JP2021050535A - Work vehicle - Google Patents

Abstract

To provide a work vehicle allowing a posture of a vehicle body to be adequately and automatically adjusted without being affected from the surrounding environment.SOLUTION: Adjustment of a work vehicle comprises: actuating a height adjustment cylinder in either one of an extension direction and a contraction direction (S13) till an angle β detected with an angle sensor is not changed (S14:Yes); and actuating the height adjustment cylinder in the other of the extension direction and the contraction direction (S16) till the angle β detected with the angle sensor reaches a threshold value {βmax-(αmax-α)} (S17:No) where a value of the angle β when the angle β no longer changes is set to an angle βmax (S15).SELECTED DRAWING: Figure 5

Description

The present invention relates to a work vehicle whose vehicle height can be automatically adjusted.

Conventionally, a work vehicle whose height can be adjusted by expanding and contracting a cylinder between a vehicle body and a front axle has been known. As a method of using the vehicle height adjustment function, for example, the cylinder is extended to separate the vehicle body from the road surface when traveling on rough terrain, and the cylinder is contracted to stabilize the vehicle body when working with the front work machine. Can be considered.

As one of such work vehicles, Patent Document 1 discloses a technique for keeping the posture of the work vehicle constant by automatically adjusting the vehicle height. More specifically, the work vehicle described in Patent Document 1 automatically adjusts the vehicle height according to the difference between the distance between the vehicle body and the axle detected by the distance detector and the predetermined set distance.

Japanese Unexamined Patent Publication No. 7-132723

The distance detector described in Patent Document 1 has a structure that directly detects the distance between the vehicle body and the axle. Therefore, the distance detector exposed at the lower part of the vehicle body may be damaged due to collision of gravel or the like rolled up by the tire when the work vehicle travels on rough terrain, for example. That is, the vehicle height automatic adjustment function described in Patent Document 1 has a problem that it is easily affected by the environment around the work vehicle.

The present invention has been made in view of the above-mentioned actual conditions, and an object of the present invention is to provide a work vehicle capable of appropriately and automatically adjusting the posture of a vehicle body without being affected by the surrounding environment.

In order to achieve the above object, the present invention comprises adjusting the height of the vehicle body, a front axle that rotatably supports the wheels in the lower front portion of the vehicle body, and a rear axle that rotatably supports the wheels in the lower rear portion of the vehicle body. A work vehicle including a vehicle height adjusting mechanism that adjusts the vertical distance between the vehicle body and the front axle by expanding and contracting the cylinder, and a target angle of the vehicle body when the work vehicle is driven on a horizontal plane. _{A storage device that stores an angle α max} , which is the angle α max of the vehicle body when the height adjusting cylinder is operated to the maximum in one of extension and contraction on the horizontal plane, and an actual actual vehicle body with respect to the horizontal plane. It includes an angle sensor that detects an angle β, which is an angle, and a controller that controls the vehicle height adjustment mechanism, and the controller is either stretched or contracted until the angle β detected by the angle sensor does not change. When the height adjusting cylinder is operated and the value of the angle β when it does not change is set to the angle β _max , the angle β detected by the angle sensor becomes the threshold angle {β _max − (α _max − α)}. It is characterized in that the height adjusting cylinder is operated on the other side of extension and contraction until it is reached.

According to the present invention, the posture of the vehicle body can be appropriately and automatically adjusted without being affected by the surrounding environment. 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 hydraulic excavator which is a typical example of the work vehicle which concerns on this embodiment. It is a schematic diagram of a vehicle height adjustment mechanism. It is a figure which shows the outrigger of the overhanging posture. It is a hardware block diagram of a hydraulic excavator. It is a flowchart of a vehicle height adjustment process. It is a figure which shows the angle α, α _max1 , α _max2. It is a figure which shows the angle β, β _max1 , β _max2. It is a flowchart of a running control process.

An embodiment of a work vehicle according to the present invention will be described with reference to the drawings. FIG. 1 is a side view of a hydraulic excavator 1 which is a typical example of a work vehicle according to the present embodiment. Unless otherwise specified, the front, rear, left, and right directions in this specification are based on the viewpoint of the operator who operates the hydraulic excavator 1. Further, the specific example of the work vehicle is not limited to the hydraulic excavator 1, and the present invention can be applied to a dump truck, a wheel loader, a crane vehicle, and the like.

The hydraulic excavator 1 includes a lower traveling body 2 and an upper rotating body 3 supported by the lower traveling body 2. The lower traveling body 2 and the upper turning body 3 are examples of a vehicle body.

The lower traveling body 2 rotatably supports a pair of left and right front wheels 8f at the front lower portion of the lower traveling body 2 and a pair of left and right rear wheels 8r at the rear lower portion of the lower traveling body 2. It mainly has a rear axle 9r. The front wheels 8f and the rear wheels 8r (hereinafter, these are collectively referred to as "wheels 8") rotate by transmitting the driving force of the traveling motor 22 (FIG. 4). As a result, the lower traveling body 2 travels.

Further, the lower traveling body 2 includes a vehicle height adjusting mechanism 10. FIG. 2 is a schematic view of the vehicle height adjusting mechanism 10. The vehicle height adjusting mechanism 10 is arranged between the lower traveling body 2 and the front axle 9f, and adjusts the vertical distance between the lower traveling body 2 and the front axle 9f. On the other hand, in the hydraulic excavator 1 according to the present embodiment, the vertical distance between the lower traveling body 2 and the rear axle 9r is fixed.

As shown in FIG. 10, the vehicle height adjusting mechanism 10 mainly includes a link 11 and a pair of left and right height adjusting cylinders 12R and 12L. The link 11 supports the front axle 9f so as to be swingable in the left-right direction with respect to the lower traveling body 2. More specifically, one end (upper end) of the link 11 is swingably connected to the lower surface of the lower traveling body 9. The other end (lower end) of the link 11 is swingably connected to the center of the front axle 9f.

The pair of left and right height-adjusting cylinders 12R and 12L (hereinafter, these are collectively referred to as "height-adjusting cylinder 12") expand and contract to expand and contract the distance between the lower traveling body 2 and the front axle 9f in the vertical direction. To change. More specifically, one end (bottom side) of the height adjusting cylinder 12 is swingably connected to the lower traveling body 2. The other end (rod side) of the height adjusting cylinder 12 is swingably connected to the front axle 9f.

Then, when the hydraulic oil is supplied to the bottom chamber of the height adjusting cylinder 12 and is extended, the link 11 swings clockwise in FIG. 2, and the distance between the lower traveling body 2 and the front axle 9f becomes longer in the vertical direction. .. On the other hand, when hydraulic oil is supplied to the rod chamber of the height adjusting cylinder 12 and contracts, the link 11 swings counterclockwise in FIG. 2, and the vertical distance between the lower traveling body 2 and the front axle 9f becomes short. Become.

Further, the lower traveling body 2 includes an outrigger 13f provided at the front end of the lower traveling body 2 and an outrigger 13r provided at the rear end of the lower traveling body 2. FIG. 3 is a diagram showing the outriggers 13r in the overhanging posture. The outriggers 13f and 13r (hereinafter, collectively referred to as "outriggers 13") project to the left and right of the lower traveling body 2 due to the expansion and contraction of the hydraulic cylinder, and are in contact with the road surface (FIG. 3). The posture can be changed to the retracted posture (FIG. 1) which is separated from the road surface and stored in the lower traveling body 2.

The upper swivel body 3 is supported by the lower traveling body 2 in a swivelable state by a swivel motor (not shown). The upper swivel body 3 includes a swivel frame 5 as a base, a front working machine 4 rotatably attached to the center of the front end of the swivel frame 5 in the vertical direction, and a counterweight 6 arranged at the rear of the swivel frame 5. A cab (driver's seat) 7 arranged on the front left side of the turning frame 5 and an engine building 14 are mainly provided.

The front working machine 4 has a boom 4a undulatingly supported by the upper swing body 3, a first arm 4b swingably supported by the tip of the boom 4a, and swingable by the tip of the first arm 4b. A hydraulic cylinder 4e to drive a supported second arm 4c, a bucket 4d swingably supported at the tip of the second arm 4c, a boom 4a, a first arm 4b, a second arm 4c, and a bucket 4d. Including 4h. The counter weight 6 is for balancing the weight with the front working machine 4, and is a heavy object attached to the rear end of the upper swing body 3.

The cab 7 is formed with an internal space on which an operator who operates the hydraulic excavator 1 is boarded. Inside the cab 7, a seat on which the operator is seated (not shown) and an operating device (steering, pedal, lever, switch, etc.) operated by the operator seated on the seat are arranged. Then, when the operator on the cab 7 operates the operating device, the lower traveling body 2 travels, the upper rotating body 3 turns, the front working machine 4 operates, and the outrigger 13 changes its posture.

More specifically, the operating device includes an outrigger switch 7a (see FIG. 4) that changes the posture of the outrigger 13 and a lock switch 7b (see FIG. 4) that locks the outrigger 13 in the retracted posture. Then, the operation device outputs an operation signal corresponding to the operation of the operator to the controller 30 (see FIG. 4).

The engine building 14 is provided on the swivel frame 5 behind the front work machine 4 and the cab 7 and in front of the counterweight 6. The engine 21, the hydraulic pump 24, the direction switching valve 25, the angle sensor 26, and the like shown in FIG. 4 are housed in the internal space of the engine building 14. Further, the internal space of the engine building 14 is covered with a building cover. That is, the internal space of the engine building 14 is not easily affected by the environment around the hydraulic excavator 1 (for example, rough terrain, dust, rain, etc.).

FIG. 4 is a hardware configuration diagram of the hydraulic excavator 1. The hydraulic excavator 1 includes an engine 21, a traveling motor 22, a transmission 23, a hydraulic pump 24, a direction switching valve 25, an angle sensor 26, a display (display device) 27, and a controller 30.

The engine 21 generates a driving force for operating the hydraulic excavator 1. The traction motor 22 is rotated by electric power generated by a generator (not shown) using the rotational driving force of the engine 21. The transmission 23 shifts (decelerates) the rotational driving force of the engine 21, which is indirectly transmitted via the traveling motor 22, and transmits it to the wheels 8.

More specifically, the transmission 23 can switch between a low gear 23a that decelerates and transmits the driving force of the engine 21 to the wheels 8 and a high gear 23b that decelerates and transmits the driving force of the engine 21 to the wheels 8 at a reduction ratio lower than that of the low gear 23a. It is configured. The gear switching of the transmission 23 may be performed by the operation of the operator with respect to the operating device, or may be performed by the instruction of the controller 30 based on the detection result of the angle sensor 26.

The hydraulic pump 24 rotates by transmitting the rotational driving force of the engine 21, and the hydraulic oil stored in the hydraulic oil tank (not shown) is used as a hydraulic actuator (swivel motor, hydraulic cylinders 4e to 4h, height adjusting cylinder). 12, pumped to the out trigger 13). The directional control valve 25 is arranged in the oil passage of the hydraulic oil from the hydraulic pump 24 to each actuator. The direction switching valve 25 is configured to be able to switch the supply direction and supply amount of hydraulic oil to the corresponding hydraulic actuator according to the control of the controller 30. That is, there are as many direction switching valves 25 as there are hydraulic actuators mounted on the hydraulic excavator 1.

The angle sensor 26 detects the angle of the upper swivel body 3 (more specifically, the swivel frame 5) with respect to the horizontal plane, and outputs a detection signal indicating the detection result to the controller 30. More specifically, the angle sensor 26 detects the angle formed by _{the reference plane L 0} of the upper swing body 3 with respect to _{the horizontal plane L H.} The display 27 is installed in the cab 7. The display 27 is an example of a notification device that notifies an operator boarding the cab 7 of information.

The controller 30 includes a CPU (Central Processing Unit) 31, a ROM (Read Only Memory) 32, and a RAM (Random Access Memory) 33. The controller 30 realizes the processing described later by the CPU 31 reading and executing the program code stored in the ROM 32. The RAM 33 is used as a work area when the CPU 31 executes a program.

However, the specific configuration of the controller 30 is not limited to this, and may be realized by hardware such as an ASIC (Application Specific Integrated Circuit) and an FPGA (Field-Programmable Gate Array).

The controller 30 controls the directional control valve 25 that supplies hydraulic oil to the hydraulic cylinder of the outrigger 13 based on the operation signals output from the outrigger switch 7a and the lock switch 7b. More specifically, when the lock switch 7b is OFF, the controller 30 controls the direction switching valve 25 to change the posture of the outrigger 13 in response to the operator's operation on the outrigger switch 7a. On the other hand, when the lock switch 7b is ON, the controller 30 fixes the outrigger 13 in the retracted posture even if the outrigger switch 7a is operated.

Further, the controller 30 executes the vehicle height adjustment process based on the detection signal output from the angle sensor 26. FIG. 5 is a flowchart of the vehicle height adjustment process. FIG. 6 is a diagram showing _{angles α, α max1} , and α _max2. FIG. 7 is a diagram showing _{angles β, β max1} , and β _max2.

First, the controller 30 monitors the operation signal output from the lock switch 7b (S11). The controller 30 waits for the execution of the processing after step S12 while the lock switch 7b is OFF (S11: No). Then, when the controller 30 determines that the lock switch 7b has been switched to ON based on the operation signal (S11: Yes), the controller 30 acquires the angle β detected by the angle sensor 26 (S12).

The fact that the lock switch 7b is switched to ON is an example of the hydraulic excavator 1 being in the traveling posture. The traveling posture refers to a state suitable for driving the lower traveling body 2 to move the hydraulic excavator 1.

However, specific examples of the running posture are not limited to the above-mentioned examples. As another example, the fact that the outrigger switch 7a is operated and the outrigger 13 is in the retracted state may be set as the traveling posture of the hydraulic excavator 1. As yet another example, the traveling posture of the hydraulic excavator 1 may be defined as the turning angle of the upper swing body 3 being 0 ° (a state in which the front working machine 4 faces the forward direction of the lower traveling body 2).

Next, the controller 30 monitors the change in the angle β detected by the angle sensor 26 (S14) while contracting the height adjusting cylinder 12 (S13). That is, the controller 30 controls the direction switching valve 25 to supply hydraulic oil to the rod chamber of the height adjustment cylinder 12 (S13). Further, the controller 30 acquires the detection signal output from the angle sensor 26 at predetermined time intervals, and determines whether or not the angle β has changed (S14). That is, the controller 30 may determine whether or not the difference between the latest angle β and the immediately preceding angle β is within the threshold range (a minute range including 0 °).

The controller 30 continues contraction of the height adjustment cylinder 12 while the angle β is changing (S14: Yes) (S13). Then, when it is determined that the angle β does not change (S14: No), the controller 30 stops the contraction of the height adjusting cylinder 12. That is, the controller 30 contracts the height adjusting cylinder 12 to the maximum in steps S13 and S14.

Next, the controller 30 stores the latest angle β detected by the angle sensor 26 (that is, when the height adjusting cylinder 12 contracts to the maximum) in the _{RAM 33 as the angle β max} (S15). In the present embodiment, the angle beta _max1 shown in FIG. 2 is set as beta _max. The angle β _{max 1} refers to the angle of the upper swing body 3 with respect to _{the horizontal plane L H} when the height adjusting cylinder 12 is fully contracted.

Next, the controller 30 monitors the value of the angle β detected by the angle sensor 26 (S17) while extending the height adjusting cylinder 12 (S16). That is, the controller 30 controls the direction switching valve 25 to supply hydraulic oil to the bottom chamber of the height adjustment cylinder 12 (S16). Further, the controller 30 acquires the detection signal output from the angle sensor 26 at predetermined time intervals, _{and determines whether or not the angle β has reached the threshold angle {β max −} Δα} (S17).

The threshold angle is _{represented by the difference between the angle β max} set in step S15 and the predetermined angle difference Δα. The angle difference Δα according to the present embodiment is the difference between the angle α _max1 and the angle α shown in FIG. The angles α, α _max1 , and α _max2 are stored in advance in the ROM (storage device) 32.

The angle alpha, if placing the hydraulic excavator 1 on a horizontal surface L _H, the reference plane L ₀ angle of the upper swing body 3 with respect to the horizontal plane L _H (e.g., 0 °) is. The angle α is in the case of traveling the hydraulic excavator 1 on a horizontal plane L _H, it refers to the vertical orientation to direct the upper turning body 3. That is, the angle α is a target value for stably traveling the hydraulic excavator 1. Angle alpha _max1 refers to the angle between the reference plane L ₁ of the upper rotating body 3 with respect to the horizontal plane L _H when horizontal L _H on a tone high cylinder 12 is contracted to the maximum.

That is, the angular difference Δα refers to the angle difference to the case of placing the hydraulic excavator 1 on a horizontal surface L _H, a state in which tone high cylinder 12 suitable for traveling from a contracted state to the maximum. Further, the angle β _max corresponds to a value obtained by adding the angle γ (hereinafter, referred to as “inclination angle γ”) formed by the actual mounting surface of the hydraulic excavator 1 with respect to the horizontal plane to the angle α _max. As a result, the threshold angle {β _max -Δα} is the target angle of the upper frame 3 at the time of travel to stabilize the hydraulic excavator 1 on a horizontal plane L _H alpha, adds the inclination angle γ of the real placement surface Corresponds to the value.

The controller 30 continues to extend the height adjusting cylinder 12 until the angle β reaches the threshold angle (S17: No) (S16). Then, when the controller 30 determines that the angle β has reached the threshold angle (S17: Yes), the controller 30 stops the extension of the height adjustment cylinder 12. That is, in steps S16 and S17, the controller 30 extends the height adjusting cylinder 12 until _{the target angle {β max} −Δα} of the upper swing body 3 when the hydraulic excavator 1 is run on the road surface having the inclination angle γ is reached. Let me.

Next, the controller 30 causes the display 27 to display the value of the angle β finally acquired in step S17 (that is, the threshold angle {β _{max −} Δα}) (S18). Then, the controller 30 ends the vehicle height adjustment process.

Further, when the hydraulic excavator 1 starts traveling after the vehicle height adjustment processing is completed, the controller 30 executes the traveling control processing. FIG. 8 is a flowchart of the traveling control process. The travel control process is a process of controlling the transmission 23 according to the value of the inclination angle γ of the road surface on which the hydraulic excavator 1 travels.

First, the controller 30 acquires the angle β detected by the angle sensor 26 (S21). Next, the controller 30 determines whether or not the absolute value of the difference between the angle β acquired in step S21 and the angle α stored in the ROM 32 exceeds a predetermined threshold value (S22). That is, in step S22, the controller 30 determines whether or not the hydraulic excavator 1 is traveling on a steep uphill or a steep downhill.

Then, when the absolute values of the angle β and the angle α exceed the threshold value (S22: Yes), the controller 30 fixes the transmission 23 to the low gear 23a (S23). That is, the controller 30 automatically switches to the low gear 23a when the high gear 23b is selected in step S23. Further, even if the controller 30 accepts the operation of the operator to switch from the low gear 23a to the high gear 23b, the controller 30 does not switch.

On the other hand, when the absolute values of the angle β and the angle α are within the threshold value (S22: No), the controller 30 executes the processing of step S24 and subsequent steps without executing the processing of step S23. Then, the controller 30 repeatedly executes the processes of steps S21 to S23 while the hydraulic excavator 1 is running (S24: Yes). On the other hand, the controller 30 ends the traveling control process when the hydraulic excavator 1 is stopped (S24: No).

According to the above embodiment, for example, the following effects are exhibited.

According to the above embodiment, the vehicle height of the hydraulic excavator 1 can be adjusted based on the angle β of the upper swing body 3 detected by the angle sensor 26. The angle sensor 26 has a higher degree of freedom in installation position than the distance detector of Patent Document 1, and can be arranged in the engine building 14 surrounded by the building cover. As a result, the posture of the upper swing body 3 can be appropriately and automatically adjusted without being affected by the environment around the hydraulic excavator 1. However, the installation position of the angle sensor 26 is not limited to the inside of the engine building 14.

In the above embodiment, an example has been described in which the height adjusting cylinder 12 is first contracted to the maximum (S13), and then the height adjusting cylinder 12 is extended until the angle β reaches the threshold angle (S16). However, the height adjusting cylinder 12 may be first extended to the maximum (S13), and then the height adjusting cylinder 12 may be contracted until the angle β reaches the threshold angle (S16).

In this case, controller 30, in step S15, the angle beta _max2 reference plane _{L 2} of the upper rotating body 3 with respect to the horizontal plane _{L H} when adjusting high cylinder 12 is extended to the maximum, it is stored as the angle beta _max to RAM33 .. The angle difference Δα in step S17 is obtained by subtracting the angle alpha from the angle alpha _max2 of the reference plane L ₂ of the upper rotating body 3 with respect to the horizontal plane L _H when horizontal L _H on a tone high cylinder 12 is extended to a maximum Corresponds to the value.

That is, in steps S13 and S14, the controller 30 may operate the height adjusting cylinder 12 in either extension or contraction until the angle β detected by the angle sensor 26 does not change. Further, in steps S16 and S17, the controller 30 adjusts the height adjusting cylinder 12 to the other side of expansion and contraction until the angle β detected by the angle sensor 26 reaches the threshold angle {β _max − (α _{max − α)}.} You just have to make it work.

However, in the hydraulic excavator 1 provided with the heavy front work machine 4, when the height adjustment cylinder 12 is contracted, the height adjustment cylinder 12 may be contracted more than expected due to the weight of the front work machine 4. Therefore, in steps S16 and S17 that require fine adjustment, the error between the angle β and the threshold angle can be reduced by extending the height adjusting cylinder 12 rather than contracting it.

Further, in the above embodiment, the vehicle height of the hydraulic excavator 1 is adjusted at the timing when the hydraulic excavator 1 is in the traveling posture. As a result, the hydraulic excavator 1 can be driven in an appropriate posture. Further, in the above embodiment, since the angle β detected by the angle sensor 26 is displayed on the display 27, the operator recognizes the angle formed by _{the reference surface L 0} of the upper swivel body 3 with respect to _{the horizontal plane L H.} The hydraulic excavator 1 can be operated.

Further, in the above embodiment, the transmission 23 is fixed to the low gear 23a when the hydraulic excavator 1 travels on a steep uphill. As a result, high torque can be transmitted to the wheels 8 to climb an uphill. Further, in the above embodiment, the transmission 23 is fixed to the low gear 23a when the hydraulic excavator 1 travels on a steep downhill. As a result, it is possible to go down the slope with the engine brake applied.

The above-described embodiments are examples for the purpose of explaining the present invention, and the scope of the present invention is not limited to those embodiments. One of ordinary skill in the art can practice the present invention in various other aspects without departing from the gist of the present invention.

1 Hydraulic excavator 2 Lower traveling body 3 Lower traveling body 4 Front working machine 4a Boom 4b 1st arm 4c 2nd arm 4d Bucket 4e, 4f, 4g, 4h Hydraulic cylinder 5 Swing frame 6 Counter weight 7 Cab 7a Out trigger switch 7b Lock switch 8 Wheels 8f Front wheels 8r Rear wheels 9f Front axle 9r Rear axle 10 Vehicle height adjustment mechanism 11 Link 12, 12R, 12L Height adjustment cylinder 13, 13f, 13r Out trigger 14 Engine building 21 Engine 22 Travel motor 23 Transmission 23a Low gear 23b High gear 24 Hydraulic pump 25 Direction switching valve 26 Angle sensor 27 Display (display device)
30 controller 31 CPU
32 ROM
33 RAM

Claims (5)

With the car body
A front axle that rotatably supports the wheels in the lower front part of the vehicle body,
A rear axle that rotatably supports the wheels in the lower rear part of the vehicle body,
A work vehicle including a vehicle height adjustment mechanism that adjusts the vertical distance between the vehicle body and the front axle by expanding and contracting the height adjustment cylinder.
The angle α, which is the target angle of the vehicle body when the work vehicle is driven on the horizontal plane, and the angle, which is the angle of the vehicle body when the height adjusting cylinder is operated to the maximum in one of extension and contraction on the horizontal plane. A storage device that stores α _max,
An angle sensor that detects the angle β, which is the actual angle of the vehicle body with respect to the horizontal plane,
It is equipped with a controller that controls the vehicle height adjustment mechanism.
The controller
The height adjusting cylinder is operated in one of expansion and contraction until the angle β detected by the angle sensor does not change.
When the value of the angle β when it does not change is defined as the angle β _max , the other of expansion and contraction is performed until the angle β detected by the angle sensor reaches the threshold angle {β _max − (α _{max − α)}.} A work vehicle characterized in that the height adjusting cylinder is operated. In the work vehicle according to claim 1,
A front working machine supported at the front end of the vehicle body is provided.
The angle α _max is the angle of the vehicle body when the height adjusting cylinder is contracted to the maximum.
The controller
The height adjusting cylinder is contracted until the angle β detected by the angle sensor does not change.
A work vehicle characterized in that the height adjusting cylinder is extended until the angle β detected by the angle sensor _{reaches the threshold angle {β max} − (α _{max − α)}.} In the work vehicle according to claim 1,
It is equipped with an outrigger that can change its posture to the overhanging posture that overhangs to the left and right of the vehicle body and touches the road surface, and the retracted posture that is stored in the vehicle body away from the road surface.
The controller changes its posture to the retracted posture when the outrigger changes its posture.
The height adjusting cylinder is operated in one of expansion and contraction until the angle β detected by the angle sensor does not change.
A work vehicle, characterized in _{that - {(α max -α) β} max} to reach, operating the adjusting high cylinder to the other of extension and retraction said angle beta is the detected by the angle sensor threshold angle. In the work vehicle according to claim 1,
A work vehicle including a display device that displays an angle β detected by the angle sensor. In the work vehicle according to claim 1,
An engine that generates rotational driving force and
It is provided with a transmission capable of switching between a low gear that decelerates and transmits the rotational driving force generated by the engine to the wheels and a high gear that decelerates and transmits the rotational driving force to the wheels at a reduction ratio lower than that of the low gear.
The controller is a work vehicle characterized in that the transmission is fixed to the low gear when the absolute value of the difference between the angle β and the angle α exceeds a predetermined threshold value.

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