Sugar cane harvester

Abstract

To provide a sugar cane configured to easily cut the parts closer to a field at a root of a crop by a cutting device by suppressing a risk of the cutting device coming into contact with the field when driving on a slope field.SOLUTION: A harvester includes: a cutting device for cutting a root of a crop on a field; and double-working right-left front wheel vertically movable cylinders 21, 22 which perform a vertical operation of right-left front wheels with respect to a vehicle body. There are also provided: a supply oil path 71 in which a work fluid of the hydraulic pump 52 is supplied; and right-left front wheel supply oil path 31, 32 in which the work fluid of the supply oil path 71 is supplied. Right-left front wheel vertical movement control valves 41, 42 are provided for supplying and discharging the work fluid of the right-left front wheel supply oil paths 31, 32 to and from the right-left front wheel vertically movable cylinders 21, 22.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a configuration for lifting and lowering the front wheels of a sugarcane harvester. [Background technology]

[0002] As disclosed in Patent Document 1, some sugarcane harvesters are equipped with a cutting device on the machine body that cuts the base of crops in the field, and right and left lifting cylinders that raise and lower the right and left front wheels on the machine body. Hydraulic oil is supplied in parallel to the right and left lifting cylinders from a single lifting control valve, causing the right and left lifting cylinders to extend and retract. The right and left front wheels are raised and lowered, causing the machine body to be raised and lowered, thereby changing the height of the cutting device relative to the field.

[0003] In a sugarcane harvester, the crop is cut by a cutting device and becomes the harvested product. Therefore, in order to harvest the crop without waste, it is necessary to cut the part of the base of the crop close to the field using the cutting device. In this case, there is a high possibility that the cutting device will come into contact with the field, and if it does come into contact with the field, a large load will be placed on the cutting device, so as mentioned above, it is necessary to raise and lower the front wheels (machine body) to set the cutting device to an appropriate height above the field. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 20231-40561 (see FIG. 9) Summary of the Invention [Problem to be solved by the invention]

[0005] For example, if the field is inclined left or right relative to the forward direction of the machine, when the machine tilts downward along the slope of the field, the machine's own weight may cause it to tilt further downward, and the cutting device may no longer be parallel to the field. When the above-described situation occurs, the possibility of the cutting device coming into contact with the field increases, making it difficult for the cutting device to cut the part of the base of the crop that is close to the field, so there is room for improvement.

[0006] The present invention aims to configure a sugarcane harvester so that, when traveling on a sloping field, the possibility of the cutting device coming into contact with the field is reduced, and the cutting device is more likely to cut the part of the base of the crop that is closest to the field. [Means for solving the problem]

[0007] The sugarcane harvester of the present invention comprises a body having right and left front wheels, a cutting device mounted on the body and configured to cut the base of crops in a field, a double-acting right front wheel lifting cylinder for raising and lowering the right front wheel relative to the body, a double-acting left front wheel lifting cylinder for raising and lowering the left front wheel relative to the body, a hydraulic pump, a supply oil line to which hydraulic oil from the hydraulic pump is supplied, a right front wheel supply oil line to which hydraulic oil from the supply oil line is supplied, a left front wheel supply oil line to which hydraulic oil from the supply oil line is supplied, a right front wheel lifting control valve that supplies and discharges hydraulic oil from the right front wheel supply oil line to the right front wheel lifting cylinder to extend and retract the right front wheel lifting cylinder, and a left front wheel lifting control valve that supplies and discharges hydraulic oil from the left front wheel supply oil line to the left front wheel lifting cylinder to extend and retract the left front wheel lifting cylinder.

[0008] For example, if a field slopes downward to the right relative to the forward direction of the machine, and the machine tilts downward to the right along the slope of the field, the center of gravity of the machine will shift to the right. When the center of gravity of the machine shifts to the right, the load on the right lift cylinder increases and the load on the left lift cylinder decreases.

[0009] In a configuration in which hydraulic oil is supplied in parallel to the right and left lift cylinders from a single lift control valve, if a difference in the load on the right and left lift cylinders occurs as described above, it is thought that hydraulic oil will have difficulty flowing to the lift cylinder with the greater load and will flow more easily to the lift cylinder with the lesser load, resulting in a difference in length between the right and left lift cylinders. As a result, when the machine body tilts downward along the slope of the field, it is thought that the machine body's own weight will cause it to tilt further downward along the slope of the field.

[0010] According to the present invention, there are provided right and left front wheel lift cylinders for lifting and lowering the right and left front wheels, and right and left front wheel lift control valves. Hydraulic oil from a hydraulic pump is supplied from a supply oil passage to right and left front wheel supply oil passages, and the hydraulic oil in the right and left front wheel supply oil passages is supplied to and discharged from the right and left front wheel lift cylinders via the right and left front wheel lift control valves.

[0011] As a result, the right front wheel lifting cylinder and right front wheel lifting control valve are independent of the left front wheel lifting cylinder and left front wheel lifting control valve, so even if a difference occurs in the loads applied to the right and left front wheel lifting cylinders, the right and left front wheels can be lifted and lowered independently of each other without being affected by the difference in load.

[0012] According to the present invention, for example, on a level field, the right and left front wheels are raised and lowered so that the cutting device is set parallel to the field and at an appropriate height above the field. For example, when the field slopes downward to the right relative to the forward direction of the machine body and the machine body slopes downward to the right along the slope of the field, the right front wheel may be operated to lower relative to the machine body, the left front wheel may be operated to raise relative to the machine body, or the right front wheel may be operated to lower relative to the machine body and the left front wheel may be operated to raise relative to the machine body. For example, when the field slopes downward to the left relative to the forward direction of the machine body and the machine body slopes downward to the left along the slope of the field, the left front wheel may be operated to lower relative to the machine body, the right front wheel may be operated to raise relative to the machine body, or the left front wheel may be operated to lower relative to the machine body and the right front wheel may be operated to raise relative to the machine body.

[0013] This allows the cutting device to be set at an appropriate height above the field in a position parallel to the field (or close to parallel).The right and left front wheel lifting cylinders are configured as double-acting, so that the right and left front wheel lifting cylinders can be smoothly extended and retracted even when the machine body is tilted to the right or left on a sloped field as described above.

[0014] As described above, according to the present invention, in a sloping field, the cutting device can be more easily set to a position parallel to the field in the left-right direction (a position close to parallel), and can be more easily set at an appropriate height above the field, thereby reducing the possibility of the cutting device coming into contact with the field and making it easier for the cutting device to cut the part of the base of the crop that is closest to the field, thereby improving the harvesting performance of the sugarcane harvester.

[0015] In the present invention, it is preferable that the machine body is provided with a conveying device that conveys and releases from the machine body the crops that have been harvested after the base of the plant has been cut by the cutting device, and that the machine body is provided with a conveying lifting cylinder that raises and lowers the conveying device, a conveying lifting supply oil line to which the hydraulic oil of the supply oil line is supplied, and a conveying lifting control valve that supplies and discharges the hydraulic oil of the conveying lifting supply oil line to the conveying lifting cylinder, thereby extending and contracting the conveying lifting cylinder.

[0016] The sugarcane harvester is equipped with a conveying device that conveys and releases the harvested crop, which has been cut at the base by the cutting device, onto the carrier of a transport vehicle traveling alongside the sugarcane harvester. In this case, the conveying device must be set to an appropriate height depending on the height of the carrier of the transport vehicle.

[0017] According to the present invention, a conveying lift cylinder for lifting the conveying device and a conveying lift control valve are provided. Hydraulic oil from a hydraulic pump is supplied from a supply oil line to a conveying lift supply oil line, and the hydraulic oil in the conveying lift supply oil line is supplied to and discharged from the conveying lift cylinder via the conveying lift control valve. As a result, the conveying device is raised and lowered independently of the right and left front wheels by the conveying lifting cylinder and conveying lifting control valve, so the conveying device can be set to an appropriate height regardless of the lifting and lowering operation of the right and left front wheels, which is advantageous in terms of improving the harvesting performance of the sugarcane harvester.

[0018] In the present invention, a switching valve is provided that can be switched between a first position in which the hydraulic oil in the supply oil passage is supplied to the front wheel supply oil passage and a second position in which the hydraulic oil in the supply oil passage is supplied to the conveying lifting supply oil passage, and it is preferable that the switching valve is operated to the first position when the conveying lifting control valve is operated to a neutral position in which the conveying lifting cylinder is stopped, and is operated to the second position when the conveying lifting control valve is operated to an operating position in which the conveying lifting cylinder operates to extend and retract.

[0019] In a sugarcane harvester, the transport device transports a large amount of crops, so the weight of the large amount of crops is placed on the transport lifting cylinder. The weight of the machine body is placed on the front wheel lifting cylinder.

[0020] According to the present invention, when the conveying lifting control valve is operated to the neutral position (when the conveying lifting cylinder stops), the switching valve is operated to the first position, and hydraulic oil is not supplied to the conveying lifting control valve and the conveying lifting cylinder, but hydraulic oil is supplied to the front wheel lifting control valve and the front wheel lifting cylinder, allowing the front wheel lifting cylinder to extend and retract. When the conveying lifting control valve is operated to the operating position, the switching valve is operated to the second position, and hydraulic oil is not supplied to the front wheel lifting control valve and the front wheel lifting cylinder, but hydraulic oil is supplied to the conveying lifting control valve and the conveying lifting cylinder, allowing the conveying lifting cylinder to extend and retract.

[0021] This allows either the front wheel lifting cylinder or the transport lifting cylinder to operate in an extending or retracting manner, and prevents both the front wheel lifting cylinder and the transport lifting cylinder from operating in an extending or retracting manner at the same time, thereby avoiding problems such as a shortage of hydraulic oil caused by both the front wheel lifting cylinder and the transport lifting cylinder operating in an extending or retracting manner at the same time.

[0022] In the present invention, it is preferable that an unloading valve operable to an unloading position for discharging hydraulic oil from the switching valve operated to the first position is provided.

[0023] In a sugarcane harvester, the transport device transports a large amount of crops while being loaded with them, so maintenance work on the transport device is performed relatively frequently.

[0024] According to the present invention, when maintenance work is being performed on the transport device, the unload valve is operated to the unload position, so that the front wheel lifting cylinder can be stopped. As a result, when maintenance work is being performed on the conveying device, the front wheel lifting cylinder is stopped and the lifting and lowering operation of the conveying device for maintenance work is performed by the conveying lifting cylinder, thereby improving the workability of maintenance work on the conveying device.

[0025] In the present invention, it is preferable that a conveying device is provided on the machine body, which conveys and releases crops harvested after the base of the plant has been cut by the cutting device to the outside of the machine body, and that the machine body is provided with a conveying direction cylinder which operates to change the direction of the conveying device to the right and left, a conveying direction supply oil line to which hydraulic oil from the supply oil line is supplied, and a conveying direction control valve which operates to supply and discharge hydraulic oil from the conveying direction supply oil line to the conveying direction cylinder, thereby extending and retracting the conveying direction cylinder.

[0026] The sugarcane harvester is equipped with a transport device that transports and releases the harvested crop, which has been cut at the base by the cutting device, onto the carrier of a transport vehicle traveling alongside the sugarcane harvester. In this case, the transport device must be set in an appropriate direction depending on the position of the transport vehicle relative to the sugarcane harvester.

[0027] According to the present invention, a conveying direction cylinder for changing the direction of the conveying device and a conveying direction control valve are provided. Hydraulic oil from a hydraulic pump is supplied from a supply oil passage to a conveying direction supply oil passage, and the hydraulic oil from the conveying direction supply oil passage is supplied to or discharged from the conveying direction cylinder via the conveying direction control valve.

[0028] As a result, the direction of the conveying device is changed and operated independently of the right and left front wheels by the conveying direction cylinder and conveying direction control valve, so the conveying device can be set to an appropriate direction regardless of the lifting and lowering operation of the right and left front wheels, which is advantageous in terms of improving the harvesting performance of the sugarcane harvester.

[0029] In the present invention, it is preferable to provide a right divider that separates crops in the field into crops to be harvested and other crops, and a left divider that separates crops in the field into crops to be harvested and other crops, a right separation lifting cylinder that raises and lowers the right divider, a left separation lifting cylinder that raises and lowers the left divider, a right separation supply oil passage to which hydraulic oil from the supply oil passage is supplied, a left separation supply oil passage to which hydraulic oil from the supply oil passage is supplied, a right separation lifting control valve that supplies and discharges hydraulic oil from the right separation supply oil passage to the right separation lifting cylinder, thereby extending and retracting the right separation lifting cylinder, and a left separation lifting control valve that supplies and discharges hydraulic oil from the left separation supply oil passage to the left separation lifting cylinder, thereby extending and retracting the left separation lifting cylinder.

[0030] Sugarcane harvesters are equipped with right and left dividers that separate the crop to be harvested from other crops in the field, and in this case, the right and left dividers must be set to appropriate heights depending on the condition of the crops in the field.

[0031] According to the present invention, there are provided right and left separation lift cylinders for lifting and lowering the right and left dividers, and right and left separation lift control valves. Hydraulic oil from a hydraulic pump is supplied from a supply oil passage to the right and left separation supply oil passages, and the hydraulic oil in the right and left separation supply oil passages is supplied to and discharged from the right and left separation lift cylinders via the right and left separation lift control valves.

[0032] As a result, the right and left dividers are raised and lowered independently of the right and left front wheels by the separation lifting cylinder and separation lifting control valve, so that the right and left dividers can be set to an appropriate height regardless of the lifting and lowering operation of the right and left front wheels, which is advantageous in terms of improving the harvesting performance of the sugarcane harvester. The right separation lifting cylinder and right separation lifting control valve are independent of the left separation lifting cylinder and left separation lifting control valve, and the right and left dividers are raised and lowered independently of each other, and each of the right and left dividers is set to an appropriate height, which is advantageous in terms of improving the harvesting performance of the sugarcane harvester.

[0033] In the present invention, it is preferable that the machine body is provided with an upper cutting device that cuts the upper parts of crops in the field, a cutting lifting cylinder that raises and lowers the upper cutting device, a cutting lifting supply oil line to which hydraulic oil from the supply oil line is supplied, and a cutting lifting control valve that supplies and discharges hydraulic oil from the cutting lifting supply oil line to the cutting lifting cylinder, thereby extending and retracting the cutting lifting cylinder.

[0034] Sugarcane harvesters are equipped with an upper cutting device that cuts the top of the crop in the field. In this case, the upper cutting device needs to be set to an appropriate height depending on the height of the crop in the field.

[0035] According to the present invention, a cutting lift cylinder for lifting the upper cutting device and a cutting lift control valve are provided. Hydraulic oil from a hydraulic pump is supplied from a supply oil passage to a cutting lift supply oil passage, and the hydraulic oil in the cutting lift supply oil passage is supplied to and discharged from the cutting lift cylinder via the cutting lift control valve.

[0036] As a result, the upper cutting device is raised and lowered independently of the right and left front wheels by the cutting lifting cylinder and cutting lifting control valve, so the upper cutting device can be set to an appropriate height regardless of the lifting and lowering operation of the right and left front wheels, which is advantageous in terms of improving the harvesting performance of the sugarcane harvester.

[0037] In the present invention, it is preferable to provide a load sensor that detects the load on the cutting device, and a lifting control unit that, when the detected value of the load sensor becomes higher than a preset upward setting value, operates the right and left front wheel lifting control valves and activates the right and left front wheel lifting cylinders to lift the machine body.

[0038] According to the present invention, the cutting device is provided with a load sensor that detects the load applied to the cutting device, and a lifting control unit. As the cutting device cuts the part of the crop plant base close to the field surface, the cutting device comes into contact with the field surface more often, and if a large load is placed on the cutting device, when the load sensor detection value becomes higher than the upper set value, the right and left front wheels are lowered relative to the machine body by the right and left front wheel lifting cylinders, and the machine body and cutting device are raised.

[0039] This reduces the amount of contact the cutting device with the field surface, reducing the load on the cutting device and preventing damage caused by excessive load on the cutting device. Reduced contact of the cutting device with the field surface also reduces wear on the cutting device.

[0040] In the present invention, it is preferable to provide an inclination sensor that detects the inclination angle of the aircraft in the left-right direction relative to the horizontal plane, a setting unit that can set and change the set inclination angle in the left-right direction relative to the horizontal plane, and an inclination control unit that operates at least one of the right and left front wheel lifting / lowering control valves and activates at least one of the right and left front wheel lifting / lowering cylinders based on the detection value of the inclination sensor so that the inclination angle becomes the set inclination angle.

[0041] According to the present invention, an inclination sensor for detecting the inclination angle in the left-right direction relative to the horizontal plane of the aircraft body, a setting unit, and an inclination control unit are provided. For example, in a horizontal field, when the set tilt angle is set to a value parallel to the horizontal plane, the front wheels are automatically raised and lowered by the front wheel lifting cylinder based on the detection value of the tilt sensor, and the machine body is maintained in a horizontal position in the left-right direction (a position parallel to the field in the left-right direction). For example, in a sloping field, when the set tilt angle is set to a value parallel to the field, the front wheels are automatically raised and lowered by the front wheel lifting cylinder based on the detection value of the tilt sensor, and the machine body is maintained in a position parallel to the field in the left-right direction. This allows the cutting device to be automatically maintained in a position parallel to the field in the left-right direction, which is advantageous in terms of improving the harvesting performance of the sugarcane harvester. [Brief explanation of the drawings]

[0042] [Figure 1] FIG. 2 is a left side view of the sugarcane harvester. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. 2 is a schematic diagram showing the entire hydraulic circuit. [Figure 5] FIG. 2 is a diagram illustrating the vicinity of a switching valve and an unloading valve in a hydraulic circuit. [Figure 6] 10A and 10B are diagrams illustrating an outline of the lifting and lowering operations of the right and left front wheels. DETAILED DESCRIPTION OF THE INVENTION

[0043] Figures 1 to 6 show a sugarcane harvester, and in Figures 1 to 6, F indicates the forward direction, B indicates the backward direction, U indicates the upward direction, D indicates the downward direction, R indicates the rightward direction, and L indicates the leftward direction.

[0044] (Overall configuration of sugarcane harvester) As shown in Figure 1, the reaping unit 3 and the first conveying device 4 are connected to form the machine body 10, and the first conveying device 4 extends diagonally upward and rearward from the rear of the reaping unit 3.

[0045] A right front wheel 1 and a left front wheel 2 are provided on the right and left parts of the reaping unit 3. An upper cutting device 7 is provided on the top of the reaping unit 3 and is positioned above and in front of the reaping unit 3. Right and left rear wheels 8 are provided on the lower part of the rear part of the first conveying device 4, and the machine body 10 is supported by the front wheels 1, 2 and the rear wheels 8.

[0046] The sorting device 5 is provided in the vertical direction at the rear of the first conveying device 4, and the second conveying device 6 extends diagonally upward from the bottom of the sorting device 5. A driving unit 9 is provided at the top of the reaping unit 3, and an engine 19 is provided at the top of the front part of the first conveying device 4.

[0047] (Configuration of reaping unit 3) As shown in FIGS. 1 and 2, the reaping unit 3 has right and left cutters 11, 12, right dividers 13, 14, left dividers 15, 16, a tipping roller 17, and right and left side wall units 18.

[0048] Right and left side wall portions 18 are provided along the front-to-rear direction, and the rear portions of the side wall portions 18 are connected to the front portion of the first conveying device 4. A right front wheel 1 is provided on the right side wall portion 18, and a left front wheel 2 is provided on the left side wall portion 18.

[0049] The right and left cutters 11, 12 are arranged side by side in the left-right direction at the bottom of the rear part between the right and left side wall parts 18. The laying roller 17 is arranged at the top of the front part between the right and left side wall parts 18, and is driven to rotate by a hydraulic motor 28 around an axis P7 that extends in the left-right direction.

[0050] The right dividers 13, 14 are provided in front of the right lateral wall portion 18. The right dividers 13, 14 are driven to rotate by a hydraulic motor 24 around axes P3, P4 along the longitudinal direction of the dividers 13, 14.

[0051] The left dividers 15, 16 are provided in front of the left lateral wall portion 18. The left dividers 15, 16 are driven to rotate by a hydraulic motor 24 around axes P5, P6 along the longitudinal direction of the dividers 15, 16.

[0052] (Configuration of right and left cutters 11, 12) As shown in FIGS. 2 and 3, the right and left cutters 11 and 12 have shaft portions 11a and 12a, disk portions 11b and 12b, and cutting blades 11c and 12c.

[0053] A transmission case 29 is connected across the right and left side wall portions 18. Shaft portions 11a, 12a are attached to the transmission case 29 and extend downward so as to be rotatable around axes P1, P2 that extend in the up-down direction. Disc portions 11b, 12b are attached to the lower portions of the shaft portions 11a, 12a, and multiple cutting blades 11c, 12c are attached to the outer peripheries of the disc portions 11b, 12b.

[0054] A hydraulic motor 34 is attached to the transmission case 29, and the power of the hydraulic motor 34 is transmitted to the shafts 11a and 12a via a transmission gear (not shown) inside the transmission case 29. The hydraulic motor 34 rotates the cutter 11 counterclockwise in FIG. 2, and the cutter 12 clockwise in FIG. 2.

[0055] (Sugarcane harvester in operation) As shown in Figures 1 and 2, as the machine body 10 moves forward, the upper leaves of the crops in the field are cut by the upper cutting device 7, and the crops in the field are separated into crops to be harvested and other crops by the right dividers 13, 14 and the left dividers 15, 16, and the crops to be harvested are guided between the right and left dividers 13, 15.

[0056] The crops guided between the right and left dividers 13, 15 are guided between the right and left side walls 18 while being tilted forward by the tilting rollers 17, and the bases of the crops are cut by the cutters 11, 12.

[0057] The crops with their bases cut are supplied from the base to the first conveying device 4, transported diagonally upward and rearward along the first conveying device 4, cut to a predetermined length at the rear end of the first conveying device 4, and then supplied to the top of the sorting device 5.

[0058] The crops supplied to the top of the sorting device 5 fall into the front part of the second conveying device 6. A sorting fan (not shown) is provided at the top of the sorting device 5, and the sorting fan generates sorting wind directed upward inside the sorting device 5. Inside the sorting device 5, the crops fall into the front part of the second conveying device 6 below, and impurities are separated from the crops by the sorting wind and discharged from the top of the sorting device 5.

[0059] The crops that fall onto the front of the second conveying device 6 are transported diagonally upward by the second conveying device 6. A transport vehicle (not shown) accompanies the sugarcane harvester, and the crops are dumped from the rear of the second conveying device 6 onto the loading platform of the transport vehicle.

[0060] (Overview of hydraulic systems in sugarcane harvesters) As shown in Figure 4, the drive case 38 is attached to the engine 19, and the hydraulic pumps 39, 44, 48, 49, 51, 52, 53, and 58 are provided in the drive case 38. The power of the engine 19 is transmitted to the hydraulic pumps 39, 44, 48, 49, 51, 52, 53, and 58 via a gear transmission system inside the drive case 38, thereby driving the hydraulic pumps 39, 44, 48, 49, 51, 52, 53, and 58.

[0061] Hydraulic oil from the hydraulic pump 39 is supplied to the reaping unit 3 and then to the hydraulic motors 24, 28, and 34, which rotate and drive the cutters 11 and 12, the right and left dividers 13-16, and the tipping roller 17. Hydraulic oil from the hydraulic pump 44 is supplied to the first conveying device 4, which operates the first conveying device 4. Hydraulic oil from the hydraulic pump 48 is supplied to the sorting device 5, which operates the sorting fan of the sorting device 5.

[0062] As will be described later, a hydraulic steering device 20 is provided to steer the front wheels 1, 2. Hydraulic oil from a hydraulic pump 49 is supplied to the upper cutting device 7 and the hydraulic steering device 20, causing the upper cutting device 7 and the hydraulic steering device 20 to operate.

[0063] A blower fan (not shown) is provided to supply cooling air to a radiator (not shown) and an oil cooler (not shown). Hydraulic oil from a hydraulic pump 51 is supplied to the blower fan, causing the blower fan to operate.

[0064] As will be described later, a control valve unit 59 is provided, and hydraulic oil from the hydraulic pump 52 is supplied to the control valve unit 59. Hydraulic oil from the hydraulic pump 53 is supplied to the second transfer device 6, causing the second transfer device 6 to operate.

[0065] A hydrostatic continuously variable transmission (not shown) is provided. The continuously variable transmission has a travel pump 54, a travel motor (not shown), and a charge pump 55. The travel pump 54 and the charge pump 55 are provided in the drive case 38 and are driven by the power of the engine 19.

[0066] A travel motor is provided in a transmission case (not shown) on which rear wheels 8 (see FIG. 1) are mounted. Hydraulic oil from a travel pump 54 is supplied to the travel motor, which operates to drive the rear wheels 8. A hydraulic pump 58 circulates lubricating oil in the drive case 38 and the transmission case through an oil cooler (not shown), which cools the lubricating oil in the drive case 38 and the transmission case.

[0067] (Configuration of control valve unit 59) - 1 4 and 5, the control valve unit 59 has a control valve 46, a control valve 76, a control valve 41, a control valve 42, a control valve 43, a control valve 45, a control valve 77, a switching valve 68, an unloading valve 69, etc. An oil passage 71 extends from the hydraulic pump 52 and is connected to the control valve unit 59 and is also connected to the switching valve 68.

[0068] In the control valve unit 59, the oil passage 36 extends from the switching valve 68 and is connected to the control valve 46. The oil passage 72 extends from the switching valve 68. The oil passage 66 branches off from the oil passage 72 and is connected to the control valve 76. An oil passage 31 branches off from the oil passage 72 and is connected to the control valve 41. An oil passage 32 branches off from the oil passage 72 and is connected to the control valve . An oil passage 33 branches off from the oil passage 72 and is connected to the control valve 43. An oil passage 35 branches off from the oil passage 72 and is connected to the control valve 45. An oil passage 67 branches off from the oil passage 72 and is connected to a control valve 77 .

[0069] As a result, the hydraulic oil from the hydraulic pump 52 is supplied in parallel from the oil passage 71 to the control valves 46, 76, 41, 42, 43, 45, and 77 through the switching valve 68, the oil passage 72, and the oil passages 36, 66, 31, 32, 33, 35, and 67.

[0070] (Configuration of control valve unit 59)-2 As shown in Fig. 4, a hydraulic cylinder 26 is provided to raise and lower the second transfer device 6 (see Fig. 1) with the front part of the second transfer device 6 as a fulcrum. Hydraulic oil in an oil passage 36 is supplied to and discharged from a control valve 46 to the hydraulic cylinder 26, causing the hydraulic cylinder 26 to expand and contract, thereby raising and lowering the second transfer device 6.

[0071] A hydraulic cylinder 56 is provided that uses the front part of the second transfer device 6 (see FIG. 1) as a fulcrum to change the direction of the second transfer device 6 to the right or left. Hydraulic oil in an oil passage 66 is supplied to or discharged from a control valve 76 to the hydraulic cylinder 56, causing the hydraulic cylinder 56 to expand or contract, changing the direction of the second transfer device 6 to the right or left.

[0072] A hydraulic cylinder 21 is provided to raise and lower the right front wheel 1 (see FIGS. 1, 2, and 3) relative to the machine body 10 (cutting unit 3). Hydraulic oil in an oil passage 31 is supplied to and discharged from a control valve 41 to the hydraulic cylinder 21, causing the hydraulic cylinder 21 to expand and contract, thereby raising and lowering the right front wheel 1.

[0073] A hydraulic cylinder 22 is provided to raise and lower the left front wheel 2 (see FIGS. 1, 2, and 3) relative to the machine body 10 (cutting unit 3). Hydraulic oil in an oil passage 32 is supplied to and discharged from a control valve 42 to the hydraulic cylinder 22, causing the hydraulic cylinder 22 to expand and contract, thereby raising and lowering the left front wheel 2.

[0074] The right dividers 13, 14 (see Figures 1 and 2) are attached to the front of the right side wall portion 18 so that they can be raised and lowered, and are provided with a hydraulic cylinder 23 that raises and lowers the right dividers 13, 14. Hydraulic oil in an oil passage 33 is supplied to and discharged from a control valve 43 to the hydraulic cylinder 23, causing the hydraulic cylinder 23 to expand and contract, thereby raising and lowering the right dividers 13, 14.

[0075] The left dividers 15, 16 (see Figures 1 and 2) are attached to the front of the left lateral wall portion 18 so that they can be raised and lowered, and are provided with a hydraulic cylinder 25 that raises and lowers the left dividers 15, 16. Hydraulic oil in an oil passage 35 is supplied to and discharged from a control valve 45 to the hydraulic cylinder 25, causing the hydraulic cylinder 25 to expand and contract, thereby raising and lowering the left dividers 15, 16.

[0076] The upper cutting device 7 (see FIG. 1) is attached to the reaping unit 3 so that it can be raised and lowered, and is provided with a hydraulic cylinder 57 that raises and lowers the upper cutting device 7. Hydraulic oil in an oil passage 67 is supplied to and discharged from a control valve 77 to the hydraulic cylinder 57, causing the hydraulic cylinder 57 to expand and contract, thereby raising and lowering the upper cutting device 7.

[0077] (Configuration of the switching valve 68) 5, the switching valve 68 is configured as a pilot-operated type, having a first position 68a, a second position 68b, and a spring 68c, and is biased to the second position 68b by the spring 68c. A pilot oil passage 73 is connected between the oil passage 36 and the first position 68a of the switching valve 68.

[0078] The control valve 46 has an up position 46a, a down position 46b, and a neutral position 46c. An oil passage 74 is connected between the control valve 46 and the hydraulic cylinder 26, and a pilot-operated check valve 75 is provided in the oil passage 74.

[0079] A pilot oil passage 78 is connected between the control valve 46 and the check valve 75. A pilot oil passage 79 branching from the pilot oil passage 78 and a pilot oil passage 80 branching from the oil passage 74 are connected to the check valve 82. A pilot oil passage 81 is connected between the second position 68b of the switching valve 68 and the check valve 82.

[0080] (Operation state of the switching valve 68) 5 shows a state in which the control valve 46 is operated to the neutral position 46c, and the oil passage 36 is blocked by the neutral position 46c of the control valve 46. In this state, the hydraulic oil from the hydraulic cylinder 26 is stopped by the check valve 75, and the hydraulic cylinder 26 is stopped.

[0081] With the control valve 46 operated to the neutral position 46c, the pilot hydraulic oil in the pilot oil passages 78 to 81 is discharged to the hydraulic oil tank 83 through the neutral position 46c of the control valve 46. The pilot hydraulic oil in the oil passage 36 is supplied to the first position 68a of the switching valve 68 through the pilot oil passage 73, and the switching valve 68 is operated to the first position 68a against the spring 68c.

[0082] As shown in Figures 4 and 5, when the switching valve 68 is operated to the first position 68a, the hydraulic oil in the oil passage 71 is supplied to the oil passage 72 through the switching valve 68 (first position 68a), and then supplied from the oil passage 72 to the oil passages 66, 31, 32, 33, 35, and 67 (control valves 76, 41, 42, 43, 45, and 77).

[0083] When the control valve 46 is operated to the raised position 46a, the pilot hydraulic oil in the oil passage 36 is supplied to the first position 68a of the switching valve 68 through the pilot oil passage 73, and the pilot hydraulic oil in the oil passage 36 is supplied to the second position 68b of the switching valve 68 through the control valve 46 (raised position 46a) and the pilot oil passages 80 and 81.

[0084] When the control valve 46 is operated to the lowered position 46b, the pilot hydraulic oil in the oil passage 36 is supplied to the first position 68a of the switching valve 68 through the pilot oil passage 73, and the pilot hydraulic oil in the oil passage 36 is supplied to the second position 68b of the switching valve 68 through the control valve 46 (lowered position 46b) and the pilot oil passages 78, 79, and 81.

[0085] When the control valve 46 is operated to the raised position 46a and the lowered position 46b, the pilot hydraulic oil supplied to the first position 68a of the switching valve 68 and the pilot hydraulic oil supplied to the second position 68b of the switching valve 68 are balanced, but the switching valve 68 is operated to the second position 68b by the spring 68c that biases the switching valve 68 to the second position 68b.

[0086] When the control valve 46 is operated to the raised position 46a and the switching valve 68 is operated to the second position 68b, the hydraulic oil in the oil passage 71 is supplied to the oil passage 36 through the switching valve 68 (second position 68b), and then supplied to the hydraulic cylinder 26 through the control valve 46 (raised position 46a), the oil passage 74 and the check valve 75, and the second conveying device 6 is raised by the hydraulic cylinder 26. The hydraulic oil in the oil passage 71 is not supplied to the oil passage 72, and is not supplied to the oil passages 66, 31, 32, 33, 35, and 67 (control valves 76, 41, 42, 43, 45, and 77).

[0087] When the control valve 46 is operated to the lowered position 46b and the switching valve 68 is operated to the second position 68b, the hydraulic oil in the oil passage 71 is supplied to the oil passage 36 through the switching valve 68 (second position 68b), and is supplied to the check valve 75 through the control valve 46 (lowered position 46b) and the pilot oil passage 78, causing the check valve 75 to be opened.

[0088] With the control valve 46 operated to the lowered position 46b and the switching valve 68 operated to the second position 68b, the hydraulic oil in the hydraulic cylinder 26 is discharged through the oil passage 74, the check valve 75, and the control valve 46 (lowered position 46b) to the hydraulic oil tank 83, and the second conveying device 6 is lowered by the hydraulic cylinder 26. The hydraulic oil in the oil passage 71 is not supplied to the oil passage 72, and is not supplied to the oil passages 66, 31, 32, 33, 35, and 67 (control valves 76, 41, 42, 43, 45, and 77).

[0089] (Configuration of unloading valve 69) 5, an unloading valve 69 is connected to a portion of the oil passage 72 between the switching valve 68 and the oil passage 66. The unloading valve 69 has a shutoff position 69a and an unloading position 69b, and is manually operated.

[0090] 5 shows a state in which the unloading valve 69 is operated to the shutoff position 69a. In this state, when the switching valve 68 is operated to the first position 68a, the hydraulic oil in the oil passage 71 is supplied from the switching valve 68 (first position 68a) to the oil passage 72 and the oil passages 66, 31, 32, 33, 35, and 67 (control valves 76, 41, 42, 43, 45, and 77).

[0091] When the unloading valve 69 is operated to the unloading position 69b, even if the switching valve 68 is operated to the first position 68a, the hydraulic oil in the oil passage 72 is discharged to the hydraulic oil tank 83 and is not supplied to the oil passages 66, 31, 32, 33, 35, 67 (control valves 76, 41, 42, 43, 45, 77).

[0092] When the unloading valve 69 is operated to the unloading position 69b, the control valve 46 is operated to the raised position 46a and the lowered position 46b, thereby raising and lowering the second conveying device 6 and performing maintenance work on the second conveying device 6.

[0093] (Overview of the hydraulic system of the upper cutting device 7 and the hydraulic steering device 20) As shown in Fig. 4, there is provided a hydraulic steering device 20 that steers the front wheels 1 and 2. The upper cutting device 7 is configured to be provided with two sets of disc cutters (not shown) similar to the cutters 11 and 12, and is provided with a hydraulic motor 27 that rotates the disc cutters of the upper cutting device 7, and a control valve 47 that supplies and discharges hydraulic oil to and from the hydraulic motor 27.

[0094] A flow priority valve 84 is provided, and an oil passage 85 extends from the hydraulic pump 49 and is connected to the flow priority valve 84. An oil passage 40 extends from the flow priority valve 84 and is connected to the hydraulic steering device 20, and an oil passage 37 extends from the flow priority valve 84 and is connected to the control valve 47.

[0095] When hydraulic oil from the hydraulic pump 49 is supplied to the flow priority valve 84 through the oil passage 85, the controlled flow of the flow priority valve 84 is supplied to the oil passage 40 and then to the hydraulic steering device 20. The surplus flow of the flow priority valve 84 is supplied to the oil passage 37 and then to the upper cutting device 7 (the control valve 47 and the hydraulic motor 27).

[0096] The control valve 47 has a forward rotation position 47a, a reverse rotation position 47b, and a neutral position 47c. When the control valve 47 is operated to the forward rotation position 47a, the hydraulic oil in the oil passage 37 is supplied in the forward direction from the control valve 47 (forward rotation position 47a) to the hydraulic motor 27, and the hydraulic motor 27 operates in the forward direction to drive the upper cutting device 7 in the forward direction.

[0097] When the control valve 47 is operated to the reverse position 47b, the hydraulic oil in the oil passage 37 is supplied in the reverse direction from the control valve 47 (reverse position 47b) to the hydraulic motor 27, causing the hydraulic motor 27 to operate in the reverse direction and drive the upper cutting device 7 in the reverse direction.

[0098] When the control valve 47 is operated to the neutral position 47c, the hydraulic oil in the oil passage 37 is discharged from the control valve 47 (neutral position 47c) to the hydraulic oil tank 83, and the hydraulic motor 27 and the upper cutting device 7 stop.

[0099] If crops become stuck in the upper cutting device 7, the control valve 47 is operated to the reverse position 47b, and the upper cutting device 7 is driven in reverse to clear the jam. The control valve 47 is operated to the neutral position 47c, and the hydraulic motor 27 and the upper cutting device 7 are stopped, allowing maintenance work on the upper cutting device 7 to be performed.

[0100] (Configuration of lifting and lowering operation of front wheels 1 and 2 by hydraulic cylinders 21 and 22) 2 and 3, right and left support arms 61 are provided on the lower parts of the right and left side wall portions 18 so as to be able to swing up and down about an axis P8 along the front-to-rear direction. Right and left brackets 62 are provided on the upper parts of the right and left side wall portions 18.

[0101] The hydraulic cylinders 21, 22 (see FIG. 4) have main bodies 21a, 22a and pistons 21b, 22b, and are configured as double-acting cylinders, with knuckle arms 21c, 22c attached to the upper parts of the main bodies 21a, 22a.

[0102] The lower parts of the main bodies 21a, 21a of the hydraulic cylinders 21, 22 are rotatably attached to a support part 61a at the end of a support arm 61 around vertical axes P21, P22. The upper parts of the pistons 21b, 22b of the hydraulic cylinders 21, 22 are attached to a bracket 62. The front wheels 1, 2 are rotatably attached to an axle part 63 connected to the main bodies 21a, 22a of the hydraulic cylinders 21, 22.

[0103] The right front wheel 1 is raised and lowered relative to the machine body 10 (the reaping unit 3) as the hydraulic cylinder 21 extends and retracts. The left front wheel 2 is raised and lowered relative to the machine body 10 (the reaping unit 3) as the hydraulic cylinder 22 extends and retracts.

[0104] When the front wheels 1, 2 and rear wheels 8 are in contact with the field, the hydraulic cylinders 21, 22 are extended and retracted, causing the machine body 10 (cutting unit 3) to be raised and lowered relative to the front wheels 1, 2, with the rear wheels 8 as the fulcrum, thereby changing the height of the cutters 11, 12 relative to the field (front wheels 1, 2).

[0105] (Configuration of hydraulic steering device 20) 3 and 4, the hydraulic steering device 20 has a control valve 50 and double-acting right and left hydraulic cylinders 60, 70. An oil passage 40 is connected to the control valve 50, and an oil passage 65 is connected to the oil chambers on the main body sides of the hydraulic cylinders 60, 70.

[0106] A support frame 64 is connected across the right and left side wall portions 18, and right and left brackets 64a are provided on the support frame 64. The right hydraulic cylinder 60 is attached to the right bracket 64a of the support frame 64 so as to be able to swing up and down, and is connected to the knuckle arm 21c of the right hydraulic cylinder 21. The left hydraulic cylinder 70 is attached to the left bracket 64a of the support frame 64 so as to be able to swing up and down, and is connected to the knuckle arm 22c of the left hydraulic cylinder 22.

[0107] A steering handle 30 is provided on the driving section 9 (see FIG. 1), and an operator of the driving section 9 manually operates the steering handle 30 to operate the control valve 50. By operating the control valve 50, hydraulic oil in the oil passage 40 is supplied to or discharged from the control valve 50 to the hydraulic cylinders 60, 70, and the front wheels 1, 2 are steered as described below.

[0108] When hydraulic oil from the control valve 50 is supplied to the oil chamber on the piston side of the right hydraulic cylinder 60, the right hydraulic cylinder 60 contracts. Accordingly, hydraulic oil from the oil chamber on the main body side of the right hydraulic cylinder 60 is supplied to the oil chamber on the main body side of the left hydraulic cylinder 70 through the oil passage 65, causing the left hydraulic cylinder 70 to extend.

[0109] As a result, the main bodies 21a, 22a of the hydraulic cylinders 21, 22 are rotated clockwise in plan view about the axes P21, P22 relative to the pistons 21b, 22b of the hydraulic cylinders 21, 22, and the front wheels 1, 2 are steered to the right.

[0110] When hydraulic oil from the control valve 50 is supplied to the oil chamber on the piston side of the left hydraulic cylinder 70, the left hydraulic cylinder 70 contracts. Accordingly, hydraulic oil from the oil chamber on the main body side of the left hydraulic cylinder 70 is supplied to the oil chamber on the main body side of the right hydraulic cylinder 60 through the oil passage 65, causing the right hydraulic cylinder 60 to extend.

[0111] As a result, the main bodies 21a, 22a of the hydraulic cylinders 21, 22 are rotated counterclockwise in plan view about the axes P21, P22 relative to the pistons 21b, 22b of the hydraulic cylinders 21, 22, and the front wheels 1, 2 are steered to the left.

[0112] (Configuration related to lift control and tilt control of front wheels 1 and 2) 6, a load sensor 87 is provided in an oil passage 86 that supplies hydraulic oil to the hydraulic motor 34 that rotates and drives the cutters 11, 12, and the detection value of the load sensor 87 is input to the control device 100. The load sensor 87 detects the pressure of the hydraulic oil in the oil passage 86 as the load applied to the hydraulic motor 34 and the cutters 11, 12.

[0113] Right and left height sensors 88 are provided to detect the vertical angle of the support arm 61 relative to the right and left side wall portions 18, and the detection values ​​of the right and left height sensors 88 are input to the control device 100.

[0114] The height sensor 88 detects the vertical angle of the support arm 61 relative to the side wall portion 18, thereby detecting the vertical positions of the front wheels 1, 2 relative to the machine body 10 (cutting unit 3), and thereby detecting the height of the cutters 11, 12 relative to the field. The control device 100 detects the average value of the detection values ​​of the right and left height sensors 88 as the height of the cutters 11, 12 relative to the field.

[0115] A dial-operated height setting unit 89 is provided in the driving unit 9 (see FIG. 1), and a signal from the height setting unit 89 is input to the control device 100. The height setting unit 89 sets a reference height, which will be described later, and the reference height can be changed arbitrarily by the operator manually operating the height setting unit 89.

[0116] An inclination sensor 90 that detects the inclination angle of the machine body 10 (cutting unit 3) in the left-right direction relative to the horizontal plane is provided on the cutter unit 3, and the detected value of the inclination sensor 90 is input to the control device 100.

[0117] A dial-operated tilt setting unit 91 is provided in the driving unit 9 (see FIG. 1), and a signal from the tilt setting unit 91 is input to the control device 100. The tilt setting unit 91 sets a set tilt angle, which will be described later, and the set tilt angle can be changed arbitrarily by an operator manually operating the tilt setting unit 91.

[0118] (Tilt control of front wheels 1 and 2) - 1 As shown in Fig. 6, the tilt control unit 102 is provided as software in the control device 100. Based on the tilt angle set by the tilt setting unit 91 and the detected value of the tilt sensor 90, the tilt control unit 102 operates the control valves 41, 42 (see Fig. 4) independently of each other, and operates the right and left hydraulic cylinders 21, 22 to extend and retract independently of each other, as described below.

[0119] When the machine body 10 moves forward on a horizontal field, the operator simply operates the inclination setting unit 91 to set the set inclination angle to horizontal. This causes the control valves 41, 42 to be operated independently, and the right and left hydraulic cylinders 21, 22 are extended or retracted, setting the right and left hydraulic cylinders 21, 22 to the same length.

[0120] When the machine body 10 is moving forward on a horizontal field, if the machine body 10 (cutting unit 3) tilts to the right or left due to unevenness in the field, the control valves 41, 42 are operated, the right and left hydraulic cylinders 21, 22 are extended and retracted, the right and left front wheels 1, 2 are raised and lowered, and the detection value of the tilt sensor 90 is maintained at the set tilt angle (horizontal).

[0121] (Tilt control of front wheels 1 and 2) - 2 As shown in Figure 6, when the field is tilted downward to the right (downward to the left) relative to the forward direction of the machine body 10, if the right and left hydraulic cylinders 21, 22 are the same length, the machine body 10 will assume a posture parallel to the field and a posture downward to the right (downward to the left) relative to the horizontal plane. However, the machine body 10 is likely to tilt further to the right (left) downwards due to its own weight, and the cutters 11, 12 may no longer be parallel to the field.

[0122] If the field is inclined downward to the right relative to the forward direction of the machine body 10, the operator simply operates the inclination setting unit 91 to set the set inclination angle to a value that slopes downward to the right relative to the horizontal plane (an inclination angle parallel to the field).

[0123] When the field is tilted downward to the right relative to the forward direction of the machine body 10, the right and left hydraulic cylinders 21, 22 are set to the same length, and when the machine body 10 (cutting unit 3) maintains a posture parallel to the field, the right and left hydraulic cylinders 21, 22 are maintained to be the same length.

[0124] In the above-described state, if the machine body 10 tilts further downward to the right, the control valve 41 extends the right hydraulic cylinder 21, lowering the right front wheel 1, and the control valve 42 contracts the left hydraulic cylinder 22, raising the left front wheel 2. This maintains the detection value of the tilt sensor 90 at the set tilt angle (a tilt angle parallel to the field).

[0125] If the field is inclined downward to the left relative to the forward direction of the machine body 10, the operator simply operates the inclination setting unit 91 to set the set inclination angle to a value that is downward to the left relative to the horizontal plane (an inclination angle parallel to the field).

[0126] When the field is tilted downward to the left relative to the forward direction of the machine body 10, the right and left hydraulic cylinders 21, 22 are set to the same length, and when the machine body 10 (cutting unit 3) maintains a posture parallel to the field, the right and left hydraulic cylinders 21, 22 are maintained to be the same length.

[0127] In the above-described state, if the machine body 10 further tilts downward to the left, the control valve 41 contracts the right hydraulic cylinder 21, raising the right front wheel 1, and the control valve 42 extends the left hydraulic cylinder 22, lowering the left front wheel 2. This maintains the detection value of the tilt sensor 90 at the set tilt angle (a tilt angle parallel to the field). As described above, the detection value of the tilt sensor 90 is maintained at the set tilt angle, and the cutters 11, 12 are maintained in a position parallel to the field.

[0128] (Tilt control of front wheels 1 and 2) - 3 6, there are extension and retraction limits for the right and left hydraulic cylinders 21, 22. The right and left height sensors 88 detect the lengths of the right and left hydraulic cylinders 21, 22 in addition to detecting the up-down positions of the front wheels 1, 2 relative to the machine body 10 (the reaping unit 3).Therefore, it can be determined from the detection values ​​of the right and left height sensors 88 whether the right and left hydraulic cylinders 21, 22 have reached their extension and retraction limits.

[0129] When the field is tilted downward to the right (downward to the left) relative to the forward direction of the machine body 10, the right and left hydraulic cylinders 21, 22 reach their extension and contraction limits, and the detection value of the tilt sensor 90 cannot be maintained at the set tilt angle (a tilt angle parallel to the field), creating the possibility that the cutters 11, 12 may come into contact with the field.

[0130] In this case, the control device 100 displays on the operation panel (not shown) of the driving unit 9 that the detected value of the tilt sensor 90 cannot be maintained at the set tilt angle (a tilt angle parallel to the field). When the operator checks the display on the operation panel of the driving unit 9, as will be described later, he or she can operate the height setting unit 89 to change the reference height to a slightly higher value to avoid contact between the cutters 11, 12 and the field. In this case, the configuration may be such that the reference height is automatically changed to a slightly higher value.

[0131] (Front wheel 1 and 2 lift control) 6, a lift control unit 101 is provided as software in the control device 100. The lift control unit 101 operates the control valves 41, 42 and extends or retracts the right and left hydraulic cylinders 21, 22 based on the reference height of the height setting unit 89, the detection values ​​of the right and left height sensors 88, and the detection value of the load sensor 87, as described below.

[0132] The average of the detection values ​​of the right and left height sensors 88 is detected as the height of the cutters 11, 12 relative to the field. The control valves 41, 42 are operated to extend and retract the right and left hydraulic cylinders 21, 22, and raise and lower the right and left front wheels 1, 2, so that the height of the cutters 11, 12 relative to the field is maintained at the reference height of the height setting unit 89. This allows the operator to operate the height setting unit 89 to arbitrarily change the height of the cutters 11, 12 relative to the field.

[0133] An upper set value and a lower set value that is lower than the upper set value are set in advance in the control device 100 with respect to the detected value of the load sensor 87 . When the detected value of the load sensor 87 is between the upper set value and the lower set value, as described above, the control valves 41, 42 are operated, the right and left hydraulic cylinders 21, 22 are extended or retracted, and the height of the cutters 11, 12 relative to the field is maintained at the reference height of the height setting unit 89.

[0134] When the detected value of the load sensor 87 becomes higher than the upper set value, it is determined that the cutters 11, 12 have come into contact with the field and the load on the hydraulic motor 34 and the cutters 11, 12 has increased.

[0135] When the above-mentioned state is reached, the control valves 41, 42 are operated, the right and left hydraulic cylinders 21, 22 are extended, the machine body 10 (cutting unit 3) is raised, and the cutters 11, 12 are raised from the reference height of the height setting unit 89.

[0136] After this, when the detected value of the load sensor 87 becomes lower than the upper set value, it is determined that the cutters 11, 12 have finished contacting the field, and the control valves 41, 42 are operated to stop the right and left hydraulic cylinders 21, 22. This keeps the cutters 11, 12 at a position higher than the reference height of the height setting unit 89.

[0137] Next, when the detected value of the load sensor 87 becomes lower than the lowering set value, it is determined that the load on the hydraulic motor 34 and the cutters 11, 12 has decreased. When this state is reached, the control valves 41, 42 are operated, the right and left hydraulic cylinders 21, 22 are contracted, and the cutters 11, 12 are lowered from a position higher than the reference height of the height setting unit 89.

[0138] When the detected value of the load sensor 87 falls between the upper set value and the lower set value, it is determined that the load on the hydraulic motor 34 and the cutters 11, 12 has returned to an appropriate value. As a result, the control valves 41, 42 are operated so that the height of the cutters 11, 12 relative to the field is maintained at the reference height of the height setting unit 89, and the right and left hydraulic cylinders 21, 22 return to a state in which they are extended and retracted.

[0139] (First Alternative Embodiment of the Invention) In a state where the field is tilted downward to the right with respect to the forward movement direction of the machine body 10, the tilt control unit 102 may not operate the control valve 42 (the left hydraulic cylinder 22 is not contracted), but may operate the control valve 41 to extend the right hydraulic cylinder 21. The tilt control unit 102 may not operate the control valve 41 (the right hydraulic cylinder 21 is not extended), but may operate the control valve 42 to retract the left hydraulic cylinder 22.

[0140] (Second Alternative Embodiment of the Invention) In a state where the field is tilted downward to the left with respect to the forward movement direction of the machine body 10, the tilt control unit 102 may operate the control valve 42 to extend the left hydraulic cylinder 22 without operating the control valve 41 (the right hydraulic cylinder 21 is not contracted). The tilt control unit 102 may operate the control valve 41 to retract the right hydraulic cylinder 21 without operating the control valve 42 (the left hydraulic cylinder 22 is not extended).

[0141] (Third Alternative Embodiment of the Invention) The distance (tread) between the right and left rear wheels 8 may be set to be smaller than the distance (tread) between the right and left front wheels 1, 2. With this configuration, the right and left front wheels 1, 2 and the right and left rear wheels 8 are close to a three-point contact state, so when the right and left hydraulic cylinders 21, 22 are extended or retracted, the machine body 10 (cutting unit 3) is more easily tilted, and the detection value of the tilt sensor 90 is more easily maintained at the set tilt angle (a tilt angle parallel to the field).

[0142] (Fourth Alternative Embodiment of the Invention) The tilt control unit 102 may be eliminated. According to this configuration, the control valves 41 and 42 may be configured to be operated independently of each other by manual operation of the operator of the driving unit 9.

[0143] (Fifth Alternative Embodiment of the Invention) The lift control unit 101 may be eliminated. According to this configuration, the control valves 41 and 42 may be operated simultaneously by manual operation of the driving unit 9 by an operator.

[0144] (Sixth Alternative Embodiment of the Invention) The switching valve 68 may be eliminated. According to this configuration, the oil passage 72 is connected to the oil passage 71, the oil passage 36 is connected to the oil passage 72, and the hydraulic oil in the oil passage 71 is supplied in parallel to the oil passages 36, 66, 31, 32, 33, 35, and 67 through the oil passage 72.

[0145] (Seventh Alternative Embodiment of the Invention) A crawler type traveling device may be provided in place of the rear wheels 8, and the machine body 10 may be configured to be supported by the front wheels 1, 2 and the crawler type traveling device. Instead of the cutters 11 and 12, a clipper-type cutting device may be provided.

[0146] (Correspondence to claims)-1 The second conveying device 6 corresponds to the conveying device, and the cutters 11 and 12 correspond to the cutting device. The oil passage 71 corresponds to the supply oil passage. The control valve 46 corresponds to the conveyance lift control valve, and the control valve 76 corresponds to the conveyance direction control valve. The control valve 41 corresponds to the right front wheel lift control valve, and the control valve 42 corresponds to the left front wheel lift control valve. The control valve 43 corresponds to the right separate lift control valve, and the control valve 45 corresponds to the left separate lift control valve.

[0147] The oil passage 36 corresponds to the conveyance lifting supply oil passage, and the oil passage 66 corresponds to the conveyance direction supply oil passage. The oil passage 31 corresponds to the oil supply passage for the right front wheel, and the oil passage 32 corresponds to the oil supply passage for the left front wheel. The oil passage 33 corresponds to the right separated supply oil passage, and the oil passage 35 corresponds to the left separated supply oil passage. The oil passage 67 corresponds to the cutting lifting / lowering supply oil passage.

[0148] The hydraulic cylinder 26 corresponds to the conveying lifting cylinder, and the hydraulic cylinder 56 corresponds to the conveying direction cylinder. The hydraulic cylinder 21 corresponds to the right front wheel lifting cylinder, and the hydraulic cylinder 22 corresponds to the left front wheel lifting cylinder. The hydraulic cylinder 23 corresponds to the right separation lifting cylinder, and the hydraulic cylinder 25 corresponds to the left separation lifting cylinder. The hydraulic cylinder 57 corresponds to the cutting lifting cylinder.

[0149] The neutral position 46c of the control valve 46 corresponds to the neutral position of the transfer lift control valve, and the raised position 46a and lowered position 46b of the control valve 46 correspond to the operating positions of the transfer lift control valve. The inclination setting unit 91 corresponds to the setting unit.

[0150] (Correspondence to claims)-2 The machine is provided with a machine body 10 having right and left front wheels 1, 2. The machine body 10 is provided with cutting devices (cutters 11, 12) that cut the bases of crops in a field. A double-acting right front wheel lifting cylinder (hydraulic cylinder 21) is provided to raise and lower the right front wheel 1 relative to the machine body 10. A double-acting left front wheel lifting cylinder (hydraulic cylinder 22) is provided to raise and lower the left front wheel 2 relative to the machine body 10.

[0151] A hydraulic pump 49 is provided. A supply oil passage (oil passage 71) through which hydraulic oil for the hydraulic pump 49 is supplied is provided. There is provided a right front wheel supply oil passage (oil passage 31) to which hydraulic oil is supplied from the supply oil passage (oil passage 71). There is provided a left front wheel supply oil passage (oil passage 32) to which hydraulic oil is supplied from the supply oil passage (oil passage 71).

[0152] A right front wheel lift control valve (control valve 41) is provided which supplies and discharges hydraulic oil from the right front wheel supply oil passage (oil passage 31) to the right front wheel lift cylinder (hydraulic cylinder 21) to extend and retract the right front wheel lift cylinder (hydraulic cylinder 21). A left front wheel lift control valve (control valve 42) is provided to supply and discharge hydraulic oil from the left front wheel supply oil passage (oil passage 32) to the left front wheel lift cylinder (hydraulic cylinder 22), thereby extending and retracting the left front wheel lift cylinder (hydraulic cylinder 22).

[0153] (Correspondence to claims) - 3 The machine body 10 is provided with a conveying device (second conveying device 6) that conveys and discharges the harvested crops from the machine body 10 to the outside after the bases of the plants have been cut by the cutting devices (cutters 11, 12). A transfer lifting cylinder (hydraulic cylinder 26) is provided to lift and lower the transfer device (second transfer device 6).

[0154] There is provided a conveying / lifting supply oil passage (oil passage 36) to which hydraulic oil is supplied from the supply oil passage (oil passage 71). There is provided a conveying / lifting control valve (control valve 46) that supplies and discharges hydraulic oil from the conveying / lifting supply oil passage (oil passage 36) to the conveying / lifting cylinder (hydraulic cylinder 26) to extend and retract the conveying / lifting cylinder (hydraulic cylinder 26).

[0155] A transfer direction cylinder (hydraulic cylinder 56) is provided to change the direction of the transfer device (second transfer device 6) to the right or left. There is provided a conveying direction supply oil passage (oil passage 66) to which hydraulic oil is supplied from the supply oil passage (oil passage 71). There is provided a conveying direction control valve (control valve 76) that supplies and discharges hydraulic oil from the conveying direction supply oil passage (oil passage 66) to the conveying direction cylinder (hydraulic cylinder 56) to extend and retract the conveying direction cylinder (hydraulic cylinder 56).

[0156] (Correspondence to claims)-4 A switching valve 68 is provided which can be switched between a first position 68a where the hydraulic oil in the supply oil passage (oil passage 71) is supplied to the front wheel supply oil passage (oil passages 31, 32) and a second position 68b where the hydraulic oil in the supply oil passage (oil passage 71) is supplied to the conveying lifting supply oil passage (oil passage 36).

[0157] The switching valve 68 is operated to a first position 68a when the conveying lifting control valve (control valve 46) is operated to a neutral position 46c where the conveying lifting cylinder (hydraulic cylinder 26) is stopped, and is operated to a second position 68b when the conveying lifting control valve (control valve 46) is operated to an operating position (upward position 46a, downward position 46b) where the conveying lifting cylinder (hydraulic cylinder 26) operates to extend and retract.

[0158] An unloading valve 69 is provided which can be operated to an unloading position 69b for discharging hydraulic oil from the switching valve 68 operated to the first position 68a.

[0159] (Correspondence to claims) - 5 There are provided right dividers 13, 14 for separating the crops in the field into crops to be harvested and other crops, and left dividers 15, 16 for separating the crops in the field into crops to be harvested and other crops.

[0160] There is provided a right separation lifting cylinder (hydraulic cylinder 23) for lifting and lowering the right dividers 13 and 14. There is provided a left separation lifting cylinder (hydraulic cylinder 25) for lifting and lowering the left dividers 15 and 16.

[0161] A right separate supply oil passage (oil passage 33) is provided to which the hydraulic oil of the supply oil passage (oil passage 71) is supplied. A left separate supply oil passage (oil passage 35) is provided to which the hydraulic oil of the supply oil passage (oil passage 71) is supplied.

[0162] A right separation lift control valve (control valve 43) is provided to supply and discharge hydraulic oil from the right separation supply oil passage (oil passage 33) to the right separation lift cylinder (hydraulic cylinder 23), thereby causing the right separation lift cylinder (hydraulic cylinder 23) to extend and retract. A left separation lift control valve (control valve 45) is provided which supplies and discharges hydraulic oil from the left separation supply oil passage (oil passage 35) to the left separation lift cylinder (hydraulic cylinder 25) to extend and retract the left separation lift cylinder (hydraulic cylinder 25).

[0163] (Correspondence to claims) - 6 The machine body 10 is provided with an upper cutting device 7 that cuts the upper part of the crops in the field. A cutting lifting cylinder (hydraulic cylinder 57) is provided to lift and lower the upper cutting device 7. There is provided a cutting lift supply oil passage (oil passage 67) to which hydraulic oil is supplied from the supply oil passage (oil passage 71). There is provided a cutting lift control valve (control valve 77) that supplies and discharges hydraulic oil from the cutting lift supply oil passage (oil passage 67) to the cutting lift cylinder (hydraulic cylinder 57) to extend and retract the cutting lift cylinder (hydraulic cylinder 57).

[0164] (Correspondence to claims) - 7 A load sensor 87 is provided to detect the load applied to the cutting device (cutters 11, 12). When the detected value of the load sensor 87 becomes higher than a preset upward setting value, an elevation control unit 101 is provided which operates the right and left front wheel elevation control valves (control valves 41, 42) and activates the right and left front wheel elevation cylinders (hydraulic cylinders 21, 22) to raise the machine body 10.

[0165] (Correspondence to claims) - 8 An inclination sensor 90 is provided to detect the angle of inclination of the aircraft 10 in the left-right direction relative to the horizontal plane. A setting section (inclination setting section 91) is provided that can set and change the set inclination angle in the left-right direction relative to the horizontal plane. A tilt control unit 102 is provided which operates at least one of the right and left front wheel lift control valves (control valves 41, 42) and activates at least one of the right and front wheel lift cylinders (hydraulic cylinders 21, 22) based on the detection value of the tilt sensor 90 so that the tilt angle becomes the set tilt angle. [Industrial Applicability]

[0166] The present invention is applicable to sugarcane harvesters. [Explanation of symbols]

[0167] 1 front wheel 2 front wheels 6 Second conveying device (conveying device) 7 Upper cutting device 10 aircraft 11 Cutter (cutting device) 12 Cutter (cutting device) 13 Divider 14 Divider 15 Divider 16 Divider 21 Hydraulic cylinder (front wheel lift cylinder) 22 Hydraulic cylinder (front wheel lift cylinder) 23 Hydraulic cylinder (separate lifting cylinder) 25 Hydraulic cylinder (separate lifting cylinder) 26 Hydraulic cylinder (transport lifting cylinder) 31 Oil passage (front wheel supply oil passage) 32 Oil passage (front wheel supply oil passage) 33 Oil line (separate supply oil line) 35 Oil line (separate supply oil line) 36 Oil passage (transport lift supply oil passage) 41 Control valve (front wheel lift control valve) 42 Control valve (front wheel lift control valve) 43 Control valve (separate lift control valve) 45 Control valve (separate lift control valve) 46 Control valve (transport lift control valve) 46a Raised position (operating position) 46b Lower position (operating position) 46c neutral position 56 Hydraulic cylinder (conveyance cylinder) 52 Hydraulic pump 57 Hydraulic cylinder (cutting lifting cylinder) 67 Oil passage (cutting lift supply oil passage) 68 Switching valve 68a 1st position 68b 2nd position 69 Unloading valve 69b Unload position 71 Oil passage (oil supply passage) 76 Control valve (conveyance direction control valve) 77 Control valve (cutting lift control valve) 87 Load Sensor 90 Tilt sensor 91 Inclination setting unit (setting unit) 101 Lift control section 102 Tilt control section

Claims

1. a body having right and left front wheels; A cutting device provided on the machine body for cutting the base of a crop in the field; a double-acting right front wheel lift cylinder that lifts and lowers the right front wheel relative to the aircraft body; a double-acting left front wheel lift cylinder that lifts and lowers the left front wheel relative to the aircraft body; A hydraulic pump; a supply oil passage through which hydraulic oil for the hydraulic pump is supplied, a right front wheel supply oil passage to which the hydraulic oil from the supply oil passage is supplied; a left front wheel supply oil passage to which the hydraulic oil from the supply oil passage is supplied; a right front wheel lift control valve that supplies or discharges hydraulic oil from the right front wheel supply oil passage to the right front wheel lift cylinder to extend or contract the right front wheel lift cylinder; a left front wheel lift control valve that supplies and discharges hydraulic oil from the left front wheel supply oil passage to the left front wheel lift cylinder, thereby extending and contracting the left front wheel lift cylinder.

2. A conveying device is provided on the machine body, which conveys and discharges the harvested crops whose bases have been cut by the cutting device out of the machine body, a conveying lifting cylinder for lifting and lowering the conveying device; a conveying / lifting supply oil passage to which the hydraulic oil of the supply oil passage is supplied; 2. The sugarcane harvester according to claim 1, further comprising a conveying / lifting control valve for supplying / discharging hydraulic oil from the conveying / lifting supply oil passage to / from the conveying / lifting cylinder, thereby causing the conveying / lifting cylinder to extend / contract.

3. a switching valve that can be switched between a first position where the hydraulic oil in the supply oil passage is supplied to the front wheel supply oil passage and a second position where the hydraulic oil in the supply oil passage is supplied to the conveying / lifting supply oil passage; 3. The sugarcane harvester according to claim 2, wherein the switching valve is operated to the first position when the conveying lifting control valve is operated to a neutral position where the conveying lifting cylinder is stopped, and is operated to the second position when the conveying lifting control valve is operated to an operating position where the conveying lifting cylinder is extended and retracted.

4. 4. The sugarcane harvester according to claim 3, further comprising an unloading valve operable to an unloading position for discharging hydraulic oil from the switching valve operated to the first position.

5. A conveying device is provided on the machine body, which conveys and discharges the harvested crops whose bases have been cut by the cutting device out of the machine body, a conveying direction cylinder for changing the direction of the conveying device to the right or left; a conveying-direction supply oil passage to which the hydraulic oil of the supply oil passage is supplied; 2. The sugarcane harvester according to claim 1, further comprising a conveying direction control valve that supplies and discharges hydraulic oil from the conveying direction supply oil passage to the conveying direction cylinder, thereby expanding and contracting the conveying direction cylinder.

6. a right divider for separating the crops in the field into those to be harvested and other crops; a left divider for separating the crops in the field into the crop to be harvested and other crops; a right separation lifting cylinder for lifting the right divider; a left separation lifting cylinder for lifting the left divider; a right separate oil supply passage to which the hydraulic oil in the oil supply passage is supplied; a left separated oil supply passage to which the hydraulic oil in the oil supply passage is supplied; a right separation lift control valve that supplies or discharges hydraulic oil from the right separation supply oil passage to or from the right separation lift cylinder, thereby causing the right separation lift cylinder to extend or contract; 2. The sugarcane harvester according to claim 1, further comprising a left separation lift control valve for supplying and discharging hydraulic oil from the left separation supply oil passage to the left separation lift cylinder, thereby extending and contracting the left separation lift cylinder.

7. An upper cutting device is provided on the machine body and cuts the upper part of the crop in the field, a cutting lifting cylinder for lifting and lowering the upper cutting device; a cutting lifting / lowering supply oil passage to which the hydraulic oil of the supply oil passage is supplied; 2. The sugarcane harvester according to claim 1, further comprising a cutting lift control valve for supplying and discharging hydraulic oil from the cutting lift supply oil passage to the cutting lift cylinder, thereby extending and contracting the cutting lift cylinder.

8. a load sensor that detects a load applied to the cutting device; 2. The sugarcane harvester according to claim 1, further comprising a lifting control unit that operates the right and left front wheel lifting control valves and actuates the right and left front wheel lifting cylinders to lift the machine body when the detected value of the load sensor becomes higher than a preset upper set value.

9. an inclination sensor that detects the inclination angle of the aircraft in the left-right direction relative to a horizontal plane; a setting unit that can set and change a set tilt angle in the left-right direction relative to a horizontal plane; 2. The sugarcane harvester according to claim 1, further comprising a tilt control unit that operates at least one of the right and left front wheel lift control valves and actuates at least one of the right and left front wheel lift cylinders based on the detected value of the tilt sensor so that the tilt angle becomes the set tilt angle.

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