b is turned off.

[0120] With the automatic mowing height mode selected, mowing work is commenced, and during mowing work, the mowing height adjustment dial 202 is adjusted to one of the scales "1" to "5." In the example shown in FIG. 12A, the mowing height adjustment dial 202 is set to the scale "3." As a result, the mowing height corresponding to the scale set by the mowing height adjustment dial 202 is set as the target mowing height value, and the mowing height is controlled so as to be automatically maintained at the target mowing height value based on the detection signal of the mowing height detection device 40.

[0121] When working in the automatic lift mode, with the engine 11 running, the automatic lift mode is selected by operating the automatic mowing height switch 205. When the automatic lift mode is selected, as shown in FIG. 12B, the second display unit 206b is turned on and the first display unit 206a is turned off.

[0122] When the automatic lift mode is selected and mowing work is started, if the mowing height detected by the mowing height detection device 40 is detected to be equal to or less than a set height (e.g., 10 mm) during mowing work, the mowing unit 5 is controlled to automatically rise a predetermined amount (e.g., 1 to 2 cm). Also, if the machine is stopped while the automatic lift mode is selected, or if the mowing height detected by the mowing height detection device 40 is detected to be equal to or more than another set height (e.g., 20 mm), the mowing unit 5 is controlled to stop rising. The set height and predetermined amount for the automatic lift mode are preset and stored in the control device 200.

[0123] The lifting range limit control will be described. The lifting range limit control limits the lifting range of the reaping unit 5 to within a range of a predetermined amount of ascent and descent with respect to a reference reaping height, which is a reference value for the height relative to the machine body detected by the machine body height sensor 203. The reference reaping height is stored in the control device 200.

[0124] The reference mowing height is, for example, a height relative to the machine body that is stored when a certain period of time has elapsed during automatic control of the mowing height during which the target mowing height value, which is set as a value within a predetermined range, remains within the dead zone. In this case, the reference mowing height is a value stored in the control device 200 based on the value detected by the mowing height detection device 40. The height relative to the machine body stored in the control device 200 is subject to calculation of an average value, as described below, and the average value may be used as the reference mowing height.

[0125] As shown in Fig. 13, in the lifting range limit control, a mowing reference height H0 is set as a reference value for the height of the mowing unit 5 relative to the machine body. A body height that is higher than the mowing reference height H0 by a predetermined amount of rise ΔH1 is set as an ascent prohibited height H1. Also, a body height that is lower than the mowing reference height H0 by a predetermined amount of descent ΔH2 is set as a descent prohibited height H2.

[0126] In this embodiment, the lift amount ΔH1 is set to a value greater than the lowering amount ΔH2. Specifically, for example, the lift amount ΔH1 is set to 50 mm, and the lowering amount ΔH2 is set to 30 mm. Note that the values ​​of the lift amount ΔH1 and the lowering amount ΔH2 and the magnitude relationship between them are not limited, but from the viewpoint of suppressing the plunging of the cutting unit 5 into the ground, the lift amount ΔH1 is set to a value greater than the lowering amount ΔH2 in order to ensure a certain degree of lift amount ΔH1.

[0127] In the lifting range limit control, the control device 200 controls the height of the cutting unit 5 relative to the body by controlling the operation of the solenoid valve 221 of the cutting lifting cylinder 18 based on the detection signal detected by the body height sensor 203 so that the body height is below the prohibited ascent height H1 on the upward side of the cutting reference height H0, and is above the prohibited descent height H2 on the downward side of the cutting reference height H0.

[0128] That is, when the automatic mowing height control based on the detection signal of the mowing height detection device 40 attempts to control the mowing unit 5 to rise to a height higher than the prohibited ascent height H1 relative to the machine body, the lifting range limit control limits (prohibits) the lifting control of the mowing unit 5 so that the height of the mowing unit 5 relative to the machine body does not exceed the prohibited ascent height H1. Similarly, when the automatic mowing height control based on the detection signal of the mowing height detection device 40 attempts to control the mowing unit 5 to fall to a height lower than the prohibited descent height H2, the lifting range limit control limits (prohibits) the descent control of the mowing unit 5 so that the height of the mowing unit 5 relative to the machine body does not fall below the prohibited descent height H2.

[0129] In this way, according to the lifting range limiting control, the lifting range of the cutting unit 5 is limited to within a range of a predetermined lifting amount ΔH1 and a predetermined lowering amount ΔH2 with respect to the cutting reference height H0. The lifting amount ΔH1 and the lowering amount ΔH2 are set and stored in advance in a storage unit included in the control device 200.

[0130] In the configuration in which the automatic mowing height control and lifting range limit control are performed as described above, the control device 200 performs control to disable the lifting range limit control for a certain period of time from the timing of the start of mowing in mowing work, that is, at the beginning of the mowing work. In other words, the control device 200 performs only the automatic mowing height control without performing the lifting range limit control for a certain period of time from the timing of the start of mowing. Note that the state in which the automatic mowing height control is performed is a state in which either the automatic mowing height mode or the automatic lift mode described above is selected as a control mode.

[0131] As a first control mode in which the lifting / lowering range limit control is disabled at the beginning of mowing work, the control device 200 disables the lifting / lowering range limit control and performs only automatic mowing height control from the start of mowing, which is the time when control begins, until the traveling distance of the running body 4 reaches a predetermined distance.

[0132] As shown in FIG. 14, when the combine harvester 1 starts a reaping operation at an arbitrary start position Q0, the time when the reaping starts is the control start time when the control of the reaping unit 5 is started. Regarding the time when reaping starts, the control device 200 determines the time when the following conditions are satisfied, for example: (1) a predetermined condition (e.g., the vehicle speed is equal to or higher than a certain speed) for the vehicle speed of the combine harvester 1 detected by the vehicle speed sensor 201 is satisfied, and (2) a predetermined condition (e.g., the vehicle speed is equal to or higher than a certain height) for the cutting height (height relative to the ground) detected by the cutting height detection device 40 is satisfied, or a predetermined condition (e.g., the vehicle height is equal to or lower than a certain height) for the vehicle height detected by the vehicle height sensor 203 is satisfied, and (3) the working clutch (reaping clutch) is turned ON by the operation of the clutch operating tool disposed in the driving unit 14.

[0133] Then, after the combine harvester 1 starts harvesting, the control device 200 disables the lifting range limit control and performs only the automatic harvesting height control until the travel distance D of the combine harvester 1 (of the traveling body 4) from the start position Q0 reaches a predetermined distance D1. That is, the travel section E1 from the start position Q0 where the combine harvester 1 starts harvesting work at the start position Q0 where the travel distance D is 0 to the position Q1 where the travel distance D becomes the distance D1 is the disabled section of the lifting range limit control.

[0134] In the example shown in Fig. 14, a predetermined position at approximately the center in the front-rear direction of the traveling body 4 is used as the reference position of the combine harvester 1. In addition, in Fig. 14, the travel distance D shown on the horizontal axis represents the distance traveled by the combine harvester 1 regardless of the traveling direction of the combine harvester 1, and corresponds to the reaping distance, which is the travel distance of the combine harvester 1 after reaping starts.

[0135] The travel distance D of the combine 1 is calculated in the control device 200 based on detection information from the vehicle speed sensor 201, which detects, for example, the rotational speed of the crawler section 3, and time information measured by a timer function of the control device 200.

[0136] As shown in Fig. 14, when the travel distance D of the combine harvester 1 from the start of mowing reaches distance D1, the process of disabling the lifting range limit control is released and the lifting range limit control is started. That is, in the combine harvester 1, after mowing work or travel accompanied only by the automatic mowing height control is performed for the mowing distance of distance D1 from the start of mowing, the control device 200 enters a state in which the automatic mowing height control and the lifting range limit control are performed in parallel, and this state continues until the end of mowing.

[0137] The end of reaping is the end of control when the control of the reaping unit 5 ends. Regarding the end of reaping, the control device 200 determines the end of reaping as the timing when a predetermined condition is satisfied regarding at least one of the vehicle speed of the combine harvester 1 detected by the vehicle speed sensor 201, the mowing height (height from the ground) detected by the mowing height detection device 40, and the height relative to the machine body detected by the machine body height sensor 203, or the timing when the working clutch (mowing clutch) is turned OFF by operating the clutch operating tool. As shown in FIG. 14, in this example, the calculation of the mowing distance (traveling distance D) is continuously performed by the control device 200 from the start of reaping to the end of reaping, that is, during the reaping work (see arrow F1).

[0138] According to the above-described lifting control of the reaping unit 5, the following control is performed as the control method of the combine harvester 1. That is, the control method of the combine harvester 1 detects the mowing height (height above the ground) and the height relative to the machine body, controls the height of the reaping unit 5 based on the detected mowing height and height relative to the machine body, performs automatic mowing height control and lifting range limit control, and disables the lifting range limit control from the start of control until the traveling distance D of the traveling machine body 4 becomes the predetermined distance D1.

[0139] The mowing reference height H0 used in the lifting range limit control may be calculated and updated during mowing work by the control device 200. As an example of a control mode in which the mowing reference height H0 is calculated and updated, the control device 200 calculates the mowing reference height H0 as an average value of the height relative to the machine body stored at predetermined time intervals, and updates the height at predetermined time intervals.

[0140] Specifically, as shown in Fig. 15A, each time a predetermined time Δt1 elapses during mowing work, the control device 200 stores the machine-to-body height detected by the machine-to-body height sensor 203 at that time as the mowing reference height H0. The machine-to-body height varies as appropriate due to automatic mowing height control by the mowing height detection device 40, and the machine-to-body height that varies as appropriate under the control of the automatic mowing height control is detected by the machine-to-body height sensor 203.

[0141] In Fig. 15A, the dashed line graph G1 shows an example of the change in height relative to the aircraft at each time point after the lapse of a predetermined time Δt1. That is, the graph G1 shows the detection value (measurement value) of the height relative to the aircraft at each time point after the lapse of the predetermined time Δt1, and these detection values ​​of the height relative to the aircraft are stored each time in the control device 200. In the graph shown in Fig. 15A, the horizontal axis represents time, and the vertical axis represents the height relative to the aircraft.

[0142] The control device 200 calculates the average value of all the values ​​of the machine-relative height stored at each timing of storing the machine-relative height every time the predetermined time Δt1 elapses, and sets the calculated average value as the reaping standard height H0 at that time. In Fig. 15A, the graph G2 shown by the solid line shows an example of the change in the reaping standard height H0 calculated every time the predetermined time Δt1 elapses.

[0143] Specifically, in the example shown in Fig. 15A, the mowing reference height H0 (see point R1) calculated at any time ta is the average value of the machine-relative heights (see graph G1) stored every predetermined time Δt1 up to that time, including the machine-relative height (see point R2) detected at that time ta. In other words, the value of the mowing reference height H0 calculated at time ta is the total value of all machine-relative heights (including the machine-relative height stored at time ta) stored every predetermined time Δt1 from the start of mowing to time ta, divided by the number of times stored from the start of mowing to time ta (including storage at time ta), that is, the number of times the predetermined time Δt1 has elapsed since the start of mowing.

[0144] The standard reaping height H0 calculated as described above is used for the lifting / lowering range limit control. That is, the standard reaping height H0 used for the lifting / lowering range limit control is calculated and updated every time the predetermined time Δt1 elapses.

[0145] When the mowing standard height H0 is calculated and updated in the lifting range limit control, the prohibited ascent height H1 and prohibited descent height H2 in the lifting range limit control also vary in response to the variation of the mowing standard height H0. In Fig. 15B, graph G3 shows an example of the variation of the prohibited ascent height H1 every time a predetermined time Δt1 elapses, and graph G4 shows an example of the variation of the prohibited descent height H2 every time a predetermined time Δt1 elapses. That is, as shown in Fig. 15B, the prohibited ascent height H1 and prohibited descent height H2, which are determined by the amount of ascent ΔH1 and the amount of descent ΔH2, respectively, relative to the mowing standard height H0, vary following the variation of the mowing standard height H0, which is calculated and updated every predetermined time Δt1.

[0146] In this manner, in the control method for the combine harvester 1, a method may be used in which the standard reaping height H0 is calculated as an average value of the heights relative to the machine body stored at predetermined time intervals, and updated at predetermined time intervals.

[0147] When the mowing reference height H0 is calculated and updated, the calculation and update process of the mowing reference height H0 is not performed in the travel section E1 where the lifting / lowering range limit control is disabled, as shown in Fig. 14. Then, when the travel distance D of the combine 1 from the start position Q0 reaches a predetermined distance D1 and the lifting / lowering range limit control is released from being disabled, the calculation and update process of the mowing reference height H0 is started together with the start of the lifting / lowering range limit control, and is performed until the end of mowing (see arrow F2).

[0148] A second control mode in which the lifting / lowering range limit control is disabled in the early stage of mowing work will be described. In the second control mode, the control device 200 disables the lifting / lowering range limit control and performs only automatic mowing height control from the start of mowing, which is the start of control, until a predetermined time has elapsed. That is, in the first control mode, the period in which the lifting / lowering range limit control is disabled from the start of mowing is determined based on the travel distance, whereas in the second control mode, the same period is determined based on time.

[0149] As shown in Fig. 16, when the combine harvester 1 starts a reaping operation at an arbitrary start time T0, the start time of reaping becomes the control start time for starting control of the reaping unit 5. Then, after the combine harvester 1 starts reaping, the control device 200 disables the lifting range limit control and performs only the automatic mowing height control from the start time T0 to a predetermined time T1. In other words, the lifting range limit control is disabled during time J1, which is the elapsed time T from the start time T0 to time T1.

[0150] As shown in Fig. 16, when time J1 has elapsed from the start of mowing and it becomes time T1, the process of disabling the lift-up range limit control is released and the lift-up range limit control is started. That is, in the combine harvester 1, after mowing work or traveling accompanied only by automatic mowing height control is performed for time J1 from the start of mowing, the automatic mowing height control and the lift-up range limit control are performed in parallel by the control device 200, and this state continues until the end of mowing. The other control contents are the same as those in the first control mode, so the explanation will be omitted.

[0151] According to the above-described lifting control of the reaping unit 5, the following control is performed as the control method of the combine harvester 1. That is, the control method of the combine harvester 1 detects the mowing height (height relative to the ground) and the height relative to the machine body, controls the height of the mowing unit 5 based on the detected mowing height and height relative to the machine body, performs automatic mowing height control and lifting range limit control, and disables the lifting range limit control until a predetermined time has elapsed from the start of control.

[0152] A third control mode of control in which the lifting / lowering range limit control is disabled at the beginning of mowing work will be described. In the third control mode, the control device 200 disables the lifting / lowering range limit control and performs only automatic mowing height control from the start of mowing, which is the start of control, until the vehicle speed of the traveling machine body 4 reaches a predetermined speed. That is, while in the first control mode, the period during which the lifting / lowering range limit control is disabled from the start of mowing is determined based on the travel distance, in the third control mode, the same period is determined based on the vehicle speed.

[0153] As shown in FIG. 17, when the combine harvester 1 starts a reaping operation at an arbitrary vehicle speed V0, the time when the reaping operation starts is the control start time when the control of the reaping unit 5 is started. After the combine harvester 1 starts reaping, the control device 200 disables the lifting range limiting control and performs only the automatic mowing height control until the vehicle speed V increases from the vehicle speed V0 to reach a predetermined vehicle speed V1. In other words, the section K1 during which the vehicle speed V increases from the vehicle speed V0 to reach the vehicle speed V1 is an ineffective section of the lifting range limiting control. The vehicle speed V is the vehicle speed of the combine harvester 1 detected by the vehicle speed sensor 201. The vehicle speed V0 at the start of reaping may be a state in which the vehicle speed V is 0, that is, a state in which the combine harvester 1 is stopped.

[0154] As shown in Fig. 17, at the timing when the vehicle speed V increases from vehicle speed V0 to vehicle speed V1 from the start of mowing, the process of disabling the lift-up range limit control is released and the lift-up range limit control is started. That is, in the combine harvester 1, from the start of mowing until the vehicle speed V increases to vehicle speed V1, mowing work or traveling is performed with only automatic mowing height control, and then the automatic mowing height control and the lift-up range limit control are performed in parallel by the control device 200, and this state continues until the end of mowing. The other control contents are similar to those of the first control mode, so a description thereof will be omitted.

[0155] According to the above-described lifting control of the reaping unit 5, the following control is performed as the control method of the combine harvester 1. That is, the control method of the combine harvester 1 detects the mowing height (height above the ground) and the height relative to the machine body, controls the height of the reaping unit 5 based on the detected mowing height and height relative to the machine body, performs automatic mowing height control and lifting range limit control, and disables the lifting range limit control from the start of control until the vehicle speed of the traveling machine body 4 reaches a predetermined speed.

[0156] An example of the control process related to the reference mowing height in the above-mentioned lifting range limit control will be described with reference to the flowchart shown in Fig. 18. The control process described below is performed by the CPU of the control device 200 reading and executing a predetermined control program stored in a storage device such as a RAM.

[0157] As shown in Fig. 18, first, when calculating and updating the standard mowing height, a determination is made as to whether any one of the following conditions is met: "Mowing manual up operation in progress," "Mowing manual down operation in progress," "Mowing auto-lift in progress," "Mowing auto-set in progress," and "Mowing height adjustment dial moved" is met (S10).

[0158] In step S10, "manual raising operation in progress" and "manual lowering operation in progress" correspond to raising and lowering operation by manual operation of the mowing lift lever 35, respectively. "Auto-lift in progress" refers to automatic raising of the mowing unit 5 by operation of the mowing autolift switch 36. "Auto-set in progress" refers to automatic lowering of the mowing unit 5 by operation of the mowing autoset switch 37. "The mowing height adjustment dial has been moved" refers to the target mowing height being changed by operation of the mowing height adjustment dial 202.

[0159] In step S10, if it is determined that any one of the above conditions is satisfied (S10, Yes), the calculation / update of the standard mowing height is not performed, and the following process is performed. That is, the standard mowing height is not set (not set), the value stored in the buffer, that is, the value of the height relative to the machine body stored in the control device 200 up to that point, is cleared, the lifting / lowering stop time is reset to 0 (S20), and the process ends. In the control process related to the standard mowing height, the control device 200 constantly measures the time during which the mowing unit 5 is not lifted or lowered as the lifting / lowering stop time based on the control signal to the control valve of the mowing lifting cylinder 18, etc.

[0160] On the other hand, if it is determined in step S10 that none of the above conditions are met (S10, No), it is determined whether the standard mowing height has not been set (S30). If it is determined in step S30 that the standard mowing height has not been set (S30, Yes), it is determined whether the following conditions are met: "Mowing distance is equal to or greater than a certain level," "Straight-line vehicle speed of the machine is equal to or greater than a certain level," "Vertical transport stalk detection sensor is ON," and "Mowing height is within the target range of automatic mowing height control" (S40).

[0161] In step S40, "the mowing distance is equal to or greater than a certain distance" means that the travel distance of the combine harvester 1 after the start of mowing is equal to or greater than a predetermined distance set in advance. The travel distance is calculated based on the detection information of the vehicle speed sensor 201 and the time elapsed information as described above. "The straight-line vehicle speed of the machine is equal to or greater than a certain distance" means that the vehicle speed detected by the vehicle speed sensor 201 when the machine is moving straight is equal to or greater than a predetermined speed set in advance.

[0162] Also in step S40, "vertical transport culm detection sensor = ON" means that the culm detection sensor 204 (see FIG. 10) that detects the presence or absence of culms cut by the reaping unit 5 is in the ON state. The culm detection sensor 204 is, for example, a contact sensor that is arranged in the reaping unit 5 with respect to the transport path of vertical transport by the culm transport device 25 and detects the presence or absence of culms based on the presence or absence of contact with the culms. However, the type of the culm detection sensor 204 is not limited. The detection signal of the culm detection sensor 204 is input to the control device 200. The culm detection sensor 204 being in the ON state means that the culms cut by the reaping unit 5 are being transported by the culm transport device 25, which corresponds to reaping work being performed.

[0163] Also in step S40, "the mowing height is within the target range of the automatic mowing height control" means that when the mowing height target value is set to a value within a predetermined range in the automatic mowing height control, the mowing height (height above the ground) detected by the mowing height detection device 40 is within the range of the mowing height target value (within the dead zone). When this condition is met, the lifting and lowering of the mowing unit 5 is stopped in the automatic mowing height control.

[0164] In step S40, if it is not determined that all of the above conditions are met (S40, No), that is, if at least one of the above conditions is not satisfied, the process ends.

[0165] On the other hand, in step S40, if it is determined that all of the above conditions are met (S40, Yes), the current (at that time) machine-to-machine height is stored in a buffer (S50), and the mowing reference height is calculated as the average value of the machine-to-machine height values ​​stored in the control device 200 up to that point (S60). The mowing reference height calculated here is updated as the mowing reference height used in the lifting range limit control. This ends the process.

[0166] Returning to step S30, if it is not determined that the standard mowing height has not been set (S30, No), that is, if a predetermined value has been set as the standard mowing height, a determination is made as to whether the following conditions are met: That is, a determination is made as to whether all of the following conditions are met: "the straight-line vehicle speed of this machine is equal to or greater than a certain value," "the mowing height is equal to or less than a certain value," "the mowing height is within the target range of the automatic mowing height control," "the height relative to the machine body is lower than the prohibited height for ascent," and "the height relative to the machine body is higher than the prohibited height for descent" (S70).

[0167] In step S70, "the cutting height is equal to or less than a certain level" means that the cutting height (height relative to the ground) detected by the cutting height detection device 40 is equal to or less than a predetermined cutting height set in advance. This condition is intended to exclude, for example, a state in which the cutting height detection device 40 is completely lifted off the ground 30 (a state in which the grounding body 42 is not on the ground). Furthermore, "the height relative to the machine body is lower than the prohibited ascent height" means that the height relative to the machine body detected by the height relative to the machine body sensor 203 is lower than the prohibited ascent height H1 in the above-mentioned lift range limit control, and "the height relative to the machine body is higher than the prohibited descent height" means that the height relative to the machine body is higher than the prohibited descent height H2 in the lift range limit control.

[0168] In step S70, if it is determined that all of the above conditions are satisfied (S70, Yes), the count-up of the lifting / lowering stop time is started (S80). Then, it is determined whether the lifting / lowering stop time is equal to or longer than a certain time (S90), and if it is determined that the lifting / lowering stop time is equal to or longer than the certain time (S90, Yes), the current machine-to-body height is stored in the buffer, and the lifting / lowering stop time is reset to 0 (S100). That is, when the height of the cutting unit 5 is within the range of the prohibited height of the lifting / lowering range limit control while traveling at a certain vehicle speed or higher, and is within the dead zone of the automatic mowing height control for a certain period of time, the machine-to-body height at that time is stored. Then, the mowing reference height is calculated as the average value of the machine-to-body height values ​​stored in the control device 200 up to that point (S60). In step S70, if it is not determined that all of the above conditions are satisfied (S40, No), the count-up of the lifting / lowering stop time is not started, and the process proceeds to step S90.

[0169] In step S90, if it is not determined that the lift stop time is equal to or longer than the certain time (S90, No), the mowing reference height is calculated as the average value of the values ​​of the heights relative to the machine body stored in the control device 200 up to that point (S60), and the mowing reference height is updated. In other words, unless the lift stop time has elapsed for a certain time in step S90, the height relative to the machine body at that point in time is not stored, and the average value of the heights relative to the machine body from the stored information up to that point is calculated as the mowing reference height. The certain time in step S90 is, by way of example only, about one second to several seconds.

[0170] Through the series of control processes described above, the reference mowing height in the lifting range limit control is calculated and updated.

[0171] According to the combine harvester 1 having the above-described configuration and the control method for the combine harvester 1, it is possible to prevent the cutting part 5 from contacting or crashing into the ground, and also to prevent the cutting part from leaving any grass uncut.

[0172] In the automatic mowing height control, for example, when the mowing unit 5 approaches a depression in the ground, the ground detected by the mowing height detection device 40 is partially lowered, and the height of the mowing unit 5 from the ground (height above the ground) is erroneously recognized as being higher. In such a case, the lowering control of the mowing unit 5 is activated, and there is a possibility that the grass dividing board 21 of the mowing unit 5 will plunge into the ground.

[0173] In order to prevent such malfunction, for example, a lifting control may be considered in which the height of the mowing unit with respect to the machine body when the lifting control of the mowing unit is activated is stored, and when the height of the mowing unit with respect to the machine body falls below the stored height of the machine body (the height at which lowering is prohibited) during automatic mowing height control, the lowering control of the mowing unit is prohibited. However, such a lifting control has the following problems.

[0174] As shown in FIG. 19A, for example, when the combine harvester 1 enters a field, the combine harvester 1 may be positioned on a downwardly inclined slope 211 continuing from a flat field 210, causing the machine body to tilt forward and the reaping unit 5 to be positioned above the field 210. In such a state, when the reaping unit 5 is raised by the detection of the cutting height detection device 40, the machine body height becomes higher than the machine body height that should be detected because the inclined surface 211 is located above the field 210, and this value is stored as the prohibited lowering height. In such a case, as shown in FIG. 19B, during reaping work in the flat field 210, the prohibited lowering height stored as a height higher than necessary makes it impossible to position the reaping unit 5 at the target reaping height.

[0175] Also, as shown in Fig. 20A, at the beginning of the mowing work (start of mowing), for example, if the mowing height detection device 40 hits the crop 212 in the field, the mowing height detection device 40 may detect the crop 212 and cause the ascent control to be activated before the mowing unit 5 reaches the target height. In such a case, as shown in Fig. 20B, that height may be erroneously stored as the prohibited lowering height, and the mowing unit 5 may not be positioned at the target mowing height. Also, not only at the start of mowing, but even during the mowing work, there is a possibility that the mowing height detection device 40 may run over the crop 212, causing the ascent control to be activated unintentionally.

[0176] Therefore, in the combine harvester 1 according to this embodiment, as the lifting and lowering control of the reaping unit 5, from the start of the control, the lifting and lowering range limiting control is disabled for a certain section defined based on at least one of the travel distance, elapsed time, and an increase in vehicle speed of the traveling machine body 4, and automatic mowing height control is performed. In other words, from the start of mowing, after performing mowing work for a certain period with the automatic mowing height control being performed, the lifting and lowering range limiting control is started.

[0177] According to this configuration, when the field is stable, it is possible to perform stable mowing work, prevent the mowing unit 5 from contacting or crashing into the ground, and prevent mowing problems such as leaving grass uncut. In other words, when the attitude of the machine body is unstable, the lifting range limiting control that limits the lifting range of the mowing unit 5 is not performed, and automatic mowing height control is performed by the mowing height detection device 40 in a state where the lifting range of the mowing unit 5 is not restricted, and when the machine body becomes stable (for example, when the vehicle speed becomes relatively high), the lifting range limiting control is started, thereby making it possible to prevent the mowing unit 5 from contacting or crashing into the ground, for example, when the mowing height detection device 40 detects an uneven portion of the field.

[0178] In addition, by performing lifting range limiting control in parallel with the automatic mowing height control, a no-descent height can be set for the lifting range of the cutting unit 5, thereby preventing the cutting unit 5 from running into a depression in the ground, for example, and by setting a no-ascent height for the lifting range of the cutting unit 5, it is possible to prevent the cutting unit 5 from rising due to running over crops.

[0179] The height relative to the harvester, which is the basis for the prohibited lowering height and prohibited ascent height, is calculated, updated, and stored as the standard mowing height each time a specific condition is satisfied during the mowing operation. By performing the above-mentioned invalid control of the lift range limit control at the start of mowing, it is possible to prevent an erroneous value from being stored when the combine harvester 1 enters the field or when mowing begins, and it is possible to track the height of the mowing unit 5 to the target height.

[0180] In addition, when calculating and updating the standard mowing height, the average value of the heights relative to the machine that have been stored as the standard mowing height up to that point is used as the standard mowing height. With this configuration, even if an unusual value is stored as the standard mowing height due to unevenness of the ground, the average value can be used to smooth out the value and reduce the influence of the unusual stored value. This effectively prevents the mowing unit 5 from crashing into the ground or leaving grass uncut, improving the operability of the mowing unit 5.

[0181] The above-described embodiment is an example of the present invention, and the present invention is not limited to the above-described embodiment. Therefore, even if it is not the above-described embodiment, various modifications are possible according to the design, etc., as long as they do not deviate from the technical idea of ​​the present invention. In addition, the effects described in this disclosure are merely examples and are not limited, and other effects may be present.

[0182] The present technology can have the following configurations. Note that the configurations described below can be selected and combined as desired. (1) A combine harvester comprising: a cutting section that is provided so as to be raised and lowered with respect to a traveling machine body; a cutting height detection device for detecting a cutting height, which is the height of the cutting section relative to the ground; a machine-to-machine height detection device for detecting a machine-to-machine height, which is the height of the cutting section relative to the traveling machine body; and a control device for controlling the height of the cutting section based on detection signals from the cutting height detection device and the machine-to-machine height detection device, The control device includes: A cutting height control that controls the height of the cutting unit so that the cutting height detected by the cutting height detection device becomes a predetermined target value; and performing a lifting range limiting control for limiting the lifting range of the reaping unit to a range of a predetermined amount of ascent and descent with respect to a reaping reference height, which is a reference value for the machine body height detected by the machine body height detection device. The lift range limit control is disabled from the start of the control until the travel distance of the traveling machine body reaches a predetermined distance or until a predetermined time has elapsed. A combine harvester characterized by the above. (2) A combine harvester comprising: a cutting section that is provided so as to be raised and lowered with respect to a traveling machine body; a cutting height detection device for detecting a cutting height, which is the height of the cutting section relative to the ground; a machine-to-machine height detection device for detecting a machine-to-machine height, which is the height of the cutting section relative to the traveling machine body; and a control device for controlling the height of the cutting section based on detection signals from the cutting height detection device and the machine-to-machine height detection device, The control device includes: A cutting height control that controls the height of the cutting unit so that the cutting height detected by the cutting height detection device becomes a predetermined target value; and performing a lifting range limiting control for limiting the lifting range of the reaping unit to a range of a predetermined amount of ascent and descent with respect to a reaping reference height, which is a reference value for the machine body height detected by the machine body height detection device. The lift range limit control is disabled from the start of the control until the vehicle speed of the traveling machine body reaches a predetermined speed. A combine harvester characterized by the above. (3) The control device includes: The mowing reference height is calculated as an average value of the heights relative to the machine body stored at each predetermined time, and is updated at each predetermined time. The combine harvester according to (1) or (2), characterized in that (4) A method for controlling a combine harvester, comprising: detecting a cutting height, which is the height of a cutting unit relative to the ground, and a machine-to-body height, which is the height of the cutting unit relative to a traveling machine body; and controlling the height of the cutting unit based on the detected cutting height and machine-to-body height, A cutting height control that controls the height of the cutting unit so that the detected cutting height becomes a predetermined target value; and a lifting / lowering range limiting control that limits the lifting / lowering range of the reaping unit to a range of a predetermined amount of lifting and a predetermined amount of lowering with respect to a reference reaping height, which is a reference value for the height relative to the machine body. The lift range limit control is disabled from the start of the control until the travel distance of the traveling machine body reaches a predetermined distance or until a predetermined time has elapsed. A method for controlling a combine harvester. (5) A method for controlling a combine harvester, comprising: detecting a cutting height, which is the height of a cutting unit relative to the ground, and a machine-to-body height, which is the height of the cutting unit relative to a traveling machine body; and controlling the height of the cutting unit based on the detected cutting height and machine-to-body height, A cutting height control that controls the height of the cutting unit so that the detected cutting height becomes a predetermined target value; and a lifting / lowering range limiting control that limits the lifting / lowering range of the reaping unit to a range of a predetermined amount of lifting and a predetermined amount of lowering with respect to a reference reaping height, which is a reference value for the height relative to the machine body. The lift range limit control is disabled from the start of the control until the vehicle speed of the traveling machine body reaches a predetermined speed. A method for controlling a combine harvester. (6) The mowing reference height is calculated as an average value of the heights relative to the machine body stored at each predetermined time, and is updated at each predetermined time. The method for controlling a combine harvester according to (4) or (5) above. [Explanation of symbols]

[0183] 1. Combine Harvester 4 Running body 5 Reaping section 40 Cutting height detection device 43 Cutting height sensor 200 Control device 201 Vehicle speed sensor 202 Mowing height adjustment dial 203 Aircraft height sensor (aircraft height detection device)

Claims

1. A combine harvester comprising: a cutting section that is provided so as to be raised and lowered with respect to a traveling machine body; a cutting height detection device for detecting a cutting height, which is the height of the cutting section relative to the ground; a machine-to-machine height detection device for detecting a machine-to-machine height, which is the height of the cutting section relative to the traveling machine body; and a control device for controlling the height of the cutting section based on detection signals from the cutting height detection device and the machine-to-machine height detection device, The control device includes: A cutting height control that controls the height of the cutting unit so that the cutting height detected by the cutting height detection device becomes a predetermined target value; and performing a lifting range limiting control for limiting the lifting range of the reaping unit to a range of a predetermined amount of ascent and descent with respect to a reaping reference height, which is a reference value for the machine body height detected by the machine body height detection device. The lift range limit control is disabled from the start of the control until the travel distance of the traveling machine body reaches a predetermined distance or until a predetermined time has elapsed. A combine harvester characterized by the above.

2. A combine harvester comprising: a cutting section that is provided so as to be raised and lowered with respect to a traveling machine body; a cutting height detection device for detecting a cutting height, which is the height of the cutting section relative to the ground; a machine-to-machine height detection device for detecting a machine-to-machine height, which is the height of the cutting section relative to the traveling machine body; and a control device for controlling the height of the cutting section based on detection signals from the cutting height detection device and the machine-to-machine height detection device, The control device includes: A cutting height control that controls the height of the cutting unit so that the cutting height detected by the cutting height detection device becomes a predetermined target value; and performing a lifting range limiting control for limiting the lifting range of the reaping unit to a range of a predetermined amount of ascent and descent with respect to a reaping reference height, which is a reference value for the machine body height detected by the machine body height detection device. The lift range limit control is disabled from the start of the control until the vehicle speed of the traveling machine body reaches a predetermined speed. A combine harvester characterized by the above.

3. The control device includes: The mowing reference height is calculated as an average value of the heights relative to the machine body stored at each predetermined time, and is updated at each predetermined time. The combine harvester according to claim 1 or 2.

4. A method for controlling a combine harvester, comprising: detecting a cutting height, which is the height of a cutting unit relative to the ground, and a machine-to-body height, which is the height of the cutting unit relative to a traveling machine body; and controlling the height of the cutting unit based on the detected cutting height and machine-to-body height, A cutting height control that controls the height of the cutting unit so that the detected cutting height becomes a predetermined target value; and a lifting / lowering range limiting control that limits the lifting / lowering range of the reaping unit to a range of a predetermined amount of lifting and a predetermined amount of lowering with respect to a reference reaping height, which is a reference value for the height relative to the machine body. The lift range limit control is disabled from the start of the control until the travel distance of the traveling machine body reaches a predetermined distance or until a predetermined time has elapsed. A method for controlling a combine harvester.

5. A method for controlling a combine harvester, comprising: detecting a cutting height, which is the height of a cutting unit relative to the ground, and a machine-to-body height, which is the height of the cutting unit relative to a traveling machine body; and controlling the height of the cutting unit based on the detected cutting height and machine-to-body height, A cutting height control that controls the height of the cutting unit so that the detected cutting height becomes a predetermined target value; and a lifting / lowering range limiting control that limits the lifting / lowering range of the reaping unit to a range of a predetermined amount of lifting and a predetermined amount of lowering with respect to a reference reaping height, which is a reference value for the height relative to the machine body. The lift range limit control is disabled from the start of the control until the vehicle speed of the traveling machine body reaches a predetermined speed. A method for controlling a combine harvester.

6. The mowing reference height is calculated as an average value of the heights relative to the machine body stored at each predetermined time, and is updated at each predetermined time. The method for controlling a combine harvester according to claim 4 or 5.

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