JP6757759B2 - Work vehicle - Google Patents

Description

The present invention relates to a work vehicle such as a wheel loader, and more particularly to a work vehicle having a monitoring function for detecting an obstacle behind the vehicle body.

A wheel loader, which is an example of a work vehicle, is connected to the front side of the rear body so that the front body can swing in the left-right direction, and a front work machine (cargo handling device) consisting of a lift arm, a bucket, etc. is attached to the front body. Has been done. Further, a driver's cab is provided in the front part of the rear vehicle body, and an engine room and a counterweight are provided in the rear part of the rear vehicle body. A work machine lever, accelerator pedal, etc. are arranged inside the driver's cab, and the operator in the driver's cab operates the work machine lever and accelerator pedal to operate the front work machine for excavation, loading, etc. It is designed to perform various tasks.

Conventionally, in order to prevent contact accidents between a work vehicle such as a wheel loader and an obstacle existing in the vicinity, an image pickup device, a radar device, etc. are used to grasp the situation around the vehicle, and an operator is based on the result. There is known a technique that enables the detection of the presence or absence of obstacles existing around the work vehicle.

For example, in Patent Document 1, a camera that captures an image within the monitoring range and a sensor that detects an obstacle existing within the monitoring range are installed at the rear of the upper swivel body constituting the vehicle body of the hydraulic excavator. A surrounding monitoring device that displays a camera image and an image with a mark emphasizing obstacles drawn on the display device in the driver's cab and emits an alarm to notify the operator of the presence of obstacles is disclosed. There is.

Further, in Patent Document 2, an object detection device for detecting an object existing behind the vehicle body of the dump truck is provided, an alarm is notified to the operator based on the detection result of the object detection device, and the vessel stands up. A surrounding monitoring device that does not execute an alarm when the cargo is discharged is disclosed.

Japanese Unexamined Patent Publication No. 2008-179940 Japanese Patent No. 5595565

If the technology described in Patent Document 1 and Patent Document 2 is applied to the wheel loader and an obstacle sensor is mounted on the vehicle body to detect the rear situation, the vehicle body is used during excavation work or running of the wheel loader. It is possible to notify the operator that there is an obstacle behind the. However, at the time of scooping work (work of scooping earth and sand into the bucket while running the car body, and then pushing the excavated earth and sand to the upper part or the other side of the mountain while climbing the ground as it is), which is a unique work of the wheel loader. Since the vehicle body climbs a mountain that slopes with respect to the ground, there is a problem that the obstacle sensor mounted on the vehicle body erroneously detects the ground behind as an obstacle.

The present invention has been made from the actual situation of such a prior art, and an object of the present invention is to provide a work vehicle capable of accurately informing an operator of the presence or absence of an obstacle existing behind a vehicle body.

In order to achieve the above object, the present invention typically includes a vehicle body, a driver's cab mounted on the vehicle body, an alarm device installed in the driver's cab, and a control device for controlling the alarm device. , An obstacle sensor that detects an obstacle existing behind the vehicle body, a lift arm connected to the front portion of the vehicle body, an arm cylinder that rotates the lift arm in the vertical direction, and a tip of the lift arm. In a work vehicle including a bucket connected to a bucket and a bucket cylinder for rotating the bucket in the vertical direction, the control device includes a gradient detecting unit for calculating or measuring a vehicle body gradient angle of the vehicle body, and the gradient. A gradient determination unit that compares the vehicle body gradient angle calculated or measured by the detection unit with a preset reference gradient angle, and an alarm that executes a notification process that activates the alarm device based on the detection result of the obstacle sensor. A control unit is provided, and the alarm control unit is characterized in that when the vehicle body gradient angle exceeds the reference gradient angle, the notification process based on the detection result of the obstacle sensor is invalidated.

According to the work vehicle according to the present invention, it is possible to accurately notify the operator of the presence or absence of an obstacle existing behind the vehicle body. Issues, configurations, and effects other than those described above will be clarified by the following description of the embodiments.

It is a side view of the wheel loader which concerns on embodiment of this invention. It is a side view explaining the scooping work of the wheel loader which concerns on embodiment. It is a block diagram of the control device which concerns on 1st Example. It is a flowchart which shows the processing content of the control device shown in FIG. It is a block diagram of the control device which concerns on 2nd Example. It is a flowchart which shows the processing content of the control device shown in FIG.

Hereinafter, embodiments of the wheel loader according to the present invention will be described with reference to FIGS. 1 to 6.

FIG. 1 is a side view of the wheel loader 1 according to the embodiment of the present invention. As shown in FIG. 1, the wheel loader 1 has a front vehicle body (vehicle body) 5 having a lift arm 2, a bucket 3, tires 4, and the like, and a rear vehicle body (vehicle body) having a driver's cab 6, an engine chamber 7, tires 8, and the like. ) It is composed of 9. An engine (not shown) is mounted in the engine chamber 7, and a counterweight 10 is mounted behind the rear vehicle body 9.

The lift arm 2 rotates in the vertical direction (depression and elevation) by driving the arm cylinder 11, and the bucket 3 rotates in the vertical direction (cloud or dump) by driving the bucket cylinder 12. A link mechanism including a bell crank 13 is interposed between the bucket cylinder 12 and the bucket 3, and the bucket cylinder 12 rotates the bucket 3 through the link mechanism. The front working machine (cargo handling device) is composed of the lift arm 2, the bucket 3, the arm cylinder 11, the bucket cylinder 12, the bell crank 13, and the like.

An arm angle sensor 14 is attached to a connecting portion between the lift arm 2 and the front vehicle body 5, and the rotation angle of the lift arm 2 is detected by the arm angle sensor 14. The arm cylinder 11 includes a pressure sensor 15, and the pressure sensor 15 detects the working machine pressure applied to the front working machine. The bucket cylinder 12 includes a proximity switch 16, and when the rod of the bucket cylinder 12 is shortened by a predetermined amount, the proximity switch 16 is turned on.

The front vehicle body 5 and the rear vehicle body 9 are rotatably connected to each other by a center pin 17, and the front vehicle body 5 is bent left and right with respect to the rear vehicle body 9 due to expansion and contraction of a steering cylinder (not shown). The driver's cab 6 mounted on the front of the rear vehicle body 9 includes a driver's seat on which the operator sits, a steering wheel that controls the steering angle of the wheel loader 1, a key switch that starts and stops the wheel loader 1, and information to the operator. Display devices (none of which are shown) and the like are installed.

An obstacle sensor 18 is installed at a predetermined position at the rear of the rear vehicle body 9, for example, at a counterweight 10. The obstacle sensor 18 is a sensor that detects the presence or absence of an obstacle existing behind the rear vehicle body 9 by using a millimeter-wave radar, a laser beam (three-dimensional laser), or the like, and the obstacle is another work vehicle. Workers and related persons who enter and leave the work site, structures at the work site, etc. The detection signal of the obstacle sensor 18 is taken into the control device 19 described later shown in FIG. 3, and the control device 19 calculates the gradient angle of the vehicle body (front vehicle body 5 and rear vehicle body 9) to obtain the calculated vehicle body gradient angle. Based on this, the output of the control signal to the alarm device 20 is controlled. The obstacle sensor 18 may be provided on the rear grille which is the rearmost cover of the engine chamber 7.

The wheel loader 1 according to the present embodiment performs various operations such as excavation and loading in addition to the traveling operation of traveling the front vehicle body 5 and the rear vehicle body 9, and as an example of such operations, FIG. The case of performing "raising work" is shown. Specifically, after scooping the earth and sand into the bucket 3 while running the front body 5 and the rear body 9, the excavated earth and sand is pushed to the upper part or the other side of the mountain while climbing the ground M as it is. The operation is shown.

Hereinafter, the above-mentioned control device 19 will be described. FIG. 3 is a block diagram of the control device 19 according to the first embodiment. As shown in FIG. 3, the control device 19 includes a gradient detection unit 21, a storage unit 22, a gradient determination unit 23, and an alarm control unit 24. Various processes by the control device 19 are realized by a CPU (not shown) loading a program stored in a storage device such as an HDD into a memory and executing the program.

A detection signal of the IMU (Inertial Measurement Unit) 25 that detects the vehicle body angular velocity and the vehicle body acceleration and a detection signal of the vehicle speed sensor 26 that detects the vehicle speed are input to the gradient detection unit 21, and the gradient detection unit 21 receives these IMU 25s. And the vehicle body gradient angle θ1 is calculated based on the detection signal of the vehicle speed sensor 26. When the vehicle body gradient angle θ1 is calculated using the IMU (Inertial Measurement Unit) 25 and the vehicle speed sensor 26 in this way, a highly accurate vehicle body gradient excluding the influence of the road surface gradient can be estimated, but instead of these IMU 25 and the vehicle speed sensor 26. It is also possible to measure the vehicle body gradient angle θ1 using an inclination sensor.

A predetermined reference gradient angle θ (for example, 10 degrees) is stored in the storage unit 22. The reference gradient angle θ is a preset invariant value, but it is also possible to allow the operator to change the value of the reference gradient angle θ by using an input device (not shown) and store the value in the storage unit 22. is there.

The gradient determination unit 23 compares the magnitude of the vehicle body gradient angle θ1 calculated by the gradient detection unit 21 with the reference gradient angle θ stored in the storage unit 22, and outputs the determination result to the alarm control unit 24.

The detection signal of the obstacle sensor 18 is input to the alarm control unit 24, and the alarm control unit 24 outputs a predetermined control signal to the alarm device 20 based on the determination result of the gradient determination unit 23. The obstacle sensor 18 constantly detects the presence or absence of an obstacle, and inputs the detection signal to the alarm control unit 24.

Specifically, when the vehicle body gradient angle θ1 does not exceed the reference gradient angle θ, the alarm control unit 24 sends the detection signal when the obstacle sensor 18 detects an obstacle existing behind the rear vehicle body 9. Based on this, an operation signal is output to the alarm device 20. On the other hand, when the vehicle body gradient angle θ1 exceeds the reference gradient angle θ, the alarm control unit 24 does not output an operation signal to the alarm device 20 regardless of whether or not there is an obstacle behind the rear vehicle body 9. It has become like.

The alarm device 20 includes a speaker and an alarm device installed in the driver's cab 6, and when an operation signal is input from the alarm control unit 24, the alarm device 20 generates a warning sound such as a speaker sound or an alarm sound to notify the operator. .. The alarm device 20 only needs to be able to notify the operator in the driver's cab 6 that an obstacle exists behind the rear vehicle body 9, and is not only an auditory notification using a speaker sound or an alarm sound, but also a display device. It may be a visual notification using the display screen of.

Next, the control operation of the control device 19 will be described with reference to the flowchart shown in FIG.

When the wheel loader 1 is in an operable state, that is, when the key switch (not shown) is in the start state (at the time of start), the control device 19 starts the process shown in FIG. First, the gradient detection unit 21 calculates the vehicle body gradient angle θ1 based on the detection signals of the IMU 25 and the vehicle speed sensor 26 (step S1).

Next, the gradient determination unit 23 compares the vehicle body gradient angle θ1 calculated by the gradient detection unit 21 with the reference gradient angle θ stored in the storage unit 22, and the vehicle body gradient angle θ1 exceeds the reference gradient angle θ. It is determined whether or not it is (step S2).

If it is determined in step S2 that the vehicle body gradient angle θ1 does not exceed the reference gradient angle θ (No in step S2), the alarm control unit 24 proceeds to step S3.

In step S3, the alarm control unit 24 is controlled to allow the output of the operation signal to the alarm device 20, and the notification process is enabled. When the obstacle sensor 18 detects an obstacle existing behind the rear vehicle body 9 in this state, the alarm device 20 is activated by the operation signal, and the alarm device 20 emits a warning sound such as a speaker sound or an alarm sound. Since it occurs, the operator in the driver's cab 6 can grasp the presence of an obstacle by a warning sound.

On the other hand, in step S2, when it is determined that the vehicle body gradient angle θ1 exceeds the reference gradient angle θ (Yes in step S2), the alarm control unit 24 determines whether or not there is an obstacle behind the rear vehicle body 9. Regardless of this, the operation signal output to the alarm device 20 is controlled to the disallowed state, and the notification process is invalidated. (Step S4), whereby the alarm device 20 maintains a non-operating state in which no warning sound is generated. After that, when the vehicle body gradient angle θ1 becomes equal to or less than the reference gradient angle θ, the process proceeds from step S2 to step S3, and the alarm control unit 24 is controlled to allow the output of the operation signal to the alarm device 20 for notification. The process becomes effective, and the alarm device 20 operates in response to the signal from the obstacle sensor 18.

In the wheel loader 1 according to the present embodiment, as shown in FIG. 1, the postures of the vehicle bodies (front vehicle body 5 and rear vehicle body 9) are maintained substantially parallel to the ground P during traveling and excavation work, which is an obstacle. When the object sensor 18 detects an obstacle such as a worker or a structure existing behind the rear vehicle body 9, the alarm device 20 is activated to notify the operator in the driver's cab 6 of the existence of the obstacle. Can be done.

On the other hand, when the wheel loader 1 is performing the "raising work", as shown in FIG. 2, the front vehicle body 5 and the rear vehicle body 9 climb the ground M which is inclined with respect to the ground P, so that the rear portion The obstacle sensor 18 mounted on the rear part of the vehicle body 9 may erroneously detect the ground P as an obstacle. In the wheel loader 1 according to the present embodiment, when the vehicle body gradient angle θ1 of the vehicle body climbing the ground M exceeds a preset reference gradient angle θ during such “raising work”, the alarm control unit 24 Does not output an operation signal to the alarm device 20, so that even if the obstacle sensor 18 recognizes the ground P as an obstacle, the alarm will not be given. After that, when the vehicle body gradient angle θ1 becomes equal to or less than the reference gradient angle θ, the alarm control unit 24 is allowed to output the operation signal to the alarm device 20, so that the operator is based on the detection result of the obstacle sensor 18. Can grasp the presence or absence of obstacles existing behind the rear vehicle body 9.

FIG. 5 is a block diagram of the control device 27 according to the second embodiment, and the parts corresponding to FIG. 3 are designated by the same reference numerals.

As shown in FIG. 5, the control device 27 according to the second embodiment includes a gradient detection unit 21, a storage unit 22, a gradient determination unit 23, an alarm control unit 24, an attitude determination unit 28, and a pressure determination unit. It has 29 and.

A detection signal of the IMU 25 for detecting the vehicle body angular velocity and the vehicle body acceleration and a detection signal of the vehicle speed sensor 26 for detecting the vehicle speed are input to the gradient detection unit 21, and the gradient detection unit 21 receives the detection signals of the IMU 25 and the vehicle speed sensor 26. The vehicle body gradient angle θ1 is calculated based on.

The storage unit 22 stores a predetermined reference gradient angle θ (for example, 10 degrees), a predetermined reference arm angular velocity, and a predetermined reference working machine pressure, respectively. These reference gradient angles θ, reference arm angular velocities, and reference work machine pressures may be preset invariant values, but the operator can change each value using an input device (not shown), and set the values. It is also possible to store it in the storage unit 22. The reference arm angular velocity is set in consideration of the reaching height of the bucket during the lifting operation, which is performed while raising the arm, and is set to, for example, about 50% of the full operation.

The gradient determination unit 23 compares the magnitude of the vehicle body gradient angle θ1 calculated by the gradient detection unit 21 with the reference gradient angle θ stored in the storage unit 22, and outputs the determination result to the alarm control unit 24.

The posture determination unit 28 compares the angular velocity calculated from the rotation angle of the lift arm 2 detected by the arm angle sensor 14 with the reference arm angular velocity stored in the storage unit 22, and determines the determination result as an alarm control unit. Output to 24.

The pressure determination unit 29 compares the work machine pressure applied to the front work machine detected by the pressure sensor 15 with the reference work machine pressure stored in the storage unit 22, and outputs the determination result to the alarm control unit 24. ..

The detection signal of the obstacle sensor 18 is input to the alarm control unit 24, and the alarm control unit 24 sends the alarm device 20 to the alarm device 20 based on the determination results of the gradient determination unit 23, the attitude determination unit 28, and the pressure determination unit 29. Controls whether or not to allow the output of a predetermined operation signal.

Next, the control operation of the control device 27 will be described with reference to the flowchart shown in FIG.

When the wheel loader 1 becomes operable, the control device 27 starts the process shown in FIG. First, the gradient detection unit 21 calculates the vehicle body gradient angle θ1 based on the detection signals of the IMU 25 and the vehicle speed sensor 26 (step S11).

Next, the gradient determination unit 23 compares the vehicle body gradient angle θ1 calculated by the gradient detection unit 21 with the reference gradient angle θ stored in the storage unit 22, and the vehicle body gradient angle θ1 exceeds the reference gradient angle θ. It is determined whether or not it is (step S12).

If it is determined in step S12 that the vehicle body gradient angle θ1 does not exceed the reference gradient angle θ (No in step S12), the process proceeds to step S13.

In step S13, the alarm control unit 24 controls the operation signal output to the alarm device 20 from the disallowed state to the permitted state, and the notification process becomes effective. When an obstacle is detected by the obstacle sensor 18, an operation signal is output to the alarm device 20, and a warning sound such as a speaker sound or an alarm sound is generated from the alarm device 20, so that the operator in the driver's cab 6 can use it. The presence of obstacles can be grasped by the warning sound.

On the other hand, in step S12, when it is determined that the vehicle body gradient angle θ1 exceeds the reference gradient angle θ (Yes in step S12), the attitude determination unit 28 rotates the lift arm 2 detected by the arm angle sensor 14. The arm angular velocity based on the moving angle is compared with the reference arm angular velocity stored in the storage unit 22, and it is determined whether or not the arm angular velocity of the lift arm 2 is equal to or higher than the set reference arm angular velocity (step S14).

In step S14, when it is determined that the arm angular velocity is less than the reference arm angular velocity (No in step S14), the process returns to step S11, and when it is determined that the arm angular velocity is equal to or greater than the reference arm angular velocity (Yes in step S14). Proceeds to step S15.

In step S15, the pressure determination unit 29 compares the work machine pressure applied to the front work machine detected by the pressure sensor 15 with the reference work machine pressure stored in the storage unit 22, and the work machine pressure of the front work machine. Is determined whether or not is equal to or higher than the set reference working machine pressure. Then, when it is determined that the working machine pressure of the front working machine is less than the reference working machine pressure (No in step S15), the process returns to step S11, and the working machine pressure of the front working machine is equal to or higher than the standard working machine pressure. If it is determined (Yes in step S15), the process proceeds to step S16.

In step S16, the alarm control unit 24 controls the output of the operation signal to the alarm device 20 from the permitted state to the disallowed state, and invalidates the notification process. Therefore, the alarm device 20 is in a non-operating state without generating a warning sound. After that, when the vehicle body gradient angle θ1 becomes equal to or less than the reference gradient angle θ, the process proceeds from step S12 to step S13, and the alarm control unit 24 transfers the output of the operation signal to the alarm device 20 from the disallowed state to the permitted state. And enable the notification processing.

As described above, in the control device 27 according to the second embodiment, not only the magnitude of the vehicle body inclination angle by the gradient determination unit 23 but also the attitude determination unit 28 allows or disallows the operation signal output to the alarm device 20. Since the posture of the front work machine by the above and the work machine pressure of the front work machine by the pressure determination unit 29 are taken into consideration, the difference between the "raising work" operation of the wheel loader 1 and other operations can be accurately recognized. be able to. For example, the "simple running operation" and the "running operation during work" are distinguished based on the posture determination unit 28 that determines the arm angular velocity of the lift arm 2, and the pressure determination that determines the working machine pressure applied to the scooping front work machine. Since the "excavation operation" and the "non-excavation operation" are distinguished based on the part 29, the obstacle sensor 18 erroneously detects the ground P behind as an obstacle during the "raising work" due to the combination of these. Can be prevented.

In the control device 27 according to the second embodiment, either the attitude determination unit 28 or the pressure determination unit 29 is omitted, and the alarm control unit 24 permits or disallows the output of the operation signal to the alarm device 20. As a determination condition, only one of the posture of the front work machine by the posture determination unit 28 and the work machine pressure of the front work machine by the pressure determination unit 29 is added to the magnitude of the vehicle body inclination angle by the gradient determination unit 23. You may do so.

Further, in the control device 27 according to the second embodiment, the posture determination unit 28 determines the posture of the front work machine based on the arm angular velocity of the lift arm 2, but the arm angular velocity of the lift arm 2 and the bucket of the bucket 3 The posture of the front working machine may be determined based on both the angle and the angle. Specifically, it can be determined whether or not the bucket 3 exceeds a predetermined set angle based on the operation signal of the proximity switch 16, and if the bucket 3 exceeds the set angle, it can be determined as "hopper loading operation". Therefore, it is distinguished from the "raising work", and it is possible to more accurately prevent an erroneous alarm by the alarm device 20 during the hoisting work. Further, although the bucket angle is detected by the proximity switch 16, the rotation angle of the bucket 3 may be detected by the angle sensor.

In the wheel loader 1 according to the above embodiment, when the vehicle body gradient angle θ1 exceeds the reference gradient angle θ, the alarm control unit 24 permits or disallows the output of the operation signal to the alarm device 20. However, by stopping the operation of the obstacle sensor 18, the obstacle may not be detected and the alarm device 20 may not generate a warning sound.

Further, in the first embodiment, the "raising work" is determined by the "vehicle body gradient angle", but the "vehicle body forward motion" can be added in addition to the "vehicle body gradient angle". In this case, the "forward movement of the vehicle body" can be detected by switching the forward / backward changeover switch (not shown) to forward, or by the vehicle speed and the speed stage information of the transmission.

In addition, when the "raising work" is judged, the operation signal output to the alarm device 20 is disallowed to prevent erroneous detection of the ground, and when the slope angle of the vehicle body becomes equal to or less than the reference slope angle, The operation signal output to the alarm device 20 is permitted, but considering that the scooping work is often repeated in a certain period of time, the operation signal output to the alarm device 20 is disallowed and then constant. It is also possible to allow the operation signal output to the alarm device 20 after an hour.

Moreover, the above-described embodiment is an example for the purpose of explaining the present invention, and it is not intended to limit the scope of the present invention only to those embodiments. One of ordinary skill in the art can carry out the present invention in various other aspects without departing from the gist of the present invention.

1 Wheel loader (work vehicle)
2 Lift arm 3 Bucket 4, 8 Tire 5 Front body (body)
6 Driver's cab 9 Rear vehicle body 11 Arm cylinder 12 Bucket cylinder 13 Bell crank 14 Arm angle sensor 15 Pressure sensor 16 Proximity switch 18 Obstacle sensor 19, 27 Control device 20 Alarm device 21 Gradient detection unit 22 Storage unit 23 Gradient judgment unit 24 Alarm Control unit 25 IMU (Inertial measurement unit)
26 Vehicle speed sensor 28 Posture judgment unit 29 Pressure judgment unit

Claims (4)

A vehicle body, a driver's cab mounted on the vehicle body, an alarm device installed in the driver's cab, a control device for controlling the alarm device, and an obstacle sensor for detecting an obstacle existing behind the vehicle body. A lift arm connected to the front portion of the vehicle body, an arm cylinder for rotating the lift arm in the vertical direction, a bucket connected to the tip of the lift arm, and the bucket being rotated in the vertical direction. In a work vehicle equipped with a bucket cylinder
The control device is
A gradient detection unit that calculates or measures the vehicle body gradient angle of the vehicle body,
A gradient determination unit that compares the vehicle body gradient angle calculated or measured by the gradient detection unit with a preset reference gradient angle.
It is provided with an alarm control unit that executes an alarm process for operating the alarm device based on the detection result of the obstacle sensor.
The alarm control unit is a work vehicle characterized in that when the vehicle body gradient angle exceeds the reference gradient angle, the notification process based on the detection result of the obstacle sensor is invalidated. In the work vehicle according to claim 1,
The control device further includes a posture determining unit for determining whether or not the arm angular velocity of the lift arm is equal to or higher than a predetermined angular velocity.
When the vehicle body gradient angle exceeds the reference gradient angle and the arm angular velocity of the lift arm is equal to or higher than a predetermined angular velocity, the alarm control unit invalidates the notification process based on the detection result of the obstacle sensor. A work vehicle characterized by doing. In the work vehicle according to claim 1,
The control device further includes a pressure determination unit for determining whether or not the cylinder pressure of the arm cylinder is equal to or higher than a predetermined pressure.
The alarm control unit invalidates the notification process based on the detection result of the obstacle sensor when the vehicle body gradient angle exceeds the reference gradient angle and the cylinder pressure of the arm cylinder is equal to or higher than a predetermined pressure. A work vehicle characterized by doing. In the work vehicle according to claim 1,
The control device includes a posture determination unit that determines whether or not the arm angular velocity of the lift arm is equal to or higher than a predetermined angular velocity, and a pressure determination unit that determines whether or not the cylinder pressure of the arm cylinder is equal to or higher than a predetermined pressure. Is further equipped with
The alarm control unit is described when the vehicle body gradient angle exceeds the reference gradient angle, the arm angular velocity of the lift arm is equal to or higher than a predetermined angular velocity, and the cylinder pressure of the arm cylinder is equal to or higher than a predetermined pressure. A work vehicle characterized in that the notification process based on the detection result of an obstacle sensor is invalidated.

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