JP7627668B2 - Work vehicles - Google Patents

Description

The present invention relates to a work vehicle that has a bucket and is used for loading.

Some work vehicles that use tools such as buckets to perform loading and unloading work are equipped with a high dump function that allows the tools to be dumped from a position higher than the normal dump position, making it possible to conveniently dump the load into a dump truck or hopper. When using this high dump function, an optional operation lever is required in addition to the normal operation lever, which increases the number of parts. Therefore, for example, Patent Document 1 discloses a hydraulic excavator that is equipped with a selection switch that allows one-touch switching between normal main operation and optional operation with a single operation lever.

Japanese Patent Application Publication No. 10-60947

However, in the hydraulic excavator described in Patent Document 1, the operator must release the control lever to operate the selection switch, which interrupts the operation and makes it difficult to move smoothly. In addition, the operator must look at his or her hands every time he or she releases the lever, which makes it difficult for the operator to check what is ahead.

The object of the present invention is to provide a work vehicle that allows the operator to smoothly switch from normal main operations to optional operations without any effort.

In order to achieve the above object, the present invention provides a work implement having a vehicle body, an arm member whose base end is attached to the vehicle body and which rotates vertically relative to the vehicle body, a bucket for dumping a load at a dumping destination, and a support member which is rotatably attached to the tip of the arm member and rotatably supports the bucket, a main operation device for operating the arm member and the support member as a main operation, a controller which controls the drive of the arm member, the bucket, and the support member, respectively, and an optional electromagnetic control valve which controls the drive of the bucket so as to rotate the bucket relative to the support member in accordance with a command signal output from the controller, and the bucket is dumped from a position higher than the position at which the entire work implement is dumped. In a work vehicle capable of high dumping, the controller has a posture sensor that detects the posture of the arm member relative to the vehicle body and an angle sensor that detects the angle of the work tool relative to the arm member. The controller receives a main operation signal output from the main operation device, and determines whether a high dump start condition is met in which the tip of the arm member is located higher than the dump destination and the bottom surface of the bucket is located on an extension of the arm member based on the posture of the arm member detected by the posture sensor and the angle of the work tool detected by the angle sensor. If the high dump start condition is met, the controller outputs a command signal related to the high dumping operation to the electromagnetic control valve and automatically switches to the high dumping operation, which is an optional operation.

According to the present invention, it is possible to smoothly switch from normal main operations to optional operations without the operator having to make any effort. Problems, configurations, and effects other than those described above will become clear from the description of the embodiments below.

1 is an external side view showing one configuration example of a wheel loader according to each embodiment of the present invention. FIG. FIG. 2 is a side view showing the wheel loader during a high dump operation. FIG. 11 is an explanatory diagram illustrating a case where the entire working tool rotates. FIG. 11 is an explanatory diagram illustrating a case where the bucket rotates independently. FIG. 2 is a configuration diagram illustrating the configuration of a drive system of the loading and unloading apparatus. FIG. 2 is a functional block diagram showing functions of a controller according to the first embodiment. 5 is a flowchart showing a flow of processing executed by a controller according to the first embodiment. FIG. 11 is a functional block diagram showing functions of a controller according to a second embodiment. 10 is a flowchart showing a flow of processing executed by a controller according to a second embodiment.

Below, we will explain a wheel loader, which performs loading and unloading work such as digging up work objects such as soil and minerals and loading them onto a dump truck, as one type of work vehicle according to each embodiment of the present invention.

<Configuration of Wheel Loader 1>
First, the configuration of a wheel loader 1 according to each embodiment of the present invention will be described with reference to FIGS.

Figure 1 is an external side view showing one configuration example of a wheel loader 1 according to each embodiment of the present invention. Figure 2 is a side view showing the wheel loader 1 during high dump operation. Figure 3 is an explanatory diagram explaining a case where the entire working implement 23 rotates. Figure 4 is an explanatory diagram explaining a case where the bucket 231 rotates independently. Figure 5 is a configuration diagram explaining the configuration of the drive system of the loading and unloading device 2.

The wheel loader 1 is an articulated work vehicle that is steered by bending the vehicle body near the center. Specifically, a front frame 1A, which forms the front part of the vehicle body, and a rear frame 1B, which forms the rear part of the vehicle body, are connected by a center joint 10 so that they can rotate freely in the left-right direction, and the front frame 1A bends in the left-right direction relative to the rear frame 1B.

A pair of left and right front wheels 11A are provided on the front frame 1A, and a pair of left and right rear wheels 11B are provided on the rear frame 1B. Of the pair of left and right front wheels 11A and rear wheels 11B, only the left front wheel 11A and rear wheel 11B are shown in Figures 1 and 2. In addition, a loading and unloading device 2 used for loading and unloading work is attached to the front of the front frame 1A.

The rear frame 1B is provided with a cab 12 in which an operator sits, a machine room 13 that houses the various devices required to drive the wheel loader 1, and a counterweight 14 that maintains balance with the loading and unloading device 2 so that the vehicle body does not tilt. In the rear frame 1B, the cab 12 is located at the front, the counterweight 14 at the rear, and the machine room 13 between the cab 12 and the counterweight 14.

The loading and unloading device 2 includes a lift arm 21 as an arm member whose base end is attached to the front frame 1A and which rotates vertically relative to the vehicle body, two lift arm cylinders 22 (see Figures 2 and 5) that drive the lift arm 21, a bucket 231 that dumps a load at a dumping destination, and a work tool 23 having a support member 232 that is rotatably attached to the tip of the lift arm 21 and rotatably supports the bucket 231, a first work tool cylinder 24 that drives the support member 232 to operate the entire work tool 23, two second work tool cylinders 25 (see Figures 4 and 5) that drive the bucket 231, and a bell crank 26 that is rotatably connected to the lift arm 21 and forms a link mechanism between the work tool 23 (support member 232) and the first work tool cylinder 24.

As shown in FIG. 2, this loading and unloading device 2 is capable of performing a high dump operation that dumps a load into a dump destination such as a dump truck or hopper from a position higher than the standard dump position. In FIG. 2, the bucket 231 is shown in a state in which it is tilted forward most after performing a high dump operation, with a two-dot chain line, and the lift arm 21 is shown in a state in which it is raised to its highest position.

As shown in FIG. 3, the support member 232 is L-shaped in a side view and extends in the width direction of the bucket 231 along the back surface 231C and bottom surface 231B of the bucket 231. The support member 232 is arranged to be able to tilt or dump (rotate up and down) together with the bucket 231 relative to the lift arm 21, centered on the connecting pin 232A, which is the connecting part with the lift arm 21, in conjunction with the extension and contraction of the first work tool cylinder 24 shown in FIG. 1.

In FIG. 3, the broken lines show the working implement 23 tilted to the most rearward tilt position Y1 and dumped to the most forward tilt position Y2. In addition, the diagram shows the posture of the bucket 231 when the two second working implement cylinders 25 are fully contracted and the support member 232 and the bucket 231 are integrated.

As shown in FIG. 4, the bucket 231 is rotatably supported on the support member 221 via the support pin 231A on the bottom surface 231B side, and is provided so that it can tilt or dump with respect to the support member 232 around the support pin 231A in conjunction with the extension and contraction of the two second implement cylinders 25. Here, the two second implement cylinders 25 are attached to the bottom side by a pin 251 at a position between the attachment position of the connecting pin 232A and the attachment position of the support pin 231A on the support member 232, and the rod 25A side is attached to the lower end of the side of the bucket 231 by another pin 252.

In this way, the bucket 231 is arranged so that it can be dumped around the support pin 231A, which is located further forward than the connecting pin 232A, so that the bucket 231 can be dumped (high dumped) from a position higher than the position at which the implement 23 normally dumps (the standard dump position). Note that FIG. 4 shows only one of the two second implement cylinders 25.

When the operator manually operates the high dump operation, the operator first operates the main operating lever 121 (see FIG. 5) to rotate the lift arm 21 and the support member 232 to the high dump operation switching position Y3 shown in FIG. 3. At this high dump operation switching position Y3, the support member 232 is located on an extension of the lift arm 21. At this time, the bucket 231 has not yet been operated, so the bottom surface 231B is in contact with the support member 232. Therefore, at the high dump operation switching position Y3, the bottom surface 231B of the bucket 231 is located on an extension of the lift arm 21.

When the lift arm 21 and the implement 23 are positioned at the high dump operation switching position Y3, the operator releases his/her hand from the main operation lever 121 and switches his/her hand to the option operation lever 122 (see FIG. 5), and operates the option operation lever 122 to dump the bucket 231.

Here, in the operation of the loading and unloading device 2, the operation of the bucket 231, which is the operation performed when performing a high dump operation, corresponds to the optional operation, and the operation of the lift arm 21 and the operation of the support member 232 (the operation of the entire work implement 23) corresponds to the main operation. Note that the main operation lever 121 is one aspect of the main operation device for performing the main operation, and the option operation lever 122 is one aspect of the option operation device for performing the option operation, and is provided in the driver's cab 12 (see Figures 1 and 2).

As shown in FIG. 5, the drive system of the loading and unloading device 2 includes two lift arm cylinders 22, a first implement cylinder 24, two second implement cylinders 25, a hydraulic pump 40 that supplies hydraulic oil to each of the cylinders 22, 24, and 25, first to third directional control valves 41 to 43 that switch the flow (direction and flow rate) of the hydraulic oil discharged from the hydraulic pump 40 and supplied to each of the cylinders 22, 24, and 25, a hydraulic oil tank 44 that stores the hydraulic oil, first to third electromagnetic proportional control valves 410, 420, and 430 that control the first to third directional control valves 41 to 43, and a controller 5 that outputs command signals to the first to third electromagnetic proportional control valves 410, 420, and 430 to control the drive of the lift arm 21, the support member 232, and the bucket 231, respectively.

The third electromagnetic proportional control valve 430 is an optional electromagnetic control valve that controls the drive of the bucket 231 to rotate the bucket 231 relative to the support member 232 in accordance with a command signal output from the controller 5.

The first directional control valve 41 has a first switching position 41L, a neutral position 41N, a second switching position 41R, and a float position 41F.

The first switching position 41L allows the hydraulic oil discharged from the hydraulic pump 40 to flow into the bottom chambers 22B of the two lift arm cylinders 22, and directs the hydraulic oil discharged from the rod chamber 22C to the hydraulic oil tank 44.

The neutral position 41N directs the hydraulic oil discharged from the hydraulic pump 40 directly to the hydraulic oil tank 44.

The second switching position 41R allows the hydraulic oil discharged from the hydraulic pump 40 to flow into the rod chambers 22C of the two lift arm cylinders 22, and directs the hydraulic oil discharged from the bottom chamber 22B to the hydraulic oil tank 44.

The float position 41F is a position that connects both the rod chamber 22C and the bottom chamber 22B of each of the two lift arm cylinders 22 to the hydraulic oil tank 44, and allows the two lift arm cylinders 22 to move freely due to external forces acting on the two lift arm cylinders 22.

The second directional control valve 42 has a first switching position 42L, a neutral position 42N, and a second switching position 42R. The first switching position 42L allows the hydraulic oil discharged from the hydraulic pump 40 to flow into the bottom chamber 24B of the first implement cylinder 24, and guides the hydraulic oil discharged from the rod chamber 24C to the hydraulic oil tank 44. The neutral position 42N guides the hydraulic oil discharged from the hydraulic pump 40 directly to the hydraulic oil tank 44. The second switching position 42R allows the hydraulic oil discharged from the hydraulic pump 40 to flow into the rod chamber 24C of the first implement cylinder 24, and guides the hydraulic oil discharged from the bottom chamber 24B to the hydraulic oil tank 44.

Similarly, the third directional control valve 43 has a first switching position 43L, a neutral position 43N, and a second switching position 43R. The first switching position 43L allows the hydraulic oil discharged from the hydraulic pump 40 to flow into the bottom chambers 25B of the two second implement cylinders 25, respectively, and guides the hydraulic oil discharged from the rod chambers 25C to the hydraulic oil tank 44. The neutral position 43N guides the hydraulic oil discharged from the hydraulic pump 40 directly to the hydraulic oil tank 44. The second switching position 43R allows the hydraulic oil discharged from the hydraulic pump 40 to flow into the rod chambers 25C of the two second implement cylinders 25, respectively, and guides the hydraulic oil discharged from the bottom chambers 25B to the hydraulic oil tank 44.

For example, when the main operating lever 121 is operated in a direction to raise the lift arm 21, a main operating signal related to the lifting operation of the lift arm 21 is output from the main operating lever 121. Based on the main operating signal, the controller 5 outputs a command signal corresponding to the amount of lifting operation of the lift arm 21 to the first electromagnetic proportional control valve 410. As a result, the first directional control valve 41 switches to the first switching position 41L, and hydraulic oil is supplied to the bottom chambers 22B of the two lift arm cylinders 22 to extend the rods 22A, so that the lift arms 21 operate upward.

For example, when the main operating lever 121 is operated in a direction to tilt the support member 232 forward (the direction to dump the work implement 23), a main operating signal related to the forward tilt operation of the support member 232 is output from the main operating lever 121. Based on the main operating signal, the controller 5 outputs a command signal corresponding to the forward tilt operation amount of the support member 232 to the second electromagnetic proportional control valve 420. As a result, the second directional control valve 42 switches to the second switching position 42R, and hydraulic oil is supplied to the rod chamber 24C of the first work implement cylinder 24 to retract the rod 24A, so that the support member 232 moves in the forward tilt direction (the entire work implement 23 is dumped).

For example, when the option operation lever 122 is operated in a direction to dump the bucket 231, an option operation signal related to the dump operation of the bucket 231 is output from the option operation lever 122. Based on the option operation signal, the controller 5 outputs a command signal corresponding to the amount of dump operation of the bucket 231 to the third electromagnetic proportional control valve 430. As a result, the third directional control valve switches to the second switching position 43R, and hydraulic oil is supplied to the rod chambers 25C of the two second implement cylinders 25, respectively, and the rods 25A contract, causing the bucket 231 to dump (high dump).

As mentioned above, when operating the bucket 231, including the high dump operation, the operator must take his/her hand off the main operation lever 121 and switch to the option operation lever 122, which makes the operation complicated. Therefore, in the drive system of the loading and unloading device 2, the controller 5 can automatically switch to the operation of the bucket 231 without the operator having to operate the option operation lever 122. The configuration of the controller 5 will be described below for each embodiment.

First Embodiment
First, the controller 5 according to the first embodiment of the present invention will be described with reference to FIGS.

(Configuration of Controller 5)
The configuration of the controller 5 will be described with reference to FIG.

Figure 6 is a functional block diagram showing the functions of the controller 5 according to the first embodiment.

The controller 5 is configured by connecting a CPU, RAM, ROM, HDD, input I/F, and output I/F to each other via a bus. Various operating devices such as a main operating lever 121, an optional operating lever 122, and a selection switch 123, as well as various sensors such as a lift arm angle sensor 61 and a work tool angle sensor 62, are connected to the input I/F, and the first electromagnetic proportional control valve 410, the second electromagnetic proportional control valve 420, and the third electromagnetic proportional control valve 430 are connected to the output I/F. The selection switch 123 corresponds to a selection device that selects automatic switching to an optional operation (high dump operation) by the controller 5.

In such a hardware configuration, the CPU reads out a control program (software) stored in a recording medium such as a ROM, HDD, or optical disk, expands it on RAM, and executes the expanded control program, whereby the control program and the hardware work together to realize the functions of the controller 5.

In this embodiment, the controller 5 is described as a computer configured by a combination of software and hardware, but this is not limited thereto. For example, as an example of another computer configuration, an integrated circuit that realizes the functions of a control program executed on the wheel loader 1 side may be used.

The lift arm angle sensor 61 is one type of posture sensor that detects the posture of the lift arm 21 relative to the vehicle body, and is attached to the base end of the lift arm 21 (the connection part with the front frame 1A). It is possible to detect the height of the lift arm 21 from the ground based on the lift arm angle detected by the lift arm angle sensor 61. Note that the posture sensor does not necessarily have to be a sensor that detects the lift arm angle, and may also be a sensor that detects, for example, the stroke length or bottom pressure of the lift arm cylinder 22.

The implement angle sensor 62 is an angle sensor that detects the angle of the implement 23 relative to the lift arm 21, and is attached to the bell crank 26. Note that the angle sensor does not necessarily have to be a sensor that detects the implement angle, and may also be a sensor that detects, for example, the stroke length or bottom pressure of the first implement cylinder 24.

As shown in FIG. 6, the controller 5 includes a data acquisition unit 51, a condition determination unit 52, a memory unit 53, and a signal output unit 54.

The data acquisition unit 51 acquires data relating to the main operation signal output from the main operation lever 121, the automatic switching selection signal output from the selection switch 123, the lift arm angle θ1 detected by the lift arm angle sensor 61, and the work tool angle θ2 detected by the work tool angle sensor 62.

When the data acquisition unit 51 acquires the main operation signal and the automatic switch selection signal, the condition determination unit 52 determines whether or not the high dump start condition is met based on the lift arm angle θ1 and the implement angle θ2 acquired by the data acquisition unit 51. This "high dump start condition" is the minimum condition required for the wheel loader 1 to start a high dump operation, and is that the tip of the lift arm 21 is positioned higher than the dump destination and the bottom surface 231B of the bucket 231 is positioned on an extension of the lift arm 21.

In this embodiment, the condition determination unit 52 determines whether the lift arm angle θ1 acquired by the data acquisition unit 51 is equal to or greater than a predetermined first threshold value α1 (hereinafter simply referred to as the "first threshold value α1") and whether the work tool angle θ2 acquired by the data acquisition unit 51 is equal to or less than a predetermined second threshold value α2 (hereinafter simply referred to as the "second threshold value α2"). Here, the first threshold value α1 is the lift arm angle associated with the height of the dump destination, and the second threshold value α2 is the work tool angle when the bottom surface 231B of the bucket 231 is located on the extension of the lift arm 21, and both of these threshold values are stored in advance in the storage unit 53, which is a memory.

When the condition determination unit 52 determines that the high dump start condition is met, the signal output unit 54 outputs a command signal for high dump operation to the third electromagnetic proportional control valve 430. This automatically switches to high dump operation, which is an optional operation.

(Processing in the controller 5)
Next, the flow of processing executed within the controller 5 will be described with reference to FIG.

Figure 7 is a flowchart showing the flow of processing executed by the controller 5 according to the first embodiment.

First, the controller 5 determines whether the data acquisition unit 51 has acquired an automatic switching selection signal from the selection switch 123, i.e., whether the selection switch 123 has been turned ON (step S501). If it is determined in step S501 that the selection switch 123 has been turned ON (step S501/YES), the controller 5 then determines whether the data acquisition unit 51 has acquired a main operation signal from the main operation lever 121, i.e., whether the main operation lever 121 has been operated (step S502).

When it is determined in step S502 that the main operating lever 121 has been operated (step S502/YES), the data acquisition unit 51 acquires the lift arm angle θ1 detected by the lift arm angle sensor 61 and the implement angle θ2 detected by the implement angle sensor 62 (step S503).

Next, the condition determination unit 52 determines whether the lift arm angle θ1 acquired in step S503 is equal to or greater than the first threshold value α1 and the implement angle θ2 acquired in step S502 is equal to or less than the second threshold value α2, i.e., whether the high dump start condition is satisfied (step S504).

If it is determined in step S504 that the lift arm angle θ1 is equal to or greater than the first threshold value α1 (θ1≧α1) and the implement angle θ2 is equal to or less than the second threshold value α2 (θ2≦α2) (step S504/YES), the signal output unit 54 outputs a command signal related to the high dump operation to the third electromagnetic proportional control valve 430 (step S505), and the controller 5 automatically switches from the main operation based on the operation of the main operating lever 121 to the high dump operation.

If the selection switch 123 is not turned ON (remains OFF) in step S501 (NO in step S501), if the main operating lever 121 is not operated in step S502 (NO in step S502), and if it is determined in step S504 that the lift arm angle θ1 is less than the first threshold value α1 (θ1<α1) or the implement angle θ2 is greater than the second threshold value α2 (θ2>α2) (NO in step S504), the processing in the controller 5 ends.

In this way, when the high dump start conditions are met, the controller 5 executes a process to automatically switch to high dump operation, eliminating the need for the operator to operate the option operation lever 122. This allows the operator to smoothly switch from normal main operation to the option operation, high dump operation, without any effort on his/her part. In addition, the operator does not need to check what is in front of him/her when switching from the main operation lever 121 to the option operation lever 122, allowing him/her to adequately check what is ahead.

In addition, in this embodiment, the controller 5 determines the high dump start conditions based on a table that associates the height of the dump destination with the posture of the lift arm 21, so it is possible to automatically switch to a flexible high dump operation for dump destinations with various specifications.

Furthermore, in this embodiment, the operator can arbitrarily select automatic switching to high dump operation by the controller 5 using the selection switch 123, and even if the high dump start conditions are met, operation can be performed using the option operation lever 122 as long as the selection switch 123 is in the OFF state.

Second Embodiment
Next, a wheel loader 1 according to a second embodiment of the present invention will be described with reference to Figures 8 and 9. In Figures 8 and 9, components common to those described for the wheel loader 1 according to the first embodiment are given the same reference numerals and descriptions thereof will be omitted.

Figure 8 is a functional block diagram showing the functions of the controller 5A according to the second embodiment. Figure 9 is a flowchart showing the flow of processing executed by the controller 5A according to the second embodiment.

In this embodiment, unlike the first embodiment, the wheel loader 1 further includes a learning mode changeover switch 124 as a learning mode changeover device for switching to a learning mode in which the high dump start conditions are learned based on the operation of the main operation lever 121 and the operation of the option operation lever 122. As shown in FIG. 8, the controller 5A includes a learning unit 55 in addition to the data acquisition unit 51A, condition determination unit 52A, memory unit 53A, and signal output unit 54.

As shown in FIG. 9, first, the controller 5A determines whether the data acquisition unit 51A has acquired a mode switching signal output from the learning mode switching switch 124, i.e., whether the learning mode switching switch 124 has been turned ON (step S506).

If it is determined in step S506 that the learning mode changeover switch 124 is ON (step S506/YES), the learning unit 55 learns the lift arm angle β1 and the implement angle β2 at the start of the high dump operation acquired by the data acquisition unit 51A, and the learned lift arm angle β1 is stored as the first learned value β1, and the learned implement angle β2 is stored as the second learned value β2 in the memory unit 55A (step S507).

When the first learning value β1 and the second learning value β2 are stored in step S507, the controller 5A turns off the learning mode (step S508). After that, when the data acquisition unit 51A acquires the main operation signal output from the main operation lever 121 (step S502/YES), the condition determination unit 52A determines whether the lift arm angle θ1 acquired in step S503 is equal to or greater than the first learning value β1 and whether the implement angle θ2 acquired in step S503 is equal to or less than the second learning value β2 (step S504A).

If it is determined in step S504A that the lift arm angle θ1 is equal to or greater than the first learned value β1 (θ1≧β1) and the implement angle θ2 is equal to or less than the second learned value β2 (θ2≦β2) (step S504/YES), the process proceeds to step S505. If it is determined that the lift arm angle θ1 is less than the first learned value β1 (θ1<β1) and the implement angle θ2 is greater than the second learned value β2 (θ2>β2) (step S504/NO), the process in controller 5A ends.

In this way, the controller 5A according to this embodiment does not automatically switch to high dump operation using high dump start conditions based on preset thresholds, but instead automatically switches to high dump operation using high dump start conditions based on learning values learned from the operator's initial operation of the main operation lever 121 and the operation of the optional operation lever 122. This makes it possible to change the high dump start conditions at any time to suit various specifications of dump destinations and on-site environments, making it possible to perform automatic switching to high dump operation with high precision.

The above describes an embodiment of the present invention. Note that the present invention is not limited to the above embodiment, and various modified examples are included. For example, the above embodiment has been described in detail to clearly explain the present invention, and is not necessarily limited to having all of the configurations described. It is also possible to replace part of the configuration of this embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of this embodiment. Furthermore, it is also possible to add, delete, or replace part of the configuration of this embodiment with other configurations.

For example, in the above embodiment, a wheel loader 1 has been described as a work vehicle capable of high dumping operations, but the present invention is not limited to this, and can also be applied to other work vehicles, such as lift trucks with extendable arm members.

1: Wheel loader (work vehicle)
5, 5A: Controller 21: Lift arm (arm member)
23: Working tool 43: Third electromagnetic proportional control valve (electromagnetic control valve)
61: Lift arm angle sensor (position sensor)
62: Work tool angle sensor (angle sensor)
121: Main operation lever (main operation device)
122: Optional operation lever (optional operation device)
123: Selection switch (selection device)
124: Learning mode changeover switch (learning mode changeover device)
231: Bucket 231B: Bottom surface 232: Support member α1: First threshold value α2: Second threshold value β1: First learned value β2: Second learned value

Claims (4)

a vehicle body, an arm member having a base end attached to the vehicle body and pivoting vertically relative to the vehicle body, a working tool having a bucket for dumping a load to a dump destination, and a support member pivotally attached to the tip of the arm member and rotatably supporting the bucket, a main operation device for operating the arm member and the support member as a main operation, a controller for controlling the drive of the arm member, the bucket, and the support member, respectively, and an optional electromagnetic control valve for controlling the drive of the bucket so as to rotate the bucket relative to the support member in accordance with a command signal output from the controller, and which is capable of a high dump operation in which the bucket is dumped from a position higher than a position at which the entire working tool is dumped,
a posture sensor for detecting a posture of the arm member relative to the vehicle body;
an angle sensor for detecting an angle of the working tool relative to the arm member,
The controller:
A main operation signal output from the main operation device is input,
determining whether or not a high dump start condition is satisfied, where the tip of the arm member is positioned higher than the dump destination and the bottom surface of the bucket is positioned on an extension of the arm member, based on the posture of the arm member detected by the posture sensor and the angle of the work tool detected by the angle sensor;
A work vehicle characterized in that, when the high dump start condition is satisfied, a command signal related to the high dump operation is output to the electromagnetic control valve, and the operation is automatically switched to the high dump operation, which is an optional operation. The work vehicle according to claim 1,
The controller:
The posture of the arm member associated with the height of the dump destination is stored as a predetermined first threshold value, and the angle of the work tool when the bottom surface of the bucket is located on an extension of the arm member is stored as a predetermined second threshold value,
a work vehicle which determines that the high dump start condition is satisfied when the posture of the arm member detected by the posture sensor is equal to or greater than the first threshold value and the angle of the work tool detected by the angle sensor is equal to or less than the second threshold value. The work vehicle according to claim 1,
An option operation device for performing the option operation;
a learning mode switching device for switching to a learning mode in which the high dump start condition is learned based on an operation of the main operation device and an operation of the option operation device,
The controller:
when a mode switching signal output from the learning mode switching device is input, the posture of the arm member and the angle of the work tool at the start of the high dump operation are learned,
storing the learned posture of the arm member as a first learned value and the learned angle of the work tool as a second learned value,
a high dump start condition being satisfied when the posture of the arm member detected by the posture sensor is equal to or greater than the first learned value and the angle of the work tool detected by the angle sensor is equal to or less than the second learned value. The work vehicle according to claim 1,
A selection device for selecting automatic switching to the optional operation by the controller is further provided,
The controller:
a command signal relating to the high dump operation being output to the electromagnetic control valve when an automatic switch selection signal is input from the selection device and the high dump start condition is satisfied.

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