CN110583216A

CN110583216A - Travel control device for harvester and work vehicle

Info

Publication number: CN110583216A
Application number: CN201910504814.1A
Authority: CN
Inventors: 井本翼; 山中之史; 仲岛铁弥; 池田博; 高崎和也
Original assignee: Kubota Corp
Current assignee: Kubota Corp
Priority date: 2018-06-13
Filing date: 2019-06-12
Publication date: 2019-12-20
Also published as: KR20190141087A

Abstract

The invention provides a travel control device for a harvester and a working vehicle. The travel control device for a harvester can improve safety and convenience when an abnormality that travel control information cannot be acquired occurs in the harvester. An HST (31) is provided between the engine and the pair of left and right traveling devices. The HST (31) is configured to include a hydraulic pump driven by power of an engine (32) and a hydraulic motor driven by pressure oil discharged from the hydraulic pump. The power of the hydraulic motor is transmitted to the pair of left and right traveling devices. In the travel control by the normal method, the operation of the HST (31) is controlled using the information for travel control. When an abnormality that the travel control information cannot be acquired occurs, the method of travel control is switched from a normal method to a retraction method that does not use the travel control information in accordance with the occurrence of the abnormality, and then the operation of the HST (31) is controlled by the retraction method.

Description

Travel control device for harvester and work vehicle

Technical Field

The present invention relates to a travel control device for a harvester that harvests grains and the like.

Background

For example, in a combine equipped with a hydrostatic continuously variable Transmission (HST), a hydraulic pump is driven by power of an engine, a hydraulic motor is driven by oil discharged from the hydraulic pump, and power of the hydraulic motor is transmitted to left and right crawler belts. The left and right crawler belts are driven at the same speed to move the machine body straight forward and backward, and the left and right crawler belts are driven at a speed difference to swing the machine body left and right.

Unlike a passenger car and a tractor, a combine is generally not equipped with a brake device for braking the machine body. Therefore, in the combine harvester, when an abnormality occurs in which information for travel control (information for travel control) cannot be acquired, such as a failure of a sensor related to travel, a measure is taken to completely prohibit travel by stopping (prohibiting operation) of the engine in order to ensure safety.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2008-57358

In a combine equipped with a hydrostatic continuously variable Transmission (HST), for example, a hydraulic pump of the HST is driven by power of an engine, a hydraulic motor is driven by oil discharged from the hydraulic pump, and power of the hydraulic motor is transmitted to left and right crawler belts. The left and right crawler belts are driven at the same speed to move the machine body straight forward and backward, and the left and right crawler belts are driven at a speed difference to swing the machine body left and right.

A shift lever is provided on the driver's seat so as to be displaceable from a neutral position to the front and rear sides. In a configuration employing an electronic control type (electronic servo type), a shift lever sensor that outputs a detection value corresponding to a position of the shift lever is provided in addition to the shift lever. The detection value of the shift lever sensor is input to an ECU (Electronic Control Unit). In addition, the HST is provided with a pump swash plate position sensor that outputs a detection value corresponding to the position (angle) of the swash plate of the hydraulic pump, and the detection value of the pump swash plate position sensor is input to the ECU.

When a shift lever is operated from a neutral position to a front side or a rear side, in an ECU, a target position of a swash plate of a hydraulic pump is set based on a detection value of a shift lever sensor. Then, the ECU controls a servo mechanism that changes the position of the swash plate so that the deviation between the target position and the actual position of the swash plate of the hydraulic pump approaches 0, based on the detection value of the pump swash plate position sensor. The direction and the flow rate of the oil discharged from the hydraulic pump are changed by changing the position of the swash plate of the hydraulic pump, so that the rotation direction and the rotation number of the hydraulic motor are changed.

Documents of the prior art

Patent document

Patent document 2: japanese patent laid-open No. 2008-57358

Disclosure of Invention

Problems to be solved by the invention

However, in the first aspect, when the travel of the combine harvester is prohibited during the road self-travel, the travel situation may be dangerous during crossing of a railroad crossing or traveling on a slope. When the travel of the combine is prohibited when the combine enters the field, the combine must be lifted up and carried out of the field by a crane, placed on a loading truck, and carried to a repair shop in order to replace or repair travel-related components in the field or replace or repair travel-related components in the repair shop.

The invention aims to provide a travel control device of a harvester, which can improve the safety and the convenience when the harvester generates an abnormal condition that the travel control information can not be obtained.

Means for solving the problems

In order to achieve the above object, a travel control device for a harvester according to the present invention is a travel control device for a harvester, the harvester including: an engine; a pair of left and right traveling devices; a power transmission device that includes a pump driven by power of the engine and a motor driven by pressure oil discharged from the pump, and that transmits power of the motor to the traveling device; the travel control device of the harvester comprises: an information acquisition means for acquiring information for travel control; a normal control means for controlling the power transmission device by a normal method using the information for travel control when the information acquisition means can acquire the information for travel control; and a retraction control means for controlling the power transmission device by a retraction method not using the travel control information when the information acquisition means cannot acquire the abnormality of the travel control information.

According to this configuration, the power transmission device is provided between the engine and the pair of left and right traveling devices. The power transmission device includes a pump driven by power of the engine and a motor driven by pressure oil discharged from the pump. The power of the motor is transmitted to the pair of left and right traveling devices.

In the normal state, the power transmission device is controlled by a normal method, and the travel control information is used in the control. When an abnormality that the travel control information cannot be acquired occurs in the harvester, the method of controlling the power transmission device is switched from the normal method to the retraction method that does not use the travel control information in response to the occurrence of the abnormality, and then the power transmission device is controlled by the retraction method. Thus, even if an abnormality occurs in the harvester in which the travel control information cannot be acquired, the power transmission device can be made to retract, and power can be transmitted from the power transmission device to the travel device, so that the harvester can continue traveling.

Therefore, when an abnormality occurs in which the travel control information cannot be acquired during the crossing of the railroad crossing, the harvester can cross the railroad crossing, and the risk of the harvester getting stuck in the railroad crossing can be reduced. Further, when an abnormality occurs in which the travel control information cannot be acquired while the harvester is traveling on a slope, it is possible to suppress the power from being transmitted from the power transmission device to the traveling device, and it is possible to reduce the risk of the harvester traveling downhill against the intention of the driver. Further, when an abnormality occurs in the harvester in the field in which the travel control information cannot be acquired, the harvester can be separated from the field by traveling by itself.

This can improve safety and convenience when an abnormality occurs in which the travel control information cannot be acquired in the harvester.

The harvester may be provided with a shift operation member that is operated from a neutral position to one side to advance the harvester and from the neutral position to the other side to retreat the harvester, and an operation position detection mechanism that detects a position of the shift operation member. In this configuration, the information acquisition means may acquire the position information of the shift operation member as the travel control information based on the detection signal input from the operation position detection means, and the normal control means may control the power transmission device as follows: when the position information of the shift operation member acquired by the information acquisition mechanism is information indicating a position on one side with respect to the neutral position, power in a direction to advance the harvester is output from the power transmission device to the travel device, and when the position information of the shift operation member acquired by the information acquisition mechanism is information indicating a position on the other side with respect to the neutral position, power in a direction to retract the harvester is output from the power transmission device to the travel device.

In the harvester, a switch operation member that switches between a first state and a second state may be provided, unlike the shift operation member. When the harvester includes the threshing device, the switch operating member may be a threshing depth switch that selectively sets the length of the grain bar entering the threshing device to a first length and a second length shorter than the first length. In addition, in the case of an abnormality in which the position information of the shift operation member cannot be acquired because the detection signal of the operation position detection means is not input, the retraction control means may control the power transmission device so as to output the power in the direction of advancing the harvester from the power transmission device to the travel device when the switch operation member is in the first state, and may control the power transmission device so as to output the power in the direction of retracting the harvester from the power transmission device to the travel device when the switch operation member is in the second state. Thus, when abnormality in which the position information of the shift operation member cannot be acquired, the harvester can be moved forward and backward by the operation of the switch operation member.

The power transmission device may also be a structure that further includes a servo mechanism that controls the position of a pump swash plate of the pump. In this configuration, it is preferable that the normal control means sets a target position of the pump swash plate corresponding to the position of the shift operation member based on the position information of the shift operation member acquired by the information acquisition means, and feedback-controls the servo mechanism so that the position of the pump swash plate coincides with the target position. On the other hand, the retraction control means may set the target position of the pump swash plate to a fixed position on the forward side when the switch operating member is in the first state, and set the target position of the pump swash plate to a fixed position on the backward side when the switch operating member is in the second state, and perform feed-forward control on the servo mechanism. Accordingly, when abnormality in the position information of the shift operation member cannot be acquired, a certain amount of pressure oil can be discharged from the pump, and a certain amount of power can be transmitted from the motor to the power transmission device.

The harvester may further include a control device communicably connected to the travel control device, and the control device may hold operation position adjustment data for adjusting the position detected by the operation position detecting means so as to be aligned with the actual position of the shift operation member. In this configuration, the information acquisition means may acquire the position information of the shift operation member from a detection signal, which is input from the operation position detection means, using the operation position adjustment data, and the retraction control means may set the target position of the pump swash plate corresponding to the position detected by the operation position detection means and perform feed-forward control on the servo mechanism in the case of an abnormality in which the information acquisition means cannot acquire the position information of the shift operation member because the information acquisition means cannot use the operation position adjustment data.

In the case where the power transmission device further includes a servo mechanism for controlling the position of the pump swash plate of the pump, and the harvester is provided with a swash plate position detection mechanism for detecting the position of the pump swash plate, the information acquisition mechanism may acquire the position information of the pump swash plate as the information for travel control based on a detection signal input from the swash plate position detection mechanism, the communication control mechanism may set the target position of the pump swash plate based on the position information of the pump swash plate, perform feedback control on the servo mechanism so that the position of the pump swash plate coincides with the target position, and the retraction control mechanism may set the target position of the pump swash plate and perform feed-forward control on the servo mechanism.

In this case, the control device may hold the swash plate position adjustment data for adjusting the position detected by the swash plate position detecting means so as to be aligned with the actual position of the pump swash plate. The information acquisition means may acquire position information of the pump swash plate from a detection signal, which is input from the swash plate position detection means, using the swash plate position adjustment data, and the retraction control means may set a target position of the pump swash plate based on the position detected by the swash plate position detection means and perform feed-forward control on the servo mechanism when the information acquisition means fails to acquire the position information of the pump swash plate due to failure to use the swash plate position adjustment data.

Effects of the invention

According to the present invention, even if an abnormality occurs in the harvester in which the travel control information cannot be acquired, the harvester can be caused to continue traveling, and therefore, it is possible to improve safety and convenience when the abnormality occurs.

Problems to be solved by the invention

In the second aspect, the shift lever sensor and the pump swash plate position sensor are constituted by, for example, potentiometers that output voltages corresponding to the displacement amounts from the reference position of the detection object. Therefore, the detection value of the sensor when the detection object is located at the reference position deviates from the reference value corresponding to the reference position due to the assembling variation of the sensors of the shift lever sensor and the pump swash plate position sensor. Therefore, when the combine is shipped at a factory, adjustment data for adjusting the detection values of the sensors in accordance with the positional relationship between the object to be detected and the sensors is stored in the ECU, and the adjustment data is used for the control of the servo of the HST by the ECU.

However, when the memory storing the adjustment data fails or the ECU is replaced together with the memory, the adjustment data that is not suitable for the positional relationship between the sensor and the detection target object is used for controlling the servo mechanism. In this case, the HST may perform an operation against the intention of the operator who operates the shift lever.

Another object of the present invention is to provide a work vehicle capable of suppressing use of adjustment data unsuitable for detecting a positional relationship between an object and a sensor in control of a servo mechanism.

Means for solving the problems

In order to achieve the above object, a work vehicle according to the present invention includes: an engine; a pair of left and right traveling devices; a power transmission device that includes a pump driven by power of the engine, a motor driven by pressure oil discharged from the pump, and a servo mechanism that changes a position of a swash plate of the pump, and that transmits power of the motor to the traveling device; a detection object which is provided to be displaceable; a sensor that outputs a detection value corresponding to a position of a detection object; a first control unit for controlling the servo mechanism; a second control unit communicably connected to the first control unit; the first control unit and the second control unit hold adjustment data for adjusting the detection value of the sensor in accordance with the positional relationship between the detection object and the sensor, and when the adjustment data held by the first control unit and the adjustment data held by the second control unit match, the first control unit adjusts the detection value of the sensor using the matching adjustment data and controls the servo mechanism based on the adjusted detection value.

According to this configuration, the power transmission device is provided between the engine and the pair of left and right traveling devices. The power transmission device includes a pump driven by power of an engine, a motor driven by pressure oil discharged from the pump, and a servo mechanism for changing a position of a swash plate of the pump. The power of the motor is transmitted to the pair of left and right traveling devices.

A first control unit for controlling the servo mechanism holds adjustment data for adjusting the detection value of the sensor. On the other hand, the adjustment data is also held in the second control section communicably connected to the first control section. In the factory shipment of the work vehicle, the same adjustment data is held in the first control unit and the second control unit, but for example, when the first control unit or the second control unit is replaced after the factory shipment, the adjustment data held in the first control unit and the adjustment data held in the second control unit are different. In this case, when the adjustment data held in the first control unit or the second control unit is used for controlling the servo mechanism, there is a risk that the power transmission device makes a motion that violates the intention of the operator using the work vehicle because the adjustment data that is not suitable for the positional relationship between the sensor and the detection target object is used for controlling the servo mechanism.

Therefore, when the adjustment data held by the first control unit and the adjustment data held by the second control unit match, the detection value of the sensor is adjusted using the matching adjustment data, and the servo mechanism is controlled based on the adjusted detection value. This can suppress the use of adjustment data that is not suitable for detecting the positional relationship between the object and the sensor in the control of the servo mechanism. As a result, the power transmission device can be prevented from moving against the intention of the operator.

The engine start may be prohibited when the adjustment data held by the first control unit and the adjustment data held by the second control unit are different from each other. By not starting the engine, the power transmission device can be prevented from moving against the intention of the operator.

However, it is preferable that the work vehicle is provided with a receiving unit that receives an instruction of abnormal operation of the engine in a situation where the engine cranking is prohibited, and allows the engine cranking for the abnormal operation of the engine in accordance with the receiving unit receiving the instruction of the abnormal operation of the engine. By the abnormal operation of the engine, the work vehicle can be automatically driven to a repair shop or the like.

The object to be detected by the sensor may be a shift operation member that is operated from a neutral position to one side for forward movement of the work vehicle and that is operated from the neutral position to the other side for reverse movement of the work vehicle. In this case, the detection value of the sensor may be adjusted using default data different from the adjustment data during abnormal operation of the engine. The default data is data in which the detection value of the sensor is adjusted by a certain amount. For example, a detection value of a sensor when the detection object is located at the reference position may be acquired for a plurality of units of the work vehicle, an average value of deviation amounts of the detection value and the reference value of the sensor corresponding to the reference position of the detection object may be obtained, and the average value may be set as default data. By adjusting the detection value of the sensor using the default data, the detection value of the sensor can be adjusted using the average level to suppress the movement of the power transmission device against the intention of the operator.

The work vehicle may further include a switch operation member that switches between a first state and a second state, the detection target object may be a shift operation member that is operated from a neutral position to one side for forward movement of the work vehicle and from the neutral position to the other side for reverse movement of the work vehicle, and the servo mechanism may be controlled as follows: during abnormal operation of the engine, when the switch operation member is in the first state, the swash plate of the pump is located at a predetermined position in the forward direction, and when the switch operation member is in the second state, the swash plate of the pump is located at a predetermined position in the backward direction. Thus, the work vehicle can be moved forward and backward by operating the switch operating member.

When the detection object is a swash plate of a pump, a target position of the swash plate of the pump may be set and the servo mechanism may be feedforward controlled during abnormal operation of the engine.

In the case where the detection object is a swash plate of a pump, the swash plate of the pump is located at a neutral position when the engine is stopped before cranking, and therefore, in the abnormal operation of the engine, a detection value of a sensor before cranking used for the abnormal operation of the engine may be set to a value corresponding to the neutral position of the swash plate of the pump, and a default data different from the adjustment data may be used to adjust the detection value of the sensor.

The detection target object may be a steering member that is operated from a neutral position to one side for left turning of the work vehicle and that is operated from the neutral position to the other side for right turning of the work vehicle. In this case, during abnormal operation of the engine, default data different from the adjustment data may be used for adjustment of the detection value of the sensor. As a result, as described above, the detection value of the sensor can be adjusted using the average level to suppress the motion of the power transmission device against the intention of the operator.

Effects of the invention

According to the present invention, it is possible to suppress the use of adjustment data unsuitable for the positional relationship between the detection target object and the sensor in the control of the servo mechanism of the power transmission device, and to suppress the movement of the power transmission device against the intention of the operator using the work vehicle.

Drawings

Fig. 1 is a right side view of the front of a combine harvester illustrating one embodiment of the present invention.

Fig. 2 is a diagram showing the structure of an HST mounted on a combine harvester.

Fig. 3 is a block diagram showing the main parts of the electrical structure of the combine harvester.

Fig. 4 is a block diagram showing a specific configuration for running control.

Fig. 5 is a right side view of the front of the combine harvester showing one embodiment of the present invention.

Fig. 6 is a diagram showing the structure of an HST mounted on a combine harvester.

Fig. 7 is a block diagram showing a main part of an electrical structure of the combine harvester.

Fig. 8 is a flowchart showing a flow of processing executed for the control of the HST.

Description of the reference numerals

The invention of the first aspect:

1 combine harvester (harvester)

12 running device

15 threshing device

21 Main gear shift lever (Shift operating parts)

31 HST (Power transmission device)

32 engine

41 hydraulic pump

42 hydraulic motor

66 servo mechanism

81 Main ECU (control device)

83 running control ECU (running control device, information acquisition means, normal control means, retraction control means)

85 Main gear lever sensor (operation position detection mechanism)

87 switch (switch operation parts)

89 pump swash plate position sensor (swash plate position detection mechanism)

102 actual swash plate position calculating part (swash plate position detecting mechanism)

The invention of the second aspect:

1' combine harvester (working vehicle)

12' running gear

21' main gear lever

22' steering rod

31' HST (Power Transmission device)

32' engine

41' hydraulic pump (pump)

42' hydraulic motor (motor)

66' servo mechanism

81' Main ECU (second control section)

83' running control ECU (first control section)

85' main gear lever sensor

86' steering rod sensor

87' switch (switch operation parts)

89' pump swash plate position sensor

Detailed Description

The invention of the first aspect:

hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

< combine harvester >

The combine harvester 1 is a working vehicle that cuts and threshes grain stalks while traveling in a field. The body 11 of the combine harvester 1 is supported by a pair of left and right traveling devices 12. On the travel device 12, in order to enable the combine harvester 1 to travel on the field, a crawler having a rough ground traveling capability is employed.

The machine body 11 is provided with a cab 13, a harvesting device 14, a threshing device 15, and a grain tank 16.

The cab 13 is disposed above the front end of the traveling device 12. The cab 13 is provided with a driver seat 17 on which a worker sits, and operation panels 18 operated by the worker are provided, for example, in front of and to the left of the driver seat 17. The operation panel 18 includes a main shift lever 21, a steering lever 22, and the like.

The main shift lever 21 is provided to be movable obliquely in the front-rear direction. The main shift lever 21 is operated to tilt, so that the body 11 can be switched between forward and backward movement, and the forward and backward speed can be changed.

The steering rod 22 is provided to be movable obliquely in the left-right direction and the front-rear direction. The forward movement, the left turning, and the right turning of the body 11 can be switched by the tilting operation of the steering lever 22 in the left-right direction. Further, the harvesting device 14 can be raised and lowered by the tilting operation of the steering rod 22 in the front-rear direction.

The harvesting device 14 is disposed in front of the traveling device 12. The harvesting device 14 includes a dividing implement 23 at a front end thereof, and a cutter 24 at a rear side of the dividing implement 23. The dividing implement 23 and the cutter 24 are supported by the harvesting device frame 25F. A cutting cross frame 25L extending in the left-right direction is provided at the rear end of the cutting frame 25F. One end of the cutting main frame 25M is connected to the cutting cross frame 25L. The cutting main frame 25M extends from the cutting cross frame 25L to the rear side, and the other end portion (front lower and rear higher, rear end portion) thereof is rotatably connected to the frame of the machine body 11. By the tilting operation of the steering rod 22 in the front-rear direction, the air cylinder (not shown) is operated to swing the mowing main frame 25M, and by this swing, the mowing tool 23 and the cutting blade 24 are raised and lowered between a high raised position where they are raised from the ground and a lowered position where they are lowered to be close to the ground. When the machine body 11 is advanced in a state where the dividing implement 23 and the cutter 24 are located at the lowered position, the stems of the cereal stalks planted in the field are cut by the cutter 24 while being divided by the dividing implement 23.

The threshing device 15 and the grain box 16 are arranged side by side above the running device 12 and behind the harvesting device 14. The harvested straw is transported to the threshing device 15 by the harvesting device 14. The threshing device 15 conveys the stem root side of the grain stalks rearward by a threshing conveyor chain, and supplies the ear tip side of the grain stalks to a threshing chamber for threshing. Then, the grain is transferred from the threshing device 15 to the grain tank 16, and the grain is stored in the grain tank 16. A grain discharging auger 26 is connected to the grain tank 16, and grains stored in the grain tank 16 can be discharged to the outside of the machine by the grain discharging auger 26.

< continuously variable transmission >

Fig. 2 is a diagram showing the structure of HST 31.

The combine harvester 1 is mounted with an HST (Hydro Static Transmission) 31. The HST31 changes the speed of the power of the engine 32 (see fig. 3) and outputs the changed speed. The power output from the HST31 is transmitted to the left and right travel devices 12 via a swing mechanism (not shown). As the turning mechanism, for example, a turning mechanism having the following structure is adopted: a plurality of hydraulic clutches are provided, and by a combination of engagement (engagement) and release (disengagement) of these clutches, a state in which constant speed power is transmitted to the left and right travel devices 12, a state in which power that is lower in speed than power transmitted to one of the left and right travel devices 12 is transmitted to the other, a state in which power is transmitted only to one of the left and right travel devices 12, and a state in which power in the opposite direction to power transmitted to one of the left and right travel devices 12 is transmitted to the other can be obtained.

The HST31 has a closed circuit structure that connects the hydraulic pump 41 and the hydraulic motor 42 to the first oil passage 43 and the second oil passage 44 so that the hydraulic oil circulates between the hydraulic pump 41 and the hydraulic motor 42. The first oil passage 43 is connected to a first port 45 of the hydraulic pump 41 and a first port 46 of the hydraulic motor 42. The second oil passage 44 is connected to a second port 47 of the hydraulic pump 41 and a second port 48 of the hydraulic motor 42.

Further, the HST31 is additionally provided with a supply pump 51. The feed pump 51 is a fixed displacement hydraulic pump, and discharges the hydraulic oil to the feed oil passage 53 by rotation of the pump rotation shaft 52. The supply oil passage 53 is connected to the first oil passage 43 via a first check valve 54, and is connected to the second oil passage 44 via a second check valve 55. The supply oil passage 53 is connected to the oil tank 57 via a supply/relief valve 56.

The hydraulic pressure of the supply oil passage 53 is maintained at a predetermined supply pressure by the function of the supply relief valve 56. When the hydraulic pressure of the first oil passage 43 is lower than the hydraulic pressure of the supply oil passage 53, that is, the supply pressure, the first check valve 54 opens, and the hydraulic oil is supplied from the supply oil passage 53 to the first oil passage 43 via the first check valve 54. When the hydraulic pressure of the second oil passage 44 is lower than the supply pressure, the second check valve 55 opens, and the hydraulic oil is supplied from the supply oil passage 53 to the second oil passage 44 via the second check valve 55. Thereby, the hydraulic pressures of the first oil passage 43 and the second oil passage 44 are maintained at the supply pressure or higher.

The HST31 is configured as an integrated HST in which the hydraulic pump 41, the hydraulic motor 42, the first oil passage 43, the second oil passage 44, the first check valve 54, the second check valve 55, the supply/relief valve 56, and the like are housed in a single housing.

The hydraulic pump 41 is a variable displacement swash plate type piston pump, and includes a cylinder block, a plurality of pistons radially arranged in the cylinder block, a pump swash plate on which the pistons slide, and the like. The hydraulic pump 41 and the feed pump 51 have a common pump rotating shaft 52, and the cylinder block is provided so as to rotate integrally with the pump rotating shaft 52.

In order to change the inclination angle of the pump swash plate of the hydraulic pump 41, an electronically controlled servo cylinder 58 is provided. The servo cylinder 58 has a first pressure chamber 62 to which hydraulic pressure is supplied from the forward side pressure control valve 61 and a second pressure chamber 64 to which hydraulic pressure is supplied from the reverse side pressure control valve 63. The servo cylinder 58 has a rod 65 that is linearly moved by a pressure difference between the first pressure chamber 62 and the second pressure chamber 64, and the inclination angle of the swash plate of the pump is changed by the linear movement of the rod 65. A servo mechanism 66 is configured to control the inclination angle of the pump swash plate of the hydraulic pump 41 by the servo cylinder 58, the forward pressure control valve 61, and the reverse pressure control valve 63.

The discharge amount of the hydraulic oil from the hydraulic pump 41 decreases as the inclination angle of the pump swash plate of the hydraulic pump 41 with respect to the axis of the pump rotary shaft 52 (the rotation axis of the cylinder block) increases, and when the inclination angle of the pump swash plate is 90 °, the discharge of the hydraulic oil from the hydraulic pump 41 is stopped. In addition, the discharge direction of the working oil from the hydraulic pump 41 is reversed when the inclination angle of the pump swash plate exceeds 90 ° (when the inclination is reversed) and when the inclination angle does not reach 90 °.

The hydraulic motor 42 is a variable displacement swash plate type piston motor, and includes a motor rotary shaft 71, a cylinder block that rotates integrally with the motor rotary shaft 71, a plurality of pistons radially arranged in the cylinder block, a motor swash plate that presses the pistons, and the like. When the inclination angle of the motor swash plate of the hydraulic motor 42 with respect to the axis of the motor rotary shaft 71 is constant, the number of revolutions of the motor rotary shaft 71 increases as the amount of hydraulic oil supplied to the hydraulic motor 42, that is, the amount of hydraulic oil discharged from the hydraulic pump 41 increases.

In addition, when the amount of hydraulic oil supplied to the hydraulic motor 42 is constant, the rotation number of the motor rotary shaft 71 decreases as the inclination angle of the motor swash plate increases. To change the inclination angle of the motor swash plate of the hydraulic motor 42, a sub-shift piston 72 is provided. The sub-transmission piston 72 is connected to a low-speed switching valve 73 and a high-speed switching valve 74. By opening the low-speed switching valve 73 and closing the high-speed switching valve 74, hydraulic pressure is supplied from the low-speed switching valve 73 to the sub-transmission piston 72, so that the rod 75 of the sub-transmission piston 72 is positioned at the low-speed position, and the inclination angle of the swash plate of the motor becomes relatively large. On the other hand, the low-speed switching valve 73 is closed, and the high-speed switching valve 74 is opened to supply the hydraulic pressure from the high-speed switching valve 74 to the sub-transmission piston 72, so that the rod 75 of the sub-transmission piston 72 is positioned at the high-speed position, and the inclination angle of the motor swash plate is made relatively small. Therefore, the position of the swash plate of the motor can be switched between the following two stages by switching the opening/closing of the low-speed switching valve 73 and the high-speed switching valve 74: a high-speed side position where the number of rotations of the motor rotation shaft 71 becomes relatively large and a low-speed side position where the number of rotations of the motor rotation shaft 71 becomes relatively small.

< Electrical Structure >

Fig. 3 is a block diagram showing the main parts of the electrical structure of the combine harvester 1.

A single main ECU (Electronic Control Unit) 81 for overall integrated Control and a plurality of ECUs for individual specific Control are mounted on the combine harvester 1. Among the ECUs for individual concrete control, for example, an engine ECU82 for controlling the engine 32 and a travel control ECU83 for controlling the HST31 are included. The main ECU81, the engine ECU82, and the travel control ECU83 are structures each including a microcontroller Unit (MCU).

The main ECU81 is communicably connected to each ECU for individual specific control, i.e., the engine ECU82, the travel control ECU83, and the like. Further, to the main ECU81, an instrument panel 84 disposed on the operation panel 18 (see fig. 1) of the cab 13 is connected as a control target. The main ECU81 controls various instruments such as an odometer provided on the instrument panel 84 and a display. For example, when an abnormality occurs in the combine harvester 1, the main ECU81 transmits information relating to the abnormality to the dashboard 84, and causes the display to display the content of the abnormality. The display is constituted by a liquid crystal display, for example.

The travel control ECU83 is connected to and receives detection signals from a main shift lever sensor 85 and a steering lever sensor 86, the main shift lever sensor 85 outputting a detection signal corresponding to the operation position of the main shift lever 21, and the steering lever sensor 86 outputting a detection signal corresponding to the operation position of the steering lever 22.

The switch 87 provided on the operation panel 18 of the driver's cab 13 is connected to the travel control ECU83, and the switch 87 is used for other than travel control and swing control, and a signal corresponding to the state of the switch 87 is input. An example of the switch 87 is a threshing depth switch for adjusting the length of the grain bar entering the threshing device 15, that is, the threshing depth (こぎ deep さ). The threshing depth switch may be a switch that selectively sets the threshing depth to a first length (deep) and a second length (shallow) shorter than the first length, for example.

A swing mode switch is provided on the operation panel 18. The swing mode switch is a dial switch for switching the mode of swing control among a soft swing mode, a brake swing mode, and a swing (スピン) swing mode, and a soft position, a brake position, and a swing position corresponding to the soft swing mode, the brake swing mode, and the swing mode are set in the movable region. The swing mode switch has a knob that is held by a finger of an operator and is operated to rotate, and switches its position by the rotation operation of the knob, and outputs signals corresponding to each of the soft position, the brake position, and the rotation position.

Further, the travel control ECU83 is connected to and receives detection signals from a current sensor 88 and a swash plate position sensor 89, the current sensor 88 outputting detection signals corresponding to the values of currents supplied to the pressure control valves 61 and 63 included in the HST31, respectively, and the swash plate position sensor 89 outputting detection signals corresponding to the position (inclination angle from a reference position) of the swash plate of the hydraulic pump 41 included in the HST 31.

The main ECU81 receives information acquired by each ECU for individual specific control from detection signals of various sensors and the like, and transmits commands and information necessary for control of each ECU to each ECU. For example, the main ECU81 receives an engine start permission transmitted from the travel control ECU83, and transmits a start command of the engine 32 to the engine ECU 82. Further, the main ECU81 holds adjustment data for adjusting detection values obtained from the detection signals of the main shift lever sensor 85, the steering lever sensor 86, and the current sensor 88 connected to the travel control ECU83, and transmits the adjustment data to the travel control ECU 83.

The travel control ECU83 controls the pressure control valves 61 and 63, the low-speed switching valve 73, the high-speed switching valve 74, valves for switching engagement and release of the clutches provided in the swing mechanism, and the like included in the engine 32 and the HST31, in order to control travel and swing of the machine body 11, based on information obtained from the detection signals of the main shift lever sensor 85, the steering lever sensor 86, the current sensor 88, and the swash plate position sensor 89, information obtained from the signal input from the switch 87, and information input from the main ECU 81.

< Driving control >

The travel of the machine body 11 is controlled by the travel control ECU 83. In this travel control, the position of the main shift lever 21 is obtained from the detection signal of the main shift lever sensor 85.

When the position of the main shift lever 21 is the stop position, the respective opening degrees of the forward pressure control valve 61 and the reverse pressure control valve 63 of the HST31 are adjusted by controlling the currents supplied thereto so that the position of the swash plate of the hydraulic pump 41 is set to a position inclined at an angle of 90 °. Accordingly, since the hydraulic oil is not discharged from the hydraulic pump 41, the hydraulic motor 42 does not rotate, and the power is not output from the HST 31. Therefore, the traveling device 12 does not operate, and the machine body 11 stops.

When the main shift lever 21 is tilted to the front side from the stop position, the hydraulic pressure supplied from the pressure control valve 61 on the forward side to the first pressure chamber 62 of the servo cylinder 58 is made larger than the hydraulic pressure supplied from the pressure control valve 63 on the reverse side to the second pressure chamber 64 by the control of the current supplied to the pressure control valves 61, 63 of the HST 31. Thereby, a differential pressure is generated between the first pressure chamber 62 and the second pressure chamber 64, and the position of the pump swash plate of the hydraulic pump 41 is set to a position where the inclination angle is not more than 90 ° by the differential pressure. As a result, the hydraulic oil is discharged from the hydraulic pump 41, the hydraulic motor 42 receives the hydraulic oil and rotates, and the power in the forward direction is output from the HST 31. At this time, if the state of the swivel mechanism is a state in which power at a constant speed is transmitted to the left and right travel devices 12, the body 11 is caused to travel straight forward by rotating the left and right travel devices 12 in the forward direction at a constant speed.

When the main shift lever 21 is tilted from the stop position to the rear side, the hydraulic pressure supplied from the pressure control valve 63 on the reverse side to the second pressure chamber 64 is made larger than the hydraulic pressure supplied from the pressure control valve 61 on the forward side to the first pressure chamber 62 of the servo cylinder 58 by the control of the current supplied to the pressure control valves 61 and 63 of the HST 31. Thereby, a differential pressure is generated between the first pressure chamber 62 and the second pressure chamber 64, and the position of the pump swash plate of the hydraulic pump 41 is set to a position larger than the inclination angle 90 ° by the differential pressure. As a result, the hydraulic oil is discharged from the hydraulic pump 41 in the direction opposite to the forward direction, the hydraulic motor 42 receives the hydraulic oil and rotates in the direction opposite to the forward direction, and the power in the reverse direction is output from the HST 31. At this time, if the state of the swivel mechanism is a state in which power at a constant speed is transmitted to the left and right running devices 12, the power in the reverse direction output from the HST31 is transmitted to the running devices 12, so that the left and right running devices 12 are rotated in the reverse direction at a constant speed, and the machine body 11 is caused to travel straight rearward.

When the inclination angle of the swash plate of the hydraulic pump 41 is changed by controlling the current supplied to the pressure control valves 61 and 63 during forward movement or backward movement, the discharge amount of the hydraulic oil from the hydraulic pump 41 changes, and the rotation number of the hydraulic motor 42 changes. Therefore, by adjusting the inclination angle of the pump swash plate of the hydraulic pump 41 in accordance with the amount of inclination movement of the main shift lever 21 from the stop position, the speed of forward and backward movement of the machine body 11 can be steplessly changed.

Further, by switching the opening/closing of the low-speed switching valve 73 and the high-speed switching valve 74, it is possible to switch between two stages, a high-speed stage in which the rotation number of the hydraulic motor 42 becomes relatively large and a low-speed stage in which the rotation number becomes relatively small. Therefore, the forward and reverse speeds of the body 11 can be changed by switching between the high speed stage and the low speed stage. A sub-shift lever (not shown) may be provided on the operation panel 18 of the driver's seat 13, and switching between the high-speed stage and the low-speed stage may be instructed by operating the sub-shift lever.

< turning control >

When the steering lever 22 is operated to tilt from the center straight position to the left or right turning position during the straight travel (forward/reverse travel) of the machine body 11, the travel control ECU83 starts turning control for turning the machine body 11.

In the swing control, it is determined from an output signal of the swing mode switch which of the soft position, the braking position, and the rotational position the position of the swing mode switch is.

When the position of the swing mode switch is the soft position, valves for switching engagement/release of the clutches provided in the swing mechanism are controlled, and the swing mechanism is switched from a state in which power at a constant speed is transmitted to the left and right traveling devices 12 to a state in which power at a lower speed than power transmitted to one of the left and right traveling devices 12 is transmitted to the other.

When the position of the swing mode switch is the brake position, valves for switching engagement and release of the clutches provided in the swing mechanism are controlled, and the swing mechanism is switched from a state in which power at a constant speed is transmitted to the left and right travel devices 12 to a state in which power is transmitted to only one of the left and right travel devices 12.

When the position of the swing mode switch is the rotational position, valves for switching engagement and release of the clutches provided in the swing mechanism are controlled, and the swing mechanism is switched from a state in which power at a constant speed is transmitted to the left and right traveling devices 12 to a state in which power in a direction opposite to the direction of power transmitted to one of the left and right traveling devices 12 is transmitted to the other.

< concrete Structure for travel control >

Fig. 4 is a block diagram showing a specific configuration for running control.

The travel control ECU83 substantially includes, as processing units for travel control, a target swash plate position calculation unit 101, an actual swash plate position calculation unit 102, a deviation calculation unit 103, a PI (Proportional-Integral) calculation unit 104, an FF (feed forward) control unit 105, an addition unit 106, a forward side current detection unit 107, a forward side average current calculation unit 108, a forward side deviation calculation unit 109, a forward side PI calculation unit 110, a forward side FF control unit 111, a forward side addition unit 112, a reverse side current detection unit 113, a reverse side average current calculation unit 114, a reverse side deviation calculation unit 115, a reverse side PI calculation unit 116, a reverse side FF control unit 117, and a reverse side addition unit 118. Each processing unit is realized by software through program processing or by hardware such as a logic circuit.

The target swash plate position calculating unit 101 adjusts a detection value obtained by digitizing a detection signal of the main shift lever sensor 85 using adjustment data transmitted from the main ECU81 to the travel control ECU83, and sets the adjusted detection value to a value corresponding to the position of the main shift lever 21. For example, due to variations in assembly of the main shift lever sensor 85, a detection value of the main shift lever sensor 85 when the main shift lever 21 is located at the neutral position (reference position) may deviate from a reference value corresponding to the reference position. The adjustment data is data for adjusting the detection value of the main shift lever sensor 85 to eliminate the deviation. The target swash plate position calculating unit 101 calculates a target swash plate position, which is a target of the position of the pump swash plate of the hydraulic pump 41 corresponding to the position of the main shift lever 21, in a range equal to or less than a preset maximum vehicle speed, in accordance with a predetermined calculation formula. Note that, a map for specifying the relationship between the position of the main shift lever 21 and the target swash plate position may be stored in the memory of the travel control ECU83, and the target swash plate position calculation unit 101 may set the target swash plate position corresponding to the position of the main shift lever 21 in accordance with the map.

The actual swash plate position calculating unit 102 adjusts a detection value obtained by digitizing a detection signal of the pump swash plate position sensor 89 using adjustment data transmitted from the main ECU81 to the travel control ECU83, and sets the adjusted detection value to a value corresponding to an actual swash plate position that is an actual position (inclination angle) of the pump swash plate of the hydraulic pump 41. For example, due to variations in the assembly of the pump swash plate position sensor 89, the detection value of the pump swash plate position sensor 89 when the pump swash plate of the hydraulic pump 41 is at the reference position may deviate from the reference value corresponding to the reference position. The adjustment data is data for adjusting the detection value of the pump swash plate position sensor 89 to eliminate the deviation.

The deviation calculation unit 103 subtracts a value corresponding to an actual swash plate position calculated by the target swash plate position calculation unit 101 from a value corresponding to the target swash plate position calculated by the actual swash plate position calculation unit 102, thereby calculating a swash plate position deviation that is a deviation between the target swash plate position and the actual swash plate position.

The PI operation unit 104 calculates a target current value that is a target of the current value supplied to the pressure control valves 61 and 63 by adding a P control term obtained by multiplying the swash plate position deviation by a predetermined proportional gain (proportional operation) and an I control term obtained by multiplying the swash plate position deviation by a predetermined integral gain (integral operation).

The FF control unit 105 obtains a correction amount of the target current value corresponding to the swash plate position deviation, for example, following a map stored in a memory of the travel control ECU 83. For example, a map for specifying the relationship between the swash plate position deviation and the correction amount of the target current value is stored in the memory of the travel control ECU 83.

The addition unit 106 adds the target current value obtained by the PI operation unit 104 to the correction amount of the target current value set by the FF control unit 105.

The forward-side current detection unit 107 detects the value of the current supplied to the forward-side pressure control valve 61 from a detection signal of the current sensor 88 provided in association with the forward-side pressure control valve 61.

The forward-side average-current calculating unit 108 calculates a moving average of the current values detected by the forward-side current detecting unit 107, and calculates the value obtained thereby as an actual current value.

The forward-side deviation calculation unit 109 subtracts the actual current value calculated by the forward-side average current reading unit 108 from the sum of the target current value output from the addition unit 106 and the correction amount thereof, thereby calculating the current value deviation, which is the deviation between the sum of the target current value and the correction amount and the actual current value.

The forward PI operation unit 110 calculates the duty ratio of chopper control for controlling the current supplied to the pressure control valve 61 by adding a P control term obtained by multiplying the current value deviation by a predetermined proportional gain (proportional operation) and an I control term obtained by multiplying the current value deviation by a predetermined integral gain (integral operation).

The forward-side FF control unit 111 obtains a correction amount of the duty ratio corresponding to the current value deviation, for example, following a map stored in a memory of the travel control ECU 83. For example, a map for specifying the relationship between the current value deviation and the correction amount of the duty ratio is stored in the memory of the travel control ECU 83.

The forward-side adder 112 adds the duty ratio obtained by the forward-side PI calculator 110 to the adjustment amount of the duty ratio set by the forward-side FF controller 111. Then, the current supplied to the forward pressure control valve 61 is subjected to chopper control using a duty ratio corresponding to the added value.

The reverse side current detection unit 113 detects the value of the current supplied to the reverse side pressure control valve 61 from the detection signal of the current sensor 88 provided in association with the reverse side pressure control valve 61.

The backward-side average current calculation unit 114 obtains a moving average of the current values detected by the backward-side current detection unit 113, and calculates the value obtained thereby as an actual current value.

The reverse-side deviation calculating unit 115 calculates a current value deviation, which is a deviation between the target current value output from the adding unit 106 and the actual current value calculated by the reverse-side average current reading unit 114, and the added value of the correction amount thereof by subtracting the actual current value from the added value of the target current value output from the adding unit 106.

The backward PI operation unit 116 calculates the duty ratio of chopper control for controlling the current supplied to the pressure control valve 61 by adding a P control term obtained by multiplying the current value deviation by a predetermined proportional gain (proportional operation) and an I control term obtained by multiplying the current value deviation by a predetermined integral gain (integral operation).

The reverse-side FF control unit 117 obtains a correction amount of the duty ratio corresponding to the current value deviation, for example, following a map stored in a memory of the travel control ECU 83. For example, a map for specifying the relationship between the current value deviation and the correction amount of the duty ratio is stored in the memory of the travel control ECU 83.

The backward side addition unit 118 adds the adjustment amount of the duty ratio determined by the backward side PI operation unit 116 and the duty ratio set by the backward side FF control unit 117. Then, the current supplied to the pressure control valve 63 on the reverse side is subjected to chopping control using the duty ratio corresponding to the added value.

With the above configuration, during travel control when the respective units of the combine harvester 1 normally operate, the current supplied to the forward pressure control valve 61 and the backward pressure control valve 63 is controlled in accordance with a change in the position of the main shift lever 21, and the position of the pump swash plate of the hydraulic pump 41 is adjusted to steplessly change the forward and backward speeds of the machine body 11. The travel control is a travel control using a general method.

When an abnormality occurs in the combine harvester 1 and the travel control information required for the travel control by the normal method cannot be acquired, the travel control ECU83 executes the travel control by the retraction method different from the normal method. The contents of the travel control by the retraction method differ depending on the type of abnormality occurring in the combine harvester 1. Specific examples of the travel control (retraction control) by the retraction method are described below.

(1) Failure to obtain an abnormality in the position of the main shift lever 21

It is conceivable that the travel control ECU83 cannot acquire an abnormality in the position of the main shift lever 21 due to an abnormality such as a failure of the main shift lever sensor 85 or a disconnection of a signal line connected to the main shift lever sensor 85. When the abnormality occurs, the travel control ECU83 sets the switch 87 to be usable for the instruction of forward and backward movement of the machine body 11. Then, the information of the contents is transmitted from the travel control ECU83 to the main ECU81, and the contents used for the instruction to move the switch 87 forward or backward with respect to the body 11 are displayed on the display of the instrument panel 84 by the control of the main ECU 81. For example, the threshing depth switch can be used to instruct the forward and backward movement of the machine body 11, the forward movement of the machine body 11 can be instructed by turning on the threshing depth switch that sets the threshing depth to the first length, and the backward movement of the machine body 11 can be instructed by turning on the threshing depth switch that sets the threshing depth to the second length.

In this case, when the threshing depth switch for setting the threshing depth to the first length is turned on, the target swash plate position calculation unit 101 does not calculate the target swash plate position corresponding to the position of the main shift lever 21, and the target swash plate position, which is the target of the position of the pump swash plate of the hydraulic pump 41, is set to a fixed position on the forward side. On the other hand, when the threshing depth switch for setting the threshing depth to the second length is on, the target swash plate position calculation unit 101 does not calculate the target swash plate position corresponding to the position of the main shift lever 21, and the target swash plate position, which is the target of the position of the pump swash plate of the hydraulic pump 41, is set to a fixed position on the backward side.

In addition, in the case of correlation, the proportional gain and the integral gain of each of the PI operation unit 104, the forward PI operation unit 110, and the reverse PI operation unit 116 are lower than those in the normal control, for example, are set to 0 (zero). Thereby, the effectiveness of the feedback control term of the running control becomes zero, and the servo mechanism 66 including the servo cylinder 58 and the pressure control valves 61, 63 is feed-forward controlled.

(2) Communication between the master ECU81 and the travel control ECU83 is abnormal (one of them).

When the travel control ECU83 cannot acquire the adjustment data for detecting the position of the main shift lever 21 from the main ECU81 due to an abnormality in communication between the main ECU81 and the travel control ECU83, the detection value obtained from the detection signal of the main shift lever sensor 85 is not adjusted and is set to a value corresponding to the position of the main shift lever 21 as it is when the position of the main shift lever 21 is acquired by the target swash plate position calculation unit 101.

The proportional gain and the integral gain of each of the PI operation unit 104, the forward PI operation unit 110, and the reverse PI operation unit 116 are lower than those in the normal control, for example, are set to 0 (zero). Thereby, the effectiveness of the feedback control term of the running control becomes zero, and the servo mechanism 66 including the servo cylinder 58 and the pressure control valves 61, 63 is feed-forward controlled.

(3) The communication between the master ECU81 and the travel control ECU83 is abnormal (two thereof).

When the travel control ECU83 cannot acquire the adjustment data for calculating the value corresponding to the actual swash plate position of the pump swash plate of the hydraulic pump 41 from the main ECU81 due to an abnormality in communication between the main ECU81 and the travel control ECU83, the adjustment of the detection value obtained by digitizing the detection signal of the pump swash plate position sensor 89 is not performed when the value corresponding to the actual swash plate position is calculated by the actual swash plate position calculation unit 102, and the detection value is set to the value corresponding to the actual swash plate position as it is.

< Effect >

As described above, the HST31 exists between the engine 32 and the pair of left and right running devices 12. The HST31 includes a hydraulic pump 41 driven by the power of the engine 32 and a hydraulic motor 42 driven by pressure oil discharged from the hydraulic pump 41. The power of the hydraulic motor 42 is transmitted to the pair of left and right traveling devices 12.

In the normal state, the HST31 is controlled by a normal method, and the travel control information is used in the control. When an abnormality that the travel control information cannot be acquired occurs in the combine harvester 1, the method of controlling the HST31 is switched from the normal method to the retracting method that does not use the travel control information in accordance with the occurrence of the abnormality, and then the HST31 is controlled by the retracting method. Thus, even if an abnormality occurs in the combine harvester 1 in which the travel control information cannot be acquired, the HST31 can be retracted to transmit power from the HST31 to the travel device 12, thereby enabling the combine harvester 1 to continue traveling.

Therefore, when an abnormality occurs in which the travel control information cannot be acquired during the crossing of the railroad crossing by the combine harvester 1, the combine harvester 1 can cross the railroad crossing, and the risk of the combine harvester 1 getting stuck in the railroad crossing can be reduced. Further, when an abnormality occurs in which the travel control information cannot be acquired while the combine harvester 1 is traveling on a slope, it is possible to suppress the power from being transmitted from the HST31 to the travel device 12, and it is possible to reduce the risk of the combine harvester 1 traveling downhill against the intention of the driver. Further, when an abnormality occurs in the combine harvester 1 in the field, in which the travel control information cannot be acquired, the combine harvester 1 can be caused to move out of the field by self-travel.

This can improve safety and convenience when an abnormality occurs in the combine harvester 1 in which the travel control information cannot be acquired.

< modification example >

While one embodiment of the present invention has been described above, the present invention may be implemented in other embodiments.

For example, although the combine harvester 1 is described as an example of the harvester in the above-described embodiment, the present invention is not limited to the combine harvester 1, and can be applied to a harvester that harvests vegetables such as carrots, white radishes, green beans, and cabbages.

In the above-described configuration, design changes can be made within the scope of the items described in the claims.

The invention of the second aspect:

< combine harvester >

Fig. 5 is a right side view of the front of the combine harvester 1' showing one embodiment of the present invention.

The combine harvester 1' is a working vehicle that cuts and threshes grain stalks while traveling in a field. The body 11 ' of the combine harvester 1 ' is supported by a pair of left and right traveling devices 12 '. On the travelling means 12 ', in order to enable the combine harvester 1' to travel over the field, tracks with rough terrain traversing capability are used.

The machine body 11 'is provided with a driving platform 13', a harvesting device 14 ', a threshing device 15' and a grain box 16.

The cab 13 'is disposed above the front end of the traveling device 12'. The operator's seat 13 ' is provided with an operator's seat 17 ' on which an operator sits, and operation panels 18 ' operated by the operator are provided, for example, in front of and to the left of the operator's seat 17 '. The operation panel 18 ' includes a main shift lever 21 ' and a steering lever 22 '.

The main shift lever 21' is provided to be movable obliquely in the front-rear direction. The main shift lever 21 'is operated to tilt, so that the body 11' can be switched between forward and backward movement, and the forward and backward speed can be changed.

The steering rod 22' is provided to be movable obliquely in the left-right direction and the front-rear direction. The forward movement, the left turning, and the right turning of the body 11 'can be switched by the tilting operation of the steering rod 22' in the left-right direction. Further, the cutting device 14 'can be lifted and lowered by the tilting operation of the steering rod 22' in the front-rear direction.

The harvesting device 14 'is arranged in front of the travel device 12'. The harvesting device 14 'has a dividing implement 23' at its front end and a cutter 24 'behind the dividing implement 23'. The dividing device 23 ' and the cutter 24 ' are supported on the cutting device frame 25F '. A cutting cross frame 25L 'extending in the left-right direction is provided at the rear end of the cutting frame 25F'. One end of the main cutting frame 25M 'is connected to the transverse cutting frame 25L'. The cutting main frame 25M ' extends from the cutting cross frame 25L ' to the rear side, and the other end portion (front lower and rear higher, rear end portion) thereof is rotatably connected to the frame of the machine body 11 '. By the tilting operation of the steering rod 22 'in the front-rear direction, the air cylinder (not shown) can be operated to swing the mowing main frame 25M', and by this swing, the mowing tool 23 'and the cutting blade 24' can be raised and lowered between a raised position where they are raised high above the ground and a lowered position where they are lowered to a position where they are close to the ground. When the machine body 11 ' advances with the dividing implement 23 ' and the cutter 24 ' in the lowered position, the stalks are cut by the cutter 24 ' while the roots of the stalks planted in the field are divided by the dividing implement 23 '.

The threshing device 15 'and the grain box 16' are arranged in a left-right array above the running device 12 'and behind the harvesting device 14'. The harvested straw is transported by the harvesting device 14 'to the threshing device 15'. The threshing device 15' conveys the stem root side of the grain stalks backward through a threshing conveyor chain, and supplies the ear tip side of the grain stalks to a threshing chamber for threshing. The grain is then transported from the threshing device 15 ' to a grain bin 16 ', where the grain is stored in the grain bin 16 '. A grain discharging auger 26 'is connected to the grain tank 16', and grains stored in the grain tank 16 'can be discharged to the outside of the machine by the grain discharging auger 26'.

< continuously variable transmission >

Fig. 6 is a diagram showing the structure of HST 31'.

The combine harvester 1 'is mounted with an HST (Hydro Static Transmission) 31'. The HST31 'changes the speed of the power of the engine 32' (see fig. 7) and outputs the changed speed. The power output from the HST31 'is transmitted to the left and right travel devices 12' via a swivel mechanism (not shown). As the turning mechanism, for example, a turning mechanism having the following structure is adopted: a plurality of hydraulic clutches are provided, and by a combination of engagement (engagement) and release (disengagement) of these clutches, a state in which constant speed power is transmitted to the left and right travel devices 12 ', a state in which power having a lower speed than power transmitted to one of the left and right travel devices 12' is transmitted to the other, a state in which power is transmitted only to one of the left and right travel devices 12 ', and a state in which power having a direction opposite to the direction of power transmitted to one of the left and right travel devices 12' is transmitted to the other can be obtained.

The HST31 ' has a closed circuit structure connecting the hydraulic pump 41 ' and the hydraulic motor 42 ' between the first oil passage 43 ' and the second oil passage 44 ' to circulate the hydraulic oil between the hydraulic pump 41 ' and the hydraulic motor 42 '. The first oil passage 43 ' is connected to a first port 45 ' of the hydraulic pump 41 ' and a first port 46 ' of the hydraulic motor 42 '. The second oil passage 44 ' is connected to a second port 47 ' of the hydraulic pump 41 ' and a second port 48 ' of the hydraulic motor 42 '.

Further, the HST31 'is additionally provided with a supply pump 51'. The feed pump 51 ' is a fixed displacement hydraulic pump, and discharges the hydraulic oil to the feed oil passage 53 ' by rotation of the pump rotation shaft 52 '. The supply oil passage 53 ' is connected to the first oil passage 43 ' via a first check valve 54 ', and is connected to the second oil passage 44 ' via a second check valve 55 '. The supply oil passage 53 ' is connected to the tank 57 ' via a supply/relief valve 56 '.

The hydraulic pressure of the supply oil passage 53 'is maintained at a predetermined supply pressure by the function of the supply relief valve 56'. When the hydraulic pressure of the first oil passage 43 'is lower than the hydraulic pressure of the supply oil passage 53', that is, the supply pressure, the first check valve 54 'is opened, and the hydraulic oil is supplied from the supply oil passage 53' to the first oil passage 43 'via the first check valve 54'. When the hydraulic pressure of the second oil passage 44 ' is lower than the supply pressure, the second check valve 55 ' opens, and the hydraulic oil is supplied from the supply oil passage 53 ' to the second oil passage 44 ' via the second check valve 55 '. Thereby, the hydraulic pressures of the first oil passage 43 'and the second oil passage 44' are maintained at the supply pressure or higher.

The HST31 'is configured as an integrated HST in which the hydraulic pump 41', the hydraulic motor 42 ', the first oil passage 43', the second oil passage 44 ', the first check valve 54', the second check valve 55 ', the supply/relief valve 56', and the like are housed in a single housing.

The hydraulic pump 41' is a variable displacement swash plate type piston pump, and includes a cylinder block, a plurality of pistons radially arranged in the cylinder block, a pump swash plate on which the pistons slide, and the like. The hydraulic pump 41 'and the feed pump 51' share a pump rotating shaft 52 ', and the cylinder block is provided so as to rotate integrally with the pump rotating shaft 52'.

In order to change the inclination angle of the swash plate of the hydraulic pump 41 ', an electronically controlled servo cylinder 58' is provided. The servo cylinder 58 ' has a first pressure chamber 62 ' for supplying hydraulic pressure from the forward side pressure control valve 61 ' and a second pressure chamber 64 ' for supplying hydraulic pressure from the reverse side pressure control valve 63 '. The servo cylinder 58 ' has a rod 65 ' that is linearly moved by a pressure difference between the first pressure chamber 62 ' and the second pressure chamber 64 ', and the inclination angle of the pump swash plate is changed by the linear movement of the rod 65 '. A servo mechanism 66 ' is configured to control the inclination angle of the swash plate of the hydraulic pump 41 ' by the servo cylinder 58 ', the forward pressure control valve 61 ', and the reverse pressure control valve 63 '.

The discharge amount of the hydraulic oil from the hydraulic pump 41 'is reduced as the inclination angle of the pump swash plate of the hydraulic pump 41' with respect to the axis of the pump rotary shaft 52 '(the rotation axis of the cylinder block) is increased, and when the inclination angle of the pump swash plate is 90 °, the discharge of the hydraulic oil from the hydraulic pump 41' is stopped. In addition, the discharge direction of the working oil from the hydraulic pump 41' is reversed when the inclination angle of the pump swash plate exceeds 90 ° (when the inclination is reversed) and when the inclination angle does not reach 90 °.

The hydraulic motor 42 ' is a variable displacement swash plate type piston motor, and includes a motor rotary shaft 71 ', a cylinder block rotating integrally with the motor rotary shaft 71 ', a plurality of pistons radially arranged in the cylinder block, a motor swash plate pressed by the pistons, and the like. When the inclination angle of the motor swash plate of the hydraulic motor 42 ' with respect to the axis of the motor rotary shaft 71 ' is constant, the number of revolutions of the motor rotary shaft 71 ' increases as the amount of hydraulic oil supplied to the hydraulic motor 42 ', that is, the amount of hydraulic oil discharged from the hydraulic pump 41 ' increases.

In addition, when the amount of hydraulic oil supplied to the hydraulic motor 42 'is constant, the rotation number of the motor rotary shaft 71' decreases as the inclination angle of the motor swash plate increases. To change the inclination angle of the motor swash plate of the hydraulic motor 42 ', a sub-shift piston 72' is provided. The sub-transmission piston 72 ' is connected to a low-speed switching valve 73 ' and a high-speed switching valve 74 '. By opening the low-speed switching valve 73 'and closing the high-speed switching valve 74', hydraulic pressure is supplied from the low-speed switching valve 73 'to the sub-transmission piston 72', so that the rod 75 'of the sub-transmission piston 72' is positioned at the low-speed position, and the inclination angle of the swash plate of the motor becomes relatively large. On the other hand, the low-speed switching valve 73 'is closed, and the high-speed switching valve 74' is opened to supply the hydraulic pressure from the high-speed switching valve 74 'to the sub-transmission piston 72', so that the rod 75 'of the sub-transmission piston 72' is positioned at the high-speed position, and the inclination angle of the swash plate of the motor becomes relatively small. Therefore, the position of the swash plate of the motor can be switched between the following two stages by switching the opening/closing of the low-speed switching valve 73 'and the high-speed switching valve 74': a high-speed side position where the number of rotations of the motor rotation shaft 71 'becomes relatively large and a low-speed side position where the number of rotations of the motor rotation shaft 71' becomes relatively small.

< Electrical Structure >

Fig. 7 is a block diagram showing a main part of an electrical structure of the combine harvester 1.

A single main ECU (Electronic Control Unit) 81 'for overall integrated Control and a plurality of ECUs for individual specific Control are mounted on the combine harvester 1'. Among the ECUs for individual specific control, for example, an engine ECU82 'for controlling the engine 32' and a travel control ECU83 'for controlling the HST 31' are included. The main ECU81 ', the engine ECU82 ', and the travel control ECU83 ' are structures each including a microcontroller Unit (MCU).

The main ECU81 ' is communicably connected to each ECU for individual specific control, that is, the engine ECU82 ' and the travel control ECU83 ', and the like. The instrument panel 84 ' disposed on the operation panel 18 ' (see fig. 5) of the driver's cab 13 ' is connected to the main ECU81 ' as a control target. The main ECU81 'controls various instruments and displays such as an odometer provided on the instrument panel 84'. For example, when an abnormality occurs in the combine harvester 1 ', the main ECU81 ' transmits information relating to the abnormality to the dashboard 84 ' and causes the display of the content of the abnormality. The display is constituted by a liquid crystal display, for example.

To the travel control ECU83 ', a main shift lever sensor 85 ' and a steering lever sensor 86 ' are connected, and detection signals thereof are input, the main shift lever sensor 85 ' outputs a detection signal corresponding to the operation position of the main shift lever 21 ', and the steering lever sensor 86 ' outputs a detection signal corresponding to the operation position of the steering lever 22 '.

Further, to the travel control ECU83 ', a switch 87' provided on the operation panel 18 'of the driver's cab 13 'is connected, and a signal corresponding to the state of the switch 87' is input, the switch 87 'being a switch 87' other than the travel control and the swing control. An example of the switch 87 'is a threshing depth switch for adjusting the length of the grain bar entering the threshing device 15', that is, the threshing depth (こぎ deep さ). The threshing depth switch may be a switch that selectively sets the threshing depth to a first length (deep) and a second length (shallow) shorter than the first length, for example. In addition, the switch 87 'includes an abnormal starting switch that is operated to indicate abnormal starting of the engine 32'.

A rotary mode switch is provided on the operation panel 18'. The swing mode switch is a dial switch for switching the mode of swing control among a soft swing mode, a brake swing mode, and a swing (スピン) swing mode, and a soft position, a brake position, and a swing position corresponding to the soft swing mode, the brake swing mode, and the swing mode are set in the movable region. The swing mode switch has a knob that is held by a finger of an operator and is operated to rotate, and switches its position by the rotation operation of the knob, and outputs signals corresponding to each of the soft position, the brake position, and the rotation position.

Further, the travel control ECU83 'is connected to a current sensor 88' and a swash plate position sensor 89 ', and detection signals thereof are input, the current sensor 88' outputs detection signals corresponding to values of currents supplied to the pressure control valves 61 ', 63' included in the HST31 ', respectively, and the swash plate position sensor 89' outputs detection signals corresponding to a position (inclination angle) of a swash plate of the hydraulic pump 41 'included in the HST 31'.

The main ECU81 receives information acquired by each ECU for individual specific control from detection signals of various sensors and the like, and transmits commands and information necessary for control of each ECU to each ECU. For example, the main ECU81 'receives the engine start permission transmitted from the travel control ECU 83' and transmits a start command of the engine 32 'to the engine ECU 82'. Further, the memory provided in the main ECU81 ' holds adjustment data for adjusting detection values obtained from the respective detection signals of the main shift lever sensor 85 ', the steering lever sensor 86 ', and the pump swash plate position sensor 89 ' connected to the travel control ECU83 ', and the main ECU81 ' transmits the adjustment data to the travel control ECU83 '.

The travel control ECU83 'controls the pressure control valves 61', 63 ', the low-speed switching valve 73', the high-speed switching valve 74 ', and valves for switching engagement and release of the clutches provided in the swing mechanism included in the engine 32', the HST31 ', and the like, in order to control the travel and swing of the machine body 11', based on information obtained from the detection signals of the main shift lever sensor 85 ', the steering lever sensor 86', the current sensor 88 ', and the swash plate position sensor 89', information obtained from the signal input from the switch 87 ', and information input from the main ECU 81'.

< HST control >

Fig. 8 is a flowchart showing a flow of processing executed for control of the HST 31'.

For the running control, it is determined by the running control ECU83 'whether adjustment data is received from the main ECU 81' (step S11). As described above, the adjustment data includes adjustment data for adjusting a detection value obtained from a detection signal of the main shift lever sensor 85 '(hereinafter, referred to as "adjustment data of the main shift lever sensor 85') and adjustment data for adjusting a detection value obtained from a detection signal of the pump swash plate position sensor 89 '(hereinafter, referred to as" adjustment data of the pump swash plate position sensor 89').

When the combine harvester 1 ' is shipped at the factory, the same adjustment data as the adjustment data held in the memory of the main ECU81 ' is stored in the memory provided in the travel control ECU83 '. In the travel control ECU83 ' that has received the pieces of adjustment data from the master ECU81 ', it is determined whether or not the pieces of adjustment data received match the pieces of adjustment data stored in the memory of the travel control ECU83 ' (step S12).

Since the same pieces of adjustment data are held in the memory of the main ECU81 'and the memory of the travel control ECU 83' as long as both the main ECU81 'and the travel control ECU 83' are not replaced when shipped from the factory of the combine harvester 1 ', the pieces of adjustment data received by the travel control ECU 83' from the main ECU81 'match the pieces of adjustment data held in the memory of the travel control ECU 83' (yes in step S12). In this case, the slave running control ECU83 ' transmits a signal to permit cranking of the engine 32 ' to the master ECU81 ' (step S13). After the engine 32 ' is started, when an engine start switch provided on the operation panel 18 ' (see fig. 5) is operated, a start command for the engine 32 ' is transmitted from the main ECU81 ' to the engine ECU82 '. Receiving this, the engine 32 'is cranked by the engine ECU 82'.

Since the deviation of the assembly of the main shift lever sensor 85 ' causes the deviation of the detection value of the main shift lever sensor 85 ' from the reference value corresponding to the reference position when the main shift lever 21 ' is located at the reference position, the adjustment data of the main shift lever sensor 85 ' is provided so as to adjust the detection value of the main shift lever sensor 85 ' in accordance with the positional relationship between the main shift lever 21 ' and the main shift lever sensor 85 '. The travel control ECU83 'adjusts the detection value obtained from the detection signal of the main shift lever sensor 85' using the adjustment data of the main shift lever sensor 85 ', and controls the pressure control valves 61', 63 'of the HST 31' based on the adjusted detection value (hereinafter referred to as "adjusted main shift lever detection value") for the purpose of travel control (step S14).

Since the detection value of the pump swash plate position sensor 89 'when the pump swash plate of the hydraulic pump 41' is at the reference position deviates from the reference value corresponding to the reference position due to the variation in the assembly of the pump swash plate position sensor 89 ', the adjustment data of the pump swash plate position sensor 89' is set so as to adjust the detection value of the pump swash plate position sensor 89 'in accordance with the positional relationship between the pump swash plate and the pump swash plate position sensor 89'. The travel control ECU83 'adjusts the detection value obtained from the detection signal of the pump swash plate position sensor 89' using the adjustment data of the pump swash plate position sensor 89 ', and controls the pressure control valves 61', 63 'of the HST 31' based on the adjusted detection value (hereinafter referred to as "adjusted pump swash plate detection value") for the purpose of travel control (step S14).

In the travel control by the normal method, specifically, when the main shift lever detection value after the adjustment is a value indicating the stop position of the main shift lever 21 ', the respective opening degrees of the forward pressure control valve 61 ' and the reverse pressure control valve 63 ' of the HST31 ' are adjusted by controlling the currents supplied thereto so that the position of the swash plate of the hydraulic pump 41 ' is set to the position inclined at 90 °. Accordingly, since the hydraulic oil is not discharged from the hydraulic pump 41 ', the hydraulic motor 42 ' does not rotate, and the power is not output from the HST31 '. Therefore, the traveling device 12 'does not operate, and the machine body 11' stops.

When the main shift lever 21 'is tilted to the front side from the stop position, a value indicating a target swash plate position (a position where the tilt angle is less than 90 °) which is a target of the position of the pump swash plate of the hydraulic pump 41' corresponding to the detected value of the main shift lever after the adjustment is set, for example, in accordance with a predetermined calculation formula. Note that, a map for specifying the relationship between the main shift lever detection value and the value indicating the target swash plate position may be stored in the memory of the travel control ECU83 ', and a value indicating the target swash plate position corresponding to the position of the main shift lever 21' may be set in accordance with the map.

Then, the current supplied to the pressure control valves 61 ', 63 ' is feedback-controlled in accordance with the deviation between the value indicating the target swash plate position of the HST31 ' and the adjusted pump swash plate detection value. Accordingly, the hydraulic pressure supplied from the forward side pressure control valve 61 'to the first pressure chamber 62' of the servo cylinder 58 'is greater than the hydraulic pressure supplied from the reverse side pressure control valve 63' to the second pressure chamber 64 ', and the position of the swash plate of the hydraulic pump 41' is set to a position where the inclination angle is not more than 90 ° by the pressure difference between the first pressure chamber 62 'and the second pressure chamber 64'. As a result, the hydraulic oil is discharged from the hydraulic pump 41 ', the hydraulic motor 42 ' receives the hydraulic oil and rotates, and the power in the forward direction is output from the HST31 '. At this time, if the state of the swivel mechanism is a state in which power is transmitted at a constant speed to the left and right traveling devices 12 ', the body 11 ' is caused to travel straight forward by rotating the left and right traveling devices 12 ' at a constant speed in the forward direction.

When the main shift lever 21 'is tilted from the stop position to the rear side, a value indicating the target swash plate position (the position at which the tilt angle is larger than 90 °) of the hydraulic pump 41' corresponding to the adjusted main shift lever detection value is set, as in the case of being tilted to the front side.

Then, the current supplied to the pressure control valves 61 ', 63 ' is feedback-controlled in accordance with the deviation between the value indicating the target swash plate position of the HST31 ' and the adjusted pump swash plate detection value. Accordingly, the hydraulic pressure supplied from the reverse side pressure control valve 63 'to the second pressure chamber 64' of the servo cylinder 58 'is greater than the hydraulic pressure supplied from the forward side pressure control valve 61' to the first pressure chamber 62 ', and the position of the swash plate of the hydraulic pump 41' is set to a position where the inclination angle is greater than 90 ° by the differential pressure between the first pressure chamber 62 'and the second pressure chamber 64'. As a result, the hydraulic oil is discharged from the hydraulic pump 41 ' in the reverse direction to the forward direction, the hydraulic motor 42 ' receives the hydraulic oil and rotates in the reverse direction to the forward direction, and the power in the reverse direction is output from the HST31 '. At this time, if the state of the swivel mechanism is a state in which power of a constant speed is transmitted to the left and right traveling devices 12 ', the power in the reverse direction output from the HST31 ' is transmitted to the traveling devices 12 ' so that the left and right traveling devices 12 ' are rotated in the reverse direction at a constant speed, and the machine body 11 ' is made to travel straight backward.

Further, during forward travel or reverse travel, the opening/closing of the low-speed switching valve 73 ' and the high-speed switching valve 74 ' is switched, so that the hydraulic motor 42 ' can be switched between a high-speed stage in which the rotation number thereof is relatively large and a low-speed stage in which the rotation number thereof is relatively small. Therefore, the switching between the high-speed stage and the low-speed stage can change the forward and backward speeds of the body 11'. A sub-shift lever (not shown) may be provided on the operation panel 18 ' of the driver's cab 13 ', and switching between the high-speed stage and the low-speed stage may be instructed by operating the sub-shift lever.

On the other hand, when the main ECU81 ' is replaced after factory shipment of the combine harvester 1 ', the travel control ECU83 ' does not receive the pieces of adjustment data from the main ECU81 ' (no in step S11), or the travel control ECU83 ' receives the pieces of adjustment data from the main ECU81 ', but the received pieces of adjustment data do not match the pieces of adjustment data held in the memory of the travel control ECU83 '. In the case of this correlation (no in step S12), a signal to prohibit cranking of the engine 32 ' is transmitted from the travel control ECU83 ' to the master ECU81 ' (step S15).

Thereafter, the travel control ECU83 'determines whether or not an abnormal cranking instruction is input by operation of an abnormal cranking switch disposed on the operation panel 18' (see fig. 5), for example (step S16). Then, when an abnormal cranking instruction is input to the travel control ECU83 ', the slave travel control ECU83 transmits a signal that permits cranking for abnormal operation of the engine 32 ' to the master ECU81 ' (step S17). After receiving this, the slave ECU81 ' sends a cranking command of the engine 32 ' to the engine ECU82 ', and cranks the engine 32 ' by the engine ECU82 '.

Then, the travel control ECU 83' executes the travel control by a retraction method different from the normal method (step S18). The memory of the travel control ECU83 'holds default data different from adjustment data for adjusting a certain amount of the detection value obtained from the detection signal of the main shift lever sensor 85'. For example, the detection value of the main shift lever sensor 85 'when the main shift lever 21' is at the reference position is acquired for a plurality of individuals of the combine harvester 1 ', the average value of the deviation between the detection value and the reference value of the main shift lever sensor 85' corresponding to the reference position of the main shift lever 21 'is obtained, and the average value is held as default data in the memory of the travel control ECU 83'. In the travel control by the retraction method, the detection value obtained from the detection signal of the main shift lever sensor 85' is adjusted using the default data.

Then, a value indicating the target swash plate position of the hydraulic pump 41' is set in accordance with the adjusted detection value using the default data. The current supplied to the pressure control valves 61 ', 63 ' is feedforward controlled based on a value representing the target swash plate position of the HST31 '. That is, the target values of the currents supplied to the pressure control valves 61 ', 63' are set in accordance with the value indicating the target swash plate position of the HST31, and the currents of the target values are supplied to the pressure control valves 61 ', 63'.

< Effect >

As described above, the HST31 ' exists between the engine 32 ' and the pair of left and right running devices 12 '. The HST31 ' includes a hydraulic pump 41 ' driven by power of the engine 32 ', a hydraulic motor 42 ' driven by pressure oil discharged from the hydraulic pump 41 ', and a servo 66 ' for changing the position of the swash plate of the hydraulic pump 41 '. The power of the hydraulic motor 42 'is transmitted to the pair of left and right traveling devices 12'.

The travel control ECU83 ' that controls the servo 66 ' holds adjustment data for adjusting the detection value of the main shift lever sensor 85 '. On the other hand, the adjustment data is also held in the main ECU81 'communicably connected with the travel control ECU 83'. In factory shipment of the combine harvester 1 ', the same adjustment data is held in the travel control ECU83 ' and the main ECU81 ', but, for example, in the case where the main ECU81 ' is replaced after factory shipment of the combine harvester 1 ', the adjustment data held in the travel control ECU83 ' and the adjustment data held in the main ECU81 ' are different. In this case, when the adjustment data held in the travel control ECU83 'or the main ECU 81' is used for controlling the servo 66 ', there is a risk that the HST 31' performs a movement that violates the intention of the operator using the combine harvester 1 'because the adjustment data that is not suitable for the positional relationship between the main shift lever sensor 85' and the main shift lever 21 'is used for controlling the servo 66'.

Therefore, when the adjustment data held by the travel control ECU83 'and the adjustment data held by the main ECU 81' match, the detection value of the main shift lever sensor 85 'is adjusted using the matching adjustment data, and the servo 66' is controlled based on the adjusted detection value. This can prevent the use of adjustment data that is not suitable for the positional relationship between the main shift lever sensor 85 ' and the main shift lever 21 ' in the control of the servo mechanism 66 '. As a result, the HST 31' can be prevented from performing a movement contrary to the intention of the operator.

In the case where the adjustment data held by the travel control ECU83 and the adjustment data held by the main ECU81 'are different (including the case where the travel control ECU 83' does not receive the adjustment data from the main ECU81 '), the cranking of the engine 32' is prohibited. By not starting the engine 32 ', the HST 31' can be prevented from moving against the intention of the operator.

However, it is preferable that the switch 87 'provided on the operation panel 18' is provided with an abnormal starting switch, and starting for abnormal operation of the engine 32 'is permitted in accordance with an instruction of receiving abnormal starting of the engine 32' by an operation of the abnormal starting switch. By the abnormal operation of the engine 32 ', the combine harvester 1' can be driven to a repair facility or the like by itself.

The main gear lever 21 'of the main gear lever sensor 85' is operated from the neutral position to one side for forward movement of the combine harvester 1 'and from the neutral position to the other side for backward movement of the combine harvester 1'. During abnormal operation of the engine 32 ', the detection value of the main shift lever sensor 85' is adjusted using default data different from the adjustment data. Thus, the detection value of the main shift lever sensor 85 'can be adjusted by the average level to suppress the movement of the HST 31' against the intention of the operator. Then, a value indicating the target swash plate position of the hydraulic pump 41 ' is set in accordance with the adjusted detection value using the default data, and based on this, the combine harvester 1 can be advanced and retracted by performing feed-forward control on the current supplied to the pressure control valves 61 ', 63 '.

< modification example >

For example, in the above-described embodiment, when the respective pieces of adjustment data received by the travel control ECU83 'from the main ECU 81' do not match the respective pieces of adjustment data held in the memory of the travel control ECU83 ', the travel control by the retraction method is executed, the detection value of the main shift lever sensor 85' is adjusted using default data different from the pieces of adjustment data, and the current supplied to the pressure control valves 61 ', 63' is feedforward controlled based on the adjusted detection value by the default data. Without being limited to this, the current supplied to the pressure control valves 61 ', 63' may be feedforward controlled in the travel control by the retraction method.

That is, since the swash plate of the hydraulic pump 41 'is located at the neutral position when the engine 32' is stopped before cranking, the detection value of the pump swash plate position sensor 89 'before abnormal cranking of the engine 32' can be regarded as a value corresponding to the neutral position of the swash plate. Therefore, the memory of the travel control ECU83 ' can hold, for example, an intermediate value of the detection value obtained from the detection signal of the pump swash plate position sensor 89 ' as default data, and adjust the detection value of the pump swash plate position sensor 89 ' using a deviation between the default data and the detection value of the pump swash plate position sensor 89 ' before the abnormal start of the engine 32 '. Then, the current supplied to the pressure control valves 61 ', 63' can be feedback-controlled in accordance with the deviation between the value indicating the target swash plate position and the adjusted pump swash plate detection value.

When the pieces of adjustment data received by the travel control ECU83 ' from the main ECU81 ' do not match the pieces of adjustment data held in the memory of the travel control ECU83 ', the travel control ECU83 ' may transmit information on the pieces of adjustment data to the main ECU81 ', and the main ECU81 ' may control the display of the dashboard 84 ' to display the pieces of adjustment data used to instruct the switch 87 ', for example, the threshing depth switch, to move forward or backward with respect to the machine body 11 '. Then, when the threshing depth switch for setting the threshing depth to the first length is turned on, the target swash plate position of the pump swash plate of the hydraulic pump 41 ' is set to a fixed position on the forward side, and when the threshing depth switch for setting the threshing depth to the second length is turned on, the target swash plate position is set to a fixed position on the backward side, and the current supplied to the pressure control valves 61 ', 63 ' may be subjected to the feedforward control or the feedback control.

Further, each memory of the main ECU81 ' and the travel control ECU83 ' may hold adjustment data for adjusting a detection value obtained from a detection signal of the steering wheel sensor 86 ' (hereinafter, referred to as "adjustment data of the steering wheel sensor 86"). Since the detection value of the steering lever sensor 86 ' when the steering lever 22 ' is at the reference position deviates from the reference value corresponding to the reference position due to the variation in the assembly of the steering lever sensor 86 ', the adjustment data of the steering lever sensor 86 ' may be set so as to adjust the detection value of the steering lever sensor 86 ' in accordance with the positional relationship between the steering lever 22 ' and the steering lever sensor 86 '. The travel control ECU83 'may adjust a detection value obtained from a detection signal of the steering lever sensor 86' using adjustment data of the steering lever sensor 86 ', and control the pressure control valves 61', 63 'of the HST 31' for steering control based on the adjusted detection value.

In the above-described embodiment, the combine harvester 1 ' is described as an example of the work vehicle, but the present invention is not limited to the combine harvester 1 ', and can be applied to work vehicles other than the combine harvester 1 ' such as a harvester that harvests vegetables such as carrots, white radishes, green beans, and cabbages.

Claims

1. A travel control device for a harvester, the harvester comprising: an engine; a pair of left and right traveling devices; a power transmission device that includes a pump driven by power of the engine and a motor driven by pressure oil discharged from the pump, and that transmits power of the motor to the traveling device;

the travel control device is characterized by comprising:

an information acquisition means for acquiring information for travel control;

a normal control means for controlling the power transmission device by a normal method using the travel control information when the information acquisition means can acquire the travel control information in a normal state;

and a retraction control means for controlling the power transmission device by a retraction method not using the travel control information when the information acquisition means fails to acquire the abnormality of the travel control information.

2. The travel control device according to claim 1, wherein the harvester is provided with a shift operation member that is operated from a neutral position to one side in order to advance the harvester and from the neutral position to the other side in order to retreat the harvester, and an operation position detection mechanism that detects a position of the shift operation member,

the information acquisition means acquires the positional information of the shift operation member as the travel control information based on the detection signal input from the operation position detection means,

the normal control mechanism controls the power transmission device in the following manner: when the position information of the shift operation member acquired by the information acquisition means indicates the position on the one side with respect to the neutral position, the power transmission device outputs power in a direction to advance the harvester to the travel device, and when the position information of the shift operation member acquired by the information acquisition means indicates the position on the other side with respect to the neutral position, the power transmission device outputs power in a direction to retract the harvester to the travel device.

3. The travel control device according to claim 2, wherein the harvester further includes a switch operation member that switches between a first state and a second state,

the retraction control mechanism controls the power transmission device in the following manner: in the case of an abnormality in which the position information of the shift operation member cannot be acquired because the detection signal of the operation position detection means is not input, when the switch operation member is in the first state, power in a direction to advance the harvester is output from the power transmission device to the traveling device, and when the switch operation member is in the second state, power in a direction to retract the harvester is output from the power transmission device to the traveling device.

4. The travel control apparatus according to claim 3, wherein the power transmission device is a structure that further includes a servo mechanism that controls a position of a pump swash plate of the pump,

the normal control means sets a target position of the pump swash plate corresponding to the position of the shift operation member based on the position information of the shift operation member acquired by the information acquisition means, and performs feedback control of the servo mechanism so that the position of the pump swash plate coincides with the target position,

the retraction control means sets the target position of the pump swash plate to a fixed position on the forward side when the switch operation member is in the first state, and sets the target position of the pump swash plate to a fixed position on the backward side when the switch operation member is in the second state, and performs feed-forward control on the servo mechanism.

5. The travel control device according to claim 3 or 4, wherein the harvester further includes a threshing device that threshes grains from the straw,

the switch operation member is a threshing depth switch for selectively setting the length of a grain bar entering the threshing device to a first length and a second length shorter than the first length.

6. The travel control device according to any one of claims 2 to 5, wherein the harvester further includes a control device communicably connected to the travel control device,

the power transmission device is a structure further including a servo mechanism that controls a position of a pump swash plate of the pump,

in the control device, operation position adjustment data for adjusting in such a manner that the position detected by the operation position detecting mechanism is aligned with the actual position of the shift operating member is held,

the information acquisition mechanism acquires position information of the shift operation member from a detection signal input by the operation position detection mechanism using the operation position adjustment data

When the information acquisition means fails to acquire the positional information of the shift operation member due to the inability to use the operation position adjustment data, the retraction control means sets a target position of the pump swash plate corresponding to the position detected by the operation position detection means, and performs feed-forward control on the servo mechanism.

7. The running control apparatus according to any one of claims 1 to 6, wherein the power transmission device is a structure that further includes a servo mechanism that controls a position of a pump swash plate of the pump,

the harvester is provided with a swash plate position detection mechanism for detecting the position of the pump swash plate,

the information acquisition means acquires the position information of the pump swash plate as the traveling control information based on the detection signal input from the swash plate position detection means,

the normal control means sets a target position of the pump swash plate based on the position information of the pump swash plate, and performs feedback control on the servo means so that the position of the pump swash plate coincides with the target position,

the retraction control mechanism sets a target position of the pump swash plate and performs feed-forward control on the servo mechanism.

8. The travel control device according to claim 7, wherein the harvester further includes a control device communicably connected to the travel control device,

in the control device, swash plate position adjustment data for adjusting in such a manner that the position detected by the swash plate position detecting means is aligned with the actual position of the pump swash plate is held,

the information acquisition means acquires position information of the pump swash plate from the detection signal input by the swash plate position detection means using the swash plate position adjustment data,

when the information acquisition means fails to acquire the positional information of the pump swash plate due to the failure to use the swash plate position adjustment data, the retraction control means sets a target position of the pump swash plate based on the position detected by the swash plate position detection means, and performs feed-forward control on the servo mechanism.

9. A work vehicle, characterized by comprising:

an engine;

a pair of left and right traveling devices;

a power transmission device that includes a pump driven by power of the engine, a motor driven by pressure oil discharged from the pump, and a servo mechanism that changes a position of a swash plate of the pump, and that transmits power of the motor to the traveling device;

a detection object which is provided to be displaceable;

a sensor that outputs a detection value corresponding to a position of the detection object;

a first control unit that controls the servo mechanism;

a second control unit communicably connected to the first control unit;

the first control unit and the second control unit hold adjustment data for adjusting a detection value of the sensor in accordance with a positional relationship between the detection object and the sensor,

when the adjustment data held by the first control unit and the adjustment data held by the second control unit match, the first control unit adjusts the detection value of the sensor using the matching adjustment data, and controls the servo mechanism based on the adjusted detection value.

10. The work vehicle according to claim 9, characterized in that the first control portion prohibits cranking of the engine when the adjustment data held by the first control portion and the adjustment data held by the second control portion are different.

11. The work vehicle according to claim 10, characterized in that a receiving portion that receives an instruction of abnormal operation of the engine in a condition where cranking of the engine is prohibited by the first control portion is provided,

the first control unit allows the engine to start for the abnormal operation of the engine in response to the reception unit receiving the instruction for the abnormal operation of the engine.

12. The work vehicle according to claim 11, wherein the detection object is a shift operation member that is operated from a neutral position to one side for forward movement of the work vehicle and from the neutral position to the other side for reverse movement of the work vehicle,

the first control unit causes the first control unit to use default data, which is held separately from adjustment data, for adjustment of the detection value of the sensor during abnormal operation of the engine.

13. The work vehicle according to claim 11, further comprising a switch operating member that switches between a first state and a second state,

the detection object is a shift operation member that is operated from a neutral position to one side for forward movement of the work vehicle and from the neutral position to the other side for reverse movement of the work vehicle,

the first control unit controls the servo mechanism as follows: in the abnormal operation of the engine, when the switch operation member is in the first state, the swash plate of the pump is located at a predetermined position in the forward direction, and when the switch operation member is in the second state, the swash plate of the pump is located at a predetermined position in the backward direction.

14. The work vehicle according to claim 11, wherein the detection object is a swash plate of the pump,

the first control unit sets a target position of a swash plate of the pump and performs feed-forward control of the servo mechanism during abnormal operation of the engine.

15. The work vehicle according to claim 11, wherein the detection object is a swash plate of the pump,

the first control unit adjusts the detection value of the sensor before the engine starts for the abnormal operation of the engine, as a value corresponding to the neutral position of the swash plate of the pump, by using default data that is held separately from adjustment data by the first control unit, during the abnormal operation of the engine.

16. The work vehicle according to claim 11, wherein the detection target object is a steering member that is operated from a neutral position to one side for left turning of the work vehicle and is operated from the neutral position to the other side for right turning of the work vehicle,

the first control portion uses default data, which is held separately from adjustment data, for adjustment of the detection value of the sensor during abnormal operation of the engine.