JP2013148036A - Engine control device of working vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an engine control device of a working vehicle having a control circuit carrying out starting control of an engine and driving/stopping control of the engine, capable of economically carrying out the starting and stopping of the engine in a proper timing.SOLUTION: A control circuit 21 has a parallel circuit 33 in which a seat switch 29 detecting sitting and a mid PTO switch 27 are connected in parallel, a series circuit 32 in which a starting switch 22 for an engine, a neutral detecting unit 28 for running, and a rear PTO switch 26 connected in series, a first switching circuit 34 arranged between the series circuit 32 and a starter motor 24 for the engine, and a second switching circuit 36 for supplying electric current to the first switching circuit 34, the parallel circuit 33 is connected to a fuel cut solenoid 23, the second switching circuit 36 is connected to a seat switch 29 and a mid PTO switch 27 side.

Description

  The present invention relates to an engine control device for a work vehicle.

  As shown in FIGS. 9A and 9B, a start switch 91 for starting the engine and a starter motor 92 for starting the engine are provided in the control circuit 90 to the rear PTO shaft provided at the rear part of the traveling machine body. A rear PTO switch 93 for detecting the presence or absence of power transmission, a mid PTO switch 94 for detecting the presence or absence of power transmission to the mid PTO shaft provided on the lower side of the middle part of the traveling vehicle body, and a neutral for detecting a traveling neutral state Only when the direct circuit connected in series with the detector 96 is connected to the control circuit 90, the power transmission to the rear PTO shaft and the power transmission to the mid PTO shaft are cut off, and the vehicle is in the traveling neutral state. 2. Description of the Related Art Conventionally, an engine control device for a work vehicle that allows engine start is known.

  Incidentally, in the one shown in FIG. 1A, a neutral detector 96 is constituted by a neutral detection switch provided in the forward / reverse switching lever, while in the one shown in FIG. The neutral detector 96 is configured by a detection switch 97 for detecting pedal operation of the HST pedal that performs acceleration / deceleration operation via the vehicle and a detection switch 98 for detecting pedal operation of the clutch pedal that performs intermittent driving power. .

  As a further improvement of the one shown in FIG. 9, a start switch, a starter motor, and a fuel cut solenoid for cutting fuel supplied to the engine are provided in the control circuit, and a rear PTO switch, a mid PTO switch, A neutral detector and a seat switch for detecting seating on the seat are connected to the control circuit, and based on these various information, engine start control and engine drive / stop control are performed at appropriate timing. An engine control device for a work vehicle shown in Patent Document 1 is known.

Japanese Patent Laying-Open No. 2011-17271 (FIG. 3-4)

However, in the engine control device for a work vehicle described in the above document, a microcomputer such as a controller is provided in the control circuit in order to perform engine start control and engine drive / stop control at appropriate timings, and a rear PTO switch, a mid PTO switch, a neutral The detector and the seat switch are connected to the input side of the controller, and the fuel cut solenoid and the starter motor are connected to the output side of the controller. The microcomputer becomes an indispensable component, and the cost increases.
[Technical Field] The present invention relates to an engine control device for a work vehicle that includes a control circuit that performs engine start control and engine drive / stop control. The engine of the work vehicle can start and stop the engine at an appropriate timing at low cost. It is an object to provide a control device.

  In order to solve the above problems, first, an engine start control includes a start switch 22 that performs an engine start operation, a starter motor 24 that starts the engine, and a fuel cut solenoid 23 that cuts fuel supplied to the engine. And a control circuit 21 for controlling driving and stopping of the engine, a rear PTO switch 26 for detecting the presence or absence of power transmission to the rear PTO shaft provided at the rear part of the traveling machine body 3, and a lower side of the middle part of the traveling machine body The control circuit includes a mid PTO switch 27 that detects the presence or absence of power transmission to the provided mid PTO shaft, a neutral detector 28 that detects a traveling neutral state, and a seat switch 29 that detects seating on the seat 11. 21, the control circuit 21 includes a seat switch 29 and a mid P A parallel circuit 33 in which an O switch 27 is connected in parallel, a series circuit 32 in which a start switch 22, a neutral detector 28, and a rear PTO switch 26 are connected in series, and a first circuit provided between the series circuit 32 and the starter motor 24. A switching circuit 34; a second switching circuit 36 that supplies current to the first switching circuit 34 so that the series circuit 32 and the starter motor 24 are connected; In addition, when the power is transmitted to the mid PTO shaft, the parallel circuit 33 is connected to the power supply side of the fuel cut solenoid 23 and is seated on the seat 11 so that the engine stops. The second switching circuit 34 is configured so that a current is supplied to the first switching circuit 34 when the power to the mid PTO shaft is cut off. The input side of the switching circuit 36, and the seat switch 29 side, it is characterized in that connected to the mid-PTO switch 27 side.

  Secondly, the seat switch 29 is arranged on the lower surface side of the seat portion 11a that is a seating portion of the seat 11, and the seat switch 29 includes a detection switch 53 that detects by turning on and off, and a bracket that supports the detection switch 53 51 and an operating pin 54 that is supported by the bracket 51 so as to be slidable up and down so that the detection switch 53 is turned on and off, and protrudes upward on the lower surface side of the seat portion 11a. Due to the displacement or deformation, the lower surface side of the seat portion 11a presses the operating pin 54 downward, and the detection switch 53 is detected and operated.

  In order to start the engine, it is necessary to supply current to the first switching circuit by the second switching circuit, so that the seat is seated, the power is cut to the mid PTO shaft, the traveling neutral and the rear PTO shaft All of the power cuts need to be detected, the engine can be started in a more appropriate state, and a parallel circuit in which the seat switch and mid PTO switch are connected in parallel is connected to the power supply side of the fuel cut solenoid to the seat The engine stops when no seating is detected and the power cut to the mid PTO shaft is not detected. Therefore, the engine stops every time you get up from the seat, and the mid PTO shaft is driven. The engine can be stopped at an appropriate timing while preventing the engine from stopping each time The complex control of the engine start and engine stop, without using the microcomputer, can be inexpensively realized by using two switching circuits.

  In addition, the seat switch is arranged on the lower surface side of the seat, which is the seating portion of the seat, and the seat switch is operated to turn on / off the detection switch for detecting by turning on / off, the bracket for supporting the detection switch, And an operating pin that is supported by the bracket so as to be slidable up and down and protrudes upward on the lower surface side of the seat portion, and the lower surface side of the seat portion causes the operating pin to move downward due to the downward displacement or deformation of the seat portion when seated. According to the device that presses and detects the detection switch, the detection switch does not directly contact the seat portion. Therefore, it is possible to efficiently prevent a failure due to the load on the seat portion being directly applied to the detection switch.

It is a top view of the agricultural tractor to which this invention is applied. It is a circuit diagram of an engine control device. It is a principal part side view by the side of the seat of a control part. It is a principal part top view of the control part of the state which removed the seat. It is a principal part expansion perspective view of FIG. (A) is a side view of a sheet switch, (B) is a side view of a receiving member. It is a top view of the tractor which shows another embodiment of this invention. It is a circuit diagram of an engine control device showing another embodiment of the present invention. (A), (B) is a circuit diagram of a conventionally well-known engine control device.

  FIG. 1 is a plan view of an agricultural tractor to which the present invention is applied. The tractor shown in the figure is a kind of work vehicle, and includes a traveling machine body 3 supported by a pair of left and right front wheels 1 and 1 and rear wheels 2 and 2, an elevating link mechanism 4 provided at a rear portion of the traveling machine body 3, And a working machine (not shown) such as a rotary tiller that is detachably attached to the link mechanism 4.

  The traveling machine body 3 covers an engine (not shown) in the front half of the traveling machine body 3 so that it can be freely opened and closed. A steering unit 7 on which an operator enters is installed behind the hood 6 in the traveling machine body 3. A rear PTO shaft (not shown) in the front-rear direction is supported on the portion so as to be rotatable around its own axis in a rearward projecting state, and a mid PTO shaft is provided around the lower side of the midway portion of the traveling machine body 3. It is supported so that it can be rotationally driven. In addition, the left and right rear wheels 2, 2 are provided with fenders 8, 8, respectively. The fender 8 for the rear wheel 2 has a mountain-shaped circular arc shape in side view so as to cover the upper side along the rear wheel 2. Is curved.

  Engine power is transmitted to one or both of the rear wheel 2 and the front wheel 1 via a transmission (not shown) in the transmission case 9, and is also transmitted to the rear PTO shaft and the mid PTO shaft. A work machine such as a rotary tiller is driven by the power output from the rear PTO shaft, and a work machine such as a mower installed on the lower side of the traveling machine body 3 by the power output from the mid PTO shaft. Is driven.

  Further, the transmission includes a forward state in which power for forward travel is transmitted to the wheels 1 and 2, a reverse state in which power for backward travel is transmitted to the wheels 1 and 2, and power to the wheels 1 and 2 are cut off. In addition to a forward / reverse switching mechanism for switching to a running neutral state, a rear PTO clutch (not shown) that interrupts transmission of engine power to the rear PTO shaft, and a mid that interrupts transmission of engine power to the mid PTO shaft A PTO clutch (not shown) is provided.

  The control unit 7 is a low position between the seat 11 disposed between the left and right fenders 8, 8 in plan view, the front operation unit 12 positioned in front of the seat 11, and the planar view seat 11 and the front operation unit 12. And a steering handle 14 formed to project obliquely upward and rearward from the front operating portion 12, and supported on the side (more specifically, the left side) of the steering handle 14 so as to be able to swing back and forth. And a rear PTO lever 17 and a mid PTO lever 18 supported on the side of the seat 11 (more specifically, on the left side) so as to be able to swing back and forth.

  An operator seated on the seat 11 performs a steering operation of the aircraft by the steering handle 14. When the forward / reverse switching lever 16 swings back and forth, the forward / backward switching mechanism is switched to a reverse state, a forward state, or a traveling neutral state. Specifically, the forward / reverse switching lever 16 is swung forward from the forward / backward neutral position to switch to the forward movement state, and the forward / backward switching lever 16 is swung backward from the forward / backward neutral position to reverse the vehicle. By switching to the state, the forward / reverse switching lever 16 is swung to the forward / backward neutral position to switch to the traveling neutral state.

  And when driving | running | working or a driving | running | working stop, each working machine is driven, and the cultivation work of a farm field, the mowing work of weeds, etc. are performed. Specifically, the rear PTO lever 17 is swung back and forth, and the rear PTO clutch is intermittently operated to turn on and off the tillage drive of the rotary tiller, while the mid PTO lever 18 is swung back and forth. Intermittent operation of the PTO clutch, turning on and off the mowing drive of the mower.

  The tractor controls engine start, drive maintenance, and drive stop based on information such as the power transmission state to the two PTO shafts, the transmission state to the traveling system power, and the seating state on the seat 11. An engine control device 19 (see FIG. 2) is installed.

Next, the engine control device 19 will be described in detail with reference to FIG.
FIG. 2 is a circuit diagram of the engine control apparatus. The engine control device 19 includes a control circuit 21 that controls engine start, drive maintenance, and drive stop.

  The control circuit 21 includes a starter switch (start switch) 22 including a key switch installed in the control unit 7, a fuel cut solenoid 23 for cutting fuel supplied to the engine, and a starter motor 24 for starting the engine. A rear PTO switch 26 for detecting the presence / absence of power transmission to the rear PTO shaft, a mid PTO switch 27 for detecting the presence / absence of power transmission to the mid PTO shaft, and a shuttle switch (neutral detector) for detecting the traveling neutral state. ) 28 and a seat switch 29 for detecting seating on the seat 11 are electrically connected. In other words, the control circuit 21 is constituted by these members.

  The starter switch 22 is connected to a power supply circuit 31 connected to a power source such as a battery, and has an engine start terminal 22a and an engine drive terminal 22b. The starter switch 22 includes an engine start state in which the engine start terminal 22a and the engine drive terminal 22b are electrically connected to the power supply circuit 31, and an engine drive state in which only the engine drive terminal 22b is electrically connected to the power supply circuit 31. The engine start terminal 22a and the engine drive terminal 22b are switched to the engine stop state in which the power supply circuit 31 is electrically disconnected.

  More specifically, when the engine is started by inserting the key and performing the maximum current turning operation from the initial position, the engine is started. When the hand is released from the key during the engine starting state, the elastic force of an elastic member (not shown) In addition to turning the engine so as to return to the initial position by the distance, the engine is driven, and the engine is stopped by turning the key to the initial position when the engine is driven.

  The rear PTO switch 26 is installed on the rear PTO clutch side or the rear PTO lever 17 side to detect connection switching or connection switching operation of the rear PTO clutch, and power transmission to the rear PTO shaft is cut off. While the power is transmitted to the rear PTO shaft, the rear PTO switch 26 is turned off while the rear PTO switch 26 is turned on (connected).

  The mid PTO switch 27 is installed on the mid PTO clutch side or the mid PTO lever 18 side to detect connection switching or connection switching operation of the mid PTO clutch, and power transmission to the mid PTO shaft is cut off. The mid PTO switch 27 is turned on (connected) while the power is transmitted to the mid PTO shaft while the mid PTO switch 27 is turned off.

  The shuttle switch 28 is installed on the forward / reverse switching mechanism side or the forward / reverse switching lever 16 side, and detects the switching or switching operation to the traveling neutral state. In the traveling neutral state, the shuttle switch 28 is While in the ON (connected) state, the shuttle switch 28 is in the OFF state in cases other than the traveling neutral state.

  The seat switch 29 is disposed on the lower surface side of a seat portion 11a (see FIG. 3) that is a seating portion of the seat 11, and when seated on the seat portion 11a, the seat switch 29 is in an ON (connected) state. On the other hand, when the seat 11a is not seated, the seat switch 29 is turned off (cut).

  The wiring configuration of the control circuit 21 composed of these members will be described. The series circuit 32 is configured by electrically connecting the engine start terminal 22a of the starter switch 22, the shuttle switch 28, and the rear PTO switch 26 in series. The parallel circuit 33 is configured by connecting the seat switch 29 and the mid PTO switch 27 in parallel.

  A first switching circuit 34 is provided between the output side end of the series circuit 32 and the power supply side terminal of the starter motor 24, and the input side of the parallel circuit 33 is electrically connected to the engine drive terminal 22 b of the starter switch 22. The output side of the parallel circuit 33 is electrically connected to the power supply side terminal of the fuel cut solenoid 23, and the input side of the second switching circuit 36 that supplies current to the first switching circuit 34 is the seat switch 29 side. And the mid PTO switch 27 side.

  In addition, the engine start terminal 22 a of the starter switch 22 is connected to the power auxiliary supply side terminal of the fuel cut solenoid 23 via the auxiliary circuit 37.

  The first and second switching circuits 34 and 36 switch connection / disconnection (ON / OFF) of a target portion depending on whether or not current is supplied. In the illustrated example, the first and second switching circuits 34 and 36 are configured by a relay circuit.

  More specifically, the first switching circuit 34 switches connection / disconnection between the series circuit 32 and the starter motor 24. The first switching circuit 34 performs the switching according to whether or not current is supplied from the second switching circuit 36 side.

  On the other hand, the second switching circuit 36 includes an output terminal of one of the mid PTO switch 27 and the seat switch 29 (mid PTO switch 27 in the illustrated example), and a current input terminal for control of the first switching circuit 34. The above connection / disconnection is switched depending on whether or not current is supplied from the other output terminal of either the mid PTO switch 27 or the sheet switch 29. That is, the control current is supplied from the second switching circuit 36 to the first switching circuit 34 only when both the mid PTO switch 27 and the seat switch 29 are in the ON state.

  According to the control circuit 21 configured as described above, when the engine start operation of the starter switch 22 is performed, the current from the power supply circuit 31 is supplied to the input side of the series circuit 32 via the engine start terminal 22a. It is supplied to the input side of the parallel circuit 33 via the engine drive terminal 22b.

  At this time, when the seat switch 29 and the mid PTO switch 27 are in the ON state, the current from the power supply circuit 31 flows in the order of the engine drive terminal 22b → the parallel circuit 33 → the second switching circuit 36, and the first switching A current is supplied to the control current input terminal of the circuit 34, and the first switching circuit 34 is connected.

  Therefore, in this state, when the shuttle switch 28 and the rear PTO switch 26 are in the ON state, the current from the power supply circuit 31 is changed from the engine start terminal 22a → the series circuit 32 → the first switching circuit 34 → the starter motor. The starter motor 24 is driven to rotate.

  At the same time, the current from the power supply circuit 31 is supplied from the engine start terminal 22a to the power auxiliary supply side terminal of the fuel cut solenoid 23 via the auxiliary circuit 37, and the engine drive terminal 22b and the parallel circuit 33 are supplied. Thus, the fuel cut solenoid 23 is supplied to the power supply terminal of the fuel cut solenoid 23, whereby the fuel cut solenoid 23 is energized and opened, and fuel is supplied to the engine.

  Thus, the engine is started. That is, only when all of the shuttle switch 28, the rear PTO switch 26, the mid PTO switch 27, and the seat switch 29 are turned on, the engine can be started by the engine starting operation. If any one of the switch 26, the mid PTO switch 27, and the seat switch 29 is in the OFF state, the engine cannot be started. In other words, the engine can be started only when the vehicle is in the traveling neutral state, the rear PTO shaft is in the drive stop state, the mid PTO shaft is in the drive stop state, and is seated on the seat 11. it can.

  On the other hand, while the starter switch 22 is in the engine drive state and the engine is being driven, the current from the power supply circuit 31 is supplied to the fuel cut solenoid 23 via the engine drive terminal 22b and the parallel circuit 33. The fuel cut solenoid 23 is energized and opened, and the fuel is supplied to the engine.

  When such an engine is driven, if both the mid PTO switch 27 and the seat switch 29 are kept ON, current is supplied to the fuel cut solenoid 23 via the parallel circuit 33. When the engine is maintained, but both the mid PTO switch 27 and the seat switch 29 are in the OFF state, the current supply to the fuel cut solenoid 23 via the parallel circuit 33 is cut off, and the fuel cut solenoid 23 Since the engine is closed in an abnormal state and the fuel supply to the engine is cut, the engine is stopped.

  In other words, when the mid PTO shaft is driven and the seat 11 is not seated, the driving of the engine is stopped. In this way, the engine is stopped at an appropriate timing while preventing the engine from being stopped unnecessarily.

Next, the seat and the seat switch 29 will be described in detail with reference to FIGS.
FIG. 3 is a side view of the main part of the control unit on the seat side, and FIG. 4 is a plan view of the main part of the control unit with the seat removed. A support frame 38 is arranged and formed at a position lower than the fender 8 between the fenders 8 for the left and right rear wheels 2, 2. The seat 11 is supported so that the front / rear slide position can be adjusted, and the seat 11 a of the seat 11 is supported on the upper surface of the seat bracket 39.

  A front-rear direction handle 41 is installed at the left and right edges of the seat bracket 39, and the front-rear position of the seat 11 can be adjusted together with the seat bracket 39 by holding the handle 41.

  The seat 11 itself has a seat portion 11a and a backrest 11b that rises rearward and obliquely upward from the rear end portion of the seat portion 11a, and a pair of left and right protrusions that protrude downward from the front end portion of the lower surface of the seat portion 11a. By supporting the portion 11c on a pair of left and right support portions 42 and 42 integrally projecting upward from the front end portion of the seat bracket 39 via a left and right rotation shaft 43, the portion 11c can be rotated back and forth. The seat 11 is supported by the seat bracket 39 so as to be pivotable back and forth about the pivot shaft at 43 fulcrums.

  A pair of left and right receiving members 44 that receive and elastically support the rear end side of the lower surface of the seat portion 11a are provided on the rear end portion of the upper surface of the seat bracket 39 so as to protrude upward.

  5 is an enlarged perspective view of a main part of FIG. 4, FIG. 6A is a side view of the seat switch, and FIG. 5B is a side view of the receiving member. Each receiving member 44 is made of an elastically deformable synthetic resin that extends in the vertical direction on a mounting plate 46 welded to the upper surface of the seat bracket 39 so as to close an installation hole 39a formed in the seat bracket 39 (more specifically, A stopper 47 made of rubber is attached and fixed via bolts 48 in the vertical direction, and a compression type coil spring 49 is externally mounted on the stopper 47.

  A flange-like engaging portion 47 a is integrally formed at the lower end of the stopper 47, and the coil spring 49 is attached to and detached from the outer periphery of the stopper 47 by engaging the engaging portion 47 a with the coil spring 49. It is freely engaged and mounted. The upper end of the coil spring 49 is positioned higher than the upper end of the stopper 47, and is configured to elastically receive the rear end side of the seat portion 11a of the seat 11.

  When the operator sits on the seat 11, the seat portion 11a sinks downward (the seat 11 rotates downward about the rotation shaft 43), the coil spring 49 is compressed, and the lower surface of the seat portion 11a is a stopper. When the operator stands up from the seat 11 while coming into contact with the upper end of the 47, the lower surface of the seat portion 11 a is positioned away from the upper end of the stopper 47 due to the elastic force of the coil spring 49.

  A seat switch 29 is installed between the lower surface side of the seat portion 11a and the upper surface side of the seat bracket 39 (see FIG. 3). In more detail, the seat switch 29 is connected to the pair of left and right receiving members 44, 44, It is a midway part (more specifically, an intermediate part) between the rotary shaft 43 and the central part of the seat bracket 39 in the left-right direction.

  The seat switch 29 is fixed to the upper surface of the seat bracket 39 and has a support bracket (bracket) 51 in the front-rear direction having a reverse U-shape in cross-section, and an inverted U-shape in front view located on the inner surface side of the support bracket 51. The front-rear mounting bracket 52, the limit switch (detection switch) 53 mounted and supported on the support bracket 51 via the mounting bracket 52, and the upper and lower supported by the support bracket 51 so as to be slidable in its own axial direction. Directional actuating pins 54.

  The operating pin 54 is inserted into an insertion hole 51a provided on the upper surface side of the support bracket 51 and protrudes upward from the upper surface of the support bracket 51, and is slidable up and down so as to be freely slidable. In the example, it is supported by a mounting bracket 52). Between the lower surface of the retaining ring 56 provided at the upper end portion of the operating pin 54 and the upper surface of the mounting bracket 52, an elastic member 57 such as a compression coil spring that is sheathed on the operating pin 54 is disposed. The operating pin 54 is always elastically biased upward by the elastic member 57.

  Both sides of the mounting bracket 51 are supported on both sides of the support bracket 51 by bolts 58, and the bolt holes 51b for the bolts 51 drilled in the support bracket 51 are formed in the shape of elongated holes in the vertical direction. ing. For this reason, the mounting bracket 51 is mounted and fixed to the support bracket 51 so that the vertical position can be adjusted within a range in which the bolt 58 moves up and down in the bolt hole 51b.

  The limit switch 53 is turned on and off by the vertical slide of the operation pin 54 (specifically, the lower side of the limit switch 53 is in contact with the detection piece 53a for turning the limit switch 53 ON / OFF). 53 is fixed to the mounting bracket 52 with bolts 59. The bolt hole 52a of the mounting bracket 52 through which the bolt 59 is inserted is also a long hole in the vertical direction. Therefore, the limit switch 53 is also adjusted in the vertical position within the range in which the bolt 59 moves up and down the bolt hole 52a. It is supported by the mounting bracket 52 as possible.

  By adjusting the vertical position of the limit switch 53 and the mounting bracket 52 in two stages, it is possible to change and adjust the vertical position of the limit switch 53 with respect to the operating pin 54.

  When the operator sits on the seat 11, the seat 11 rotates downward with the rotation shaft 43 as a fulcrum, whereby the lower surface of the seat portion 11 a presses the operation pin 54 downward, thereby lowering the operation pin 54. Presses the detection piece 53a of the limit switch 53, and the limit switch 53 is turned on (the sheet switch 29 is turned on).

  On the other hand, when the operator rises from the seat 11, the seat 11 rotates upward with the pivot shaft 43 as a fulcrum by the elastic force of the receiving member 44, thereby releasing the pressing from the seat portion 11 a to the operating pin 54 side. Then, due to the elastic force of the elastic member 57, the operating pin 54 slides upward, and the limit switch 53 is turned off (the sheet switch 29 is turned off).

  Incidentally, when the operating pin 54 slides to a lower position than necessary due to a high load, the detection piece 53a is retracted to the main body side of the limit switch 53, and the limit switch 53 itself is not subjected to a load more than the set value. A failure of the limit switch 53 is prevented. In addition, since the upper and left and right sides of the limit switch 53 are protected by the two brackets 51 and 52, failure of the limit switch 53 is also prevented from this point.

  The seat switch 29 is operated by rotating the seat 11 up and down and elastically supporting it. However, depending on whether or not the seat 11 is seated, the seat portion 11a itself is flexibly deformed up and down. Thus, the ON / OFF detection of the seat switch 29 may be performed by moving the operating pin 54 up and down.

Next, another embodiment of the present invention will be described with reference to FIGS.
FIG. 7 is a plan view of a tractor showing another embodiment of the present invention, and FIG. 8 is a circuit diagram of an engine control apparatus showing another embodiment of the present invention. The illustrated tractor uses a traveling HST (not shown) as a traveling transmission, and also performs forward / reverse switching during traveling by forward / reverse switching of the traveling HST.

  Specifically, a forward HST pedal 61 that performs switching and acceleration / deceleration to the forward traveling side via the traveling HST, and a reverse HST pedal that performs switching and acceleration / deceleration to the backward traveling side via the traveling HST. 62 and a clutch pedal 63 for turning on and off a main clutch (not shown) for intermittently transmitting power to the traveling system (specifically, the front and rear wheels 1 and 2 side) is provided on the floor surface 13 side of the control unit 7. It is arranged.

  The neutral detector 28 electrically connects the clutch switch 64 that detects the intermittent operation or intermittent operation of the main clutch and the HST switch 66 that detects the neutral operation or neutral operation of the traveling HST in series. It is configured.

  The clutch switch 64 may be provided on the main clutch side or on the clutch pedal side. On the other hand, the HST switch 66 may be provided on the traveling HST side or on the two HST pedals 61 and 52 side.

3 traveling machine body 11 seat 11a seat part 21 control circuit 22 starter switch (start switch)
23 Fuel Cut Solenoid 24 Starter Motor 26 Rear PTO Switch 27 Mid PTO Switch 28 Neutral Detector (Chartle Switch)
29 Seat switch 32 Series circuit 33 Parallel circuit 34 First switching circuit (relay circuit, switching element)
36 Second switching circuit (relay circuit, switching element)
51 Bracket 53 Detection switch 54 Actuation pin

Claims (2)

  A start switch (22) for starting the engine, a starter motor (24) for starting the engine, and a fuel cut solenoid (23) for cutting fuel supplied to the engine are provided for engine start control and engine drive / A rear PTO switch (26) that is provided in a control circuit (21) that performs stop control and detects the presence / absence of power transmission to the rear PTO shaft provided at the rear of the traveling machine body (3), and a lower side of the middle part of the traveling machine body A mid PTO switch (27) for detecting the presence or absence of power transmission to the mid PTO shaft, a neutral detector (28) for detecting a traveling neutral state, and a seat switch for detecting seating on the seat (11) (29) is connected to the control circuit (21). In the engine control device for a work vehicle, the control circuit (21) includes a seat switch. 29) and a parallel circuit (33) in which a mid PTO switch (27) is connected in parallel; a series circuit (32) in which a start switch (22), a neutral detector (28) and a rear PTO switch (26) are connected in series; The first switching circuit (34) provided between the series circuit (32) and the starter motor (24) and the first switching circuit (32) and the starter motor (24) are connected to each other. 34) and a second switching circuit (36) for supplying a current, and when the engine is not seated on the seat (11) and power is transmitted to the mid PTO shaft, The parallel circuit (33) is connected to the power supply side of the fuel cut solenoid (23) so as to stop, and is seated on the seat (11) and moving to the mid PTO shaft. So that the current is supplied to the first switching circuit (34) when the circuit is disconnected, the input side of the second switching circuit (36) is connected to the seat switch (29) side and the mid PTO switch ( 27) An engine control device for a work vehicle connected to the side.   The seat switch (29) is arranged on the lower surface side of the seat portion (11a) which is a seating portion of the seat (11), and the seat switch (29) includes a detection switch (53) for detecting by turning on and off, and a detection A bracket (51) that supports the switch (53) and an operation that is supported by the bracket (51) so as to be slidable up and down so that the detection switch (53) is turned on and off, and that protrudes upward on the lower surface side of the seat (11a). Pin (54), and when the seat (11a) is displaced or deformed downward when seated, the lower surface of the seat (11a) presses the operating pin (54) downward, and the detection switch (53) is An engine control device for a work vehicle for detecting and operating.

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