Work vehicle

Abstract

To improve safety by enhancing certainty of a brake operation.SOLUTION: A work vehicle includes: an electric motor; a brake mechanism; and a brake operation tool. The electric motor drives a traveling vehicle body to travel. The brake mechanism causes the traveling vehicle body to operate the brake. The brake operation tool is operated when the traveling vehicle body is caused to operate the brake. The brake mechanism is configured to operate the brake by power-off of the electric motor and has a brake signal generation section, a pulling margin section, and a pulling position fixing section. The brake signal generation section generates a brake signal for turning off power supply of the electric motor when switched to a brake-on position. In the pulling margin section, a pulling position moves to a prescribed position so as to be switched to the brake-on position in the brake signal generation section according to a pulling operation of the brake operation tool. The pulling position fixing section fixes the pulling position of the pulling margin section by the pulling operation of the brake operation tool to the prescribed position.SELECTED DRAWING: Figure 6

Description

Technical Field

[0001] The present invention relates to a work vehicle.

Background Art

[0002] Conventionally, in a work vehicle that travels with an electric motor and has functions of a parking brake and a foot brake, when operating the parking brake or the foot brake, in either case, a technique is known in which a brake operation signal is received and the electric motor is controlled (stopping control or deceleration control) (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the conventional technology as described above, since the parking brake and the foot brake have the same structure and function as each other, that is, since it is performed only by controlling the electric motor, for example, when the power is turned off, the brake state may be reset.

[0005] The present invention has been made in view of the above, and an object thereof is to provide a work vehicle capable of enhancing the certainty of brake operation and improving safety.

Means for Solving the Problems

[0006] In order to solve the above-described problems and achieve the object, a work vehicle (1) according to an embodiment includes a traveling vehicle body (2) and a working machine (3). The work vehicle (1) includes an electric motor (41) that drives the traveling vehicle body (2) to travel, a brake mechanism (50) that actuates a brake on the traveling vehicle body (2), and at least one of a hand lever (29) and a foot pedal (28) that is operated when the brake mechanism (60) actuates a brake on the traveling vehicle body (2), and a brake operating tool (60) including an electric actuator (30). The brake mechanism (50) is configured such that a brake is actuated inside the electric motor (41) when the power supply of the electric motor (41) is turned off. The brake mechanism (50) has a brake-on position (P1) and a brake-off position (P2), and the brake-on position (P1) and the brake-off position (P2) are switchable. When switched to the brake-on position (P1), a brake signal generation unit (54) that issues a brake signal for turning off the power supply of the electric motor (41), a pull generation unit (57) provided between the brake operating tool (60) and the brake signal generation unit (54), and the pull position of the pull generation unit (57) moves to a predetermined position in response to a pulling operation of the brake operating tool (60) so as to switch the brake signal generation unit (54) to the brake-on position (P1), and a pull position fixing unit (58) provided on the pull generation unit (57) and fixing the pull position of the pull generation unit (57) to the predetermined position by a pulling operation of the brake operating tool (60).

Effect of the Invention

[0007] According to the work vehicle according to the embodiment, the certainty of brake actuation can be enhanced and the safety can be improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the work vehicle disclosed in the present application will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments shown below.

[0010] <Overview of the Work Vehicle> First, with reference to FIGS. 1 to 5, an overview of the work vehicle 1 according to the embodiment will be described. FIG. 1 is a schematic side view showing the work vehicle 1 according to the embodiment. FIG. 2 is a schematic perspective view showing the inside of the work vehicle 1 according to the embodiment. FIG. 3 is a schematic rear view showing the work vehicle 1 according to the embodiment. FIG. 4 is a schematic side view showing the brake mechanism 50 of the work vehicle 1 according to the embodiment. FIG. 5 is a block diagram showing the control system of the work vehicle 1 according to the embodiment.

[0011] Hereinafter, as the work vehicle 1, a ride-on lawn mower that cuts lawn grass (hereinafter referred to as lawn grass) while traveling and collects the cut lawn grass will be described as an example. Note that the work vehicle 1 is not limited to a ride-on lawn mower, and may be a tractor that performs operations such as tilling while traveling in a field, a rice transplanter that performs rice seedling planting operations while traveling in a field, or the like.

[0012] As shown in FIG. 1, the work vehicle 1 includes a traveling vehicle body 2 and a work implement 3. The traveling vehicle body 2 can travel in a predetermined work area. The work implement 3 is a cutting device provided on the traveling vehicle body 2 for cutting lawn grass.

[0013] The traveling vehicle body 2 includes a pair of left and right front wheels 21 at the front and a pair of left and right rear wheels 22 at the rear. The traveling vehicle body 2 includes a bonnet portion 23 on the upper front side, a control portion 24 where a driver (also referred to as an operator) boards behind the bonnet portion 23, a safety frame (ROPS) 25 for protecting the driver behind the control portion 24, and a grass collection container 26 for storing the lawn grass cut by the work implement 3 below the safety frame 25.

[0014] The bonnet part 23 is provided with a battery 43 (see FIG. 2) that stores electric power supplied to a traveling motor 41 (see FIG. 3), which is an electric motor that drives the rear wheels 22, which are traveling wheels, and a working machine motor 42 (see FIG. 3), which is an electric motor that drives the working machine 3. The battery 43 is covered with a bonnet cover. The bonnet cover is provided on the front part of the traveling vehicle body 2 so as to be openable and closable. In this way, the space formed in the bonnet part 23 can be effectively utilized. Also, the difference in the weight balance in the front-rear direction of the work vehicle 1 can be suppressed.

[0015] A driver's seat 241 is provided at the rear part of the control unit 24. A steering wheel 242 is provided in front of the driver's seat 241. The steering wheel 242 is supported on the upper part of a steering shaft that extends in the vertical direction. The steering shaft is supported by a steering post.

[0016] On the fender 27 on the left side of the driver's seat 241, there is provided a cleaner lever for operating a cleaner that forcibly conveys the cut grass remaining in a shooter that conveys the cut grass cut by the working machine 3 to the grass collection container 26 to the grass collection container 26, and a storage case for storing a charging cable used when charging the battery 43 behind the cleaner lever. Thereby, when the charge amount of the battery 43 becomes less than or equal to a predetermined amount, without moving the work vehicle 1 to a charging station, the work vehicle 1 can be moved to a nearby warehouse or the like, and a household outlet installed in the warehouse or the like and an in-vehicle charger (hereinafter referred to as OBC) 44, which is a so-called OBC (On Board Charger), can be connected with the charging cable to charge the battery 43. Note that the input voltage of the OBC 44 corresponds to an AC voltage of 100 to 240V.

[0017] On the fender 27 (see FIG. 3) on the right side of the driver's seat 241, there is provided a lift lever for operating the lifting of the working machine 3.

[0018] On the left side of the floor step 243 of the control unit 24, a brake pedal (also referred to as a foot pedal) 28 is provided. On the right side of the floor step 243 of the control unit 24, an accelerator pedal for forward and backward movement is provided.

[0019] Below the driver's seat 241 of the control unit 24, an electrical component (hereinafter referred to as the BMS control device) 45 (see FIG. 2) that controls the battery management system (BMS) and controls the battery is provided. Thereby, the space formed below the driver's seat 241 can be effectively utilized. In addition, a seating sensor (seat detection unit) S3 (see FIG. 5) that can detect the seating of the operator by detecting the load received by the driver's seat 241 is provided at the lower part of the driver's seat 241.

[0020] The control unit 24 is provided with a brake operating tool 60. The brake operating tool 60 is operated when the brake mechanism 50 described later activates the brake on the traveling vehicle body 2 (working vehicle 1). The brake operating tool 60 is operated when applying a so-called parking brake to the traveling vehicle body 2 (working vehicle 1). The brake operating tool 60 includes at least one of the hand lever 29 and the brake pedal (foot pedal) 28. The hand lever 29 is provided on the left side of the driver's seat 241 and activates the parking brake by a pulling operation upward by the driver. The foot pedal 28 is provided on the floor step 243 and, in addition to the normal brake function, activates the parking brake by a stepping operation of the driver that exceeds a predetermined depression amount. Note that the foot pedal 28 for activating the parking brake may be provided separately from the one for activating the normal brake.

[0021] In addition, the brake operating tool 70 includes an electric actuator 30 (see FIG. 2). The electric actuator 31 includes an electric cylinder 52 (see FIG. 4) described later, and activates the parking brake by the expansion and contraction of the electric cylinder 52. The electric actuator 30 activates the parking brake even when, for example, the hand lever 29 or the foot pedal 28 is not fully operated and the parking brake is not activated.

[0022] As shown in FIGS. 2 and 3, a traveling motor 41, which is an electric motor such as a synchronous motor or an induction motor operated by a three-phase AC voltage waveform for driving the rear wheels 22, is provided below the BMS control device 45. The output shaft extending in the left-right direction of the traveling motor 41 is connected to the upper part of a gearbox 46 that decelerates the output rotation transmitted from this output shaft to increase the output torque or reverses the rotation. Note that the traveling motor 41 is provided at a position shifted to the rear wheel 22 on the left side from the center in the left-right direction.

[0023] The output rotation increased or decreased in speed by the gearbox 46 is transmitted to a drive shaft 47 extending in the left-right direction through a differential gear formed by a differential gear or the like provided at the lower part of the gearbox 46. The output rotation transmitted to the drive shaft 47 is transmitted to the left and right rear wheels 22 supported at both ends of the drive shaft 47.

[0024] Below the traveling motor 41, a working machine motor 42, which is an electric motor such as a synchronous motor or an induction motor operated by a three-phase AC voltage waveform for driving the working machine 3, is provided. The output shaft extending in the front-rear direction of the working machine motor 42 is connected to the rear part of a universal joint provided to extend in the front-rear direction.

[0025] Further, the output shaft is provided above the drive shaft 47 and orthogonal to this drive shaft 47. Thereby, the space formed below the traveling motor 41 can be effectively utilized. Also, since the transmission path between the working machine motor 42 and the working machine 3 can be shortened, the output rotation of the working machine motor 42 can be efficiently transmitted to the working machine 3. Note that the working machine motor 42 is provided at a position shifted to the rear wheel 22 side on the left side from the center in the left-right direction.

[0026] The front part of the universal joint is connected to a gearbox that decelerates the output rotation transmitted from this universal joint and increases the output torque. The output rotation transmitted to the gearbox is transmitted to the left cutting blade provided in the left discharge passage of the working machine 3 via an output shaft provided to extend in the vertical direction of the gearbox.

[0027] A connecting member extending in the left - right direction is connected to the right side of the gearbox. The right part of the connecting member is connected to the gearbox. The output rotation transmitted to the gearbox is transmitted to the right cutting blade provided in the right discharge passage of the working machine 3 via an output shaft provided to extend in the vertical direction of the gearbox.

[0028] The rotational speed of the traveling motor 41 can be increased or decreased by operating a throttle lever, which is a power setting device, provided on the left side of the steering wheel 242. When the throttle lever is in the neutral position, the output rotation of the traveling motor 41 becomes zero. When the throttle lever is tilted from the neutral position to the front - tilted position, the output rotation of the traveling motor 41 is increased or decreased according to the magnitude of the tilt angle of the front - tilted position. Also, when the shift lever is tilted from the neutral position to the rear - tilted position, the output rotation of the traveling motor 41 is increased or decreased according to the magnitude of the tilt angle of the rear - tilted position, and the rotational direction of the output rotation of the traveling motor 41 becomes reverse rotation.

[0029] In addition, in front of the steering wheel 242, a liquid - crystal display unit capable of displaying various information is provided. Also, on the left side of the steering wheel 242, a key switch S1 (see Fig. 5) and a charging switch S2 (see Fig. 5) are provided.

[0030] In addition, the work vehicle 1 is provided with a brake mechanism 50. As shown in FIG. 4, the brake mechanism 50 that brakes the rotation of the rear wheels 22 (see FIG. 1) by the output from the gearbox 46 (see FIG. 3) is connected to a rod 51 configured to be able to move forward and backward in the front-rear direction in response to the operation of the brake pedal 28. In this case, the operation and non-operation of the brake mechanism 50 are switched in conjunction with the pulling operation of the rod 51 forward. Other configurations of the brake mechanism 50 will be described later with reference to FIGS. 6 and 7.

[0031] Also, an electric cylinder 52 is connected to the rod 51. When the rod 51 expands and contracts, the electric cylinder 52 causes the rod 51 to move forward and backward regardless of the operation of the brake pedal 28. The expansion and contraction of the electric cylinder 52 are controlled by a control unit 100 (see FIG. 5) described later. Specifically, when the driver depresses the brake pedal 28, the brake pedal 28 rotates counterclockwise about a support shaft 53 extending in the left-right direction, and the rod 51 moves forward. As a result, the brake mechanism 50 operates and the rear wheels 22 are braked. That is, it enters the braking state.

[0032] Also, when the control unit 100 controls the electric cylinder 52 to contract (contracted state), the rod 51 moves forward. As a result, the brake mechanism 50 operates and the rear wheels 22 are braked. By maintaining the contracted state of the electric cylinder 52, it is possible to set it to the hold state while maintaining the braking state. On the other hand, when the control unit 100 controls the electric cylinder 52 to extend (extended state), the rod 51 moves backward. As a result, the operation of the brake mechanism 50 is released, the braking of the rear wheels 22 is released, and the hold state is released.

[0033] As shown in FIG. 5, the control system of the work vehicle 1 is a control system centered around the control unit 100. The control unit 100 is a so-called VCU (Vehicle Control Unit), has an electronic control device ECU (Electronic Control Unit), and is capable of various controls.

[0034] On the input side of the control unit 100, a key switch S1, a charging switch S2, a seating sensor (seat detection unit) S3, a brake pedal sensor S4, an accelerator pedal sensor S5, a traveling speed sensor S6, a brake operation tool sensor S7 (to be described later), etc. are connected. The control unit 100 acquires the information detected by these sensors.

[0035] Also, a traveling MDU 61, a work implement MDU 62, an electric cylinder 52, an OBC 44, a BMS control device 45, etc. are connected to the control unit 100. The control unit 100 can send and receive information with these devices.

[0036] The key switch S1 can be switched to three operation positions, namely, an OFF position, an ACC position, and an ON position, by a rotational operation. When the key switch S1 is in the OFF position, a current necessary for maintaining the minimum functions is supplied to the control unit 100. In this case, an information processing device such as the CPU of the control unit 100 maintains its operation and is configured to determine the operation position of the key switch S1 and perform the necessary minimum processing. Note that in this case, the traveling motor 41 and the work implement motor 42 are in a state where no power supply necessary for driving is provided.

[0037] When the key switch S1 is in the ACC position, a power supply necessary for normal operation is supplied to the control unit 100, and the display unit of the control unit 24 and the like are in an activated state. On the other hand, since no power supply necessary for driving is provided to the traveling motor 41 and the work implement motor 42, for example, even if the accelerator pedal is depressed, the rear wheels 22 do not rotate and the work vehicle 1 does not start.

[0038] When the key switch S1 is in the ON position, a power supply necessary for driving is provided to the traveling motor 41 and the work implement motor 42. In this case, the work vehicle 1 is in a state where the rear wheels 22 and the work implement 3 can be driven, and work traveling is possible.

[0039] The charging switch S2 is configured as a momentary switch capable of on-off operation. When in the on state, charging from an external power source to the battery 43 is possible. When the charging switch S2 is turned on, the control unit 100 executes the charging mode.

[0040] In addition, the control unit 100 can respectively obtain information regarding the seating on the driver's seat 241 by the seating sensor (seat detection unit) S3, the depression amount of the brake pedal 28 by the brake pedal sensor S4, the rotation speed of the rear wheel 22 which is a driving wheel by the traveling speed sensor S6, and the depression amount of the accelerator pedal by the accelerator pedal sensor S5.

[0041] The traveling MDU 61 is an inverter control device and has an inverter function for controlling the rotation speed of the traveling motor 41 and a simple CPU (relay circuit for the inverter) for controlling this. Note that MDU is an abbreviation for Motor Drive Unit. The traveling MDU 61 controls the on-off of the traveling motor 41 by controlling the rotation speed of the inverter, and when the rotation of the inverter becomes off, it functions to output an operation signal of a simple brake of the traveling motor 41. Also, the power supply of the simple CPU of the inverter of the traveling MDU 61 is turned on and off by the on-off of the MDU signal relay.

[0042] The working machine MDU 62 is, like the traveling MDU 61, an inverter control device and has an inverter function for controlling the rotation speed of the working machine motor 42 and a simple CPU (relay circuit for the inverter) for controlling this. The working machine MDU 62 controls the on-off of the working machine motor 42 by controlling the rotation speed of the inverter, and when the rotation of the inverter becomes off, it functions to output an operation signal of a simple brake of the working machine motor 42. Also, the power supply of the simple CPU of the inverter of the working machine MDU 62 is turned on and off by the on-off of the MDU signal relay.

[0043] The BMS control device 45 is a control device that controls the battery 43. In particular, it controls the power supply from the battery 43 by turning on and off the relay in the battery control circuit.

[0044] The control unit 100 transmits a contraction signal for instructing the electric cylinder 52 to contract and an extension signal for instructing the electric cylinder 52 to extend, thereby controlling the expansion and contraction of the electric cylinder 52. In addition, the control unit 100 can acquire a feedback signal indicating the expansion and contraction state of the electric cylinder 52.

[0045] Further, when a predetermined condition is satisfied, the control unit 100 has an auto parking function of controlling the expansion and contraction of the electric cylinder 52 to automatically brake or release the brake on the rear wheels 22 which are the driving wheels.

[0046] <Brake mechanism> Next, the brake mechanism 50 will be described with reference to FIGS. 6 and 7. FIGS. 6 and 7 are explanatory views of the brake mechanism 50. Note that FIGS. 6 and 7 schematically show the configuration of the brake mechanism 50. The brake mechanism 50 activates the brake on the traveling vehicle body 2 (work vehicle 1). The brake mechanism 50 is configured such that the brake is activated inside the traveling motor 41 (see FIG. 3), which is an electric motor, when the power supply to the traveling motor 41 is turned off. That is, the brake mechanism 50 is configured to apply the parking brake by an electric signal.

[0047] As shown in FIG. 6, the brake mechanism 50 includes a brake signal generation unit 54, a brake arm 55, a rod 56, a compensation unit 57, and a pull position fixing unit 58. The brake signal generation unit 54 has a brake-on position P1 and a brake-off position P2. When the brake signal generation unit 54 is located at the brake-on position P1, the parking brake is actuated. When the brake signal generation unit 54 is located at the brake-off position P2, the parking brake is released. The brake signal generation unit 54 can switch between the brake-on position P1 and the brake-off position P2. When the brake signal generation unit 54 is switched to the brake-on position P1, it emits a brake signal that turns off the power supply of the traveling motor 41.

[0048] The brake arm 55 extends from the brake signal generation unit 54. The rod 56 connects the brake arm 55 to each of the handle lever 29, the foot pedal 28, and the electric actuator 30, which are brake operation tools 60 (see FIGS. 1 and 2).

[0049] The compensation unit 57 is provided between each of the handle lever 29, the foot pedal 28, and the electric actuator 30, which are brake operation tools 60, and the brake signal generation unit 54. Each compensation unit 57 is connected to the handle lever 29, the foot pedal 28, and the electric actuator 30 via the rod 56. The compensation unit 57 includes an elongated hole 571 that is long along the pulling direction of the rod 56, and a pin 572 that is movable along the elongated hole 571.

[0050] The pull position fixing unit 58 is provided on the compensation unit 57. The pull position fixing unit 58 fixes the pull position of the compensation unit 57 due to the pulling operation of the brake operation tool 60 to a predetermined position. The pull position fixing unit 58 is, for example, a ratchet mechanism provided on the compensation unit 57. By the pull position fixing unit 58, the pin 572 that has been pulled and moved toward the brake operation tool 60 side along the elongated hole 571 is fixed at the moved position (pull position).

[0051] The pin 572 of the pull substitute part 57 moves to a predetermined position so as to switch to the brake-on position P1 in the brake signal generation part 54 in response to the pulling operation of the brake operating tool 60. Further, the pin 572 of the pull substitute part 57 is released from fixation and returns to its original position by the pulling operation of the brake operating tool 60 again.

[0052] According to such a configuration, in an electric control brake operation configuration in which the brake is operated by a brake signal emitted by the brake signal generation part 54, since there is a mechanism for mechanically adjusting (fixing) the pulling operation of the brake operating tool 60 in front of the brake signal generation part 54, for example, even when the power supply of the traveling motor 41 is cut off unintentionally (power off), the brake (so-called parking brake) state is maintained. Also, even when the power supply of the traveling motor 41 is turned on again after being cut off (power off), the brake (parking brake) state is not automatically reset. That is, the certainty of brake operation can be enhanced, and thereby, the safety can be improved.

[0053] As shown in FIG. 7, in the brake mechanism 50, for example, when the electric actuator 30 becomes inoperable while in the pulling operation state, the fixation of the position of the pin 572 of the pull substitute part 57 can be mechanically released.

[0054] FIG. 8 is a schematic perspective view showing the fixing release mechanism 59 of the brake mechanism 50. As shown in FIG. 8, the brake mechanism 50 includes a fixing release mechanism 59. The fixing release mechanism 59 manually releases the electric actuator 30 fixed at the brake position when the parking brake is operated on the traveling vehicle body 2.

[0055] The fixing release mechanism 59 includes a pin member 591 and a lever portion 592. The pin member 591 fixes the electric actuator 30 in the brake position. The lever portion 592 is provided at an end portion on the side opposite to the side where the electric actuator 30 of the pin member is fixed. When the lever portion 592 is pulled, the fixing release mechanism 59 releases the fixing of the electric actuator 30 by the pin member 591. Since the pin member 591 and the lever portion 592 are biased by a biasing member 593 such as a coil spring, for example, when the driver releases the hand from the lever portion 592, the pin member 591 and the lever portion 592 return to their original positions.

[0056] According to such a configuration, for example, even when the power supply of the traveling motor 41 cannot be restored, it is possible to release the fixing of the electric actuator 30 by manual operation.

[0057] <Automatic brake determination> Next, with reference to FIGS. 9 to 12, the automatic brake determination for automatically operating the electric actuator 30 will be described. FIGS. 9 to 12 are block diagrams showing an example of a control system related to the automatic brake determination.

[0058] As shown in FIG. 9, the control unit 100 (see FIG. 5) includes a brake determination unit 110. The brake determination unit 110 is connected to a traveling speed detection unit (traveling speed sensor) S6, a parking brake detection unit (brake operation tool sensor) S7, and a seat detection unit (seating sensor) S3.

[0059] The traveling speed detection unit S6 detects the traveling speed of the traveling vehicle body 2 by the traveling motor 41 which is an electric motor. The parking brake detection unit S7 detects the brake position of the electric actuator 30 among the brake operation tools 60. The seat detection unit S3 detects the driver's departure from the driver's seat 241.

[0060] The brake determination unit 110 determines whether to activate the automatic brake by the electric actuator 30 when a predetermined condition is satisfied. The brake determination unit 110 sets the predetermined condition for automatic brake determination as the speed of the traveling vehicle body 2 exceeding the speed detected by the traveling speed detection unit S6. That is, when the traveling speed becomes equal to or higher than a predetermined speed at which the speed exceeds, the brake determination unit 110 determines whether to activate the automatic brake by the electric actuator 30. Further, when the brake determination unit 110 activates the automatic brake, it activates the electric actuator 30.

[0061] According to such a configuration, for example, even when the traveling motor 41 becomes uncontrollable, the traveling vehicle body 2 can be safely stopped without depending on the driver's operation. In addition, the convenience can be improved by automatically activating the parking brake.

[0062] Further, the brake determination unit 110 sets the predetermined condition for automatic brake determination as the non-brake detected by the parking brake detection unit S7 and the driver leaving the driver's seat 241 detected by the seat detection unit S3. That is, when the driver leaves the driver's seat while the parking brake is not activated, the brake determination unit 110 determines whether to activate the automatic brake by the electric actuator 30. Further, when the brake determination unit 110 activates the automatic brake, it activates the electric actuator 30.

[0063] According to such a configuration, when the driver leaves the driver's seat 241 without applying the parking brake, the traveling vehicle body 2 can be safely stopped without depending on the driver's operation. In addition, the convenience can be improved by automatically activating the parking brake.

[0064] Also, as shown in FIG. 10, when the brake determination unit 110 determines whether or not to activate the automatic brake by the electric actuator 30, if it determines to activate the electric actuator 30. Also, in the case of the brake state, the traveling motor control unit 120 controls the traveling motor 41 so that the traveling motor 41 does not rotate. Also, the brake determination unit 110 controls the warning unit 130. When the brake does not operate even though the brake determination unit 110 outputs a brake instruction signal to the electric actuator 30, it prompts the driver to manually activate the parking brake, for example, by a warning buzzer or a warning display.

[0065] Also, as shown in FIG. 11, the brake determination unit 110 is connected to the handlebar detection unit S71, the electric actuator detection unit S72, and the seat detection unit S3. When the brake determination unit 110 determines whether or not to activate the automatic brake by the electric actuator 30 based on the detection results of the handlebar detection unit S71, the electric actuator detection unit S72, and the seat detection unit S3, it activates the electric actuator 30. Also, in the case of the brake state, the traveling motor control unit 120 controls the traveling motor 41 so that the traveling motor 41 does not rotate. Also, the brake determination unit 110 controls the warning unit 130. When the brake does not operate even though the brake determination unit 110 outputs a brake instruction signal to the electric actuator 30, it prompts the driver to manually activate the parking brake, for example, by a warning buzzer or a warning display.

[0066] Also, as shown in FIG. 12, the brake determination unit 110 is connected to the hand lever detection unit S71, the electric actuator detection unit S72, the foot pedal detection unit S73, and the seat detection unit S3. Based on the detection results of the hand lever detection unit S71, the electric actuator detection unit S72, the foot pedal detection unit S73, and the seat detection unit S3, when determining whether to activate the automatic brake by the electric actuator 30, the brake determination unit 110 activates the electric actuator 30. Also, in the case of the brake state, the traveling motor control unit 120 controls the traveling motor 41 so that the traveling motor 41 does not rotate. Further, when the foot pedal 28 is at the most depressed position and the rotation of the traveling motor 41 has not stopped, the brake determination unit 110 forcibly stops the drive instruction to the traveling motor 41. Also, the brake determination unit 110 controls the warning unit 130. When the brake does not operate even though the brake determination unit 110 outputs a brake instruction signal to the electric actuator 30, the driver is prompted to manually activate the parking brake, for example, by a warning buzzer or a warning display.

[0067] <Configuration of the water cooling circuit> Next, with reference to FIGS. 13 to 19, the configuration of the water cooling circuit 80 of the work vehicle 1 will be described. FIG. 13 is a diagram showing the configuration of the water cooling circuit 80. FIGS. 14 to 19 are block diagrams showing an example of the control system for water cooling control.

[0068] As shown in FIG. 13, the work vehicle 1 (see FIG. 1) includes a water cooling circuit 80 for cooling the traveling motor 41 which is an electric motor and the work implement motor 42 which is an electric motor. The water cooling circuit 80 includes a tank 81, an electric water pump (EMP) 82, a valve 83, a control unit 84, electric motors 41 and 42, an inverter 85, a thermometer 86, a pressure gauge 87, and a fan 89. The control unit 84 includes an OBC 44 and a DCDC converter 88. In the water cooling circuit 80, the traveling system path R1 and the work implement system path R2 are connected in parallel.

[0069] The plurality of electric motors 41, 42 have different temperatures depending on their respective operating states. Therefore, by configuring the water cooling circuit 80 with each path in parallel, cooling can be performed in a well-balanced manner. Also, the temperatures of each electric motor 41, 42 and the inverter 85 generally increase in a similar manner regardless of the operating state, and since the heat resistance of the electric motors 41, 42 is greater than that of the inverter 85, cooling is possible even if the inverter 85 is connected immediately before the electric motors 41, 42. For this reason, the circuit configuration of the water cooling circuit can be simplified.

[0070] Also, in the water cooling circuit 80, the OBC 44 and the DCDC converter 88, which are electrical components other than the electric motors 41, 42 and the inverter 85, are connected in series. Since the traveling motor 41, which is an electric motor, has a relatively slow temperature rise compared to the other electric motor 42, there is no particular problem even if another electrical component is connected. For this reason, by having the OBC 44 and the DCDC converter 88 in series, the circuit configuration can be simplified.

[0071] The plurality of electrical components connected to the water cooling circuit 80 each include an electrical component temperature detection unit 861. As shown in FIG. 14, by providing a flow rate control unit 140, the flow rate of the electric water pump 82 is changed according to the temperature detected by each electrical component temperature detection unit 861. Thereby, power loss can be suppressed.

[0072] Also, as shown in FIG. 15, by providing an air volume control unit 150, the air volume of the fan 89 is changed according to the temperature detected by each electrical component temperature detection unit 861. Thereby, power loss can be suppressed. Note that the fan 89 may be provided in each of the paths of the traveling system path R1 and the work implement system path R2.

[0073] Also, as shown in FIG. 16, by providing a reverse rotation control unit 160, the fan 89 is reversed according to the temperature detected by each electrical component temperature detection unit 861. Thereby, the dust deposited around the fan 89 can be blown away, the cooling mechanism can be restored, and overheating can be suppressed.

[0074] In addition, the water cooling circuit 80 is provided with at least one water temperature detection unit 862 for detecting the temperature of the cooling water. As shown in FIG. 17, by providing the flow rate control unit 140, the flow rate of the electric water pump 82 is changed according to the temperature detected by each water temperature detection unit 862. Thereby, power loss can be suppressed.

[0075] In addition, as shown in FIG. 18, by providing the air volume control unit 150, the flow rate of the fan 89 is changed according to the temperature detected by each water temperature detection unit 862. Thereby, power loss can be suppressed. Note that the fan 89 may be provided in each of the paths of the traveling system path R1 and the work implement system path R2.

[0076] In addition, as shown in FIG. 19, by providing the reverse rotation control unit 160, the fan 89 is reversely rotated according to the temperature detected by each electrical component temperature detection unit 861. Thereby, the dust deposited around the fan 89 can be blown away, the cooling mechanism can be restored, and overheating can be suppressed.

[0077] With the above-described embodiments, the following work vehicle 1 is realized.

[0078] (1) A work vehicle 1 including a traveling vehicle body 2 and a working machine 3, comprising: an electric motor 41 for driving the traveling vehicle body 2; a brake mechanism 50 for actuating a brake on the traveling vehicle body 2; at least one of a hand lever 29 and a foot pedal 28, which is operated when the brake mechanism 50 actuates a brake on the traveling vehicle body 2; and a brake operating tool 60 including an electric actuator 30. The brake mechanism 50 is configured such that a brake is actuated inside the electric motor 41 when the power supply of the electric motor 41 is turned off. It has a brake-on position P1 and a brake-off position P2, and the brake-on position P1 and the brake-off position P2 are switchable. When switched to the brake-on position P1, a brake signal generating unit 54 that issues a brake signal for turning off the power supply of the electric motor 41 is provided between the brake operating tool 60 and the brake signal generating unit 54. A pulling force portion 57 whose pulling position moves to a predetermined position so as to switch the brake signal generating unit 54 to the brake-on position P1 in response to the pulling operation of the brake operating tool 60, and a pulling position fixing unit 58 provided on the pulling force portion 57 for fixing the pulling position of the pulling force portion 57 due to the pulling operation of the brake operating tool 60 to a predetermined position. The work vehicle 1.

[0079] According to such a work vehicle 1, in an electric control brake operation configuration in which the brake is operated by a brake signal issued by the brake signal generating unit 54, since there is a mechanism for mechanically adjusting (fixing) the pulling operation of the brake operating tool 60 in front of the brake signal generating unit 54, for example, even when the power supply of the electric motor 41 is unintentionally cut off (turned off), the brake (so-called parking brake) state is maintained. Also, even when the power supply of the electric motor 41 is turned on again after being cut off (turned off), the brake (parking brake) state is not automatically reset. That is, the certainty of brake operation can be enhanced, thereby improving safety.

[0080] (2) In the above (1), the braking mechanism 50 of the work vehicle 1 has a fixing release mechanism 59 that can release the electric actuator 30 fixed at the braking position by manual operation when the brake is actuated on the traveling vehicle body 2.

[0081] According to such a work vehicle 1, in addition to the effect of the above (1), for example, even when the power supply of the electric motor 41 cannot be restored, the fixing of the electric actuator 30 can be released by manual operation.

[0082] (3) In the above (1) or (2), a traveling speed detection unit S6 that detects the traveling speed of the traveling vehicle body 2 by the electric motor 41, a parking brake detection unit S7 that detects the brake position of the brake operating tool 60, a seat detection unit S3 that detects the driver's departure from the driver's seat 241 of the work vehicle 1, and a brake determination unit 110 that determines whether to activate the automatic brake by the electric actuator 30 when a predetermined condition is satisfied, and the predetermined condition is the detection of the speed exceeding of the traveling vehicle body 2 by the traveling speed detection unit S6, the work vehicle 1.

[0083] According to such a work vehicle 1, in addition to the effect of the above (1) or (2), for example, even when the electric motor 41 becomes uncontrollable, the traveling vehicle body 2 can be safely stopped without depending on the driver's operation. Also, the convenience can be improved by automatically activating the parking brake.

[0084] (4) In any of the above (1) to (3), a traveling speed detection unit S6 that detects the traveling speed of the traveling vehicle body 2 by the electric motor 41, a parking brake detection unit S7 that detects the brake position of the brake operating tool 60, a seat detection unit S3 that detects the driver's departure from the driver's seat of the work vehicle 1, and a brake determination unit 110 that determines whether to activate the automatic brake by the electric actuator 30 when a predetermined condition is satisfied, and the predetermined condition is the detection of non-brake by the parking brake detection unit S7 and the detection of the driver's departure by the seat detection unit S3, the work vehicle 1.

[0085] According to such a work vehicle 1, in addition to any of the effects (1) to (3) above, when the driver leaves the driver's seat 241 without applying the parking brake, the traveling vehicle body 2 can be safely stopped without depending on the driver's operation. Further, the convenience can be improved by the automatic operation of the parking brake.

[0086] Further effects and modifications can be easily derived by those skilled in the art. For this reason, the broader aspects of the present invention are not limited to the specific details and representative embodiments shown and described above. Therefore, various changes can be made without departing from the spirit or scope of the general inventive concept defined by the appended claims and their equivalents.

Explanation of Signs

[0087] 1 Work vehicle 2 Traveling vehicle body 3 Working machine 28 Foot pedal 29 Hand lever 30 Electric actuator 41 Electric motor 50 Brake mechanism 54 Brake signal generation unit 57 Pulling force unit 58 Pulling position fixing unit 59 Fixing release mechanism 60 Brake operating tool 110 Brake determination unit P1 Brake on position P2 Brake off position S3 Seat detection unit S6 Traveling speed detection unit S7 Parking brake detection unit

Claims

1. A work vehicle comprising a traveling vehicle body and a working machine, an electric motor that drives the traveling vehicle body, a brake mechanism that activates a brake on the traveling vehicle body, a brake operating tool including at least one of a hand lever and a foot pedal, and an electric actuator, which is operated when the brake mechanism activates a brake on the traveling vehicle body and comprising wherein the brake mechanism is configured such that a brake is activated inside the electric motor when the power supply of the electric motor is turned off, has a brake-on position and a brake-off position, the brake-on position and the brake-off position are switchable, and when switched to the brake-on position, a brake signal generation unit that emits a brake signal to turn off the power supply of the electric motor, a pull substitution unit provided between the brake operating tool and the brake signal generation unit, and when the brake operating tool is pulled, the pull position moves to a predetermined position so as to switch the brake signal generation unit to the brake-on position, a pull position fixing unit provided in the pull substitution unit to fix the pull position of the pull substitution unit to the predetermined position by the pull operation of the brake operating tool and having characterized by a work vehicle.

2. The brake mechanism has a fixing release mechanism that can manually release the electric actuator fixed in the brake position when a brake is activated on the traveling vehicle body. The work vehicle according to claim 1, characterized by this.

3. A traveling speed detection unit that detects the traveling speed of the traveling vehicle body by the electric motor, a parking brake detection unit that detects the brake position of the brake operating tool, a seat detection unit that detects the departure of the driver of the work vehicle from the driver's seat, a brake determination unit that determines whether to activate an automatic brake by the electric actuator when a predetermined condition is satisfied and comprising wherein the predetermined condition is detection of speed excess of the traveling vehicle body by the traveling speed detection unit. The work vehicle according to claim 1 or 2, characterized by this.

4. A traveling speed detection unit that detects the traveling speed of the traveling vehicle body by the electric motor, a parking brake detection unit that detects the brake position of the brake operating tool, a seat detection unit that detects the departure of the driver of the work vehicle from the driver's seat, A brake determination unit that determines whether to activate the automatic brake by the electric actuator when a predetermined condition is satisfied is provided, wherein the predetermined condition is detection of non-braking by the parking brake detection unit and detection of the driver leaving the seat by the seat detection unit The work vehicle according to claim 1 or 2, characterized in that.

Images