JP2019151270A - Working vehicle - Google Patents

Abstract

To provide a working vehicle enabling reduction in load on each part on a power transmission path and a travelling brake device.SOLUTION: A working vehicle includes: an HST18 varying the speed of power from an engine 14 in a stepless manner and transmitting the power to a crawler type travelling device 2; an emergency brake pedal 15 performing brake operation of a parking brake device braking the travelling device 2; and a control part controlling a rotation speed of the engine 14 and the travelling brake device. The control part continuously operates the travelling brake device after starting an idle processing for setting the rotation speed of the engine 14 to an idle rotation speed when the brake operation is performed by the emergency brake pedal 15 when the working vehicle is in travelling.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a working vehicle such as a tractor, and more specifically, includes a hydrostatic continuously variable transmission that continuously transmits power from an engine to a traveling device and a traveling brake device that brakes the traveling device. Related to working vehicles.

  Generally, a hydrostatic continuously variable transmission that continuously supplies power from an engine to a crawler type traveling device by supplying oil to a hydraulic motor according to the angle of a swash plate of a hydraulic pump. A working vehicle such as a tractor equipped with (hereinafter referred to as HST) is known. The HST adjusts the driving speed of the traveling device according to the amount of operation of the main transmission lever that controls the angle of the swash plate, and shuts off the oil supplied from the hydraulic pump to the hydraulic motor when the main transmission lever is in the neutral position. Thus, the hydraulic motor is configured not to be driven. Also, this type of tractor is configured such that when the vehicle stops suddenly, the travel brake device is operated by operating a brake pedal, and the drive of the travel device is braked.

  Conventionally, a tractor including a main transmission lever return mechanism that moves a main transmission lever to a neutral position in conjunction with an operation of a brake pedal has been proposed (see Patent Document 1). In the tractor described in Patent Document 1, when the brake pedal is operated, the parking brake is activated to brake the driving of the crawler type traveling unit, and the main transmission lever is moved to the neutral position to supply oil to the hydraulic motor. Is shut off and stops. Thus configured, the tractor described in Patent Document 1 avoids the operation of the parking brake in a state where the driving force from the engine is applied to the airframe, thereby suppressing the shock caused by the parking brake and the braking load of the parking brake. We are trying to reduce this.

Japanese Patent No. 4195628

  However, stopping by the traveling brake device during traveling of the tractor places a heavy burden on each part on the power transmission path of the power, the traveling brake, and the like, and therefore further measures for reducing the burden have been demanded.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a working vehicle that can reduce the load on each part of the power transmission path and the traveling brake device.

The present invention relates to a hydrostatic continuously variable transmission (18) that continuously transmits power from an engine (14) to the traveling device (2) by supplying oil corresponding to the angle of the swash plate, and the traveling In a working vehicle (1) comprising a traveling brake device (29) for braking the device (2),
A brake operation unit (15) for braking the travel brake device (29);
A control unit (25) for controlling the rotational speed of the engine (14) and the traveling brake device (29),
The control unit (25) performs an idle process for setting the rotational speed of the engine (14) to an idle rotational speed when a braking operation is performed by the brake operation unit (15) while the work vehicle (1) is traveling. After the start, the running brake device (29) is continuously operated.

The present invention also includes a hydrostatic continuously variable transmission (18) that continuously changes the power from the engine (14) by oil supplied according to the angle of the swash plate and transmits it to the traveling device (2). In a work vehicle (1) comprising a travel brake device (29) for braking the travel device (2),
A brake operation unit (15) for braking the travel brake device (29);
A control unit (25) for controlling the rotational speed of the engine (14) and the traveling brake device (29),
The control unit (25) performs an idle process for setting the rotational speed of the engine (14) to an idle rotational speed when a braking operation is performed by the brake operation unit (15) while the work vehicle (1) is traveling. And the running brake device (29) is intermittently operated for a predetermined time during the idle process, and then the running brake device (29) is continuously operated.

The present invention also includes a hydrostatic continuously variable transmission (18) that continuously changes the power from the engine (14) by oil supplied according to the angle of the swash plate and transmits it to the traveling device (2). In a work vehicle (1) comprising a travel brake device (29) for braking the travel device (2),
A brake operation unit (15) for braking the travel brake device (29);
A control unit (25) for controlling the rotational speed of the engine (14) and the traveling brake device (29),
The control unit (25) performs an idle process for setting the rotational speed of the engine (14) to an idle rotational speed when a braking operation is performed by the brake operation unit (15) while the work vehicle (1) is traveling. And executing braking force gradual change control for increasing the braking force of the traveling brake device (29) with the lapse of time during the idle process for a predetermined time, and then continuously executing the traveling brake device (29). It is actuated.

For example, referring to FIG. 1 to FIG. 4, a rotation speed detecting means (27) capable of measuring the rotation speed of the engine (14) is provided,
The control unit (25) is configured to detect the rotation speed when the brake operation unit (15) performs a braking operation in a state where power from the engine (14) is transmitted to the traveling device (2). When it is detected by (27) that the rotational speed of the engine (14) has reached the idle rotational speed, the traveling brake device (29) is continuously operated.

  In addition, although the code | symbol in the said parenthesis is for contrast with drawing, it does not have any influence on the structure as described in a claim by this.

  According to the first aspect of the present invention, when a braking operation is performed by the brake operation unit while the work vehicle is traveling, the control unit starts the idling process for setting the engine rotation speed to the idle rotation speed. Operate the device continuously. For this reason, when the vehicle stops suddenly, the traveling device is braked after the rotational speed of the engine is reduced, so that it is possible to reduce the burden on each part on the power transmission path and the traveling brake device.

  According to the second aspect of the present invention, when a braking operation is performed by the brake operation unit while the work vehicle is traveling, the control unit starts the idle process for setting the engine rotation speed to the idle rotation speed. The running brake device is intermittently operated during the execution of the operation, and then the running brake device is continuously operated. For this reason, when the vehicle is suddenly stopped, the traveling brake device is first intermittently actuated, and the traveling device is braked by the continuous operation of the traveling brake device after the engine speed has decreased. The burden on the device can be reduced.

  According to the third aspect of the present invention, when a braking operation is performed by the brake operation unit while the work vehicle is traveling, the control unit starts the idle process for setting the engine rotation speed to the idle rotation speed. During the execution, the braking force gradual change control for gradually increasing the braking force of the traveling brake device is performed, and then the traveling brake device is continuously operated. For this reason, when suddenly stopping the vehicle, the braking force of the traveling brake device is first gradually increased from a small state, and the traveling device is braked by the continuous operation of the traveling brake device after the engine speed is reduced. Further, it is possible to reduce the burden on each part on the power transmission path and the traveling brake device.

  According to the fourth aspect of the present invention, when a braking operation is performed by the brake operation unit while the work vehicle is traveling, the control unit continuously operates the traveling brake device after the engine rotation speed reaches the idle rotation speed. Therefore, it is possible to reduce the burden on each part on the power transmission path and the traveling brake device. Also, when releasing the braking of the traveling device by the traveling brake device and restarting the engine, the engine rotation speed is the idle rotation speed, so that the burden on each part on the power transmission path due to the sudden start and the sudden start is reduced. Mitigation can be achieved.

The side view which shows the tractor which concerns on this Embodiment. The perspective view which looked at the operation part from back. The perspective view which looked at the operation part from the front. The functional block diagram which shows a control structure. The flowchart which shows an emergency stop process.

<Overall configuration>
Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, a tractor 1 as a working vehicle according to the present embodiment includes a pair of left and right full crawler type traveling devices 2 and a traveling vehicle body 3 having a body frame 4 supported by the traveling device 2. It is equipped with.

  The traveling machine body 3 is covered with the cabin 5 and is placed in front of the driving unit 7, the engine room 6 that houses the engine 14, and the driving unit 7. A lifting link mechanism 8 having a three-point link mechanism 8a that moves up and down and to which an arbitrary working machine is connected is provided.

  The power of the engine 14 is divided into a driving power for driving the left and right traveling devices 2 and a driving power for driving a working machine (not shown) by a transmission (not shown) housed in the transmission case. A PTO shaft (not shown) rotates. The traveling power is transmitted to a pair of left and right hydrostatic continuously variable transmissions (hereinafter referred to as HST) 18. Each of the left and right HSTs 18 includes an HST pump 18a that discharges hydraulic oil by power from the engine 14, and an hydraulic oil supplied from the HST pump 18a, that is, an HST motor 18b that is driven by the supplied oil.

  The HST 18 changes the angle of a swash plate (not shown) of the HST pump 18a, so that supply oil corresponding to the angle of the swash plate is supplied to the HST motor 18b, and the driving power from the engine 14 is continuously variable. Is configured to do. Further, an HST bypass device 30 shown in FIG. 4 capable of releasing the hydraulic pressure is provided on the oil passage of the supply oil from the HST pump 18a to the HST motor 18b. The HST bypass device 30 includes a bypass valve 30a as connection / disconnection means that can be switched between a connection state in which hydraulic pressure can be transmitted and a cutoff state in which the hydraulic pressure is released and no hydraulic pressure is transmitted, and the cutoff state and connection means of the bypass valve 30a. Has a bypass solenoid 30b. The traveling power shifted by the left and right HSTs 18 is transmitted to the left and right traveling devices 2, respectively. The left and right traveling devices 2 are each provided with a driving wheel 2a that is pivotally supported by the front portion of the body frame 4 and driven by traveling power, a driven wheel 2b that is pivotally supported at the rear portion of the body frame 4, and an aircraft body. A plurality of rolling wheels 2c that are rotatably supported at the lower part of the frame 4 and support the traveling machine body 3 are wound around an endless belt-shaped crawler 2d made of rubber.

  The left and right traveling devices 2 are each provided with a parking brake device 29 shown in FIG. 4 as a traveling brake device that is actuated by hydraulic pressure from the HST pump 18a and brakes the drive of the drive wheels 2a. The parking brake device 29 is disposed on the hydraulic oil passage from the HST pump 18a to the parking brake device 29 and can be switched between a connected state in which hydraulic pressure can be transmitted and a shut-off state in which the hydraulic pressure is released and hydraulic pressure is not transmitted. The brake valve 29a and the parking brake solenoid 29b for switching between the shut-off state and the connection / disconnection means of the parking brake valve 29a are provided. The parking brake device 29 is in a non-braking state in which the driving wheel 2a is not braked when the parking brake valve 29a is in a connected state, and is in a braking state in which the driving wheel 2a is braked when the parking brake valve 29a is in a shut-off state.

<Details of operation part>
Next, with reference to FIG.2 and FIG.3, the detail of the driving | operation part 7 is demonstrated. The driver 7 is disposed on the right side of the steering handle 10, the driver's seat 9 on which the operator is seated, the steering handle 10 disposed in front of the driver's seat 9, the main monitor 11 disposed in front of the steering handle 10. Key switch 12, emergency brake pedal 15 as a brake operation unit for braking operation of parking brake device 29, side panel 13 disposed on the right side of driver's seat 9, and the like.

  When the steering handle 10 is in the straight traveling position, the steering handle 10 is turned to either the left or right turning position so that the left and right drive wheels 2a are driven at the same speed (including stop). The rotational speeds of the left and right drive wheels 2a are adjusted so that the inner drive wheel 2a is driven at a lower speed (including stop and reverse rotation) than the outer drive wheel 2a. To do.

  The main monitor 11 includes a tachometer, a fuel gauge, a parking brake lamp 11a, and the like (not shown), and displays various types of information on the tractor 1 to the operator in the driving unit 7. The parking brake lamp 11a transitions between a lighting state that is turned on when the parking brake device 29 is in a braking state and a light-off state that is turned off when the parking brake device 29 is in a non-braking state. The state of the device 29 is notified.

  The emergency brake pedal 15 is used when the travel of the tractor 1 is stopped in a short time in an emergency or the like, unlike when the operator gradually decelerates the HST to stop the travel of the tractor 1. The emergency brake pedal 15 is operated to be braked so that the parking brake device 29 is changed from the non-braking state to the braking state by switching the parking brake valve 29a from the connected state to the shut-off state by an operator's stepping operation.

  The side panel 13 includes an engine control lever 21 for shifting the engine 14, a main shifting lever 20 as a shifting lever for shifting the HST 18, a sub-monitor unit 19 as a notification means having a touch panel type liquid crystal display 19a, Have

  The engine control lever 21 is moved in the front-rear direction by an operator's operation, and the engine 14 is operated or operated from an idle rotation speed that is a rotation speed when the operation or the operation is not performed, that is, a low idle rotation speed. A speed change operation is possible between high idle rotation speeds, which are rotation speeds.

  The main transmission lever 20 moves in the front-rear direction by an operator's operation. When the main transmission lever 20 is located at the neutral position, the hydraulic fluid is not discharged from the HST pump 18a to the HST motor 18b, and the HST motor 18b is stopped and is located at another position other than the neutral position. Then, the angle of the swash plate of the HST pump 18a is changed in conjunction with the operation of the operator so that hydraulic oil is discharged from the HST pump 18a to the HST motor 18b and the HST motor 18b is driven, and the amount of movement from the neutral position is increased. Accordingly, the HST motor 18b is configured to be capable of shifting operation. Specifically, the main transmission lever 20 is configured to be slidable in the front-rear direction. When the steering handle 10 is located at the straight advance position, the larger the amount of movement from the neutral position to the rear, the larger the tractor. The HST motor 18b is driven so that the speed at which 1 reverses increases, and the HST motor 18b is driven so that the speed at which the tractor 1 moves forward increases as the amount of forward movement from the neutral position increases.

  The sub monitor unit 19 has operation buttons 19b on the sub monitor unit 19 for operating the liquid crystal display 19a, various settings of the tractor 1, and the like. The sub monitor unit 19 constitutes the image display device in the present embodiment.

<Control configuration>
Next, the control configuration of the tractor 1 will be described with reference to FIG. The tractor 1 according to the present embodiment includes a control unit 25 formed of a microcomputer. The control unit 25 receives input signals from the emergency brake switch 15a, the engine control sensor 33, the engine speed sensor 27 as the rotational speed detection means, the main transmission position sensor 26, the vehicle speed sensor 32, and the sub monitor unit 19, and receives the tractor 1 The control for controlling each part is performed, and the parking brake lamp 11a, the parking brake solenoid 29b, the bypass solenoid 30b, the engine ECU (Electronic Control Unit) 31, the main monitor 11 and the sub monitor unit 19 are controlled based on the calculation result.

  The emergency brake switch 15 a is turned on when the emergency brake pedal 15 is depressed by an operator, and transmits an emergency brake signal to the control unit 25. Based on the reception of the emergency brake signal from the emergency brake switch 15a, the control unit 25 executes a braking process for transmitting a braking signal for turning on the parking brake solenoid 29b to the parking brake solenoid 29b. When the parking brake solenoid 29b is in the ON state, the control unit 25 outputs a parking brake lamp signal for turning on the parking brake lamp 11a to the parking brake lamp 11a. When the parking brake solenoid 29b is switched from the ON state to the OFF state, the control unit 25 stops the output of the parking brake lamp signal and the parking brake lamp 11a is turned off. The parking brake valve 29a is switched to the shut-off state when the parking brake solenoid 29b is turned on.

  The engine control sensor 33 detects the position of the engine control lever 21 in the front-rear direction, and transmits an engine control position signal corresponding to the detected position of the engine control lever 21 to the control unit 25. Based on the engine control position signal received from the engine control sensor 33, the control unit 25 transmits an engine control signal that causes the engine ECU 31 to control the rotational speed of the engine 14. The engine ECU 31 adjusts the fuel supplied to the engine 14 according to the engine control signal received from the control unit 25 and controls the rotational speed of the engine 14. The engine rotational speed sensor 27 detects the rotational speed of the engine 14 and transmits an engine rotational speed signal corresponding to the detected rotational speed of the engine 14 to the control unit 25. The control unit 25 controls the tachometer of the main monitor 11 in accordance with the engine speed signal received from the engine speed sensor 27.

  The main shift position sensor 26 detects the position of the main shift lever 20 in the front-rear direction, and transmits a main shift position signal corresponding to the detected position of the main shift lever 20 to the control unit 25. The vehicle speed sensor 32 is provided on each of the left and right drive wheels 2a, independently detects the rotational speed of each of the left and right drive wheels 2a, and outputs a vehicle speed signal corresponding to the detected rotational speed of the left and right drive wheels 2a. It transmits to the control part 25 separately.

  The sub monitor unit 19 is configured to be capable of bidirectional communication with the control unit 25, and transmits input signals from the liquid crystal display 19 a and the operation buttons 19 b to the control unit 25. The control unit 25 transmits a drawing signal for displaying an image on the liquid crystal display 19 a to the sub monitor unit 19 according to various calculation results. For example, the control unit 25 transmits a drawing signal corresponding to the state of the parking brake device 29 to the sub monitor unit 19. The sub monitor unit 19 is an image representing the braking state of the parking brake device 29 in a part of the display area of the liquid crystal display 19a based on the drawing signal corresponding to the state of the parking brake device 29 from the control unit 25. Either the parking brake icon 19c as the operation unit or the parking brake release icon 19d which is an image representing the non-braking state of the parking brake device 29 is displayed. That is, in the braking state of the parking brake device 29, the sub monitor unit 19 enters the parking brake release operation acceptance state as the first state in which the parking brake icon 19c is displayed on the liquid crystal display 19a, and the parking brake device 29 is in the non-braking state. Is a parking brake braking operation acceptance state as a second state in which the parking brake release icon 19d is displayed on the liquid crystal display 19a.

  For example, the parking brake braking operation acceptance state is a state in which an image composed of a character string “parking brake being released (parking brake is activated by touch)” is displayed as a parking brake release icon 19d in white characters on a blue background. The release operation acceptance state is a state in which an image composed of a character string “parking brake is in operation (parking brake released by touch)” is displayed as a parking brake icon 19c in yellow characters on a red background. As described above, the sub monitor unit 19 transitions between the parking brake braking operation acceptance state and the parking brake release operation acceptance state according to the state of the parking brake device 29, and the state of the parking brake device 29 as the notification content. Is displayed as an image to notify the operator.

  When the parking brake release icon 19d is pressed by the operator when the parking brake device 29 is in the non-braking state, the sub monitor unit 19 transmits a parking brake signal to the control unit 25. Based on the parking brake signal from the sub monitor unit 19, the control unit 25 executes a braking process for transmitting a braking signal for turning on the parking brake solenoid 29b to the parking brake solenoid 29b. In addition, when the parking brake device 29 is in a braking state, the sub monitor unit 19 transmits a parking brake release signal to the control unit 25 when the parking brake icon 19c is pressed by the operator. Based on the parking brake release signal from the sub monitor unit 19, the control unit 25 executes a braking release process for transmitting a braking release signal for turning the parking brake solenoid 29b to the parking brake solenoid 29b. Thus, the parking brake icon 19c enables a braking operation for switching the parking brake device 29 from the non-braking state to the braking state and a releasing operation for switching from the braking state to the non-braking state.

  Further, the control unit 25 transmits a bypass solenoid ON signal for turning on the bypass solenoid 30b and a bypass solenoid OFF signal for turning off the bypass solenoid 30b according to various calculation results. The bypass valve 30a is cut off when the bypass solenoid 30b is turned on, and is connected when the bypass solenoid 30b is turned off.

<Emergency stop process>
Next, emergency stop processing executed by the control unit 25 will be described with reference to FIG. When the emergency stop process is started by turning on the key switch (step S1), the control unit 25 determines whether or not the emergency stop flag is in the ON state (step S2). The emergency stop flag is a flag stored in a storage means such as a RAM (not shown) of the control unit 25, and is a flag that is turned on when an emergency stop is performed by the operator's depression operation of the emergency brake pedal 15. The state immediately after the key switch is switched from the OFF state to the ON state is in the OFF state.

  In the process of step S2, the control unit 25 refers to the state of the emergency stop flag in the storage means, and when the emergency stop flag is in the OFF state (NO in step S2), the control unit 25 determines that the emergency brake switch 15a is in the ON state. It is determined whether or not (step S3). In this process, the control unit 25 determines whether or not the emergency brake pedal is being operated by the operator.

  In the process of step S3, when the emergency brake switch 15a is in the ON state (YES in step S3), the control unit 25 sends to the engine ECU 31 a low idle signal that suppresses the rotational speed of the engine 14 to a rotational speed equal to or lower than a predetermined value. On the other hand, the idle process to be transmitted is started (step S4). When the engine ECU 31 receives the low idle signal from the control unit 25, the engine ECU 31 sets the engine 14 so that the rotational speed of the engine 14 is a low idle rotational speed that is a predetermined rotational speed or less regardless of the engine control position signal. Regulate the amount of fuel supplied. The low idle rotation speed constitutes the idle rotation speed in the present embodiment. In this process, the control unit 25 operates the engine based on the depression operation of the emergency brake pedal 15 even when the emergency brake pedal 15 is depressed and the tractor 1 is suddenly stopped at a high rotational speed of the engine 14. 14 to suppress the rotational speed of the engine 14 and perform a sudden start when performing a restart, and each part on the power transmission path accompanying the sudden start, that is, the engine 14, the transmission, the HST 18, the traveling device 2, and a drive (not shown) that connects them. The burden on the shaft and hydraulic hose is reduced. In the process of step S3, when the emergency brake switch is in the OFF state (NO in step S3), the control unit 25 returns the process to step S1.

  Further, in the process of step S4, the control unit 25 transmits a bypass solenoid ON signal to the bypass solenoid 30b, switches the bypass valve 30a from the cut state to the cut-off state, and depends on the angle of the swash plate of the HST pump 18a. The hydraulic pressure of the HST pump 18a is not transmitted to the left and right HST motors 18b. In this process, when the controller 25 suddenly stops the tractor 1 by depressing the emergency brake pedal 15, the power of the engine 14 is supplied to the HST motor 18b even if the operator does not move the main transmission lever 20 to the neutral position. To reduce the burden on the HST 18.

  In addition, in the process of step S4, the control unit 25 intermittently transmits a parking brake signal to the parking brake solenoid 29b, and alternately repeats the connected state and the disconnected state of the parking brake valve 29a in a short time. An intermittent operation, that is, so-called inching, in which the non-braking state and the braking state of the brake device 29 are alternately repeated in a short time is started. In this process, when the tractor 1 is suddenly stopped by depressing the emergency brake pedal 15, the control unit 25 immediately sets the parking brake device 29 in a continuous braking state, compared with the case where the traveling device 2 The load applied to each part on the parking brake device 29 and the power transmission path due to sudden braking is reduced.

  When the process of step S4 is executed, the control unit 25 determines whether or not the rotational speed of the engine 14 has reached the low idle rotational speed based on the engine rotational speed signal from the engine rotational speed sensor 27 (step S5). ). In the process of step S5, when the rotational speed of the engine 14 has not reached the low idle rotational speed (NO in step S5), the control unit 25 repeats the process of step S5.

  In the process of step S5, when the rotational speed of the engine 14 reaches the low idle rotational speed (YES in step S5), that is, when the control unit 25 detects that the rotational speed of the engine 14 has reached the low idle rotational speed. The control unit 25 continuously transmits a parking brake signal to the parking brake solenoid 29b, turns off the parking brake valve 29a, and puts the parking brake device 29 in a continuous braking state (step S6). In this process, the control unit 25 makes a sudden start or a sudden start at the time of re-starting even when the tractor 1 is suddenly stopped at a high rotational speed of the engine 14 by the depression operation of the emergency brake pedal 15. The burden on each part on the power transmission path accompanying the start is more reliably reduced.

  When the process of step S6 is executed, the control unit 25 calculates the traveling speed of the tractor 1 based on the respective vehicle speed signals from the left and right vehicle speed sensors 32, and determines whether or not the calculated traveling speed is greater than zero. (Step S7). In this process, the control unit 25 determines whether the tractor 1 is traveling or stopped. In the process of step S7, when the traveling speed of the tractor 1 is greater than 0 (NO in step S7), the control unit 25 repeats the process of step S7.

  In the process of step S7, when the traveling speed of the tractor 1 reaches 0 (YES in step S7), that is, when the control unit 25 detects the stop of the tractor 1, the control unit 25 sets the emergency stop flag to the ON state. (Step S8). In this process, the control unit 25 switches the state of the emergency stop flag stored in the storage unit from the OFF state to the ON state, and stores in the storage unit that the tractor 1 is in an emergency stop state by the operator. I am letting.

  When the emergency stop flag is in the ON state in the process of step S2 (YES in step S2), or when the process of step S8 is executed, the control unit 25 determines whether or not the emergency brake switch 15a is in the ON state. Determine (step S9). In this process, the control unit 25 determines whether or not the emergency brake pedal depressing operation has been released after the emergency stop by the operator.

  In the process of step S9, when the emergency brake switch 15a is in the ON state (YES in step S9), the control unit 25 returns the process to step S1 and maintains the ON state of the emergency stop flag. That is, after the emergency stop of the tractor 1 is performed by the operator, in the state where the depression operation of the emergency brake pedal is continuously performed, the processing of Step S1 to Step S9 is repeated, and the idle processing for the engine 14 is performed. The ON state of the bypass solenoid 30b and the braking state of the parking brake device are maintained.

  In the process of step S9, when the emergency brake switch 15a is in the OFF state (NO in step S9), the control unit 25 determines whether or not the main transmission lever 20 is located at the neutral position (step S10). In the process of step S10, when the main transmission lever 20 is located at a position other than the neutral position (NO in step S10), the control unit 25 returns the process to step S1 and maintains the emergency stop flag ON state. To do. That is, after the emergency stop of the tractor 1 is performed by the operator in a state where the main transmission lever 20 is located at a position other than the neutral position, the main transmission lever 20 continues to a position other than the neutral position. In the position, the process of step S1-step S10 is repeated, and it is comprised so that the idle process with respect to the engine 14, the ON state of the bypass valve 30a, and the braking state of a parking brake apparatus may be maintained. In the process of step S10, the control unit 25 attempts to prevent a sudden start due to the parking brake device 29 being in a non-braking state while the main transmission lever 20 is located at a position other than the neutral position. .

  When the main transmission lever 20 is in the neutral position in the process of step S10 (YES in step S10), the control unit 25 releases the parking brake from the sub monitor unit 19 after the emergency stop flag is turned on. It is determined whether or not a signal has been received (step S11). In the process of step S11, when the parking brake release signal is not received from the sub monitor unit 19 after the emergency stop flag is turned on (NO in step S11), the control unit 25 returns the process to step S1, The emergency stop flag remains on. That is, after the emergency stop of the tractor 1 by the operator, when the parking brake switching icon is not pressed, the processing of step S1 to step S11 is repeated to perform idle processing for the engine 14, bypass valve 30a. The ON state and the braking state of the parking brake device are maintained.

  In the process of step S11, when the parking brake release signal is received from the sub monitor unit 19 after the emergency stop flag is turned on (YES in step S11), the control unit 25 sends a bypass solenoid to the bypass solenoid 30b. In addition to transmitting an OFF signal, a parking brake release signal is transmitted to the parking brake solenoid 29b, and the emergency stop flag is turned OFF (step S12). In the processing of step S9 and step S11, the control unit 25 confirms whether or not the operator intends to place the parking brake device 29 in the non-braking state.

  When the process of step S12 is executed, the control unit 25 determines whether or not the main transmission lever 20 is located at a position other than the neutral position (step S13). In this process, when the main transmission lever 20 is maintained in the neutral position (YES in step S13), the control unit 25 repeats the process in step S13. In this process, the control unit 25 determines whether or not the main shift lever 20 has moved from the neutral position to another position after the main transmission lever 20 has moved to the neutral position after the emergency stop of the tractor 1 by the operator. The operator confirms whether the operator intends to restart.

  In the process of step S13, when the main transmission lever 20 is located at a position other than the neutral position (NO in step S13), the control unit 25 transmits a low idle release signal to the engine ECU 31 (step S14). When the engine ECU 31 receives the low idle release signal from the control unit 25, the engine ECU 31 adjusts the amount of fuel supplied to the engine 14 so that the rotational speed of the engine 14 becomes a rotational speed corresponding to the position of the engine control lever 21. In this process, the control unit 25 returns the rotational speed of the engine 14 to the rotational speed immediately before the idling process is started, that is, the rotational speed during traveling before the emergency stop of the tractor 1 is performed by the operator. However, the labor for adjusting the rotational speed of the engine 14 is saved, and the workability when the work is resumed after an emergency stop is improved.

<Summary>
Since the present embodiment is configured as described above, when a braking operation is performed by the emergency brake pedal 15 while the tractor 1 is traveling, the control unit 25 sets the engine 14 to the idle rotation speed. After starting the processing, the parking brake device 29 is continuously operated. For this reason, when the vehicle stops suddenly, the traveling device 2 is braked after the rotational speed of the engine 14 decreases, so that it is possible to reduce the burden on each part of the power transmission path and the parking brake device.

  When the braking operation by the emergency brake pedal 15 is performed while the tractor 1 is traveling, the control unit 25 starts the idle process for setting the rotational speed of the engine 14 to the idle rotational speed, and then parks during the idle process. The brake device 29 is intermittently operated, and then the parking brake device 29 is continuously operated. For this reason, when the vehicle stops suddenly, the parking brake device 29 is first intermittently operated, and the traveling device 2 is braked by the continuous operation of the parking brake device 29 after the rotational speed of the engine 14 is reduced. The burden on each part and the parking brake device 29 can be reduced.

  When the braking operation by the emergency brake pedal 15 is performed while the tractor 1 is traveling, the control unit 25 continuously operates the parking brake device 29 after the rotational speed of the engine 14 reaches the idle rotational speed. The burden on each part on the transmission path and the parking brake device 29 can be reduced. Also, when releasing the braking of the traveling device 2 by the parking brake device 29 and restarting, the rotational speed of the engine 14 is the idle rotational speed. The burden imposed can be reduced.

<Modification>
In the present embodiment, the control unit 25 is configured to intermittently transmit a parking brake signal to the parking brake solenoid 29b and start inching in the process of step S4 in the emergency stop process. However, it is not limited to this. For example, the control unit 25 is configured to include a timer capable of measuring time, and the parking brake valve 29a is detected until it is detected in step S5 that the rotational speed of the engine 14 has reached a low idle rotational speed. The connection state may be maintained.

  Further, for example, the control unit 25 does not depend on whether or not the engine 14 has reached the low idle speed after detecting the ON state of the emergency brake switch 15a in the process of step S3 of the emergency stop process. The parking brake device is detected from detection of the ON state of the emergency brake switch 15a, for example, when the parking brake device 29 is continuously braked after elapse of time, for example, any time from 0.1 seconds to 1 second determined in advance. 29 may be configured to delay and enter a braking state, or may be configured to start inching after a predetermined time has elapsed. Moreover, the control part 25 is not limited to what is comprised so that the switching between the connection state and interruption | blocking state of the parking brake valve 29a in the inching in an emergency stop process may be performed every fixed time. The control unit 25 may be configured to change the time during which the parking brake valve 29a is connected in the inching in the emergency stop process and the time during which the parking brake valve 29a is in the disconnected state. You may be comprised so that it may change so that a certain time may become short, or may be changed so that the time which may be in the interruption | blocking state may become long gradually. Moreover, when controlling the parking brake device 29 based on the time after detecting the ON state of the emergency brake switch 15a, the control unit 25 detects the vehicle speed of the tractor 1 when the ON state of the emergency brake switch 15a is detected. Accordingly, it may be configured to execute control according to the vehicle speed, such as changing the time until the parking brake device 29 is brought into the braking state.

  Further, for example, the tractor 1 is configured as a variable valve in which the parking brake valve 29a is operated by an actuator, and the control unit 25 detects the ON state of the emergency brake switch 15a in the process of step S3 of the emergency stop process. Thus, the braking force gradual change control for gradually increasing the braking force of the parking brake device 29 with the lapse of time by closing the variable valve gradually with the lapse of time is performed for a predetermined time. You may be comprised so that it may be in the state which continuously operates, ie, the parking brake apparatus 29 is continuously operated by opening a variable valve to the maximum. In such a configuration, when the vehicle is suddenly stopped, the braking force of the parking brake device 29 is first gradually increased, and after the rotational speed of the engine 14 decreases, the traveling device 2 is operated by the continuous operation of the parking brake device 29. Since braking is performed, it is possible to reduce the burden on each part on the power transmission path and the parking brake device 29. Further, in this case, the control unit 25 is configured to control the variable valve regardless of whether or not the engine 14 has reached the low idle speed from the time when the ON state of the emergency brake switch 15a is detected. Alternatively, it may be configured to execute control according to the vehicle speed, such as changing the speed at which the variable valve opens according to the vehicle speed of the tractor 1 when the ON state of the emergency brake switch 15a is detected. Good.

  In the present embodiment, the control unit 25 performs the process of step S4 based on the determination result only on whether or not the emergency brake switch 15a is in the ON state in the process of step S3 in the emergency stop process. However, the present invention is not limited to this. For example, when the vehicle speed is 0 with reference to the vehicle speed signal from the vehicle speed sensor 32 together with the state of the emergency brake switch 15a in the process of step S3, the control unit 25 performs the process regardless of the state of the emergency brake switch 15a. The engine 14 may be configured so that the rotational speed of the engine 14 is a low idle rotational speed by referring to the engine rotational speed signal from the engine rotational speed sensor 27 together with the state of the emergency brake switch 15a in the process of step S3. In some cases, the process of step S5 may be omitted.

  Further, in the present embodiment, the travel brake device is configured by the parking brake device 29 that brakes the drive wheel 2a, but is not limited thereto. The traveling brake device may be configured by a parking brake device 29 that brakes other parts such as a shaft that transmits power from the HST motor 18b to the driving wheel 2a, and is provided separately from the parking brake device 29. And it may be comprised by the brake device used when decelerating the tractor 1. FIG.

  Moreover, in this Embodiment, although the alerting | reporting means is comprised from the sub monitor unit 19, it is not limited to this. The notification means may be any means that notifies the state of the parking brake device 29 by transitioning to the first state and the second state different from the first state, for example, the parking brake lamp 11a of the main monitor 11. It may be a main monitor 11 having a liquid crystal display for displaying notification contents as an image, a lamp or a liquid crystal display arranged in another part, or a parking brake. The speaker which alert | reports the state of the apparatus 29 may be sufficient, and the vibration apparatus which vibrates the steering handle 10 or the driver's seat 9 according to the state of the parking brake apparatus 29 may be sufficient.

  Moreover, in this Embodiment, although the cancellation | release operation part is comprised by the parking brake icon 19c displayed on the sub monitor unit 19 with an image, it is not limited to this. The release operation unit may be anything that allows the operator to perform the release operation of the parking brake device 29. For example, the release operation unit may be an operation button 19 b provided on the sub monitor unit 19 or in the vicinity of the sub monitor unit 19. It may be an operation button provided, a lever for manually operating a parking brake, or an icon displayed as an image on the main monitor 11 having a touch panel type liquid crystal display. Alternatively, an operation button provided on or in the vicinity of the main monitor 11 may be used, and the parking brake device is operated by depressing the emergency brake pedal 15 again in the braking state of the parking brake device 29 after the emergency stop. 29 may be configured to switch to a non-braking state.

  Further, in the present embodiment, the engine 14 is configured such that the engine 14 can be shifted between a low idle rotation speed and a high idle rotation speed by the engine control lever 21, but is not limited thereto. For example, the rotational speed of the engine 14 may be configured so that a speed change operation can be performed according to the amount of depressing operation of the shift pedal, or can be switched between two stages of a low idle speed and a high idle speed by operating a button. It may be configured.

  In the present embodiment, the control unit 25 determines whether or not the emergency brake switch 15a is in the ON state in step S9 to step S11 of the emergency stop process, and whether or not the main transmission lever 20 is in the neutral position. Alternatively, the determination is made in the order of whether or not the parking brake release signal from the sub monitor unit 19 has been received after the emergency stop flag is turned on, but the present invention is not limited to this. The control part 25 may be comprised so that the process of step S9-step S11 may be determined in any other order.

  Further, the idle rotation speed of the engine 14 controlled by the engine ECU 31 is not limited to a predetermined constant value. The idle rotation speed may be a value with a certain range, or a value changed by the control unit 25 or the engine ECU 31 depending on the temperature of the engine 14, the time since the engine 14 was started, and various other settings. It may be.

  Moreover, in this Embodiment, although the tractor 1 provided with the full crawler type traveling apparatus 2 was demonstrated as a working vehicle, it is not limited to this. The work vehicle may include another device as the traveling device 2. For example, the working vehicle may include a four-wheel tire as the traveling device 2, or may include a half-crawler traveling device having a two-wheel tire and a pair of crawlers, or four crawlers. A four-crawler traveling device having The present invention can also be applied to other working vehicles other than the tractor, such as a combine harvester for harvesting and threshing rice.

1 Working vehicle (tractor)
2 traveling device 14 engine 15 brake operation part (emergency brake pedal)
18 Hydrostatic continuously variable transmission (HST)
25 Control part 27 Rotational speed detection means (engine speed sensor)
29 Traveling brake device (parking brake device)

Claims (4)

A work comprising a hydrostatic continuously variable transmission that continuously transmits power to the traveling device by supplying oil according to the angle of the swash plate, and a traveling brake device that brakes the traveling device. In the vehicle,
A brake operation unit for braking the travel brake device;
A control unit for controlling the rotational speed of the engine and the traveling brake device,
The control unit continuously operates the traveling brake device after starting an idle process for setting the engine rotation speed to an idle rotation speed when a braking operation is performed by the brake operation unit while the work vehicle is traveling. ,
A working vehicle characterized by that. A work comprising a hydrostatic continuously variable transmission that continuously transmits power to the traveling device by supplying oil according to the angle of the swash plate, and a traveling brake device that brakes the traveling device. In the vehicle,
A brake operation unit for braking the travel brake device;
A control unit for controlling the rotational speed of the engine and the traveling brake device,
The control unit executes an idle process for setting an engine rotation speed to an idle rotation speed when a braking operation is performed by the brake operation unit while the work vehicle is traveling, and the traveling is performed during the idle process. The brake device is intermittently operated for a predetermined time, and then the traveling brake device is continuously operated.
A working vehicle characterized by that. A work comprising a hydrostatic continuously variable transmission that continuously transmits power to the traveling device by supplying oil according to the angle of the swash plate, and a traveling brake device that brakes the traveling device. In the vehicle,
A brake operation unit for braking the travel brake device;
A control unit for controlling the rotational speed of the engine and the traveling brake device,
The control unit executes an idle process for setting an engine rotation speed to an idle rotation speed when a braking operation is performed by the brake operation unit while the work vehicle is traveling, and the traveling is performed during the idle process. Performing braking force gradual change control for increasing the braking force of the brake device over time for a predetermined time, and then continuously operating the traveling brake device;
A working vehicle characterized by that. A rotation speed detecting means capable of measuring the rotation speed of the engine;
When the braking operation is performed by the brake operation unit in a state where the power from the engine is transmitted to the traveling device, the control unit converts the engine rotation speed to the idle rotation speed by the rotation speed detection unit. When it is detected that the traveling brake device has been reached,
The working vehicle according to any one of claims 1 to 3.

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