JP5373684B2 - Work vehicle - Google Patents

Description

  The present invention relates to vehicle speed control in a work vehicle including a rotary tiller.

  Conventionally, as shown in Patent Document 1, the rotary tiller is used as a lift control device for controlling the position of a rotary tiller connected to a vehicle body such as a tractor so that it can be lifted and tilted right and left. Lifting actuator (lift cylinder) that moves up and down relative to the main body, vertical position operating means (position lever) for setting the vertical height of the rotary tiller, and tilling depth for setting the tilling depth of the rotary tiller Length setting means (plowing depth adjustment dial), vertical position detecting means for detecting the vertical position of the rotary tiller (lift arm sensor), and tillage position detecting means for detecting the tillage position of the rotary tiller (upper limit of the rear cover) A rotary tilling sensor) and a control means for operating the lifting actuator, and the rotary tillage Automatic height control (elevation control) that causes the detected vertical position of the device to follow the vertical position set by the vertical position operating means, and the detection tillage position of the rotary tiller set to the set tilling depth position by the tilling depth setting means 2. Description of the Related Art A lift control device configured to perform plowing depth control to be followed is known.

  When the normal tillage work is finished and the headland tillage (the field end is tilled) is started, the rotary tiller is lowered to the position as close to the field end as possible, and the vehicle main body is stopped. To start. At the start of such work, the rear cover for detecting the depth of plowing is in contact with the soil surface of the uncultivated land, so that the plowing depth becomes deeper and the soil accumulates in the plow cover of the rotary tiller. When the vehicle body is started, the rear cover rotates in the opening direction due to the dirt accumulated in the tillage cover, so that the rotary tillage device is controlled to rise and passes through the place where the dirt has accumulated. Later, since the rear cover rotates in the closing direction, control for lowering the rotary tiller is performed. When such control is performed, as shown in FIG. 14 (a), there is a risk that the field scene becomes uneven and the finish may be deteriorated. As shown in FIG. 14 (b), the rotary tiller is raised. The side movement is regulated and controlled for a certain period of time (see, for example, Patent Document 2).

JP 2000-41415 A JP 2007-110924 A

  However, in the technique shown in Patent Document 2, when starting tilling when the vehicle main body is stopped, tilling is continued while soil is accumulated in the rotary cover. Therefore, the tilling load is large, and a traveling load is also added when starting the vehicle main body. As a result, there has been a problem that the engine speed decreases due to the influence, or the engine stops in some cases.

  The present invention is a work vehicle capable of suppressing a decrease in engine speed and avoiding engine stoppage even when a tilling load or a traveling load is large when the work vehicle performing the tilling work is started. The purpose is to provide.

  The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described.

  According to a first aspect of the present invention, a transmission for shifting the traveling speed, a transmission actuator for changing the transmission ratio of the transmission, a transmission ratio setting means for setting a target transmission ratio in the transmission, and the transmission ratio are the Control means for driving and controlling the speed change actuator so as to achieve a target speed ratio, and a work vehicle on which the rotary tiller is mounted so as to be able to move up and down, and a stop state detection means for detecting a stop state of the work vehicle. A grounding state detecting means for detecting a grounding state of the rotary tiller, and a driving state detecting means for detecting a driving state of the rotary tiller. The control means stops the work vehicle, and When the tilling device is grounded and the rotary tilling device is driven and then the work vehicle starts, a specified distance or a specified time elapses from the start. Until corrects the deceleration side said target gear ratio, is for driving and controlling the shift actuator.

  According to a second aspect of the present invention, a transmission that changes the traveling speed, a transmission actuator that changes the transmission ratio of the transmission, a transmission ratio setting means that sets a target transmission ratio in the transmission, and the transmission ratio is the speed ratio. Control means for driving and controlling the speed change actuator so as to achieve a target speed ratio, and a work vehicle on which the rotary tiller is mounted so as to be able to move up and down, and a stop state detection means for detecting a stop state of the work vehicle. A grounding state detecting means for detecting a grounding state of the rotary tiller, and a driving state detecting means for detecting a driving state of the rotary tiller. The control means stops the work vehicle, and When the tilling device is grounded and the rotary tilling device is driven and then the work vehicle starts, a specified distance or a specified time elapses from the start. Until, by limiting the rate of increase of the target speed ratio at a predetermined increase rate is for driving and controlling the shift actuator.

  According to a third aspect of the present invention, load control means for detecting engine load is further provided, and the control means shortens the specified distance or the specified time when the engine load is smaller than a set value.

  According to a fourth aspect of the present invention, load control means for detecting engine load is further provided, and the control means increases the rate of change when the engine load is smaller than a set value.

  As effects of the present invention, the following effects can be obtained.

  According to the first aspect, even when the traveling load at the time of starting is large, it is possible to suppress a decrease in the engine speed and to prevent the engine from being stopped. In addition, even when the ascent of the rotary tillage device is restricted at the time of start-up and is maintained at a predetermined height for plowing work, the finish of the farm scene is kept in good condition and the engine speed is reduced. The decrease can be suppressed, and the engine stop can be avoided.

  According to the second aspect of the present invention, even when the traveling load at the time of starting is large, it is possible to suppress a decrease in the engine speed and to prevent the engine from being stopped. In addition, even when the ascent of the rotary tillage device is restricted at the time of start-up and is maintained at a predetermined height for plowing work, the finish of the farm scene is kept in good condition and the engine speed is reduced. The decrease can be suppressed, and the engine stop can be avoided.

  In claim 3, when the engine load is small, the work can be done quickly.

  In claim 4, when the engine load is small, the work can be done quickly.

The whole tractor side view. The figure which shows the power transmission structure of a tractor. The block diagram which shows the structure which concerns on control of a tractor. (A) The graph which shows the control aspect of the vehicle speed limitation control which concerns on 1st embodiment. (B) The graph which shows the control aspect of the vehicle speed limitation control which concerns on 2nd embodiment. The flowchart of the vehicle speed restriction | limiting control which concerns on 1st embodiment. The flowchart of the vehicle speed restriction | limiting control which concerns on 2nd embodiment. (A) The graph which shows the control aspect of the vehicle speed limitation control which concerns on 3rd embodiment. (B) The graph which shows the control aspect of the vehicle speed limitation control which concerns on 4th embodiment. The flowchart of the vehicle speed limitation control which concerns on 3rd embodiment. The flowchart of the vehicle speed limitation control which concerns on 4th embodiment. (A) The graph which shows the control aspect of the vehicle speed restriction | limiting control which concerns on 5th embodiment. (B) The graph which shows the control aspect of the vehicle speed restriction | limiting control which concerns on 6th embodiment. The flowchart of the vehicle speed limitation control which concerns on 5th embodiment. The flowchart of the vehicle speed limitation control which concerns on 6th embodiment. (A) A schematic diagram showing a control mode of vehicle speed limit control, at the start of vehicle speed limit control. (B) When vehicle speed limit control is continued. (C) At the end of the vehicle speed limit control. (A) The schematic diagram which shows the control aspect of the conventional rotary tiller. (B) The schematic diagram which shows the control aspect of the other rotary tillage apparatus in the past.

  Next, the overall configuration of the working vehicle according to an embodiment of the present invention will be described as a tractor 1 and a working machine connected to the tractor 1 as a rotary tiller 30.

  As shown in FIG. 1, in the tractor 1, the body frame 2 is arranged with the longitudinal direction as the front-rear direction, and is supported by a pair of left and right front wheels 3, 3 via a front axle at the front part, and at the rear part. It is supported by a pair of left and right rear wheels 4, 4 via a rear axle. An engine 5 is provided at the front of the machine body frame 2 and is covered with a bonnet 6. A mission case 7 that houses a part of the power transmission mechanism of the tractor 1 is provided at the rear of the body frame 2.

  A cabin 8 is disposed behind the bonnet 6, and a driving operation unit 10 is provided inside the cabin 8 for an operator to board and operate the tractor 1. In the driving operation unit 10, a steering handle 11 is provided at the front, and a seat 12 is disposed behind the steering handle 11. Further, on the side portion of the seat 12, there are a main transmission lever and a speed adjustment dial that are the transmission ratio setting means 63, a work implement elevating lever that is the elevating position setting means 72, a plowing depth setting dial that is the plowing depth setting means 65, and the like. The accelerator lever which is the engine speed setting means 70 and the forward / reverse switching lever 62 are arranged on the handle column side portion of the steering handle 11 (see FIG. 3). An accelerator pedal, a brake pedal, a main clutch pedal, a differential lock pedal, and the like are disposed on the step below the seat 12.

  The work machine connection device 20 mainly includes a top link 21, lower links 22 and 22, and lift rods 23 and 23. The top link 21 is rotatably connected to a top link bracket fixed to the rear portion of the mission case 7. The lower links 22 and 22 are rotatably connected to both sides of the transmission case 7 or the rear axle housing. The lift rods 23, 23 are rotatably connected at one end to the front and rear middle portions of the lower links 22, 22, and the other end is rotatably connected to lift arms 24, 24 protruding rearward from the hydraulic case. . A rotary tiller 30 is connected to the rear ends of the top link 21 and the lower links 22, 22.

  The rotary tilling device 30 includes a tilling claw 31, a tilling cover 32, a rear cover 33, a chain case 34, and the like. The tilling claws 31, 31... Are planted radially on the claw shaft 35 laid horizontally so as to be freely rotatable in the left-right direction, and the rotational trajectories 36 at the tips of the tilling claws 31, 31. A tilling cover 32 is disposed so as to cover the upper side and the side, a front end of the rear cover 33 is rotatably connected to a rear end of the tilling cover 32, and a cover angle sensor 37 is provided at a rotating base of the rear cover 33. (See FIG. 13). The claw shaft 35 is linked to a PTO shaft 49 protruding rearward from the rear surface of the transmission case 7 via a chain case 34, a universal joint, etc. (see FIG. 2).

  As shown in FIG. 2, the power of the engine 5 is transmitted to the rear wheels 4 and 4 through the main transmission mechanism 41, the forward / reverse switching mechanism 42, the auxiliary transmission mechanism 43, the rear wheel differential mechanism 44, and the like sequentially. At the same time, the power of the engine 5 is transmitted to the front wheels 3 and 3 sequentially through the main transmission mechanism 41, the forward / reverse switching mechanism 42, the auxiliary transmission mechanism 43, the front wheel drive switching mechanism 45, the front wheel differential mechanism 46, and the like. The As a result, the front wheels 3 and 3 and the rear wheels 4 and 4 are rotationally driven, and the tractor 1 travels. Further, the power of the engine 5 is transmitted to the claw shaft 35 of the rotary tiller 30 through the PTO clutch mechanism 47, the PTO transmission mechanism 48, the PTO shaft 49, and the like sequentially. As a result, the tilling claws 31, 31... Are rotated together with the pawl shaft 35, and the tilling work is performed.

  Next, the control mode of the tractor 1 will be described.

  The control device 100 is provided at an arbitrary position of the tractor 1. The control device 100 includes a central processing unit, a storage device, and the like. As shown in FIG. 3, the control device 100 includes a vehicle speed sensor 61, a forward / reverse switching lever 62, a transmission ratio setting means 63, a transmission ratio detection means 64, a tilling depth setting means 65, and a tilling depth detection means 66. A PTO switch 67, a PTO lever 68, a PTO switching dial 69, an engine speed setting means 70, an engine speed detection means 71, a lift position setting means 72, and a lift position detection means 73. The The control device 100 is connected to a speed change actuator 81 and a lift actuator 82.

  The vehicle speed sensor 61 detects the actual traveling speed (vehicle speed) of the tractor 1. In this embodiment, the vehicle speed sensor 61 detects the traveling speed by detecting the rotational speed of the axle of the rear wheel 4. The vehicle speed sensor 61 is configured by a magnetic pickup coil, a rotary encoder, or the like, and a detection value detected by the vehicle speed sensor 61 is transmitted to the control device 100 as a traveling speed.

  The forward / reverse switching lever 62 sets the traveling direction of the tractor 1. The forward / reverse switching lever 62 includes a sensor that detects an operation position, and the operation position detected by the sensor is transmitted to the control device 100. The control device 100 transmits a signal to the solenoid valve based on the operation amount to drive the hydraulic actuator, and operates the forward clutch 42a and the reverse clutch 42b to “ON” and “OFF”. More specifically, when the forward / reverse switching lever 62 is operated to the “forward” position, the forward clutch 42a of the forward / reverse switching mechanism 42 is operated to “ON”, and when operated to the “reverse” position, the reverse clutch 42b is set to “ When it is operated to the “neutral” position, the forward clutch 42a and the reverse clutch 42b are operated to “OFF” (see FIG. 2).

  The gear ratio setting means 63 sets the gear ratio (vehicle speed) of the continuously variable transmission 41a in the main transmission mechanism 41. The gear ratio setting means 63 is composed of, for example, a main gear shift lever and a speed adjustment dial. These main transmission lever and speed adjustment dial are provided with a sensor for detecting an operation amount, and the operation amount detected by the sensor is transmitted to the control device 100 as a target gear ratio.

  The gear ratio detection means 64 detects the gear ratio of the continuously variable transmission 41a in the main transmission mechanism 41. The gear ratio detecting means 64 is, for example, a sensor that detects the hydraulic pump of the continuously variable transmission or the swash plate angle of the hydraulic motor, and the signal detected by this sensor is the actual gear ratio (actual) of the continuously variable transmission 41a. (Transmission ratio) is transmitted to the control device 100.

  The tilling depth setting means 65 sets the tilling depth of the tilling claws 31 in the rotary tiller 30 to an arbitrary tilling depth. The working depth setting means 65 is, for example, a working depth setting dial that can be rotated. The plowing depth setting dial includes a sensor that detects an operation amount, and the operation amount detected by the sensor is transmitted to the control device 100 as a setting depth.

  The tilling depth detecting means 66 detects the tilling depth of the rotary tiller 30. The plowing depth detection means 66 is, for example, a cover angle sensor 37 that detects a rotation angle of the rear cover 33 with respect to the plowing cover 32 (an opening degree of the rear cover 33) (see FIG. 13). , Transmitted to the control device 100 as the tilling depth H.

  The PTO switch 67 sets power transmission to the PTO shaft 49 and cutoff. The PTO switch 67 includes a sensor that detects an operation position, and the operation position detected by the sensor is transmitted to the control device 100. The control device 100 transmits a signal to the electromagnetic valve based on the operation position of the PTO switch 67 and a PTO switching dial 69 described later to operate the hydraulic actuator, and the PTO clutch 47a of the PTO clutch mechanism 47 and the PTO clutch 47a are in conflict with each other. The PTO brake 47b that is activated automatically is turned on and off.

  The PTO lever 68 changes the rotation speed and rotation direction of the PTO shaft 49. The PTO lever 68 is connected to a shifter that selectively changes the meshing of the transmission gear in the PTO transmission mechanism 48. The PTO lever 68 includes a sensor that detects an operation position, and the operation position detected by the sensor is transmitted to the control device 100. In the present embodiment, the PTO lever 68 can be operated to the “forward”, “neutral”, and “reverse” positions. Based on this operation, the shifter of the PTO transmission mechanism 48 slides, and the PTO shaft 49 The number of rotations and direction of rotation are changed.

  The PTO switching dial 69 switches the operation mode of the PTO clutch mechanism 47. The PTO switching dial 69 includes a sensor that detects an operation position, and this sensor is connected to the control device 100. The PTO switching dial 69 can be switched to the “interlocking”, “independent” and “elevation interlocking” positions. When operated to the “interlocked” position, when the power of the traveling system transmission path is cut off, the control device 100 operates so that the PTO clutch mechanism 47 cuts off the power regardless of the operation of the PTO switch 67. . When operated to the “independent” position, the control device 100 switches the power transmission state of the PTO clutch mechanism 47 by the operation of the PTO switch 67 regardless of the power transmission state of the traveling system power transmission path. When operated to the “elevation interlocking” position, the control device 100 allows the PTO clutch mechanism 47 to be operated regardless of the operation of the PTO switch 67 when the rotary tiller 30 is set to a predetermined raised position such as a non-working position. Operates to cut off power.

  The engine speed setting means 70 sets the speed of the engine 5. The engine speed setting means 70 is, for example, an accelerator lever or an accelerator pedal. These accelerator levers and accelerator pedals are provided with a sensor such as a potentiometer for detecting the operation amount, and the operation amount detected by this sensor is transmitted to the control device 100 as a set engine speed (target engine speed Ns).

  The engine speed detector 71 detects the speed of the engine 5. The engine speed detection means 71 is configured to detect the speed of the flywheel and crankshaft of the engine 5, for example. The engine speed detecting means 71 is composed of a magnetic pickup coil, a rotary encoder, etc., and the signal detected by the engine speed detecting means 71 is transmitted to the control device 100 as the actual engine speed (actual engine speed Nr). Is done. The control device 100 drives and controls a fuel injection device (not shown) so that the actual engine speed Nr matches the target engine speed Ns.

  The raising / lowering position setting means 72 sets the height of the rotary tiller 30 with respect to the vehicle body of the tractor 1. The raising / lowering position setting means 72 includes, for example, a working machine raising / lowering lever for raising and lowering the working machine to an arbitrary height, a working machine raising switch and a working machine lowering switch for raising and lowering to a predetermined position (a raised position and a lowered position). It is said. These work implement lift levers, work implement lift switches, and work implement drop switches include sensors that detect operation amounts, and the operation amounts detected by these sensors are transmitted to the control device 100 as target lift positions.

  The lift position detection means 73 detects the height of the rotary tiller 30 with respect to the vehicle body of the tractor 1. The lift position detection means 73 is, for example, a lift angle sensor that detects the rotation angle installed at the rotation base of the lift arms 25 and 25. The detection value detected by the lift angle sensor is the actual lift position. It is transmitted to the control device 100.

  The transmission actuator 81 changes the transmission ratio of the continuously variable transmission 41a in the main transmission mechanism 41, that is, the swash plate angle. The speed change actuator 81 includes an electromagnetic proportional valve, a cylinder, a motor, and the like. The speed change actuator 81 is driven based on the signal transmitted from the control device 100 to change the swash plate angle of the continuously variable transmission 41a and change the speed ratio of the main speed change mechanism 41. The control device 100 controls the drive of the speed change actuator 81 so that the actual speed ratio detected by the speed ratio detection means 64 matches the target speed ratio set by the speed ratio setting means 63, and the continuously variable transmission. The gear ratio of 41a is changed.

  The raising / lowering actuator 82 raises / lowers the rotary tiller 30 with respect to the vehicle body. The lifting / lowering actuator 82 is configured by an electromagnetic valve or the like that switches the amount and direction of pressure oil supplied to the hydraulic cylinder that rotates the lift arms 25 and 25. The lift actuator 82 is driven based on a signal transmitted from the control device 100 to change the height of the rotary tiller 30. Specifically, the control device 100 determines that the detected value (actual lift position) detected by the lift position detection means 73 matches the set value (actual lift position) set by the lift position setting means 72. The rotary tiller 30 is moved up and down by driving and controlling 82 (lifting control). Alternatively, the control device 100 determines that the detection value (cultivation depth H) detected by the tilling depth detection means 66 matches the set value (setting depth) set by the tilling depth setting means 65. The rotary tiller 30 is moved up and down by driving and controlling 82 (plowing depth control).

  Next, the vehicle speed limit control of the tractor 1 according to the embodiment of the present invention will be described.

  When the tractor 1 starts traveling while performing the tilling work at the field end or the like, the control device 100 performs control (vehicle speed restriction control) to reduce the vehicle speed of the tractor 1. This vehicle speed restriction control is performed based on the detection values of the stop state detection means, the ground contact state detection means, the drive state detection means, and the start state detection means.

  The stop state detecting means detects the stop state (whether or not the tractor 1 is stopped). The stop state detecting means is constituted by a vehicle speed sensor 61, for example. When the traveling speed is not detected by the vehicle speed sensor 61, the control device 100 determines that the tractor 1 is stopped. The stop state detecting means can also be constituted by a forward / reverse switching lever 62 and a gear ratio setting means 63. When the forward / reverse switching lever 62 is operated to “neutral”, or when the forward / reverse switching lever 62 is operated to “forward” and the set value (target transmission ratio) is set to “zero”, the transmission ratio setting means 63 When operated, the control device 100 determines that the tractor 1 is stopped. It is also possible to use a gear ratio detection means 64 as an alternative to the gear ratio setting means 63. However, the stop state detection means is not limited to the above as long as the stop state of the tractor 1 can be detected.

  The grounding state detection means detects the grounding state (whether or not the grounding is performed) of the rotary tiller 30. The grounding state detection means can be constituted by, for example, a tilling depth detection means 66. If the detection value of the tilling depth detecting means 66 changes from the initial value, it is determined that the rotary tiller 30 is grounded in the same manner. However, the grounding state detection means is not limited to the above configuration as long as the grounding state of the rotary tiller 30 can be detected. Further, the grounding state detection means can be constituted by, for example, a plowing depth setting means 65 and a plowing depth detection means 66. When the set value (set depth) of the tilling depth setting means 65 and the detected value (plowing depth H) of the tilling depth detecting means 66 coincide with each other, the control device 100 causes the rotary tiller 30 to be grounded. It is also possible to judge that

  The drive state detection means detects the drive state (whether or not it is driven) of the rotary tiller 30. The drive state detection means is composed of, for example, an operation tool (PTO switch 67 and PTO switching dial 69) for operating the PTO clutch 47a and a PTO lever 68. When the PTO clutch 47a of the PTO clutch mechanism 47 is operated and the PTO lever 68 is operated to the “forward rotation” position, the control device 100 determines that the rotary tiller 30 is driven. However, the drive state detection means is not limited to the above configuration as long as the drive state of the rotary tiller 30 can be detected.

  The starting state detecting means detects the starting state (whether or not the vehicle has started) of the tractor 1. The starting state detecting means is composed of a forward / reverse switching lever 62 and a gear ratio setting means 63, for example. When the set value (target gear ratio) of the gear ratio setting means 63 is other than “zero” and the forward / reverse switching lever 62 is operated to the “forward” position, the control device 100 determines that the tractor has started. To do. Further, the start state detecting means can be replaced by the stop state detecting means. That is, when the tractor 1 detects “running” from “stop” by the stop state detecting means, the tractor 1 starts. to decide. However, the start state detection means is not limited to the above configuration as long as the start state of the tractor 1 can be detected.

  The load detection means detects the load of the engine 5. The load detection means includes, for example, an engine speed setting means 70 and an engine speed detection means 71. The load of the engine 5 is calculated from the target engine speed Ns set by the engine speed setting means 70 and the actual engine speed Nr detected by the engine speed detection means 71. Specifically, the load factor of the engine 5 (actual engine speed Nr / target engine speed Ns) and the engine speed down amount (target engine speed Ns−actual engine speed Nr) are calculated. Based on this, control device 100 determines whether or not the load on engine 5 is small. However, the load detection unit is not limited to the above configuration as long as it can detect the load of the engine 5.

  Next, the vehicle speed limit control of the tractor 1 according to the first embodiment of the present invention will be described.

  In the first embodiment, the control device 100 detects the stop of the tractor 1 with the stop state detection means, detects the ground contact of the rotary tiller 30 with the ground state detection means, and rotates the rotary state with the drive state detection means. When the drive of the tilling device 30 is detected and then the start of the tractor 1 is detected by the start state detecting means, as shown in FIG. 4A, a specified distance from the start position (cultivation start position). Until X elapses, the target speed ratio set by the speed ratio setting means 63 is corrected to the deceleration side at a predetermined correction rate (correction value). Then, after the specified distance X has elapsed (after reaching) from the start position (cultivation start position), the correction to the target gear ratio is stopped.

  Here, the correction ratio is a ratio to be corrected toward the deceleration side with respect to the target speed ratio. If the correction ratio is 100%, the target speed ratio is not corrected. If the correction ratio is 80%, for example, the correction ratio is 100. When the vehicle speed is 10 km / h in the case of%, the target gear ratio is corrected so that the vehicle speed becomes 8 km / h when the correction rate is 80%. In the present embodiment, the correction rate is 80%, and the specified distance X is 1 m. The correction factor and the specified distance X are set in advance in the control device 100 or set by an operator operating the operation tool.

  A specific example will be described. As shown in FIG. 5, when starting the tilling work, in step S11, the operator operates the lifting position setting means 72 to move the rotary tilling device 30 to the non-working position by lifting control. Raise to (upmost position). Then, the process proceeds to step S12. However, the operator operates the PTO switching dial 69 in the “elevation interlocking” position, the PTO switch 67 in the “ON” position, and the PTO lever 68 in the “forward” (other than “neutral” and “reverse”) positions. It is assumed that the rotary tiller 30 is stopped by operating the PTO brake 47b of the PTO clutch mechanism 47.

  In step S <b> 12, the control device 100 determines whether or not the vehicle speed of the tractor 1 is zero by the vehicle speed sensor 61. Then, the process proceeds to step S13. If the vehicle speed is not zero, the vehicle speed limit control is terminated.

  In the present embodiment, the stop state detection means is constituted by a vehicle speed sensor 61. When the vehicle speed sensor 61 detects vehicle speed = 0 in step S12, the control device 100 indicates that the tractor 1 is stopped. to decide.

  In step S <b> 13, it is determined whether or not the operator has operated a work implement lowering switch that is the lift position setting means 72. If operated, the process proceeds to step S14.

  In step S <b> 14, the control device 100 drives and controls the lifting actuator 82 to lower the rotary tiller 30. Then, the process proceeds to step S15. In step S14, when the height of the rotary tiller 30 becomes a predetermined height or less, the PTO clutch 47a of the PTO clutch mechanism 47 is operated. That is, power is transmitted to the rotary tiller 30 via the PTO clutch mechanism 47, the PTO speed change mechanism 48, and the PTO shaft 49, and the rotary tiller 30 is driven. When the rotary tiller 30 continues to descend and the tilling claw 31 comes into contact with the soil, the tilling work is performed at the stop position of the tractor 1 (for example, the field end).

  In the present embodiment, the drive state detection means includes the PTO clutch 47a and the PTO lever 68. In step S14, the PTO clutch 47a is operated and the PTO lever 68 is operated to a position other than the “neutral” position. The control device 100 determines that the rotary tiller 30 is driven.

  In step S15, the control device 100 determines whether or not the detection value (rear cover angle) of the cover angle sensor 37, which is the tilling depth detection means 66, has changed to the shallow side (open side). When changed, it is determined that the rotary tiller 30 is grounded, and the process proceeds to step S16. If not, the process proceeds to step S14.

  In the present embodiment, the ground contact state detection means includes the lift position setting means 72 and the tilling depth detection means 66. When the rear cover 33 is grounded by the lowering operation by the lift position setting means 72 in step S15, the tilling position detection means. Since the detection value of 66 changes to the open side, the control device 100 determines that the rotary tiller 30 is grounded.

  In step S16, the control apparatus 100 starts plowing depth control. That is, the lifting / lowering control is switched from the raising / lowering control to the tilling depth control, and the raising / lowering actuator 82 is driven and controlled so that the tilling depth H detected by the tilling depth detecting means 66 coincides with the set depth set by the tilling depth setting means 65. Since the rotary tiller 30 is driven at the start of this operation, the rotary tiller 30 plows the soil below the rotary tiller 36 as shown in FIG. The soil is piled up behind, and the convex part 38 is formed. At this time, till reaching the specified distance X from the start, the tilling depth control is limited as described later. Then, the process proceeds to step S17.

  In step S17, the control device 100 determines whether or not a start operation has been performed. The setting value (target transmission ratio) of the main transmission lever and the speed adjustment dial of the transmission ratio setting unit 63 which is the start state detection unit is other than “zero”, and the forward / reverse switching lever 62 is set to the “forward” position. When operated, the control device 100 activates the forward clutch 42a of the forward / reverse switching mechanism 42 by activating an electromagnetic valve or a hydraulic actuator. Then, the tractor 1 starts traveling. Then, the control device 100 determines that the start operation has been performed, and proceeds to step S18.

  In the present embodiment, the starting state detecting means includes a gear ratio setting means 63 and a forward / reverse switching lever 62. In step S17, the set value (target gear ratio) of the gear ratio setting means 63 is other than “zero”. When the forward / reverse switching lever 62 is operated to the “forward” position (the vehicle speed sensor 61 may detect forward rotation), the control device 100 determines that the tractor 1 has started.

  Note that when the tractor 1 starts traveling, the control device 100 restricts the tilling depth control and restricts the upward movement of the rotary tiller 30. In the present embodiment, the control device 100 maintains the height when the rotary tiller 30 reaches the set depth, and the height when stopped when the rotary tiller 30 reaches the set depth. As shown in FIGS. 13B and 13C, the plowing depth H of the rotary tiller 30 (the set depth of the plowing depth setting means 65) is as follows. After being maintained as it is, the tractor 1 is driven and tillage work is performed. That is, the height of the rotary tiller 30 is maintained even when the rear cover 33 that is the tilling depth detecting means 66 is rotated upward.

  In step S18, the control device 100 starts vehicle speed restriction control. That is, the target gear ratio set by the gear ratio setting means 63 is detected, and this target gear ratio is corrected to the deceleration side with a correction rate of 80% (see FIG. 4A). Then, the control device 100 drives and controls the speed change actuator 81 so that the actual speed ratio detected by the speed ratio detecting means 64 matches the corrected target speed ratio (80% of the target speed ratio). Limit the vehicle speed. Then, the process proceeds to step S19.

  In step S <b> 19, the control device 100 determines whether or not the travel distance of the tractor 1 exceeds 1 m, which is a predetermined distance X set in advance. For example, the travel distance is calculated by the control device 100 integrating the detection values of the vehicle speed sensor 61 from the start position. If the travel distance has passed 1 m (has reached 1 m), the process proceeds to step S20. When the travel distance has not passed 1 m, the travel is continued until the travel distance has passed 1 m.

  In step S20, the control device 100 stops the correction of the target gear ratio detected by the gear ratio setting means 63 (correction rate is 100%), drives and controls the gear shift actuator 81, and limits the vehicle speed of the tractor 1. To release. Thus, the vehicle speed restriction control is finished. Further, plowing depth control is performed from the end of the vehicle speed limit control (when the specified distance is reached).

  Next, the vehicle speed limit control of the tractor 1 according to the second embodiment of the present invention will be described. However, it demonstrates centering on a different point from 1st embodiment.

  In the vehicle speed limiting control of the tractor 1 according to the second embodiment, the control device 100 detects the stop of the tractor 1 with the stop state detection means, and detects the ground contact of the rotary tiller 30 with the ground state detection means, And when the drive of the rotary tiller 30 is detected by the drive state detection means, and when the start of the tractor 1 is detected by the start state detection means thereafter, as shown in FIG. Until the specified time T elapses (or reaches the specified time T), the target speed ratio set by the speed ratio setting means 63 is corrected to the deceleration side with a predetermined correction rate (correction value). Then, the correction to the target gear ratio is stopped after a specified time T has elapsed (after arrival) from the start.

  Here, in the present embodiment, the specified time T is 10 seconds and is set in advance in the control device 100 or is set by the operator operating the operating tool.

  A specific example will be described. As shown in FIG. 6, steps S11 to S18 are the same as those in the first embodiment, and the process proceeds from step S18 to step S21.

  In step S <b> 21, the control device 100 determines whether or not the traveling time of the tractor 1 has passed the specified time T of 10 seconds. The running time is calculated by, for example, a timer built in the control device 100 in advance, thereby starting counting from the start. When the traveling time has passed 10 seconds (has reached 10 seconds), the process proceeds to step S20, and the subsequent steps are the same as those in the first embodiment. If the travel time has not passed 10 seconds, the travel is continued until the travel time has passed 10 seconds.

  As described above, in the tractor 1 serving as the work vehicle according to the first and second embodiments of the present invention, the continuously variable transmission 41a that changes the traveling speed and the speed ratio of the continuously variable transmission 41a are changed. A speed change actuator 81, a speed ratio setting means 63 for setting a target speed ratio in the continuously variable transmission 41a, and a control device 100 for driving and controlling the speed change actuator 81 so that the speed ratio becomes the target speed ratio. , A tractor 1 for mounting the rotary tiller 30 so as to be movable up and down, a stop state detecting means for detecting the stop state of the tractor 1, and a ground state detecting means for detecting the ground state of the rotary tiller 30 Driving state detecting means for detecting the driving state of the rotary tiller 30. The control device 100 stops the tractor 1 and When the cultivator 30 is grounded and the rotary cultivator 30 is driven and then the tractor 1 starts, the target speed change is performed until a specified distance X or a specified time T elapses from the start. The shift actuator 81 is driven and controlled by correcting the ratio to the deceleration side at a predetermined correction rate. Thereby, even if it is a case where the driving | running | working load at the time of start is large, the fall of an engine speed can be suppressed and the stop of the engine 5 can be avoided. Further, even when the plowing work is performed while restricting the upward movement of the rotary tiller 30 at the time of starting and maintaining a predetermined height, the engine speed is improved while maintaining the finish of the field scene in a good state. Can be suppressed, and the stop of the engine 5 can be avoided.

  Next, the vehicle speed limit control of the tractor 1 according to the third embodiment of the present invention will be described. However, it demonstrates centering on a different point from 1st embodiment.

  In the vehicle speed limiting control of the tractor 1 according to the third embodiment, the control device 100 detects the stop of the tractor 1 with the stop state detection means, and detects the ground contact of the rotary tiller 30 with the ground state detection means, And when it is a case where the drive of the rotary tiller 30 is detected by the drive state detection means and the start of the tractor 1 is detected by the start state detection means thereafter, as shown in FIG. Until the specified distance X elapses from (cultivation start position), the rate of increase of the target speed ratio set by the speed ratio setting means 63 is limited to a predetermined rate of increase.

  In other words, the rate of increase until the corrected target gear ratio reaches the target gear ratio is limited to a predetermined increase rate. In the present embodiment, the correction factor is set to 0% at the start position, and thereafter gradually increased as the travel distance increases, and is changed to 100% at the specified distance X. Then, the increase rate in the target gear ratio corrected with this correction rate is limited to a predetermined increase rate. Here, the predetermined increase rate is set in advance in the control device 100 or is set by an operator operating the operation tool. However, the corrected relationship between the target gear ratio and the travel distance is not limited to a proportional relationship as shown in FIG. 7A, and may be a quadratic function or a logarithmic function, for example. Further, the correction rate at the start position is not limited to 0%, and may be, for example, 80% as in the first embodiment.

  A specific example will be described. As shown in FIG. 8, steps S11 to S17 are the same as those in the first embodiment, and the process proceeds from step S17 to step S31.

  In step S31, as shown in FIG. 7 (a), the control device 100 sets the target gear ratio correction rate proportionally between 0% and 100% according to the travel distance within 1 m which is the specified distance X. Increase with. That is, the target gear ratio corrected at the start position is gradually increased to the speed increasing side. At this time, the corrected relationship between the target gear ratio and the travel distance is limited to a predetermined increase rate. Then, the control device 100 corrects the target speed ratio detected by the speed ratio setting means 63 and drives and controls the speed change actuator 81 in accordance with the corrected target speed ratio. When the travel distance has passed 1 m (has reached 1 m), the correction of the target speed ratio detected by the speed ratio setting means 63 is stopped (correction rate 100%), and the speed change actuator 81 is driven and controlled. Thus, the vehicle speed restriction control is finished.

  Next, vehicle speed limit control of the tractor 1 according to the fourth embodiment of the present invention will be described. However, differences from the second and third embodiments will be mainly described.

  In the vehicle speed limit control of the tractor 1 according to the fourth embodiment, the control device 100 detects the stop of the tractor 1 with the stop state detection means, and detects the ground contact of the rotary tiller 30 with the ground state detection means, And when the drive of the rotary tiller 30 is detected by the drive state detection means, and when the start of the tractor 1 is detected by the start state detection means after that, as shown in FIG. Until the specified time T elapses, the rate of increase of the target speed ratio set by the speed ratio setting means 63 is limited to a predetermined rate of increase.

  In other words, the rate of increase until the corrected target gear ratio reaches the target gear ratio is limited to a predetermined increase rate. In the present embodiment, the correction rate is set to 0% at the start position, and thereafter gradually increased as the travel distance increases, and is changed to 100% at the specified time T. Then, the increase rate in the target gear ratio corrected with this correction rate is limited to a predetermined increase rate. Here, the predetermined increase rate is set in advance in the control device 100 or is set by an operator operating the operation tool. However, the relationship between the corrected target gear ratio and the travel time is not limited to a proportional relationship as shown in FIG. 7B, and may be a quadratic function or a logarithmic function, for example. Further, the correction rate at the start position is not limited to 0%, and may be 80%, for example, as in the second embodiment.

  A specific example will be described. As shown in FIG. 9, steps S11 to S17 are the same as those in the third embodiment, and the process proceeds from step S17 to step S41.

  In step S41, as shown in FIG. 7 (b), the control device 100 sets the correction ratio of the target gear ratio from 0% to 100% in proportion to the travel time within a specified time T of 10 seconds. Increase in relationship. That is, the target gear ratio corrected at the time of start is gradually increased toward the speed increasing side. At this time, the corrected relationship between the target gear ratio and the travel time is limited to a predetermined increase rate. Then, the control device 100 corrects the target speed ratio detected by the speed ratio setting means 63 and drives and controls the speed change actuator 81 in accordance with the corrected target speed ratio. When the traveling time has passed 10 seconds (has reached 10 seconds), the correction of the target speed ratio detected by the speed ratio setting means 63 is stopped (correction rate 100%), and the speed change actuator 81 is driven and controlled. . Thus, the vehicle speed restriction control is finished.

  As described above, in the tractor 1 serving as the work vehicle according to the third and fourth embodiments of the present invention, the continuously variable transmission 41a that changes the traveling speed and the speed change operation of the continuously variable transmission 41a are changed. A speed change actuator 81, a speed ratio setting means 63 for setting a target speed ratio in the continuously variable transmission 41a, and a control device 100 for driving and controlling the speed change actuator 81 so that the speed ratio becomes the target speed ratio. , A tractor 1 for mounting the rotary tiller 30 so as to be movable up and down, a stop state detecting means for detecting the stop state of the tractor 1, and a ground state detecting means for detecting the ground state of the rotary tiller 30 Driving state detecting means for detecting the driving state of the rotary tiller 30. The control device 100 stops the tractor 1 and When the cultivator 30 is grounded and the rotary cultivator 30 is driven and then the tractor 1 starts, the target speed change is performed until a specified distance X or a specified time T elapses from the start. The speed change actuator 81 is driven and controlled by limiting the rate of increase of the ratio to a predetermined rate of increase. Thereby, even if it is a case where the driving | running | working load at the time of start is large, the fall of an engine speed can be suppressed and the stop of the engine 5 can be avoided. Further, even when the plowing work is performed while restricting the upward movement of the rotary tiller 30 at the time of starting and maintaining a predetermined height, the engine speed is improved while maintaining the finish of the field scene in a good state. Can be suppressed, and the stop of the engine 5 can be avoided.

  Next, vehicle speed limit control of the tractor 1 according to the fifth embodiment of the present invention will be described. However, it demonstrates centering on a different point from 1st embodiment.

  In the vehicle speed limiting control of the tractor 1 according to the fifth embodiment, the control device 100 detects the load of the engine 5 by the load detection means, and when the load of the engine 5 is smaller than a preset set value, FIG. As shown in (a), the specified distance X (or specified time T) is shortened. Specifically, the control device 100 continues when the load factor of less than 50% of the engine 5 continues for 5 seconds or more, or when the engine down amount is less than 50 rpm, or when the load factor of less than 50% continues for 5 seconds or more. If the engine down amount is less than 50 rpm, it is determined that the engine load is small. Here, the setting value serving as the threshold is set in advance in the control device 100 or is set by the operator operating the operating tool.

  A specific example will be described. As shown in FIG. 11, steps S11 to S18 are the same as those in the first embodiment, and the process proceeds from step S18 to step S51.

  In step S51, control device 100 determines whether or not the load factor of engine 5 (actual engine speed Nr / target engine speed Ns) is less than 50% for 5 seconds or more. If it continues for 5 seconds or more, the process proceeds to step S52. If it has not continued for 5 seconds or more, the process proceeds to step S53.

  In step S52, the control device 100 sets the specified distance X = 0.2 m. Then, control goes to a step S55.

  In step S53, control device 100 determines whether or not the engine rotation down amount (target engine speed Ns−actual engine speed Nr) is less than 50 rpm. If it is less than 50 rpm, the process proceeds to step S52. If it is not less than 50 rpm, the process proceeds to step S54.

  In step S54, the control device 100 sets the specified distance X = 1 m. Then, control goes to a step S55.

  In step S55, the control device 100 determines whether or not the travel distance of the tractor 1 has exceeded Xm. If the travel distance is greater than or equal to Xm, the process proceeds to step S20, and thereafter, the process is the same as in the first embodiment. If it is less than Xm, the running is continued until Xm is reached (step S55 is repeated).

  As described above, the tractor 1 serving as the work vehicle according to the fifth embodiment of the present invention further includes load detection means for detecting the load of the engine 5, and the control device 100 sets the load of the engine 5. When the value is smaller than the value, the specified distance X or the specified time T is shortened. As a result, when the engine load is small, the duration of the vehicle speed limit control is shortened, and the work can be done quickly.

  Next, vehicle speed limit control of the tractor 1 according to the sixth embodiment of the present invention will be described. However, differences from the fourth and fifth embodiments will be mainly described.

  In the vehicle speed limiting control of the tractor 1 according to the sixth embodiment, the control device 100 detects the load of the engine 5 by the load detection means, and when the load of the engine 5 is smaller than a preset set value, FIG. As shown in (b), the inclination until the target gear ratio corrected within the specified time T (or the specified distance X) during the vehicle speed limit control reaches the target gear ratio is increased. Specifically, the control device 100 continues when the load factor of less than 50% of the engine 5 continues for 5 seconds or more, or when the engine down amount is less than 50 rpm, or when the load factor of less than 50% continues for 5 seconds or more. If the engine down amount is less than 50 rpm, it is determined that the engine load is small. Here, the setting value serving as the threshold is set in advance in the control device 100 or is set by the operator operating the operating tool.

  A specific example will be described. As shown in FIG. 12, steps S11 to S17 are the same as those in the fourth embodiment, and the process proceeds from step S17 to step S61.

  In step S61, the correction ratio of the target gear ratio is gradually increased as the travel time elapses. In other words, the corrected target gear ratio at the time of starting is gradually increased to the speed increasing side. Then, the process proceeds to step S62.

  In step S62, control device 100 determines whether or not the load factor of engine 5 (actual engine speed Nr / target engine speed Ns) is less than 50% for 5 seconds or more. When it continues for 5 seconds or more, the process proceeds to step S63. If it has not continued for 5 seconds or more, the process proceeds to step S64.

  In step S63, control device 100 increases the inclination on the acceleration side of the corrected target gear ratio. In other words, the change rate of the correction rate is increased. Then, control goes to a step S66.

  In step S64, control device 100 determines whether or not the engine rotation down amount (target engine speed Ns−actual engine speed Nr) is less than 50 rpm. If it is less than 50 rpm, the process proceeds to step S63. If it is not less than 50 rpm, the process proceeds to step S65.

  In step S65, control device 100 maintains the corrected target transmission gear ratio without increasing the acceleration-side gradient. Then, control goes to a step S66.

  In step S66, the control device 100 determines whether or not the traveling time of the tractor 1 has passed the specified time of 10 seconds. If the traveling time has exceeded 10 seconds (has reached 10 seconds), the process proceeds to step S67. If the traveling time has not passed 10 seconds, the process proceeds to step S61.

  In step S67, the control device 100 stops the correction of the target gear ratio detected by the gear ratio setting means 63 (correction rate is 100%), drives the shift actuator 81, and limits the vehicle speed of the tractor 1. To release. Thus, the vehicle speed limit control is terminated and the routine proceeds to normal vehicle speed control.

  As described above, the tractor 1 serving as a work vehicle according to the sixth embodiment of the present invention further includes load detection means for detecting the load of the engine 5, and the control device 100 sets the load of the engine 5. When the value is smaller than the value, the rate of increase to the target gear ratio is increased. As a result, when the engine load is small, the duration of the vehicle speed limit control is shortened, and the work can be done quickly.

1 Tractor (work vehicle)
DESCRIPTION OF SYMBOLS 5 Engine 30 Rotary tillage device 31 Tillage claw 32 Tillage cover 33 Rear cover 41 Main transmission mechanism 41a Continuously variable transmission (transmission)
63 gear ratio setting means 81 speed change actuator 82 lift actuator 100 control device (control means)

Claims (4)

A transmission for shifting the traveling speed;
A speed change actuator for changing the speed ratio of the transmission;
Gear ratio setting means for setting a target gear ratio in the transmission;
Control means for drivingly controlling the speed change actuator so that the speed ratio becomes the target speed ratio,
A work vehicle on which a rotary tiller is mounted so that it can be raised and lowered,
Stop state detecting means for detecting a stop state of the work vehicle;
A grounding state detecting means for detecting a grounding state of the rotary tiller;
Driving state detecting means for detecting the driving state of the rotary tiller,
In the case where the work vehicle is stopped, the rotary tiller is grounded, and the rotary tiller is driven, and then the work vehicle starts, a predetermined distance or a specified time from the start. Until the time elapses, the target gear ratio is corrected to the deceleration side, and the shift actuator is driven and controlled. A transmission for shifting the traveling speed;
A speed change actuator for changing the speed ratio of the transmission;
Gear ratio setting means for setting a target gear ratio in the transmission;
Control means for drivingly controlling the speed change actuator so that the speed ratio becomes the target speed ratio,
A work vehicle on which a rotary tiller is mounted so that it can be raised and lowered,
Stop state detecting means for detecting a stop state of the work vehicle;
A grounding state detecting means for detecting a grounding state of the rotary tiller;
Driving state detecting means for detecting the driving state of the rotary tiller,
In the case where the work vehicle is stopped, the rotary tiller is grounded, and the rotary tiller is driven, and then the work vehicle starts, a predetermined distance or a specified time from the start. Until the time elapses, the speed change actuator is drive-controlled while limiting the rate of increase of the target gear ratio to a predetermined rate of increase. Load detecting means for detecting engine load;
The work vehicle according to claim 1, wherein the control unit shortens the specified distance or the specified time when the engine load is smaller than a set value. Load detecting means for detecting engine load;
The work vehicle according to claim 2, wherein the control unit increases the increase rate when a load of the engine is smaller than a set value.

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