JP6910970B2 - Control device for work vehicles - Google Patents

Description

The present invention relates to a control device for a work vehicle such as a combine harvester.

Conventionally, a combine equipped with a hydrostatic continuously variable transmission (HST: Hydro Static Transmission) is widely known. The hydrostatic continuously variable transmission is equipped with a hydraulic pump and a hydraulic motor. In a combine equipped with a hydrostatic stepless transmission, the hydraulic pump is driven by the power of the engine, the hydraulic motor is driven by the oil discharged by the hydraulic pump, and the power of the hydraulic motor is transmitted to the left and right crawler.

The hydraulic circuit including the hydraulic pump and the hydraulic motor has, for example, a closed circuit circuit configuration, and the hydraulic pump is provided with a servo piston for changing the angle of the swash plate. By changing the angle of the slant 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. The servo piston drive system includes a mechanical type in which a shift lever provided on the operation panel of the driver's cab is mechanically connected to the servo piston to operate the servo piston by operating the shift lever, and two proportional decompression controls. There is an electronic control type (electronic servo type) in which the current supplied to the pressure control valve including the valve is controlled and the servo piston is moved by the hydraulic pressure supplied from the pressure control valve to the servo piston.

Japanese Unexamined Patent Publication No. 2009-30693

In a hydrostatic continuously variable transmission that uses an electronic control system, if the servo mechanism including the servo piston and pressure control valve fails, the angle of the slant plate of the hydraulic pump becomes uncontrollable, and the power transmitted from the hydraulic motor to the crawler. Becomes out of control and the combine behavior becomes unstable.

An object of the present invention is to provide a control device for a work vehicle capable of stabilizing the behavior of the work vehicle when the servo mechanism is abnormal.

In order to achieve the above object, the control device for a 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, and a motor driven by a pressure oil discharged from the pump. It is a control device used for work vehicles equipped with a servo mechanism that controls the angle of the pump slant plate of the pump and a stepless transmission including the above, and a power transmission device that transmits the power of the motor to a pair of left and right traveling devices. It includes an abnormality detecting means for detecting an abnormality in the servo mechanism and a fail-safe means for executing a fail-safe operation for stabilizing the behavior of the work vehicle in response to the detection of the abnormality by the abnormality detecting means.

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 continuously variable transmission including a pump driven by the power of the engine and a motor driven by the pressure oil discharged from the pump, and a servo mechanism for controlling the angle of the slant plate of the pump. By controlling the angle of the swash plate of the pump, the discharge direction and flow rate of oil from the pump are controlled, and the rotation direction and rotation speed of the motor are controlled.

When an abnormality such as a failure occurs in the servo mechanism and the abnormality is detected, a fail-safe operation for stabilizing the behavior of the work vehicle is executed. Therefore, it is possible to stabilize the behavior of the work vehicle when the servo mechanism is abnormal.

The continuously variable transmission and the servo mechanism may be provided corresponding to each of the pair of left and right traveling devices. In this case, the fail-safe means corresponds to each of the pair of left and right traveling devices as a fail-safe operation in response to the detection of an abnormality in the servo mechanism corresponding to one of the pair of left and right traveling devices by the abnormality detecting means. The servo mechanism corresponding to each of the pair of left and right traveling devices may be controlled so that the output from both of the continuously variable transmissions is stopped. As a result, the machine body of the work vehicle can be stopped, and the behavior of the work vehicle can be stabilized by stopping the machine body.

The traveling device is provided with an axle to which power is transmitted from the power transmission device, a stepless transmission and a servo mechanism are provided corresponding to each of the pair of left and right traveling devices, and the power transmission device is a pair of left and right traveling devices. It may be configured to include a clutch that is engaged in order to match the rotation speeds of the axles provided in each of the above. In this case, the fail-safe means engages the clutch as a fail-safe operation in response to the detection of an abnormality in the servo mechanism corresponding to one of the pair of left and right traveling devices by the abnormality detecting means. The servo mechanism corresponding to the other of the pair of left and right traveling devices may be controlled so that the output from the continuously variable transmission corresponding to the other of the traveling devices continues. As a result, the motor of the continuously variable transmission corresponding to the normally operating servo mechanism can be driven, and the power from the motor can drive the machine while stabilizing the behavior of the work vehicle.

The servo mechanism includes a servo piston that works with the pump diagonal plate, a forward control valve that supplies hydraulic pressure to the servo piston to position the servo piston within a predetermined forward range, and a servo piston within a predetermined reverse range to the servo piston. It is equipped with a reverse control valve that supplies hydraulic pressure to position the pump, and when the servo piston is located within the forward range, the pump sloping plate makes an angle at which pressure oil in the forward direction is discharged from the pump, and the servo piston When the pump is located within the reverse range, the pump slab is provided at an angle at which the pressure oil in the reverse direction is discharged from the pump, and the pump moves the work vehicle forward by supplying the pressure oil in the forward direction. The configuration may be such that the power in the direction is output and the power in the direction in which the work vehicle moves backward is output by supplying the pressure oil in the reverse direction. In this configuration, the fail-safe means allows control of the reverse control valve as a fail-safe operation when an abnormality of the forward control valve is detected by the abnormality detection means, and the abnormality detection means causes an abnormality of the reverse control valve. If detected, control of the forward control valve may be allowed as a fail-safe operation. As a result, the aircraft can travel forward under the control of the forward control valve that operates normally, and the aircraft can travel backward under the control of the reverse control valve that operates normally. Therefore, the machine body can be driven while stabilizing the behavior of the work vehicle.

The work vehicle may further be equipped with an operating member that is operably provided between the forward position on one side and the reverse position on the other side with respect to the neutral position. In this case, the control device includes a position detecting means for detecting the position of the operating member, a swash plate angle detecting means for detecting the angle of the pump sloping plate, and an operating member for detecting the angle of the pump sloping plate by the position detecting means. The configuration further includes a control means for controlling the servo mechanism so as to match the target angle according to the position, and the abnormality detecting means has a constant deviation between the target angle and the angle detected by the swash plate angle detecting means. When the above state is maintained for a certain period of time, it may be detected that the servo mechanism is abnormal.

The fail-safe operation when an abnormality of the servo mechanism is detected may be an operation of stopping the engine. By stopping the engine, the machine body can be stopped, and by stopping the machine body, the behavior of the work vehicle can be stabilized.

The fail-safe operation may be an operation of putting the engine in the idling state, or depending on the position of the operating member detected by the position detecting means matching the neutral position after the engine is in the idling state. It may be an operation of stopping the engine. By setting the engine in the idling state, the running speed of the machine body can be suppressed, so that the running speed of the machine body can be ensured while stabilizing the behavior of the work vehicle.

Further, the power transmission device further includes a control valve that switches the angle of the motor slant plate of the motor between a first angle at which the rotation of the motor is relatively low and a second angle at which the rotation of the motor is relatively high. In the case of the configuration, as a fail-safe operation, the swash plate of the motor may be set to the first angle under the control of the control valve. As a result, the traveling speed of the machine body can be further suppressed, and the behavior of the work vehicle can be further stabilized.

The fail-safe means further includes a storage means for storing the detection of the abnormality when the abnormality of the servo mechanism is detected by the abnormality detecting means, and the fail-safe means stores that the abnormality of the servo mechanism is detected in the storage means. During that time, the engine may be prohibited from starting. If the engine is started when the abnormality is not resolved, the work vehicle may behave in an unstable manner. However, by prohibiting the engine from starting, the unstable behavior of the work vehicle can be suppressed. Can be done.

According to the present invention, it is possible to stabilize the behavior of the work vehicle when the servo mechanism is abnormal.

It is a right side view which shows the front part of a combine. It is a figure which shows a part structure of the drive transmission system of a combine. It is sectional drawing which shows the remaining part of the drive transmission system, and shows the drive transmission system from the hydraulic motor of the left side HST and the right side HST to a traveling device. It is a block diagram which shows the main part of the electric structure of the combine which concerns on one Embodiment of this invention. It is a flowchart which shows the flow of fail-safe control. It is a flowchart which shows the flow of the fail safe control which concerns on other embodiment. It is a flowchart which shows the flow of the fail safe control which concerns on still another Embodiment.

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 rod 23 at its front end, and is provided with a cutting blade 24 behind the weeding rod 23. The weed rod 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 swing causes the weed rod 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 rod 23 and the cutting blade 24 descend near the ground. When the machine body 11 advances with the weed rod 23 and the cutting blade 24 in the descending position, the culm is separated by the weed rod 23 while the culm is separated by the weed 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 a partial configuration of the drive transmission system 32 of the combine 1. In FIG. 2, the power transmission system from the engine 31 to the drive transmission system 32 is shown in a skeleton diagram, and the configurations of the drive transmission system 32 with respect to the left side HST33 and the right side HST34 are shown in the hydraulic circuit diagram.

The combine 1 is equipped with an engine 31 and a drive transmission system 32 that transmits the power of the engine 31 to the traveling device 12.

The drive transmission system 32 includes a left side HST (Hydro Static Transmission) 33 and a right side HST 34.

The left HST 33 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 left HST 33. 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. The 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 left HST 33 accommodates 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 in a single case. It is configured as a body type 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 piston 58 is provided to change the inclination angle of the pump swash plate of the hydraulic pump 41. The servo piston 58 has a first pressure chamber 62 to which the oil pressure is supplied from the forward pressure control valve 61, and a second pressure chamber 64 to which the oil pressure is supplied from the reverse pressure control valve 63. Further, the servo piston 58 has a rod 65 that linearly moves by the differential pressure between the first pressure chamber 62 and the second pressure chamber 64, and the linear motion of the rod 65 changes the inclination angle of the pump swash plate. Will be done. The servo piston 58, the forward pressure control valve 61, and the reverse pressure control valve 63 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. At °, 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 is a motor rotating shaft 71, a cylinder block 72 that rotates integrally with the motor rotating shaft 71 (see FIG. 3), and a plurality of hydraulic motors arranged radially in the cylinder block 72. The piston 73 (see FIG. 3) and the motor swash plate 74 (see FIG. 3) to which the piston 73 is pressed are provided. When the inclination angle of the motor swash plate 74 with respect to the axis of the motor rotation shaft 71 of the hydraulic motor 42 (rotational axis of the cylinder block) is constant, the amount of hydraulic oil supplied to the hydraulic motor 42, that is, the hydraulic pump 41 discharges the hydraulic oil. The larger the amount of hydraulic oil, the higher the rotation speed of the motor rotation shaft 71.

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 74, the lower the rotation speed of the motor rotation shaft 71. An auxiliary speed change piston 75 is provided in order to change the inclination angle of the motor swash plate 74 of the hydraulic motor 42. A low-speed switching valve 76 and a high-speed switching valve 77 are connected to the auxiliary transmission piston 75. The low-speed switching valve 76 is turned on, the high-speed switching valve 77 is turned off, and oil is supplied from the low-speed switching valve 76 to the auxiliary transmission piston 75, so that the rod 78 of the auxiliary transmission piston 75 is positioned at a low speed position. , The inclination angle of the motor swash plate 74 becomes relatively large. On the other hand, the low-speed switching valve 76 is turned off, the high-speed switching valve 77 is turned on, and the flood control is supplied from the high-speed switching valve 77 to the auxiliary transmission piston 75, so that the rod 78 of the auxiliary transmission piston 75 is moved to the high-speed position. Positioned, the tilt angle of the motor swash plate 74 becomes relatively small. Therefore, by switching the low-speed switching valve 76 and the high-speed switching valve 77 on / off, the position of the motor diagonal plate 74 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 position of the motor rotating shaft 71. It is possible to switch to two stages with the position on the low speed side where the rotation speed becomes relatively small.

Since the right side HST34 has the same configuration as the left side HST33, the parts corresponding to the parts of the left side HST33 are designated by the same reference numerals as those of the left side HST33, and the description thereof will be omitted.

The power of the engine 31 is input to each of the pump rotation shafts 52 of the left HST 33 and the right HST 34. Specifically, the output shaft 81 of the engine 31 is provided with a pulley 82 that cannot rotate relative to each other. The drive transmission system 32 includes an input shaft 83 extending in parallel with the output shaft 81 of the engine 31. A pulley 84 is provided on the input shaft 83 so that it cannot rotate relative to each other. An endless belt 85 is wound between the pulleys 82 and 84. Further, the input shaft 83 is provided with an input gear 86 that cannot rotate relative to each other. An intermediate gear 87 meshes with the input gear 86, and a pump gear 88 provided on the pump rotating shaft 52 of the right HST 34 so as to be relatively non-rotatable meshes with the intermediate gear 87. The pump gear 88 meshes with a pump gear 89 provided on the pump rotating shaft 52 of the left HST 33 so as not to rotate relative to each other.

As a result, the power of the engine 31 is transmitted from the output shaft 81 to the pulley 84 via the pulley 82 and the belt 85, and the input shaft 83 is rotated integrally with the pulley 84. Then, the power (rotation) of the input shaft 83 is transmitted from the input gear 86 to the pump gear 88 of the right side HST34 via the intermediate gear 87, and the pump rotation shaft 52 of the right side HST34 is rotated in a predetermined direction together with the pump gear 88. Let me. Further, the power of the input shaft 83 is transmitted from the input gear 86 to the pump gear 88 of the right side HST34 via the intermediate gear 87, and further transmitted from the pump gear 88 to the pump gear 89, and is integrally transmitted with the pump gear 89 to the pump of the left side HST33. The rotation shaft 52 is rotated in the direction opposite to the predetermined direction. Therefore, when the inclination angles of the pump diagonal plates of the hydraulic pumps 41 of the left side HST33 and the right side HST34 are the same, the motor rotation shaft 71 of the hydraulic motor 42 of the left side HST33 and the motor rotation shaft 71 of the hydraulic motor 42 of the right side HST34 Rotate in opposite directions.

FIG. 3 is a cross-sectional view showing a part of the drive transmission system 32, and shows the configuration of the left side HST33 and the right side HST34 from the hydraulic motor 42 to the traveling device 12.

In each of the left side HST33 and right side HST34 hydraulic motors 42, the motor rotation shafts 71 are aligned on the same axis (so as to have a common axis), and the axes are parallel to the left and right axles 91L and 91R. , Are arranged symmetrically with each other.

In the following description, the motor rotating shaft 71 of the left side HST33 is referred to as "motor rotating shaft 71L", and the motor rotating shaft 71 of the right side HST34 is referred to as "motor rotating shaft 71R".

The outer ends of the motor rotation shafts 71L and 71R in the left-right direction are rotatably supported by the unit case 101 forming the outer shell of the drive transmission system 32 via bearings 102L and 102R, respectively. Motor output gears 103L and 103R are supported on the inner ends of the motor rotation shafts 71L and 71R in the left-right direction so that they cannot rotate relative to each other.

Between the motor rotating shafts 71L and 71R and the axles 91L and 91R, the first intermediate shaft 104, the second intermediate shaft 105 and the third intermediate shaft 106 are provided in parallel with the axles 91L and 91R at intervals from each other. There is. The first intermediate shaft 104 is non-rotatably supported by the unit case 101. The left end portion and the right end portion of the second intermediate shaft 105 are rotatably supported by the unit case 101 via bearings 107L and 107R, respectively. The left end portion and the right end portion of the third intermediate shaft 106 are rotatably supported by the unit case 101 via bearings 108L and 108R, respectively.

The motor output gears 103L and 103R mesh with the first intermediate gears 111L and 111R rotatably held by the first intermediate shaft 104, respectively.

A second intermediate gear 112L and a third intermediate gear 113L are supported on the left side portion of the second intermediate shaft 105 so as to be relatively non-rotatable. On the other hand, a third intermediate gear 113R is supported on the right side portion of the second intermediate shaft 105 so as to be relatively rotatable via a needle bearing. Further, on the outside of the third intermediate gear 113R, an annular second intermediate gear 112R is provided so as to surround the third intermediate gear 113R. The inner peripheral portion of the second intermediate gear 112R is fixed to the third intermediate gear 113R. As a result, the second intermediate gear 112R rotates integrally with the third intermediate gear 113R. The second intermediate gears 112L and 112R mesh with the first intermediate gears 111L and 111R, respectively. The third intermediate gears 113L and 113R mesh with the fourth intermediate gears 114L and 114R, respectively.

The fifth intermediate gears 115L and 115R are supported on the third intermediate shaft 106 so that they cannot rotate relative to each other. The fourth intermediate gears 114L and 114R form an annular shape and are provided so as to surround the outside of the fifth intermediate gears 115L and 115R, respectively. The inner peripheral portions of the fourth intermediate gears 114L and 114R are fixed to the fifth intermediate gears 115L and 115R, respectively. As a result, the fourth intermediate gears 114L and 114R rotate integrally with the fifth intermediate gears 115L and 115R, respectively. The fifth intermediate gears 115L and 115R mesh with the sixth intermediate gears 116L and 116R.

The sixth intermediate gear 116L is formed with a through hole 117 extending on the central axis. The right end portion of the axle 91L is inserted into the through hole 117 from the left side, and the right end portion thereof is spline-coupled. At the left end of the sixth intermediate gear 116R, a cylindrical portion 118 having an outer diameter smaller than the inner diameter of the through hole 117 of the sixth intermediate gear 116L is formed. The cylindrical portion 118 is inserted into the through hole 117 from the right side and is held in the sixth intermediate gear 116L so as to be relatively rotatable via a needle bearing. Further, a circular recess 119 recessed on the left side is formed at the right end portion of the sixth intermediate gear 116R. The left end portion of the axle 91R is inserted into the recess 119, and the left end portion thereof is spline-coupled. Bearings 121L and 121R are fitted on the left end of the sixth intermediate gear 116L and the right end of the sixth intermediate gear 116R, respectively, and the outer rings of the 121L and 121R are fixedly held by the unit case 101. As a result, the sixth intermediate gears 116L and 116R are rotatably held in the unit case 101. Further, the left end portion of the axle 91L and the right end portion of the axle 91R are rotatably held by the unit case 101 via bearings 122L and 122R, respectively, so that the axles 91L and 91R are rotatably held by the unit case 101. There is.

The left end of the axle 91L and the right end of the axle 91R are connected to the drive wheels 123L and 123R of the traveling device 12 so as not to rotate relative to each other.

Further, the drive transmission system 32 is provided with a center clutch 131. The center clutch 131 is engaged and disengaged to connect and disconnect the second intermediate shaft 105 and the third intermediate gear 113R. That is, by engaging the center clutch 131, the second intermediate shaft 105 and the third intermediate gear 113R are connected, and the second intermediate shaft 105 and the third intermediate gear 113R rotate integrally. By releasing the center clutch 131, the second intermediate shaft 105 and the third intermediate gear 113 are separated, and the third intermediate gear 113 can rotate with respect to the second intermediate shaft 105. The center clutch 131 is hydraulically engaged and disengaged.

Further, the drive transmission system 32 is provided with a parking brake 132. The parking brake 132 is engaged and disengaged to brake and release the second intermediate shaft 105. That is, the engagement of the parking brake 132 causes the second intermediate shaft 105 to be braked non-rotatably with respect to the unit case 101. When the parking brake 132 is released, the braking of the second intermediate shaft 105 is released, and the second intermediate shaft 105 becomes rotatable with respect to the unit case 101. The parking brake 132 is engaged and disengaged by a manual operation of the parking brake lever.

<Electrical configuration>
FIG. 4 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) 141 for overall overall control and a plurality of ECUs 142 for individual specific control. FIG. 4 shows one of the plurality of ECUs 142. The ECU 142 shown in FIG. 4 may be subdivided according to its function and may be composed of a plurality of ECUs 142. Each of the ECUs 141 and 142 has a configuration including a microcontroller unit (MCU: Micro Controller Unit).

The main ECU 141 is communicably connected to each ECU 142 for individual specific control. The main ECU 141 receives information acquired by each ECU 142 from detection signals of various sensors, and transmits commands and information required for control by each of the ECUs 142 to each ECU 142. Further, a meter panel 151 arranged on the operation panel 18 (see FIG. 1) of the driver's cab 13 is connected to the main ECU 141 as a control target, and the main ECU 141 is provided with the odometer on the meter panel 151. It controls various instruments such as an odometer and the display 152. The display 152 includes, for example, a liquid crystal display.

The ECU 142 (hereinafter, simply referred to as “ECU 142”) shown in FIG. 4 has a main speed change lever sensor 153 that outputs a detection signal according to the operation position of the main speed change lever 21 and a main speed change lever sensor 153 according to the operation position of the steering lever 22. The steering lever sensor 154 that outputs the detection signal, the left vehicle speed sensor 155 that outputs the pulse signal synchronized with the rotation of the left axle 91L as a detection signal, and the pulse signal synchronized with the rotation of the right axle 91R are detected signals. Is connected to the right vehicle speed sensor 156, and these detection signals are input.

Further, the ECU 142 has a forward valve current sensor 157 that outputs a detection signal corresponding to a current value supplied to the forward pressure control valve 61 included in each of the left side HST33 and the right side HST34, and the left side HST33 and the right side HST34, respectively. Position (angle) of the reverse valve current sensor 158 that outputs a detection signal according to the current value supplied to the included reverse pressure control valve 63, and the pump diagonal plate of the hydraulic pump 41 included in each of the left side HST33 and the right side HST34. A pump diagonal plate position sensor 159 that outputs a detection signal according to the above is connected, and these detection signals are input.

Further, in the combine 1, soft turning mode, brake turning mode and spin turning mode are set as the turning control mode (turning control mode) of the airframe 11. The operation panel 18 of the driver's cab 13 is provided with a swivel mode switch 161 for switching the swivel control mode. The swivel mode switch 161 is a dial type switch, and a soft position, a brake position, and a spin position corresponding to the swivel control mode are set in the range of motion thereof. The swivel mode switch 161 has a knob that is pinched and rotated by the operator's fingers, and outputs a different signal depending on whether the knob is in the soft position, the brake position, or the spin position.

The ECU 142 acquires from the detection signals of various sensors such as the main speed change lever sensor 153, the steering lever sensor 154, the left vehicle speed sensor 155, the right vehicle speed sensor 156, the forward valve current sensor 157, the reverse valve current sensor 158, and the swivel mode switch 161. The forward pressure control valve 61 included in each of the engine 31, the left side HST33 and the right side HST34 in order to control the traveling and turning of the body 11 based on the information to be input and the information input from the main ECU 141 and the other ECU 142. , The operation of the reverse pressure control valve 63, the low speed switching valve 76 and the high speed switching valve 77, and the operation of the center clutch 131 are controlled.

<Driving control>
The traveling of the machine body 11 is controlled by the ECU 142. In this travel control, the position of the main shift lever 21 is acquired from the detection signal of the main shift lever sensor 153.

When the position of the main speed change lever 21 is the stop position, the opening degree of each of the left side HST33 and the right side HST34 is adjusted by controlling the current supplied to the forward pressure control valve 61 and the reverse pressure control valve 63, respectively. Therefore, the inclination angle of the pump slant plate of the hydraulic pump 41 is set to 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 the power of the hydraulic motor 42 is not transmitted to the axles 91L and 91R. 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, the forward pressure control valve 61 controls the currents supplied to the forward pressure control valve 61 and the reverse pressure control valve 63 for each of the left side HST33 and the right side HST34. The oil pressure supplied to the first pressure chamber 62 of the servo piston 58 is made larger than the oil pressure supplied from the reverse pressure control valve 63 to the second pressure chamber 64. As a result, a differential pressure is generated between the first pressure chamber 62 and the second pressure chamber 64, and the differential pressure causes the inclination angle of the pump swash plate of the hydraulic pump 41 to be smaller than 90 °. As a result, the hydraulic oil is discharged from the hydraulic pump 41, and the hydraulic motor 42 receives the hydraulic oil and rotates. Then, the rotation (power) of the hydraulic motor 42 is transmitted to the axles 91L and 91R, and the drive wheels 123L and 123R of the traveling device 12 rotate integrally with the axles 91L and 91R in the forward direction, so that the machine body 11 advances. do.

When the main speed change lever 21 is tilted rearward from the stop position, the reverse pressure control valve 63 is controlled by controlling the currents supplied to the forward pressure control valve 61 and the reverse pressure control valve 63 for each of the left side HST33 and the right side HST34. The oil pressure supplied from the second pressure chamber 64 to the second pressure chamber 64 is made larger than the oil pressure supplied from the forward pressure control valve 61 to the first pressure chamber 62 of the servo piston 58. As a result, a differential pressure is generated between the first pressure chamber 62 and the second pressure chamber 64, and the differential pressure causes the inclination angle of the pump swash plate of the hydraulic pump 41 to be larger than 90 °. As a result, the hydraulic oil is discharged from the hydraulic pump 41 in the direction opposite to that at the time of advancing, and the hydraulic motor 42 receives the hydraulic oil and rotates in the direction opposite to that at the time of advancing. Then, the rotation (power) of the hydraulic motor 42 is transmitted to the axles 91L and 91R, and the drive wheels 123L and 123R of the traveling device 12 rotate integrally with the axles 91L and 91R in the reverse direction, so that the machine body 11 moves backward. do.

The center clutch 131 is engaged when the aircraft 11 moves forward and backward. By engaging the center clutch 131, the second intermediate shaft 105 and the third intermediate gear 113R are connected, and the second intermediate shaft 105 and the third intermediate gear 113R rotate integrally, so that the fourth intermediate gears 114L and 114R Rotates at the same speed. Therefore, the fifth intermediate gears 115L and 115R rotate at the same speed, the sixth intermediate gears 116L and 116R rotate at the same speed, and the axles 91L and 91R rotate at the same speed. As a result, the left and right drive wheels 123L and 123R of the traveling device 12 are rotated at the same speed, so that the aircraft 11 moves forward or backward with excellent straight-line stability.

Further, when the inclination angle of the pump diagonal plate of the hydraulic pump 41 is changed by controlling the current supplied to the forward pressure control valve 61 and the reverse pressure control valve 63 during forward movement or reverse movement, the operation from the hydraulic pump 41 is performed. The discharge amount of oil changes, and the rotation speed of the hydraulic motor 42 changes. Therefore, by adjusting the inclination angle of the pump swash plate of the hydraulic pump 41 according to the amount of inclination of the main speed change lever 21 from the stop position, the forward and reverse speeds of the machine body 11 can be changed steplessly. ..

Further, in the drive transmission system 32, as described above, by switching the low-speed switching valve 76 and the high-speed switching valve 77 on / off, the rotation speed of the hydraulic motor 42 becomes relatively large and relatively small. It is possible to switch between two stages, a low speed stage and a low speed 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.

<Turning control>
When the steering lever 22 is tilted from the central straight-ahead position to the left or right turning position during straight-ahead (forward / backward) traveling of the machine body 11, the ECU 142 starts turning control for turning the machine body 11. NS.

In the turning control, it is determined from the output signal of the turning mode switch 161 whether the position of the turning mode switch 161 is a soft position, a brake position, or a spin position.

When the position of the swivel mode switch 161 is the soft position, the swivel control mode is set to the soft swivel mode. In the normal turning control in the soft turning mode, for example, the target turning ratio, which is the target value of the turning ratio, is set to 0.3. Then, the current (of the hydraulic pump 41) supplied to the forward pressure control valve 61 and the reverse pressure control valve 63 of the left side HST33 and the right side HST34 so that the actual turning ratio (actual turning ratio) matches the target turning ratio. By controlling the inclination angle of the pump sloping plate), the rotation speed of the traveling device 12 (one of the drive wheels 123L and 123R) inside the turning can be reduced.

The turning ratio is the speed ratio of the traveling device 12 on the inside of the turn to the traveling device 12 on the outside of the turn. Specifically, when the outside of the turn is on the left side, the right side which is the inside of the turn with respect to the rotation speed of the left axle 91L. It is the ratio of the rotation speed of the axle 91R, and when the outside of the turn is on the right side, it is the ratio of the rotation speed of the left axle 91L which is the inside of the turn to the rotation speed of the right axle 91R. The rotation speed of the left axle 91L can be calculated from the detection signal of the left vehicle speed sensor 155, and the rotation speed of the right axle 91R can be calculated from the detection signal of the right vehicle speed sensor 156. When the outside of the turn is on the left side, the actual turning is performed by obtaining the ratio of the rotation speed of the axle 91R calculated from the detection signal of the right vehicle speed sensor 156 to the rotation speed of the axle 91L calculated from the detection signal of the left vehicle speed sensor 155. The ratio can be calculated. When the outside of the turn is on the right side, the actual turning is performed by obtaining the ratio of the rotation speed of the axle 91L calculated from the detection signal of the left vehicle speed sensor 155 to the rotation speed of the axle 91R calculated from the detection signal of the right vehicle speed sensor 156. The ratio can be calculated.

When the position of the turning mode switch 161 is the brake position, the turning control mode is set to the brake turning mode. In the normal turning control in the brake turning mode, for example, the target turning ratio is set to 0. Then, the currents supplied to the forward pressure control valve 61 and the reverse pressure control valve 63 of the left side HST33 and the right side HST34 are controlled so that the actual turning ratio matches the target turning ratio, so that the vehicle travels inside the turning. The rotation speed of the device 12 is reduced. When the target turning ratio is 0, the target speed of the traveling device 12 inside the turning becomes 0. Therefore, in the normal turning control when the position of the turning mode switch 161 is the brake position, the forward pressure control valve 61 and the reverse pressure control valve of the left side HST33 and the right side HST34 are stopped so that the traveling device 12 inside the turning is stopped. The current supplied to 63 is controlled.

When the position of the swivel mode switch 161 is the spin position, the swivel control mode is set to the spin swivel mode. In the normal turning control in the spin turning mode, the rotation direction of the traveling device 12 inside the turning is reversed, and the value of the rotating speed of the traveling device 12 inside the turning is obtained by adding a negative sign (-). The target value of the turning ratio (target turning ratio) is set to -0.3. Then, the currents supplied to the forward pressure control valve 61 and the reverse pressure control valve 63 of the left side HST33 and the right side HST34 are controlled so that the actual turning ratio matches the target turning ratio.

<Fail-safe operation>
FIG. 5 is a flowchart showing the flow of fail-safe control.

Fail-safe control is executed by the ECU 142 in order to operate the combine 1 on the safe side (fail-safe operation) when an abnormality such as a failure in which the traveling control cannot be normally performed occurs.

In this fail-safe control, it is determined from the detection signals of the forward valve current sensor 157 and the reverse valve current sensor 158 whether or not an abnormality affecting the traveling control has occurred in the servo mechanism 66 corresponding to the left side HST33 and the right side HST34. (Step S11).

In the following, the servo piston 58 corresponding to the left HST 33 will be referred to as "left servo mechanism 66", and the servo piston 58 corresponding to the right HST 34 will be referred to as "right servo mechanism 66".

As an abnormality of the servo mechanism 66, for example, when a failure in which the signal lines of the forward valve current sensor 157 and the reverse valve current sensor 158 are disconnected is taken up, the disconnection failure is caused by the forward valve current sensor 157 of the servo mechanism 66 on the left side. Includes disconnection failure, disconnection failure of the reverse valve current sensor 158 of the left servo mechanism 66, disconnection failure of the forward valve current sensor 157 of the right servo mechanism 66, and disconnection failure of the reverse valve current sensor 158 of the right servo mechanism 66. ..

If no abnormality has occurred in at least one of the left or right servo mechanism 66 (NO in step S11), the fail-safe control does not proceed further.

When an abnormality occurs in at least one of the left side or right side servo mechanism 66 (YES in step S11), the driving of the left side HST33 and the right side HST34 is stopped according to the occurrence of the abnormality (step S12). When the drive of the left side HST33 and the right side HST34 is stopped, the aircraft 11 is stopped.

After that, it is determined whether or not the instruction for transition from the normal mode to the emergency mode has been input (step S13). The normal mode is a mode in which normal travel control is executed, and the emergency mode is a mode in which the aircraft 11 can be temporarily traveled when an abnormality occurs. The instruction to transition to the emergency mode is given by operating the operation unit (for example, a touch panel arranged on the display 152) or the switch provided on the operation panel 18 provided on the meter panel 151 of the driver's cab 13. Is entered in. Until the instruction for transition to the emergency mode is input, the drive stop of the left side HST33 and the right side HST34 is maintained, and the aircraft 11 cannot travel.

When the instruction for transition to the emergency mode is input (YES in step S13), it is determined whether or not the only abnormality that has occurred is the forward abnormality that makes it impossible for the aircraft 11 to normally move forward (step S14). .. For example, when only the disconnection failure of the forward valve current sensor 157 has occurred, it is determined that only the forward abnormality has occurred.

When only the forward abnormality has occurred (YES in step S14), it is determined whether or not the forward command has been input (step S15). Specifically, it is determined from the detection signal of the main shift lever sensor 153 whether or not the main shift lever 21 is tilted forward.

When the main shift lever 21 is tilted forward (YES in step S15), the center clutch 131 is engaged (step S16).

Then, among the left or right servo mechanisms 66, the left or right servo mechanism 66 that can operate normally is controlled, and the hydraulic motor 42 of the left HST 33 or the right HST 34 corresponding to the servo mechanism 66 is driven in the forward direction. (Step S17). For example, when only the disconnection failure of the forward valve current sensor 157 of the servo mechanism 66 on the left side occurs, the hydraulic motor 42 of the right side HST34 is driven in the forward direction. Since the center clutch 131 is engaged, the left and right drive wheels 123L and 123R of the traveling device 12 rotate in the forward direction at the same speed by the power output from the hydraulic motor 42 of the left side HST33 or the right side HST34. As a result, the aircraft 11 moves forward.

When the forward command is not input (NO in step S15), it is determined whether or not the reverse command is input (step S18). Specifically, it is determined from the detection signal of the main shift lever sensor 153 whether or not the main shift lever 21 is tilted to the rear side.

When the main shift lever 21 is tilted to the rear side when a forward abnormality occurs (YES in step S18), the aircraft 11 can normally run backward, so that the left HST33 is controlled by the same control as the running control in the normal mode. And the hydraulic motor 42 of the right side HST34 is driven in the reverse direction (step S19). As a result, the aircraft 11 moves backward.

When neither the forward command nor the reverse command is input, that is, when the main shift lever 21 is not tilted from the stop position (NO in step S18), the main switch provided on the operation panel 18 stops the engine 31. It is determined whether or not the operation, that is, the engine stop operation is performed at the position of "" (step S20).

When the engine stop operation is performed (YES in step S20), the engine 31 is stopped and the fail-safe control ends. If the engine stop operation is not performed (NO in step S20), it is determined again whether or not a forward abnormality has occurred (step S14).

When no forward abnormality has occurred (NO in step S14), it is determined whether or not the generated abnormality is only the reverse abnormality that disables the normal reverse travel of the aircraft 11 (step S21). For example, when only the reverse valve current sensor 158 has a disconnection failure, it is determined that only the reverse abnormality has occurred.

When only the reverse movement abnormality has occurred (YES in step S21), it is determined whether or not the reverse movement command has been input (step S22). Specifically, it is determined from the detection signal of the main shift lever sensor 153 whether or not the main shift lever 21 is tilted to the rear side.

When the main shift lever 21 is tilted rearward (YES in step S22), the center clutch 131 is engaged (step S23).

Then, among the left or right servo mechanisms 66, the left or right servo mechanism 66 that can operate normally is controlled, and the hydraulic motor 42 of the left HST 33 or the right HST 34 corresponding to the servo mechanism 66 is driven in the reverse direction. (Step S24). For example, when only the reverse valve current sensor 158 of the right servo mechanism 66 has a disconnection failure, the hydraulic motor 42 of the left HST 33 is driven in the forward direction. Since the center clutch 131 is engaged, the left and right drive wheels 123L and 123R of the traveling device 12 rotate in the forward direction at the same speed by the power output from the hydraulic motor 42 of the left side HST33 or the right side HST34. As a result, the aircraft 11 moves forward.

When the reverse command is not input (NO in step S22), it is determined whether or not the forward command is input (step S25). Specifically, it is determined from the detection signal of the main shift lever sensor 153 whether or not the main shift lever 21 is tilted forward.

When the main shift lever 21 is tilted to the front side when a reverse reverse abnormality occurs (YES in step S25), the aircraft 11 can normally travel forward. The hydraulic motor 42 of the right HST 34 is driven in the forward direction (step S26). As a result, the aircraft 11 moves forward.

When neither the forward command nor the reverse command is input, that is, when the main shift lever 21 is not tilted from the stop position (NO in step S25), it is determined whether or not the engine stop operation has been performed (step S20).

When the engine stop operation is performed (YES in step S20), the engine 31 is stopped and the fail-safe control ends. If the engine stop operation is not performed (NO in step S20), it is determined again whether or not a forward abnormality has occurred (step S14).

If both the forward abnormality and the reverse abnormality have occurred (NO in step S21), the fail-safe control is terminated.

<Effect>
According to this configuration, a drive transmission system 32 is interposed between the engine 31 and the pair of left and right traveling devices 12. The drive transmission system 32 is provided with a left HST 33 and a right HST 34 corresponding to each of the pair of left and right traveling devices 12. Both the left side HST 33 and the right side HST 34 are configured to include a hydraulic pump 41 driven by the power of the engine 31 and a hydraulic motor 42 driven by the pressure oil discharged from the hydraulic pump 41. Further, the drive transmission system 32 is provided with a servo mechanism 66 that controls the inclination angle of the pump swash plate of the hydraulic pump 41 corresponding to each of the left side HST33 and the right side HST34. By controlling the inclination angle of the pump diagonal plates of the left HST 33 and the right HST 34, the discharge direction and flow rate of oil from the hydraulic pump 41 are controlled, and the rotation direction and rotation speed of the hydraulic motor 42 are controlled.

When an abnormality such as a failure occurs in the servo mechanism 66 and the abnormality is detected, a fail-safe operation for stabilizing the behavior of the combine 1 is executed. In the fail-safe operation, in response to the detection of an abnormality in the servo mechanism 66 corresponding to one of the pair of left and right traveling devices 12, as the fail-safe operation, first, the left side HST33 corresponding to each of the pair of left and right traveling devices 12 And the output from both the right side HST34 is stopped. As a result, the body 11 of the combine 1 can be stopped, and the behavior of the combine 1 can be stabilized by stopping the body 11.

The traveling device 12 includes axles 91L and 91R to which power is transmitted from the drive transmission system 32. The drive transmission system 32 includes a center clutch 131 that is engaged to match the rotation speeds of the axles 91L and 91R. In the fail-safe operation, after the output of the left side HST33 and the right side HST34 is stopped, the center clutch 131 is then engaged so that the output from the left side HST33 or the right side HST34 corresponding to the normally operating servo mechanism 66 continues. , The normally operating servo mechanism 66 is controlled. As a result, the hydraulic motor 42 of the left HST 33 or the right HST 34 corresponding to the normally operating servo mechanism 66 can be driven, and the power from the hydraulic motor 42 stabilizes the behavior of the combine 1 while allowing the machine body 11 to move. It can be run.

<Other Embodiments>
FIG. 6 is a flowchart showing a flow of fail-safe control according to another embodiment.

In the traveling control, the target swash plate angle, which is the control target value of the inclination angle of the pump swash plate of the hydraulic pump 41, is set according to the position of the main swash plate 21 acquired from the detection signal of the main shift lever sensor 153. .. Further, the actual inclination angle (actual swash plate angle) of the pump swash plate of the hydraulic pump 41 is acquired from the detection signal of the pump swash plate position sensor 159. Then, the forward pressure control valve 61 and the reverse pressure control valve 63 included in the servo mechanism 66 are controlled so that the deviation between the target slope plate angle and the actual slope plate angle approaches zero.

In the fail-safe control shown in FIG. 6, the ECU 142 refers to the target swash plate angle set in the traveling control (step S31). Further, the actual swash plate angle acquired by the traveling control is referred to (step S32).

Then, it is determined whether or not the state in which the deviation between the target swash plate angle and the actual swash plate angle is equal to or greater than a certain value is maintained for a certain period of time (step S33).

When the deviation between the target sloping plate angle and the actual sloping plate angle is less than a certain value, or when the deviation between the target sloping plate angle and the actual sloping plate angle is more than a certain value and is more than a certain value, the state continues. If the time spent is less than a certain time (NO in step S33), the target sloping plate angle and the actual sloping plate angle are referred to again (steps S31 and S32). Then, it is determined again whether or not the state in which the deviations are equal to or higher than a certain value is maintained for a certain period of time (step S33).

When the deviation between the target sloping plate angle and the actual sloping plate angle is maintained for a certain period of time (YES in step S33), the forward pressure control valve 61 and the reverse pressure control valve 63 fail or the forward valve It is determined that an abnormality such as a failure in which the signal lines of the current sensor 157 and the reverse valve current sensor 158 are disconnected has occurred in the servo mechanism 66. In this case, the engine 31 is stopped (step S34).

<Effect>
In this way, when an abnormality such as a failure occurs in the servo mechanism 66 and the abnormality is detected, the engine 31 is stopped. When the engine 31 is stopped, the driving of the hydraulic pump 41 is stopped, so that the body 11 of the combine 1 can be stopped. By stopping the aircraft 11, the behavior of the combine 1 can be stabilized.

<Third embodiment>
FIG. 7 is a flowchart showing the flow of fail-safe control according to the third embodiment.

In the fail-safe control shown in FIG. 7, the ECU 142 refers to the target swash plate angle set in the traveling control (step S41). Further, the actual swash plate angle acquired by the traveling control is referred to (step S42).

Then, it is determined whether or not the state in which the deviation between the target swash plate angle and the actual swash plate angle is equal to or greater than a certain value is maintained for a certain period of time (step S43).

When the deviation between the target sloping plate angle and the actual sloping plate angle is less than a certain value, or when the deviation between the target sloping plate angle and the actual sloping plate angle is more than a certain value and is more than a certain value, the state continues. If the time spent is less than a certain time (NO in step S43), the target sloping plate angle and the actual sloping plate angle are referred to again (steps S41 and S42). Then, it is determined again whether or not the state in which the deviations are equal to or higher than a certain value is maintained for a certain period of time (step S43).

When the deviation between the target swash plate angle and the actual swash plate angle is maintained for a certain period of time (YES in step S43), it is determined that an abnormality has occurred in the servo mechanism 66. In this case, the low-speed switching valve 76 provided corresponding to the hydraulic motor 42 is turned on and the high-speed switching valve 77 is turned off so that the motor swash plate 74 of the hydraulic motor 42 is located on the low-speed side (step). S44). Further, the engine 31 is put into an idling state (step S45).

After that, when the main shift lever 21 is returned to the stop position (YES in step S46), the engine 31 is stopped (step S47).

Further, the state of abnormality (error) generated in the servo mechanism 66 (for example, the magnitude of the deviation between the target sloping plate angle and the actual sloping plate angle) is stored in the non-volatile memory in the ECU 142 (step S48).

Then, the start of the engine 31 is prohibited (step S49), and the fail-safe control is terminated.

<Effect>
In this way, when an abnormality such as a failure occurs in the servo mechanism 66 and the abnormality is detected, the motor swash plate 74 of the hydraulic motor 42 is set to the low speed side, and the engine 31 is put into an idling state. As a result, the airframe 11 can be driven at a low speed. It is possible to secure the traveling of the aircraft 11 while stabilizing the behavior of the combine 1, and it is possible to move the combine 1 to a safe position.

After that, when the main shift lever 21 is returned to the stop position (neutral position), the engine 31 is stopped. Further, the error state is stored in the non-volatile memory, and thereafter, the engine 31 is prohibited from starting until the error state is resolved. As a result, the unstable behavior of the combine 1 can be suppressed.

<Modification example>
Although some embodiments of the present invention have been described above, the present invention can also be implemented in other embodiments, and the above-described configuration is limited to the matters described in the claims. It is possible to make various design changes.

1: Combine (work vehicle)
12: Traveling device 21: Main speed change lever (operating member)
31: Engine 32: Drive transmission system (power transmission device)
41: Hydraulic pump (pump)
42: Hydraulic motor (motor)
58: Servo piston 61: Forward pressure control valve (forward control valve)
63: Reverse pressure control valve (reverse control valve)
66: Servo mechanism 76: Low speed switching valve (control valve)
77: High-speed switching valve (control valve)
131: Center clutch (clutch)
142: ECU (control device, abnormality detecting means, fail-safe means, control means, storage means)
153: Main speed change lever sensor (position detecting means)
159: Pump swash plate position sensor (swash plate angle detecting means)

Claims (7)

Controls the angle of an engine, a pair of left and right traveling devices, a stepless transmission including a pump driven by the power of the engine and a motor driven by pressure oil discharged from the pump, and a pump diagonal plate of the pump. A control device used for a work vehicle equipped with a servo mechanism and a power transmission device for transmitting the power of the motor to the pair of left and right traveling devices.
An abnormality detecting means for detecting an abnormality in the servo mechanism and
Including a fail-safe means for executing a fail-safe operation for stabilizing the behavior of the work vehicle in response to the detection of the abnormality by the abnormality detecting means.
The continuously variable transmission and the servo mechanism are provided corresponding to each of the pair of left and right traveling devices.
The fail-safe means performs the fail-safe operation of each of the pair of left and right traveling devices in response to the detection of an abnormality of the servo mechanism corresponding to one of the pair of left and right traveling devices by the abnormality detecting means. corresponding to the so that the output from both of the continuously variable transmission is stopped, controls the servo mechanism corresponding to each of the pair of left and right traveling devices, control devices. Controls the angle of an engine, a pair of left and right traveling devices, a stepless transmission including a pump driven by the power of the engine and a motor driven by pressure oil discharged from the pump, and a pump diagonal plate of the pump. A control device used for a work vehicle equipped with a servo mechanism and a power transmission device for transmitting the power of the motor to the pair of left and right traveling devices.
An abnormality detecting means for detecting an abnormality in the servo mechanism and
Including a fail-safe means for executing a fail-safe operation for stabilizing the behavior of the work vehicle in response to the detection of the abnormality by the abnormality detecting means.
The traveling device includes an axle in which power is transmitted from the power transmission device.
The continuously variable transmission and the servo mechanism are provided corresponding to each of the pair of left and right traveling devices.
The power transmission device includes a clutch provided in each of the pair of left and right traveling devices and engaged to match the rotation speeds of the axles.
The fail-safe means engages the clutch as the fail-safe operation in response to the detection of an abnormality in the servo mechanism corresponding to one of the pair of left and right traveling devices by the abnormality detecting means. so that the output from the continuously variable transmission corresponding to the other of the pair of left and right traveling devices continues to control the servo mechanism corresponding to the other of the pair of left and right traveling devices, control devices. Controls the angle of an engine, a pair of left and right traveling devices, a stepless transmission including a pump driven by the power of the engine and a motor driven by pressure oil discharged from the pump, and a pump diagonal plate of the pump. A control device used for a work vehicle equipped with a servo mechanism and a power transmission device for transmitting the power of the motor to the pair of left and right traveling devices.
An abnormality detecting means for detecting an abnormality in the servo mechanism and
Including a fail-safe means for executing a fail-safe operation for stabilizing the behavior of the work vehicle in response to the detection of the abnormality by the abnormality detecting means.
The servo mechanism includes a servo piston that interlocks with the pump diagonal plate, a forward control valve that supplies hydraulic pressure to the servo piston to position the servo piston within a predetermined forward range, and the servo piston to the servo piston. The servo piston is provided with a reverse control valve for supplying hydraulic pressure to position the servo piston within the forward range, and when the servo piston is located within the forward range, the pump swash plate is pressed from the pump in the forward direction. The servo piston is provided at an angle of discharge, and the pump diagonal plate is provided at an angle at which pressure oil in the reverse direction is discharged from the pump when the servo piston is located within the reverse range.
The pump outputs the power in the direction in which the work vehicle moves forward by supplying the pressure oil in the forward direction, and outputs the power in the direction in which the work vehicle moves backward by supplying the pressure oil in the reverse direction.
When an abnormality of the forward control valve is detected by the abnormality detecting means, the fail-safe means allows the reverse control valve to be controlled as the fail-safe operation, and the reverse control valve is allowed to be controlled by the abnormality detecting means. If the abnormality is detected, as the fail-safe operation, allowing control of the forward control valve, the control apparatus. Controls the angle of the engine, a pair of left and right traveling devices, a stepless transmission including a pump driven by the power of the engine and a motor driven by the pressure oil discharged from the pump, and a pump diagonal plate of the pump. A power transmission device provided with a servo mechanism and transmitting the power of the motor to the pair of left and right traveling devices, and an operating member operably provided between a forward position on one side and a reverse position on the other side with respect to a neutral position. It is a control device used for work vehicles equipped with
An abnormality detecting means for detecting an abnormality in the servo mechanism and
A fail-safe means that executes a fail-safe operation for stabilizing the behavior of the work vehicle in response to the detection of the abnormality by the abnormality detecting means.
A position detecting means for detecting the position of the operating member and
A swash plate angle detecting means for detecting the angle of the pump swash plate,
It includes a control means for controlling the servo mechanism so that the angle of the pump swash plate matches the target angle corresponding to the position of the operating member detected by the position detecting means.
When the deviation between the target angle and the angle detected by the swash plate angle detecting means is maintained for a certain period of time, the abnormality detecting means detects that the servo mechanism is abnormal.
The fail-safe means, as the fail-safe operation, the engine idling, the control apparatus. As the fail-safe operation, the fail-safe means stops the engine in response to the position of the operating member detected by the position detecting means matching the neutral position after idling the engine. The control device according to claim 4. The power transmission device provides a control valve that switches the angle of the motor slop plate of the motor between a first angle at which the rotation of the motor is relatively low and a second angle at which the rotation of the motor is relatively high. Further prepare
The control device according to claim 4 or 5 , wherein the fail-safe means controls the control valve to make the swash plate of the motor the first angle as the fail-safe operation. Further including a storage means for storing the detection of the abnormality when the abnormality of the servo mechanism is detected by the abnormality detecting means.
The control device according to any one of claims 4 to 6 , wherein the fail-safe means prohibits the start of the engine while the storage means stores that an abnormality of the servo mechanism has been detected. ..

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