JP6928583B2 - Work vehicle - Google Patents

Description

The present invention relates to a work vehicle such as a harvester that harvests grains.

For example, in a combine equipped with HST (Hydro Static Transmission), the HST hydraulic pump is driven by the power of the engine, and the hydraulic motor is driven by the oil discharged by the hydraulic pump. Power is transmitted to the left and right crawler. By driving the left and right crawlers at the same speed, the aircraft moves straight forward and backward, and by driving the left and right crawlers with a speed difference, the aircraft turns left and right.

The driver's cab is provided with a speed change lever that can be displaced from the neutral position to the front side and the rear side. In the configuration adopting the electronic control type (electronic servo type), a shift lever sensor that outputs a detection value according to the position of the shift lever is provided in addition to the shift lever. The detected value of the shift lever sensor is input to the ECU (Electronic Control Unit). Further, the HST is provided with a pump swash plate position sensor that outputs a detection value according 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. Will be done.

When the shift lever is operated from the neutral position to the front side or the rear side, the ECU sets the target position of the swash plate of the hydraulic pump based on the detection value of the shift lever sensor. Then, in the ECU, a servo mechanism that changes the position of the swash plate is controlled 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 detected value of the pump swash plate position sensor. Will be done. By changing the position of the swash plate of the hydraulic pump, the discharge direction and flow rate of oil from the hydraulic pump change, and the rotation direction and rotation speed of the hydraulic motor change.

Japanese Unexamined Patent Publication No. 2008-57358

The shift lever sensor and the pump diagonal plate position sensor include, for example, a potentiometer that outputs a voltage according to the amount of displacement of the object to be detected from the reference position. Therefore, the detection value of the sensor when the detection target is located at the reference position deviates from the reference value according to the reference position due to the variation in the assembly of the shift lever sensor and the pump swash plate position sensor. Therefore, at the time of factory shipment of the combine, adjustment data for adjusting the detection value of each sensor according to the positional relationship between the detection target and the sensor is stored in the ECU, and the adjustment is performed in the control of the HST servo mechanism by the ECU. Data is used.

However, when the memory in which the adjustment data is stored fails or the ECU is replaced together with the memory, the adjustment data that does not match the positional relationship between the sensor and the detection target is used for controlling the servo mechanism. In this case, the HST may move against the intention of the operator who operates the shift lever.

An object of the present invention is to provide a work vehicle capable of suppressing the use of adjustment data that does not match the positional relationship between the detection object and the sensor for controlling the servo mechanism.

In order to achieve the above object, the work vehicle according to the present invention includes an engine, a pair of left and right traveling devices, a pump driven by the power of the engine, a motor driven by pressure oil discharged from the pump, and an inclination of the pump. A power transmission device that includes a servo mechanism that changes the position of the plate and transmits the power of the motor to the traveling device, a detection target that is displaceable, and a sensor that outputs a detection value according to the position of the detection target. A first control unit that controls the servo mechanism and a second control unit that is communicably connected to the first control unit are included, and the first control unit and the second control unit detect sensor detection values. Adjustment data for adjusting according to the positional relationship between the object and the sensor is held, and the first control unit has the adjustment data held by the first control unit and the adjustment data held by the second control unit. When they match, the detection value of the sensor is adjusted using the matching adjustment data, and the servo mechanism is controlled based on the detected value after the adjustment.

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

The first control unit that controls the servo mechanism holds adjustment data that adjusts the detection value of the sensor. On the other hand, the adjustment data is also held in the second control unit that is communicably connected to the first control unit. When the work vehicle is shipped from the factory, the same adjustment data is held in the first control unit and the second control unit. However, for example, when the first control unit or the second control unit is replaced after the factory shipment, the first control unit and the second control unit have the same adjustment data. The adjustment data held in the control unit and the adjustment data held in the second control unit are different. In this case, if the adjustment data held in the first control unit or the second control unit is used to control the servo mechanism, the adjustment data that does not match the positional relationship between the sensor and the detection target is used to control the servo mechanism. As a result, the power transmission device may move against the intention of the operator who uses the work vehicle.

Therefore, when the adjustment data held in the first control unit and the adjustment data held in the second control unit match, the detection value of the sensor is adjusted using the matching adjustment data, and the adjustment is performed. The servo mechanism is controlled based on the later detected value. As a result, it is possible to prevent the adjustment data that does not match the positional relationship between the sensor and the detection target from being used for controlling the servo mechanism. As a result, it is possible to prevent the power transmission device from moving against the intention of the operator.

When the adjustment data held by the first control unit and the adjustment data held by the second control unit are different, the start of the engine may be prohibited. By not starting the engine, it is possible to prevent the power transmission device from moving against the intention of the operator.

However, the work vehicle is provided with a reception unit that receives an instruction for emergency operation of the engine in a situation where starting of the engine is prohibited, and the reception unit receives an instruction for emergency operation of the engine. , It is preferable that the start for emergency operation of the engine is permitted. The emergency operation of the engine makes it possible to drive the work vehicle to a repair shop or the like.

The object to be detected by the sensor may be a shift operating member that is operated from the neutral position to one side for the forward movement of the work vehicle and is operated from the neutral position to the other side for the backward movement of the work vehicle. In this case, during emergency operation of the engine, the detection value of the sensor may be adjusted using default data different from the adjustment data. The default data is data that adjusts the detection value of the sensor by a certain amount. For example, for a plurality of individuals in a work vehicle, the detection value of the sensor when the detection target is located at the reference position is acquired, and the deviation between the detection value and the reference value of the sensor according to the reference position of the detection target. The average value of the quantity may be obtained and the average value may be used as the default data. By adjusting the detection value of the sensor using the default data, the detection value of the sensor can be adjusted at an average level so that the movement of the power transmission device contrary to the intention of the operator is suppressed.

The work vehicle further includes a switch operating member that can be switched between a first state and a second state, and the object to be detected is operated from a neutral position to one side for the forward movement of the work vehicle and for the backward movement of the work vehicle. It is a shift operation member that is operated from the neutral position to the other side. During emergency operation of the engine, when the switch operation member is in the first state, the swash plate of the pump is located at a fixed position in the forward direction, and the switch operation member is In the second state, the servo mechanism may be controlled so that the swash plate of the pump is located at a fixed position in the reverse direction. As a result, the work vehicle can be moved forward and backward by operating the switch operating member.

When the object to be detected is the swash plate of the pump, the target position of the swash plate of the pump may be set and the servo mechanism may be feedforward controlled during an emergency operation of the engine.

Further, when the detection target is the swash plate of the pump, the swash plate of the pump is located in the neutral position when the engine is stopped before starting. Therefore, when the engine is in emergency operation, the engine is started for emergency operation. The detection value of the sensor may be adjusted by using default data different from the adjustment data so that the detection value of the previous sensor corresponds to the neutral position of the swash plate of the pump.

The detection object may be a steering member that is operated from the neutral position to one side for turning the work vehicle to the left and is operated from the neutral position to the other side for turning the work vehicle to the right. In that case, during emergency operation of the engine, default data other than the adjustment data may be used for adjusting the detection value of the sensor. As a result, as described above, the detection value of the sensor can be adjusted at an average level so that the movement of the power transmission device contrary to the intention of the operator is suppressed.

According to the present invention, it is possible to prevent adjustment data that does not match the positional relationship between the detection object and the sensor from being used for controlling the servo mechanism of the power transmission device, and the intention of the operator who uses the work vehicle for the power transmission device. It is possible to suppress the movement contrary to.

It is a right side view which shows the front part of the combine which concerns on one Embodiment of this invention. It is a figure which shows the structure of the HST mounted on a combine. It is a block diagram which shows the main part of the electric structure of a combine. It is a flowchart which shows the flow of the process executed for the control of HST.

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

<Combine>
FIG. 1 is a right side view showing the front part of the combine 1 according to the embodiment of the present invention.

The combine 1 is a work vehicle for cutting and threshing grain culms while traveling in a field. The body 11 of the combine 1 is supported by a pair of left and right traveling devices 12. In the traveling device 12, a crawler having an ability to run on rough terrain is adopted in order to enable the combine 1 to travel in the field.

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

The driver's cab 13 is arranged above the front end portion of the traveling device 12. The driver's cab 13 is provided with a driver's seat 17 on which an operator sits. For example, an operation panel 18 operated by an operator is provided in front of and to the left of the driver's seat 17. The operation panel 18 is provided with a main speed change lever 21, a steering lever 22, and the like.

The main speed change lever 21 is provided so as to be tiltable in the front-rear direction. By tilting the main speed change lever 21, the forward and reverse speeds of the airframe 11 can be switched, and the forward or reverse speed thereof can be changed.

The steering lever 22 is provided so as to be tiltable in the left-right direction and the front-rear direction. By tilting the steering lever 22 in the left-right direction, the aircraft 11 can be switched between straight-ahead, left-turning, and right-turning. Further, the cutting device 14 can be raised and lowered by tilting the steering lever 22 in the front-rear direction.

The cutting device 14 is arranged in front of the traveling device 12. The cutting device 14 is provided with a weeding tool 23 at its front end and a cutting blade 24 behind the weeding tool 23. The weeding tool 23 and the cutting blade 24 are supported by the cutting device frame 25F. At the rear end of the cutting device frame 25F, a cutting horizontal frame 25L extending in the left-right direction is provided. One end of the cutting main frame 25M is connected to the cutting horizontal frame 25L. The cutting main frame 25M extends rearward from the cutting horizontal frame 25L, and other ends (provided to be lowered forward and rear ends) are rotatably connected to the frame of the machine body 11. By tilting the steering lever 22 in the front-rear direction, a cylinder (not shown) can be operated to swing the cutting main frame 25M, and the swinging causes the weeding tool 23 and the cutting blade 24 to move to the ground. It goes up and down to the ascending position where it rises high from the ground and the descending position where the weeding tool 23 and the cutting blade 24 descend near the ground. When the machine body 11 advances with the weeding tool 23 and the cutting blade 24 in the descending position, the culm is separated by the weeding tool 23 while the culm is separated by the culm 23. Mowed by.

The threshing device 15 and the grain tank 16 are arranged side by side at a position above the traveling device 12 and behind the cutting device 14. The cut grain culm is transported to the threshing device 15 by the cutting device 14. The threshing device 15 transports the root side of the grain culm backward by the threshing feed chain, and supplies the tip side of the grain culm to the handling chamber to thresh. Then, the grains are transported from the threshing device 15 to the grain tank 16, and the grains are stored in the grain tank 16. A grain discharge auger 26 is continuously provided in the grain tank 16, and the grains stored in the grain tank 16 can be discharged to the outside of the machine by the grain discharge auger 26.

<Stepless transmission>
FIG. 2 is a diagram showing the configuration of HST31.

The combine 1 is equipped with an HST (Hydro Static Transmission) 31. The HST 31 shifts and outputs the power of the engine 32 (see FIG. 3). The power output by the HST 31 is transmitted to the left and right traveling devices 12 via a swivel mechanism (not shown), for example, a plurality of hydraulic clutches are provided, and the clutches are engaged (engaged with each other). A state in which constant-velocity power is transmitted to the left and right traveling devices 12 and a state in which power at a lower speed than that transmitted to one of the left and right traveling devices 12 is transmitted to the other by a combination of on) and release (off). And, a state in which power is transmitted to only one of the left and right traveling devices 12 and a state in which power transmitted to one of the left and right traveling devices 12 and power in the opposite direction are transmitted to the other are adopted. Will be done. ..

The HST 31 has a closed circuit configuration in which the hydraulic pump 41 and the hydraulic motor 42 are connected by 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. Have. The first oil passage 43 is connected to the first port 45 of the hydraulic pump 41 and the first port 46 of the hydraulic motor 42. The second oil passage 44 is connected to the second port 47 of the hydraulic pump 41 and the second port 48 of the hydraulic motor 42.

A charge pump 51 is attached to the HST 31. The charge pump 51 is a fixed-capacity hydraulic pump, and the hydraulic oil is discharged to the charge oil passage 53 by the rotation of the pump rotation shaft 52. The charge oil passage 53 is connected to the first oil passage 43 via the first check valve 54, and is connected to the second oil passage 44 via the second check valve 55. Further, the charge oil passage 53 is connected to the oil tank 57 via the charge relief valve 56.

The function of the charge relief valve 56 maintains the oil pressure of the charge oil passage 53 at a predetermined charge pressure. When the oil pressure of the first oil passage 43 becomes lower than the oil pressure of the charge oil passage 53, that is, the charge pressure, the first check valve 54 is opened, and the first oil passage from the charge oil passage 53 via the first check valve 54 is opened. Hydraulic oil is supplied to 43. Further, when the oil pressure of the second oil passage 44 becomes lower than the charge pressure, the second check valve 55 is opened, and hydraulic oil is supplied from the charge oil passage 53 to the second oil passage 44 via the second check valve 55. Will be done. As a result, the oil pressure of the first oil passage 43 and the second oil passage 44 is maintained above the charge pressure.

The HST 31 is an integrated type in which a hydraulic pump 41, a hydraulic motor 42, a first oil passage 43, a second oil passage 44, a first check valve 54, a second check valve 55, a charge relief valve 56, and the like are housed in a single case. It is configured as an HST.

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

An electronically controlled servo cylinder 58 is provided to change the inclination angle of the pump swash plate of the hydraulic pump 41. The servo cylinder 58 has a first pressure chamber 62 to which the oil pressure is supplied from the pressure control valve 61 on the forward side, and a second pressure chamber 64 to which the oil pressure is supplied from the pressure control valve 63 on the reverse side. Further, the servo cylinder 58 has a rod 65 that directly moves by the differential pressure between the first pressure chamber 62 and the second pressure chamber 64, and the linear movement of the rod 65 changes the inclination angle of the pump swash plate. Will be done. The servo cylinder 58, the pressure control valve 61 on the forward side, and the pressure control valve 63 on the reverse side constitute a servo mechanism 66 that controls the inclination angle of the pump swash plate of the hydraulic pump 41.

The larger the inclination angle of the pump swash plate with respect to the axis (rotation axis of the cylinder block) of the pump rotation shaft 52 of the hydraulic pump 41, the smaller the amount of hydraulic oil discharged from the hydraulic pump 41, and the inclination angle of the pump slop plate is 90. When °, the discharge of hydraulic oil from the hydraulic pump 41 is stopped. Further, when the inclination angle of the pump inclined plate exceeds 90 ° (when the inclination is reversed), the discharge direction of the hydraulic oil from the hydraulic pump 41 is reversed when the inclination angle is less than 90 °.

The hydraulic motor 42 is a variable displacement type swash plate type piston motor, and a motor rotating shaft 71, a cylinder block that rotates integrally with the motor rotating shaft 71, a plurality of pistons radially arranged in the cylinder block, and pistons are pressed against the hydraulic motor 42. It is equipped with a motor swash plate. When the inclination angle of the motor diagonal plate with respect to the axis of the motor rotating shaft 71 of the hydraulic motor 42 is constant, the larger the amount of hydraulic oil supplied to the hydraulic motor 42, that is, the larger the amount of hydraulic oil discharged from the hydraulic pump 41. , The number of rotations of the motor rotation shaft 71 increases.

Further, when the amount of hydraulic oil supplied to the hydraulic motor 42 is constant, the larger the inclination angle of the motor swash plate, the lower the rotation speed of the motor rotation shaft 71. An auxiliary speed change piston 72 is provided to change the inclination angle of the motor swash plate of the hydraulic motor 42. A low-speed switching valve 73 and a high-speed switching valve 74 are connected to the auxiliary transmission piston 72. The low-speed switching valve 73 is turned on, the high-speed switching valve 74 is turned off, and oil is supplied from the low-speed switching valve 73 to the auxiliary transmission piston 72, so that the rod 75 of the auxiliary transmission piston 72 is positioned at a low speed position. , The tilt angle of the motor swash plate becomes relatively large. On the other hand, the low-speed switching valve 73 is turned off, the high-speed switching valve 74 is turned on, and the flood control is supplied from the high-speed switching valve 74 to the auxiliary transmission piston 72, so that the rod 75 of the auxiliary transmission piston 72 is moved to the high-speed position. It is located and the tilt angle of the motor swash plate becomes relatively small. Therefore, by switching the low-speed switching valve 73 and the high-speed switching valve 74 on / off, the position of the motor swash plate is set to the position on the high-speed side where the rotation speed of the motor rotating shaft 71 becomes relatively large, and the rotation of the motor rotating shaft 71. It is possible to switch to two stages with the position on the low speed side where the number is relatively small.

<Electrical configuration>
FIG. 3 is a block diagram showing a main part of the electrical configuration of the combine 1.

The combine 1 is equipped with a single main ECU (Electronic Control Unit) 81 for overall overall control and a plurality of ECUs for individual specific control. The ECU for each specific control includes, for example, an engine ECU 82 for controlling the engine 32 and a traveling control ECU 83 for controlling the HST 31. The main ECU 81, the engine ECU 82, and the travel control ECU 83 each include a microcontroller unit (MCU: Micro Controller Unit).

The main ECU 81 is communicably connected to each ECU for individual specific control, that is, the engine ECU 82, the travel control ECU 83, and the like. Further, a meter panel 84 arranged on the operation panel 18 (see FIG. 1) of the driver's cab 13 is connected to the main ECU 81 as a control target. The main ECU 81 controls various instruments and indicators such as an odometer provided on the meter panel 84. For example, when an abnormality occurs in the combine 1, the main ECU 81 transmits information on the abnormality to the meter panel 84 and displays the content of the abnormality on the display. The display comprises, for example, a liquid crystal display.

The travel control ECU 83 includes a main shift lever sensor 85 that outputs a detection signal according to the operation position of the main shift lever 21, and a steering lever sensor 86 that outputs a detection signal according to the operation position of the steering lever 22. They are connected and their detection signals are input.

Further, the travel control ECU 83 is connected to a switch 87 provided on the operation panel 18 of the driver's cab 13, which is used for purposes other than travel control and turning control, and a signal corresponding to the state of the switch 87 is connected. Is entered. As an example of the switch 87, a sawing depth switch for adjusting the length of the grain culm entering the threshing device 15, that is, the sawing depth can be mentioned. The saw depth switch may be, for example, a switch that selectively sets the saw depth to a first length (depth) and a second length (shallow) shorter than the first length. The switch 87 also includes an emergency start switch that is operated to direct an emergency start of the engine 32.

The operation panel 18 is provided with a swivel mode switch. The swivel mode switch is a dial type switch for switching the swivel control mode between the soft swivel mode, the brake swivel mode, and the spin swivel mode, and its range of motion includes the soft swivel mode, the brake swivel mode, and the spin swivel mode. The soft position, brake position, and spin position corresponding to each are set. The swivel mode switch has a knob that is pinched and rotated by the operator's fingers, and its position is switched by the rotation operation of the knob, and signals corresponding to each position of the soft position, the brake position, and the spin position are output. Output.

Further, the traveling control ECU 83 includes a current sensor 88 that outputs a detection signal corresponding to the value of the current supplied to the pressure control valves 61 and 63 included in the HST 31, and a pump diagonal plate of the hydraulic pump 41 included in the HST 31. The pump diagonal plate position sensor 89 that outputs a detection signal corresponding to the position (tilt angle) of is connected, and the detection signals thereof are input.

The main ECU 81 receives information acquired from detection signals of various sensors by each ECU for individual specific control, and transmits commands and information required for control by each of these ECUs to each ECU. For example, the main ECU 81 receives an engine start permission transmitted from the travel control ECU 83, and transmits a command for starting the engine 32 to the engine ECU 82. Further, in the memory provided in the main ECU 81, the detection values acquired from the detection signals of the main speed change lever sensor 85, the steering lever sensor 86, and the pump diagonal plate position sensor 89 connected to the travel control ECU 83 are stored. Adjustment data for adjustment is held, and the main ECU 81 transmits the adjustment data to the travel control ECU 83.

The travel control ECU 83 includes information acquired from each detection signal of the main speed change lever sensor 85, steering lever sensor 86, current sensor 88, and pump diagonal plate position sensor 89, and information acquired from signals input from the switch 87. The pressure control valves 61 and 63, the low-speed switching valve 73, the high-speed switching valve 74, and the turning mechanism included in the engine 32 and the HST 31 are used to control the traveling and turning of the machine body 11 based on the information input from the main ECU 81. It controls a valve for switching the engagement / disengagement of each clutch provided in the.

<HST control>
FIG. 4 is a flowchart showing a flow of processing executed for controlling the HST 31.

For travel control, the travel control ECU 83 determines whether or not adjustment data has been received from the main ECU 81 (step S11). As described above, the adjustment data includes adjustment data for adjusting the detection value acquired from the detection signal of the main shift lever sensor 85 (hereinafter, referred to as “adjustment data of the main shift lever sensor 85”), and a pump. Adjustment data for adjusting the detection value acquired from the detection signal of the swash plate position sensor 89 (hereinafter, referred to as “adjustment data of the pump sloping plate position sensor 89”) is included.

At the time of shipment from the factory of the combine 1, the memory provided in the traveling control ECU 83 stores the same adjustment data as each adjustment data stored in the memory of the main ECU 81. The travel control ECU 83 that has received each adjustment data from the main ECU 81 determines whether or not each of the received adjustment data and each adjustment data stored in the memory of the travel control ECU 83 match (step S12).

If both the main ECU 81 and the travel control ECU 83 have not been replaced since the combine 1 was shipped from the factory, the same adjustment data is held in the memory of the main ECU 81 and the memory of the travel control ECU 83, so that the travel control is performed from the main ECU 81. Each adjustment data received by the ECU 83 and each adjustment data held in the memory of the travel control ECU 83 match (YES in step S12). In this case, a signal permitting the start of the engine 32 is transmitted from the travel control ECU 83 to the main ECU 81 (step S13). When the engine start switch provided on the operation panel 18 (see FIG. 1) is operated after the start permission of the engine 32 is permitted, the start command of the engine 32 is transmitted from the main ECU 81 to the engine ECU 82. In response to this, the engine 32 is started by the engine ECU 82.

Due to variations in the assembly of the main shift lever sensor 85, the detected value of the main shift lever sensor 85 when the main shift lever 21 is located at the reference position deviates from the reference value according to the reference position. The adjustment data is provided to adjust the detected value of the main shift lever sensor 85 according to the positional relationship between the main shift lever 21 and the main shift lever sensor 85. The travel control ECU 83 adjusts the detection value acquired from the detection signal of the main shift lever sensor 85 by using the adjustment data of the main shift lever sensor 85, and the detected value after the adjustment (hereinafter,) for travel control. , "Adjusted main shift lever detection value"), the pressure control valves 61 and 63 of the HST 31 are controlled (step S14).

Due to variations in the assembly of the pump swash plate position sensor 89, the detected value of the pump swash plate position sensor 89 when the pump swash plate of the hydraulic pump 41 is located at the reference position deviates from the reference value according to the reference position. The adjustment data of the swash plate position sensor 89 is provided to adjust the detected value of the pump swash plate position sensor 89 according to the positional relationship between the pump swash plate and the pump swash plate position sensor 89. The travel control ECU 83 uses the adjustment data of the pump swash plate position sensor 89 to adjust the detection value acquired from the detection signal of the pump swash plate position sensor 89, and the detected value after the adjustment is adjusted for travel control. The pressure control valves 61 and 63 of the HST 31 are controlled based on (hereinafter, referred to as “adjusted pump swash plate detection value”) (step S14).

In the traveling control by the usual method, specifically, when the adjusted main speed change lever detection value is a value indicating the stop position of the main speed change lever 21, the pressure control valve 61 on the forward side and the pressure control valve on the reverse side of the HST 31 By controlling the current supplied to 63, each of the opening degrees thereof is adjusted, and the position of the pump swash plate of the hydraulic pump 41 is set to the position of the inclination angle of 90 °. As a result, the hydraulic oil is not discharged from the hydraulic pump 41, so that the hydraulic motor 42 does not rotate and power is not output from the HST 31. Therefore, the traveling device 12 does not operate and the machine body 11 is stopped.

When the main speed change lever 21 is tilted forward from the stop position, for example, a target swash plate which is a target of the position of the pump swash plate of the hydraulic pump 41 according to the adjusted main speed change lever detection value according to a predetermined calculation formula. A value indicating a position (a position with an inclination angle of less than 90 °) is set. A map defining the relationship between the main shift lever detection value and the value indicating the target swash plate position is stored in the memory of the traveling control ECU 83, and the target swash plate corresponding to the position of the main shift lever 21 is stored according to the map. A value indicating the position may be set.

Then, the current supplied to the pressure control valves 61 and 63 is feedback-controlled according to the deviation between the value indicating the target swash plate position of the HST 31 and the adjusted pump swash plate detection value. As a result, 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 becomes larger than the hydraulic pressure supplied from the pressure control valve 63 on the reverse side to the second pressure chamber 64. Due to the differential pressure between the first pressure chamber 62 and the second pressure chamber 64, the position of the pump diagonal plate of the hydraulic pump 41 becomes a position where the inclination angle is less than 90 °. 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 turning mechanism is a state of transmitting constant speed power to the left and right traveling devices 12, the left and right traveling devices 12 rotate at a constant speed in the forward direction, so that the machine body 11 moves straight forward. ..

When the main speed change lever 21 is tilted rearward from the stop position, the target swash plate position (tilt angle 90) of the hydraulic pump 41 according to the adjusted main speed change lever detection value is the same as when the main speed change lever 21 is tilted to the front side. A value indicating (a position larger than °) is set.

Then, the current supplied to the pressure control valves 61 and 63 is feedback-controlled according to the deviation between the value indicating the target swash plate position of the HST 31 and the adjusted pump swash plate detection value. As a result, the hydraulic pressure supplied from the pressure control valve 63 on the reverse side to the second pressure chamber 64 of the servo cylinder 58 becomes larger than the hydraulic pressure supplied from the pressure control valve 61 on the forward side to the first pressure chamber 62. Due to the differential pressure between the first pressure chamber 62 and the second pressure chamber 64, the position of the pump diagonal plate of the hydraulic pump 41 becomes a position larger than the inclination angle of 90 °. As a result, the hydraulic oil is discharged from the hydraulic pump 41 in the direction opposite to that in the forward direction, the hydraulic motor 42 receives the hydraulic oil and rotates in the opposite direction 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 turning mechanism is a state of transmitting constant velocity power to the left and right traveling devices 12, the reverse power output from the HST 31 is transmitted to the traveling devices 12, and the left and right traveling devices 12 Rotates at a constant speed in the backward direction, so that the aircraft 11 moves straight backward.

Further, when moving forward or backward, by switching the low-speed switching valve 73 and the high-speed switching valve 74 on / off, the high-speed stage in which the rotation speed of the hydraulic motor 42 is relatively large and the low-speed stage in which the rotation speed is relatively small are two. You can switch to the stage. Therefore, the forward and reverse speeds of the airframe 11 can be changed by switching between the high-speed stage and the low-speed stage. It is preferable that the operation panel 18 of the driver's cab 13 is provided with an auxiliary shift lever (not shown), and the operation of the auxiliary shift lever is instructed to switch between the high speed stage and the low speed stage.

On the other hand, when the main ECU 81 is replaced after the combine 1 is shipped from the factory, the travel control ECU 83 does not receive each adjustment data from the main ECU 81 (NO in step S11), or the travel control ECU 83 adjusts each adjustment from the main ECU 81. Although the data is received, the received adjustment data and the adjustment data stored in the memory of the travel control ECU 83 do not match. In such a case (NO in step S12), a signal prohibiting the start of the engine 32 is transmitted from the traveling control ECU 83 to the main ECU 81 (step S15).

After that, the travel control ECU 83 determines whether or not an emergency start instruction is input by operating the emergency start switch arranged on the operation panel 18 (see FIG. 1), for example (step S16). Then, when an emergency start instruction is input to the travel control ECU 83, a signal permitting the main ECU 81 to start the engine 32 for emergency operation is transmitted from the travel control ECU 83 (step S17). In response to this, the main ECU 81 transmits a start command for the engine 32 to the engine ECU 82, and the engine ECU 82 starts the engine 32.

Then, the travel control ECU 83 executes travel control by a degenerate method different from the normal method (step S18). In the memory of the travel control ECU 83, in addition to the adjustment data, default data for adjusting the detection value acquired from the detection signal of the main speed change lever sensor 85 by a certain amount is held. For example, for a plurality of individuals of the combine 1, the detected value of the main speed change lever sensor 85 when the main speed change lever 21 is located at the reference position is acquired, and the main speed change lever 21 corresponds to the detected value and the reference position of the main speed change lever 21. The average value of the amount of deviation from the reference value of the speed change lever sensor 85 is obtained, and the average value is held in the memory of the travel control ECU 83 as default data. In the traveling control by the degeneracy method, the default data is used to adjust the detection value acquired from the detection signal of the main speed change lever sensor 85.

Then, a value indicating the target swash plate position of the hydraulic pump 41 is set according to the detected value after adjustment based on the default data. The current supplied to the pressure control valves 61 and 63 is feedforward controlled based on the value indicating the target swash plate position of the HST31. That is, the target value of the current supplied to the pressure control valves 61 and 63 is set according to the value indicating the target swash plate position of the HST 31, and the current of the target value is supplied to the pressure control valves 61 and 63.

<Effect>
As described above, the HST 31 is interposed between the engine 32 and the pair of left and right traveling devices 12. The HST 31 includes a hydraulic pump 41 driven by the power of the engine 32, a hydraulic motor 42 driven by the pressure oil discharged from the hydraulic pump 41, and a servo mechanism 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 ECU 83 that controls the servo mechanism 66 holds adjustment data for adjusting the detection value of the main speed change lever sensor 85. On the other hand, the adjustment data is also held in the main ECU 81 communicably connected to the travel control ECU 83. The same adjustment data is held in the travel control ECU 83 and the main ECU 81 when the combine 1 is shipped from the factory. For example, when the main ECU 81 is replaced after the combine 1 is shipped from the factory, the adjustment held in the travel control ECU 83 is held. The data and the adjustment data held in the main ECU 81 are different. In this case, when the adjustment data held in the travel control ECU 83 or the main ECU 81 is used to control the servo mechanism 66, the adjustment data that does not match the positional relationship between the main shift lever sensor 85 and the main shift lever 21 is the adjustment data that does not match the positional relationship between the main shift lever sensor 85 and the main shift lever 21. By being used for the control of the HST 31, the HST 31 may move contrary to the intention of the operator who uses the combine 1.

Therefore, when the adjustment data held in the travel control ECU 83 and the adjustment data held in the main ECU 81 match, the detected value of the main speed change lever sensor 85 is adjusted using the matching adjustment data. The servo mechanism 66 is controlled based on the detected value after adjustment. As a result, it is possible to prevent the adjustment data that does not match the positional relationship between the main speed change lever sensor 85 and the main speed change lever 21 from being used for the control of the servo mechanism 66. As a result, it is possible to prevent the HST 31 from moving against the intention of the operator.

When the adjustment data held by the travel control ECU 83 and the adjustment data held by the main ECU 81 are different (including the case where the travel control ECU 83 does not receive the adjustment data from the main ECU 81), the start of the engine 32 is prohibited. .. By not starting the engine 32, it is possible to prevent the HST 31 from moving against the intention of the operator.

However, the switch 87 provided on the operation panel 18 is provided with an emergency start switch, and in response to the emergency start instruction of the engine 32 being received by the operation of the emergency start switch, the emergency start switch of the engine 32 is received. It is preferable that the start for operation is allowed. The emergency operation of the engine 32 makes it possible to drive the combine 1 to a repair shop or the like.

The main speed change lever 21 of the main speed change lever sensor 85 is operated from the neutral position to one side for the forward movement of the combine 1, and is operated from the neutral position to the other side for the reverse movement of the combine 1. During emergency operation of the engine 32, the detected value of the main speed change lever sensor 85 is adjusted using default data different from the adjustment data. As a result, the detection value of the main speed change lever sensor 85 can be adjusted at an average level so that the movement of the HST 31 contrary to the intention of the operator is suppressed. Then, a value indicating the target swash plate position of the hydraulic pump 41 is set according to the detected value after adjustment based on the default data, and based on this, the current supplied to the pressure control valves 61 and 63 is feed-forward controlled. By doing so, the combine 1 can be moved forward and backward.

<Modification example>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other embodiments.

For example, in the above-described embodiment, when the adjustment data received from the main ECU 81 by the travel control ECU 83 and the adjustment data stored in the memory of the travel control ECU 83 do not match, the travel control by the reduction method is executed. The detected value of the main speed change lever sensor 85 is adjusted using default data different from the adjustment data, and the current supplied to the pressure control valves 61 and 63 is fed forward based on the detected value after adjustment based on the default data. It was supposed to be controlled. Not limited to this, the current supplied to the pressure control valves 61 and 63 may be feedforward controlled even in the traveling control by the degeneracy method.

That is, when the engine 32 is stopped before starting, the pump swash plate of the hydraulic pump 41 is located in the neutral position, so that the detection value of the pump swash plate position sensor 89 before the emergency start of the engine 32 is the neutral position of the pump swash plate. It can be regarded as a value according to the position. Therefore, for example, an intermediate value of the detection value acquired from the detection signal of the pump diagonal plate position sensor 89 is stored as default data in the memory of the traveling control ECU 83, and the default data and the pump before the emergency start of the engine 32 are stored. The detection value of the pump swash plate position sensor 89 can be adjusted by using the deviation from the detection value of the swash plate position sensor 89. Then, the current supplied to the pressure control valves 61 and 63 can be feedback-controlled according to the deviation between the value indicating the target swash plate position and the adjusted pump swash plate detection value.

If the adjustment data received by the travel control ECU 83 from the main ECU 81 and the adjustment data stored in the memory of the travel control ECU 83 do not match, for example, the travel control ECU 83 transmits information to that effect to the main ECU 81. Then, under the control of the main ECU 81, the display of the meter panel 84 may indicate that the switch 87, for example, the saw depth switch is used to indicate the forward / backward movement of the machine body 11. Then, when the saw depth switch for setting the saw depth to the first length is 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 the saw depth is set to the first. When the cutting depth switch set to 2 lengths is on, the target swash plate position is set to a fixed position on the reverse side, and the current supplied to the pressure control valves 61 and 63 is feedforward controlled or feedback controlled. It is good.

Further, in each memory of the main ECU 81 and the travel control ECU 83, adjustment data for adjusting the detection value acquired from the detection signal of the steering lever sensor 86 (hereinafter, referred to as “adjustment data of the steering lever sensor 86”). ) May be retained. Due to variations in the assembly of the steering lever sensor 86, the detected value of the steering lever sensor 86 when the steering lever 22 is located at the reference position deviates from the reference value according to the reference position. The adjustment data may be provided to adjust the detected value of the steering lever sensor 86 according to the positional relationship between the steering lever 22 and the steering lever sensor 86. The travel control ECU 83 uses the adjustment data of the steering lever sensor 86 to adjust the detection value acquired from the detection signal of the steering lever sensor 86, and adjusts the detection value after the adjustment for steering control. Based on this, the pressure control valves 61 and 63 of the HST 31 may be controlled.

In the above-described embodiment, the combine 1 is taken as an example of the work vehicle, but the present invention is not limited to the combine 1, but other than the combine 1, such as a harvester for harvesting vegetables such as carrots, radishes, green soybeans, and cabbage. It can be applied to the amount of workers.

In addition, various design changes can be made to the above-mentioned configuration within the scope of the matters described in the claims.

1: Combine (work vehicle)
12: Traveling device 21: Main speed change lever 22: Steering lever 31: HST (power transmission device)
32: Engine 41: Hydraulic pump (pump)
42: Hydraulic motor (motor)
66: Servo mechanism 81: Main ECU (second control unit)
83: Travel control ECU (first control unit)
85: Main shift lever sensor (sensor)
86: Steering lever sensor (sensor)
87: Switch (switch operating member)
89: Pump swash plate position sensor (sensor)

Claims (8)

With the engine
A pair of left and right traveling devices and
Power to transmit the power of the motor to the traveling device, including a pump driven by the power of the engine, a motor driven by the pressure oil discharged from the pump, and a servo mechanism for changing the position of the swash plate of the pump. Transmission device and
Displaceable detection objects and
A sensor that outputs a detection value according to the position of the detection target, and
The first control unit that controls the servo mechanism and
Including the first control unit and the 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 according to the positional relationship between the detection target 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 uses the matching adjustment data to obtain a detection value of the sensor. A work vehicle that adjusts and controls the servo mechanism based on the detected value after the adjustment. The operation according to claim 1, wherein the first control unit prohibits the start of the engine 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. vehicle. A reception unit that receives an instruction for emergency operation of the engine in a situation where the start of the engine is prohibited by the first control unit.
The work vehicle according to claim 2, wherein the first control unit permits the reception unit to start the engine for emergency operation in response to receiving an instruction for emergency operation of the engine. The detection object is a shift operation member that is operated from the neutral position to one side for the forward movement of the work vehicle and is operated from the neutral position to the other side for the backward movement of the work vehicle.
The work vehicle according to claim 3, wherein the first control unit uses default data held by the first control unit separately from the adjustment data for adjusting the detection value of the sensor during an emergency operation of the engine. It further includes a switch operating member that can switch between the first state and the second state.
The detection object is a shift operation member that is operated from the neutral position to one side for the forward movement of the work vehicle and is operated from the neutral position to the other side for the backward movement of the work vehicle.
In the first control unit, when the switch operating member is in the first state during emergency operation of the engine, the swash plate of the pump is located at a fixed position in the forward direction, and the switch operating member is the second. The work vehicle according to claim 3, wherein the servo mechanism is controlled so that the swash plate of the pump is located at a fixed position in the reverse direction when the pump is in the state. The object to be detected is the swash plate of the pump.
The work vehicle according to claim 3, wherein the first control unit sets a target position of a swash plate of the pump and feedforward-controls the servo mechanism during an emergency operation of the engine. The object to be detected is the swash plate of the pump.
During the emergency operation of the engine, the first control unit sets the detection value of the sensor before the start for the emergency operation of the engine as a value corresponding to the neutral position of the swash plate of the pump. The work vehicle according to claim 3, wherein the detection value of the sensor is adjusted by using the default data held separately from the adjustment data. The detection object is a steering member that is operated from the neutral position to one side for turning left of the work vehicle and is operated from the neutral position to the other side for turning right of the work vehicle.
The work vehicle according to claim 3, wherein the first control unit uses default data held by the first control unit separately from the adjustment data for adjusting the detection value of the sensor during an emergency operation of the engine.

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