Work vehicle

Abstract

To provide a work vehicle desired to be able to measure the weight of loaded goods when running on uneven surfaces without a complicated configuration.SOLUTION: A vehicle body including a loading part on which goods can be loaded is provided with support mechanisms configured to support a plurality of running wheels such that the positions thereof can be changed with respect to the vehicle body. A control device C configured to control operation of the support mechanisms executes weight calculation processing for calculating the weight of the goods based on the detection results by load detection means KF configured to detect the load applied to a plurality of support mechanisms due to the load of the entire vehicle and by inclined state detection means S4 configured to detect an inclined state of the loading part.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a work vehicle suitable for traveling on uneven terrain. [Background technology]

[0002] A conventional work vehicle as described above has four running wheels supported on the vehicle body via an articulating link mechanism that can be extended or retracted by operating a hydraulic cylinder, and by changing the height of the running wheels, it is possible to run on uneven ground while maintaining the posture of the vehicle body (see, for example, Patent Document 1). This work vehicle is equipped with a stroke sensor that detects the stroke amount of the hydraulic cylinder, a pressure sensor that detects the pressure in the oil chamber of the hydraulic cylinder, an inclination sensor that detects the inclination angle of the vehicle body, etc., and is configured to keep the vehicle body in a horizontal position and keep the four running wheels in contact with the ground even on uneven ground. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-1440 A Summary of the Invention [Problem to be solved by the invention]

[0004] The above-mentioned work vehicle is sometimes used in a work mode in which the vehicle body is maintained in a horizontal position and a load is loaded on top of the vehicle body while traveling. In this case, the position of the vehicle body has traditionally been maintained without consideration of the weight of the loaded load.

[0005] In order to measure the weight of the loaded cargo, it is conceivable to provide a dedicated weight measurement sensor, such as a load cell, on the cargo bed of the vehicle body on which the cargo is loaded. However, such a configuration requires the provision of a separate dedicated weight measurement sensor, which has the disadvantage of making the configuration complex. Furthermore, in order to accurately measure the weight using a weight measurement sensor, the cargo bed needs to be set in a horizontal position. However, since the vehicle travels on uneven terrain, the cargo bed is not always in a horizontal position, which may result in inaccurate measurements.

[0006] Therefore, there has been a demand for a system for measuring the weight of a load carried on a work vehicle that travels on rough terrain without complicating the configuration. [Means for solving the problem]

[0007] A characteristic configuration of a work vehicle according to the present invention includes a vehicle body having a loading section capable of loading cargo, a plurality of running wheels located at the front and rear of both the left and right sides of the vehicle body, a support mechanism supported by the vehicle body and supporting the plurality of running wheels so that their positions can be changed relative to the vehicle body, a control device for controlling the operation of the support mechanism, load load detection means for detecting loads acting on the plurality of support mechanisms due to the weight of the entire vehicle, and tilt state detection means for detecting the tilt state of the loading section, and the control device executes a weight calculation process for determining the weight of the cargo based on the detection results of the load load detection means and the detection results of the tilt state detection means. a center of gravity position of the entire vehicle is determined based on the detection results of the load load detection means and the tilt state detection means, and whether or not the weight balance of the entire vehicle is appropriate is determined based on the detection results of the load load detection means and the tilt state detection means, the center of gravity position, and information on the weight of the luggage. The point is that it is configured to

[0008] According to the present invention, the tilt state of the loading section is detected by the tilt state detection means, and even if the traveling road surface is uneven, the posture of the vehicle body can be changed to a posture suitable for loading cargo by, for example, changing the positions of the multiple traveling wheels relative to the vehicle body with the support mechanism so that the loading section is in a horizontal posture. In this way, the detection information of the tilt state detection means is used to maintain the posture of the loading section, etc.

[0009] The load detection means detects the load acting on the support mechanism. The load is the combined weight of the vehicle and the weight of the loaded cargo. In this case, for example, if one of the multiple running wheels is lifted off the ground, the load acting on the corresponding support mechanism will be much smaller than the others. Therefore, if the position of the support mechanism is changed so that the load is the same as the others, the running wheel will be in a state of contact with the ground. In this way, the load detection information is used to change the position of the vehicle body and maintain contact with the ground by the running wheels.

[0010] Therefore, the total weight and the weight of the luggage can be calculated from the loads applied to the multiple support mechanisms using the information detected by the load detection means and the tilt state detection means. Depending on the road surface conditions, the loading section may not be in a horizontal position even if the support mechanisms are operated to change their position. If the loading section is tilted, the loads of the support mechanisms on the lower side of the tilt will be different from the loads of the support mechanisms on the upper side of the tilt, even if the center of gravity is located in the center of the vehicle body. Furthermore, since it is possible to know how much the loading section is tilted and how much the loads on the multiple support mechanisms differ, it is possible to calculate the weight of the luggage even when the loading section is tilted.

[0011] Therefore, by effectively utilizing the detection means that detects information used to change the vehicle body's posture and maintain ground contact with the running wheels, it has become possible to measure the weight of the cargo being loaded on a work vehicle that travels on rough terrain without complicating the configuration. In addition, the system determines whether the weight balance of the entire vehicle is inappropriate and whether there is a risk of the vehicle's posture becoming unstable.The results of this determination can be used to take countermeasures. In the present invention, the control device preferably performs the weight calculation process by performing a first process of determining the vertically downward contact pressure at the contact points of the running wheels based on the detection results of the load detection means and the tilt state detection means, a second process of determining the weight of the entire vehicle by adding up the contact pressure of each of the multiple running wheels, and a third process of determining the weight of the luggage by subtracting the weight of the vehicle body from the weight of the entire vehicle, and also performs a process of determining the position of the center of gravity of the entire vehicle based on the variation in the contact pressure of each of the multiple running wheels, determines a virtual plane consisting of the contact points of the multiple running wheels relative to the vehicle body based on information on the vertical heights of the multiple support mechanisms obtained based on the detection results of the load detection means, and further determines whether the weight balance of the entire vehicle is appropriate based on where the center of gravity position is located three-dimensionally on the vehicle body.

[0012] In the present invention, it is preferable that the control device executes a notification process in which, when the weight of the luggage calculated in the weight calculation process exceeds a set value, a notification means notifies the user of this fact.

[0013] According to this configuration, if the load weight is excessive and the vehicle is in an overloaded state, the notification means will notify the operator, allowing the operator to take measures such as reducing the amount of luggage.

[0014] In the present invention, the support mechanism is provided with a bending link mechanism in which a plurality of links are pivotally connected, and a plurality of hydraulic cylinders capable of changing the rotational postures of the plurality of links, and the load load detection means is provided with a pressure sensor that detects the internal pressure of the oil chamber of the hydraulic cylinder, and a stroke sensor that detects the extension / contraction amount of the hydraulic cylinder. can.

[0015] According to this configuration, the support drive can change the support posture of the articulated link mechanism by changing the rotational posture of the link using the hydraulic cylinder, for example, so that the posture of the vehicle body becomes a target posture. The internal pressure of the oil chamber of the hydraulic cylinder detected by the pressure sensor is information corresponding to the ground reaction force from the ground when the entire vehicle load is supported by the running wheels via the articulated link mechanism. From this internal pressure information, it is easy to determine whether the running wheels are lifted from the ground, and the running wheels can be corrected to a ground contact state.

[0016] The amount of extension and contraction of the hydraulic cylinder detected by the stroke sensor is information corresponding to changes in the position of the link. In other words, the stroke sensor can be used to determine the current position of the articulating link mechanism, allowing for smooth operation to maintain the position of the vehicle body.

[0017] The control device then uses the detection information from the pressure sensor and stroke sensor, as well as the detection results from the tilt state detection means, to determine the vertically downward contact pressure at the contact points of the running wheels. The total weight of the vehicle can be calculated by summing the contact pressures of the multiple running wheels, and the weight of the cargo can be calculated by subtracting the known weight of the vehicle body from the total weight of the vehicle.

[0018]

[0019] If the load is properly placed on the loading section and the loading section is in a horizontal position, the detection values of the pressure sensors in the multiple support mechanisms will be approximately the same. However, if the load is placed unevenly on the loading section, the detection values of the pressure sensors in the multiple support mechanisms will be different even if the loading section is maintained in a horizontal position. For example, the detection value of the pressure sensor in the support mechanism on the uneven side will be high, and the detection value of the pressure sensor in the support mechanism on the opposite side will be low. Furthermore, if the height from the contact point of the running wheels to the loading section is high, the vehicle's posture will easily become unstable if the load is unevenly placed.

[0020] Therefore, the information from the above sensors and the load thing Based on the weight information, it is possible to determine whether the overall weight balance of the vehicle is inappropriate and whether there is a risk of the vehicle becoming unstable. The results of this determination can be used to take appropriate measures.

[0021] In the present invention, it is preferable that the control device executes horizontal control for controlling the operation of the support mechanism so that the vehicle body is in a horizontal position based on the detection information of the tilt state detection means.

[0022] With this configuration, the vehicle body is maintained in a horizontal position, so that the load can be stably supported on the loading section, and weight measurement can be performed with high accuracy. However, even with this posture control, if the road surface is inclined sharply, it may not be possible to maintain the loading section in a horizontal position. However, even in such cases, the weight of the load can be measured. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. [Figure 2] FIG. [Figure 3] FIG. [Figure 4] FIG. [Figure 5] FIG. [Figure 6]FIG. [Figure 7] 10 is a flowchart of a control operation. DETAILED DESCRIPTION OF THE INVENTION

[0024] An embodiment of the present invention will be described with reference to the drawings. In the following description, the direction of the arrow FW shown in the drawings will be referred to as "front," the direction of the arrow BK as "rear," the direction of the arrow RH as "right," the direction of the arrow LH as "left," the direction of the arrow UP as "up," and the direction of the arrow DW as "down."

[0025] As shown in Figures 1 to 3, the work vehicle is equipped with a vehicle body 1 that is approximately rectangular in plan view and supports the entire vehicle, a plurality of running wheels 2 that serve as running devices that support the vehicle body 1, a plurality of auxiliary wheels 3 that are provided corresponding to each of the plurality of running wheels 2, a support mechanism A that supports the plurality of running wheels 2 so that their positions can be changed relative to the vehicle body 1, and a plurality of hydraulic motors 4 that serve as running drive devices that individually drive the plurality of running wheels 2.

[0026] The traveling wheels 2 are located at the front and rear of both the left and right sides of the vehicle body 1. In this embodiment, the work vehicle is equipped with four traveling wheels 2, located at the left front, right front, left rear, and right rear. It also has four support mechanisms A, located at the left front, right front, left rear, and right rear. The support mechanisms A include a bending link mechanism 5 and a plurality of hydraulic cylinders 6, 7 that can individually change the position of the bending link mechanism 5.

[0027] The structures of the running wheels 2, auxiliary wheels 3, and support mechanism A of the work vehicle of this embodiment are symmetrical front to rear, and the work vehicle can travel in both the forward and backward directions defined in the drawing.

[0028] The vehicle body 1 is generally rectangular in plan view, and is provided on the upper surface of the vehicle body 1 with a flat loading section 8 on which cargo can be loaded. The loading section 8 is a generally rectangular section in plan view, and extends from the right end to the left end of the vehicle body 1. The loading section 8 is configured so that cargo can be placed on it. Examples of cargo that can be placed on the loading section 8 include agricultural machinery, agricultural supplies such as fertilizer and chemicals, harvested crops and harvest baskets, and pallets on which these are placed.

[0029] The vehicle body 1 is provided, below the loading section 8, with a hydraulic supply source 9 that sends hydraulic oil toward the hydraulic cylinders 6, 7 and the hydraulic motor 4, a plurality of hydraulic control valves 10 that adjust the supply state of hydraulic oil from the hydraulic supply source 9, an ECU 11 (Electronic Control Unit) that controls the operation of the hydraulic control valves 10, a battery 12 for power supply, etc. The hydraulic supply source 9 is provided with a hydraulic pump 9b driven by an engine 9a. The hydraulic supply source 9 also is provided with a hydraulic oil tank 9c, a radiator 9d, etc. The hydraulic supply source 9 is supported by an underframe 24. A fuel tank 9e is provided at a high position on the rear side of the vehicle body 1.

[0030] The ECU 11 is equipped with a microcomputer and is capable of executing various controls according to a control program. The multiple hydraulic control valves 10 and the ECU 11 constitute a control device C. The battery 12 is charged by a generator driven by the power of the engine 9a. Reference numeral 13 in the figure denotes an operating handle that can be gripped and operated by an operator.

[0031] [Support mechanism] As described above, the support mechanism A includes the bending link mechanism 5 and a plurality of hydraulic cylinders 6, 7. As shown in Fig. 1, a plurality of (specifically, four) traveling wheels 2 are supported via the bending link mechanism 5 with respect to the vehicle body 1 so as to be able to move up and down individually.

[0032] As shown in Figures 4 and 5, the bending link mechanism 5 includes a base end portion 14 supported by the vehicle body 1, a first link 15 having an upper end portion supported on the lower portion of the base end portion 14 so as to be rotatable about a horizontal axis X1, and a second link 16 having one end portion supported on the lower end portion of the first link 15 so as to be rotatable about a horizontal axis X2 and having the running wheel 2 supported on the other end portion.

[0033] A support bracket 17 that supports the traveling wheel 2 is supported by a boss portion 18 provided at the swing side end of the second link 16 so as to be swingable around the vertical axis Y. A hydraulic cylinder 20 for swing operation (hereinafter referred to as a swing cylinder) is provided across a bracket 19 on one end side of the second link 16 and an arm portion 17a provided on the support bracket 17.

[0034] A plurality of hydraulic cylinders 6, 7 are provided corresponding to the plurality of articulating link mechanisms 5, respectively, and capable of individually changing the posture of the articulating link mechanisms 5. That is, a first hydraulic cylinder 6 is provided that can change the swing posture of the first link 15 relative to the vehicle body 1, and a second hydraulic cylinder 7 is provided that can change the swing posture of the second link 16 relative to the first link 15.

[0035] When the first hydraulic cylinder 6 is extended or retracted with the operation of the second hydraulic cylinder 7 stopped, the first link 15, the second link 16, and the traveling wheel 2 swing together around the horizontal axis X1 of the pivotal connection point with respect to the base end 14 while maintaining a constant relative posture. When the second hydraulic cylinder 7 is extended or retracted with the operation of the first hydraulic cylinder 6 stopped, the second link 16 and the traveling wheel 2 swing together around the horizontal axis X2 of the connection point between the first link 15 and the second link 16 while maintaining a constant posture of the first link 15.

[0036] An auxiliary wheel 3 is rotatably supported at an intermediate bending portion of each of the multiple bending link mechanisms 5. The auxiliary wheel 3 is configured as a wheel having approximately the same outer diameter as the running wheel 2. A support shaft that pivotally connects the first link 15 and the second link 16 is extended so as to protrude outward in the vehicle body width direction, and the auxiliary wheel 3 is rotatably supported at the extended protruding portion of the support shaft.

[0037] By operating the turning cylinder 20, the traveling wheel 2 can be turned around the vertical axis Y relative to the articulating link mechanism 5, thereby enabling the vehicle to be turned.

[0038] The hydraulic control valve 10 corresponding to the hydraulic motor 4 adjusts the flow rate of the hydraulic oil, so that the rotation speed of the hydraulic motor 4, that is, the rotation speed of the traveling wheels 2, can be changed.

[0039] [Sensor] This work vehicle is equipped with various sensors. As shown in Fig. 6, a head-side pressure sensor S1 and a cap-side pressure sensor S2 are provided for each of the four second hydraulic cylinders 7. The head-side pressure sensor S1 detects the internal pressure of the oil chamber in the head-side chamber of the second hydraulic cylinder 7. The cap-side pressure sensor S2 detects the internal pressure of the oil chamber in the cap-side chamber of the second hydraulic cylinder 7.

[0040] A plurality of stroke sensors S3 capable of detecting the amount of extension / contraction operation are provided for each of the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7. The amount of extension / contraction operation of each hydraulic cylinder 6, 7 is a detected value corresponding to the swing position of the first link 15 and second link 16, which are the objects of operation.

[0041] The vehicle body 1 is provided with an inclination sensor S4 as an inclination state detection means for detecting the inclination state of the vehicle body. The inclination sensor S4 is configured using an inertial measurement unit (IMU) which is a well-known configuration. The IMU has a triaxial acceleration sensor and a gyro sensor, and can detect changes in the attitude of the vehicle body 1, specifically, inclination in the front-rear and left-right directions.

[0042] A rotation sensor S5 is provided near the traveling wheels 2 to detect the rotation speed of the traveling wheels 2 driven by the hydraulic motor 4. Based on the rotation speed of the traveling wheels 2 detected by the rotation sensor S5, the supply of hydraulic oil to the hydraulic motor 4 is controlled so that the rotation speed of the traveling wheels 2 becomes a target value. A pressure sensor S6 is provided to detect the pressure of the hydraulic oil supplied to the hydraulic motor 4. Based on the pressure of the hydraulic oil detected by the pressure sensor S6, the supply (pressure) of hydraulic oil to the hydraulic motor 4 is controlled so that the drive torque of the traveling wheels 2 becomes a target value. A stroke sensor S7 capable of detecting the extension / retraction operation amount is provided for each of the four swing cylinders 20.

[0043] The pressure sensors S1, S2 and stroke sensors S3 described above constitute a load detection means KF that detects the load acting on the plurality of support mechanisms A due to the load of the entire vehicle.

[0044] [ECU] The ECU 11 (Electronic Control Unit) includes a non-volatile memory (not shown) that stores programs corresponding to the functional units described below, and a CPU (not shown) that executes the programs. The functions of the functional units are realized by the CPU executing the programs.

[0045] The ECU 11 has, as its functional units, an attitude control unit 100, a driving control unit 101, and a weight calculation unit 102. When the vehicle is traveling with the four traveling wheels 2 in contact with the ground, the driving control unit 101 controls the operation of the hydraulic motor 4 for each of the four traveling wheels 2 so that the rotational speed of the traveling wheel 2 detected by the rotation sensor S5 becomes a target speed and the drive torque detected by the pressure sensor S6 becomes a target value. Specifically, the ECU 11 performs a switching operation of the hydraulic control valve that supplies and discharges hydraulic oil to and from the hydraulic motor.

[0046] When the vehicle body is moving, the posture control unit 100 executes horizontal control, which controls the operation of the support mechanism A so that the loading section 8 of the vehicle body 1 is in a horizontal posture, based on the detection information of the inclination sensor S4. In the horizontal control, the posture control unit 100 controls the operation of the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7 so that the tilt angles in the front-to-rear direction and the left-to-right direction from the horizontal posture of the vehicle body 1 become values corresponding to the horizontal posture, based on the detection information of the inclination sensor S4 and the detection information of the stroke sensor S3.

[0047] To explain further, the target operating amounts of the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7 required to bring the loading section 8 to a horizontal position are calculated from the inclined position of the loading section 8 detected by the inclination sensor S4, and the operation of the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7 is controlled so that the actual operating amounts detected by the stroke sensor S3 become the target operating amounts. Specifically, the control unit 10 switches the hydraulic control valve 10 that supplies and discharges hydraulic oil to the four first hydraulic cylinders 6 and the four second hydraulic cylinders 7.

[0048] The actual operation amount of each hydraulic cylinder 6, 7 detected by the stroke sensor S3 indicates the state of change in the relative posture of the link to be operated with respect to the vehicle body member. That is, based on the detection value of the stroke sensor S3, it is possible to determine the swing posture of the first link 15 with respect to the vehicle body 1, the swing posture of the second link 16 with respect to the first link 15, etc. As a result, it is possible to determine the height from the ground contact part of the traveling wheel 2 to the vehicle body 1.

[0049] The weight calculation unit 102 is configured to execute a weight calculation process to determine the weight of the luggage loaded on the loading unit 8 based on the detection results of each pressure sensor S1, S2 and each stroke sensor S3 as the load detection means KF and the detection result of the inclination sensor S4.

[0050] Specifically, as weight calculation processes, the weight calculation unit 102 executes a first process of determining the vertically downward ground contact pressure at the ground contact point of the running wheel 2 based on the detection information of the pressure sensors S1, S2 and stroke sensor S3 and the detection result of the inclination sensor S4; a second process of determining the weight of the entire vehicle by adding up the ground contact pressures of each of the multiple running wheels 2; and a third process of determining the weight of the luggage by subtracting the weight of the vehicle body from the weight of the entire vehicle.

[0051] As described above, the swinging posture of the first link relative to the vehicle body 1, the swinging posture of the second link relative to the first link, etc. can be determined based on the detection value of the stroke sensor S3, so it is possible to determine the height from the ground contact portion of the running wheel 2 in each support mechanism A to the vehicle body 1.

[0052] Furthermore, based on the detection results of the pressure sensors S1 and S2, it is possible to detect the pressure acting on the hydraulic cylinders 6 and 7 via the links 15 and 16 of the support mechanism A when the running wheel 2 touches the ground. A force acting in the vertical direction at the contact point where the running wheel 2 touches the ground acts on the first hydraulic cylinder 6 via the first link 15, and also acts on the second hydraulic cylinder 7 via the second link 16.

[0053] The weight of the entire vehicle acts in the vertical direction at the ground contact point of each running wheel 2. At this time, the vertical force acting on the running wheel 2 (hereinafter referred to as ground contact pressure) acts as internal pressure in the oil chambers of the hydraulic cylinders 6, 7 via the support mechanism A. Therefore, as shown in Fig. 7, the weight calculation unit 102 calculates the ground contact pressure at each support mechanism A by using the detection information from the pressure sensors S1, S2 and stroke sensor S3 and the detection result from the tilt sensor S4 (step #1). This calculation process corresponds to the first process.

[0054] Then, the weight calculation unit 102 calculates the weight of the entire vehicle by adding up the ground contact pressures of each of the plurality of traveling wheels 2 (step #2). This calculation process corresponds to the second process. Next, the weight calculation unit 102 calculates the weight of the luggage loaded on the loading unit 8 by subtracting the weight of the vehicle body, which has been measured and known in advance, from the weight of the entire vehicle calculated by the second process (step #3). This calculation process corresponds to the third process.

[0055] If the weight of the cargo calculated in the weight calculation process exceeds a set value, the weight calculation unit 102 executes a notification process in which the notification lamp 21 serving as a notification means is turned on to notify the user (steps #4 and #7). If the load exceeds the allowable upper limit, excessive load is applied to the hydraulic cylinders 6, 7 and links 15, 16 in the support mechanism A, which may cause malfunctions. Therefore, if the weight of the cargo exceeds the set value, a notification is issued so that an external worker can understand the situation. As a notification means, instead of the notification lamp 21, a buzzer may be used to notify the user by voice.

[0056] Furthermore, the weight calculation unit 102 determines the position of the center of gravity of the entire vehicle when the luggage is loaded (step #5), and determines whether the weight balance of the entire vehicle body is good or not (step #6). To explain further, by comparing the variations in the contact pressure of each of the four running wheels 2, the position of the center of gravity of the entire vehicle in a plan view can be determined.

[0057] For example, even if the center of gravity is in the center of the loading section 8, if the vehicle body 1 is tilted, it is expected that the ground contact pressure of the running wheels 2 located on the lower side of the tilt will be greater than the ground contact pressure of the running wheels 2 located on the upper side of the tilt. Also, even if the loading section 8 is in a horizontal position, if the cargo is loaded unevenly on the loading section 8, the ground contact pressure of the running wheels 2 on the uneven side will be greater than the ground contact pressure of the running wheels 2 located on the opposite side.

[0058] Therefore, the vertical height of the multiple (four) support mechanisms A (the vertical height from the ground contact point of the running wheels to the connection point with the vehicle body) is calculated from the detection results of each of the stroke sensors S3, and a virtual plane consisting of the ground contact points of the four running wheels 2 relative to the vehicle body 1 is calculated.

[0059] Then, the system determines where the center of gravity is located three-dimensionally in the vehicle body 1, and determines whether the weight balance of the entire vehicle body is good, such as whether there is a risk of the vehicle tipping over if it continues to run in this state. If it determines that the weight balance is not good, it executes a notification process to notify this fact by using the notification lamp 21 (step 7).

[0060] [Another embodiment] (1) As the load detection means, for example, instead of the pressure sensors S1 and S2, a torque sensor or a load cell that detects the drive torque applied to each link 15 and 16 of the support mechanism A may be used, or a sensor that directly detects the vertical ground contact pressure applied to the rotation axis of the running wheel 2 may be used. Also, instead of the stroke sensor S3, a potentiometer or a rotary encoder that detects the rotation angle of the joint portion of each link 15 and 16 of the support mechanism A may be used. Also, an ultrasonic sensor may be used to detect the height from the top surface of the vehicle body 1 to the ground contact portion of each running wheel 2.

[0061] (2) As the tilt state detection means, various sensors such as a weight-type tilt sensor or an optical fiber gyro may be used instead of an inertial measurement unit (IMU).

[0062] (3) In the weight calculation process, for example, the total weight may be calculated by adding up the vertical ground contact pressures applied to the rotation axis of the traveling wheels 2, and the calculation method can be changed in various ways.

[0063] (4) If the weight of the luggage exceeds the set value, instead of performing an alarm process, the engine 9a may be brought to an emergency stop. Also, if driving operations are performed using a remote device such as a remote control device, a display provided on the remote device may be configured to display that the weight of the luggage exceeds the set value.

[0064] (5) The support mechanism A may be a mechanism having one link or three or more links, and may be provided with an electric actuator instead of a hydraulic cylinder.

[0065] (6) The traveling wheels 2 may be driven by an electric motor, an engine, or the like. [Industrial Applicability]

[0066] The present invention can be applied to a work vehicle that is suitable for traveling on uneven, rough terrain. [Explanation of symbols]

[0067] 1 Vehicle body 2 Running wheels 6,7 Hydraulic cylinder 15,16 Link A Support mechanism C Control device KF Load Load Detection Means S1, S2 pressure sensors S3 Stroke Sensor S4 Tilt sensor (means for detecting tilt state)

Claims

1. a vehicle body having a loading section capable of loading luggage; a plurality of running wheels located at the front and rear of each of the left and right sides of the vehicle body; a support mechanism that is supported by the vehicle body and supports the plurality of running wheels so that their positions can be changed relative to the vehicle body; a control device for controlling the operation of the support mechanism; a load detection means for detecting a load acting on the plurality of support mechanisms due to the load of the entire vehicle; a tilt state detection means for detecting a tilt state of the loading section, The control device a weight calculation process for calculating the weight of the luggage based on the detection results of the load detection means and the tilt state detection means; determining a center of gravity position of the entire vehicle based on the detection results of the load detection means and the tilt state detection means; A work vehicle configured to determine whether the weight balance of the entire vehicle is appropriate based on the detection results of the load detection means and the detection results of the tilt state detection means, the center of gravity position, and information on the weight of the luggage.

2. The control device The weight calculation process includes a first process for determining a vertically downward contact pressure at the contact points of the running wheels based on the detection results of the load detection means and the tilt state detection means, a second process for determining the weight of the entire vehicle by adding up the contact pressures of the respective running wheels, and a third process for determining the weight of the luggage by subtracting the weight of the vehicle body from the weight of the entire vehicle; and 2. A work vehicle as described in claim 1, wherein a process is executed to determine the center of gravity position of the entire vehicle based on the variation in the contact pressure of each of the plurality of running wheels, a virtual plane consisting of the contact points of the plurality of running wheels with respect to the vehicle body is determined based on information on the vertical heights of the plurality of support mechanisms obtained based on the detection results of the load load detection means, and further, whether the weight balance of the entire vehicle is appropriate is determined based on where the center of gravity position is located three-dimensionally on the vehicle body.

3. The control device 2. The work vehicle according to claim 1, wherein when the weight of the load calculated in the weight calculation process exceeds a set value, a notification process is executed in which a notification means notifies the user of the weight.

4. The support mechanism is provided with a bending link mechanism in which a plurality of links are pivotally connected, and a plurality of hydraulic cylinders capable of changing the rotational postures of the plurality of links, 2. The work vehicle according to claim 1, wherein the load detection means comprises a pressure sensor that detects the internal pressure of an oil chamber of the hydraulic cylinder, and a stroke sensor that detects the amount of extension and contraction of the hydraulic cylinder.

5. 5. The work vehicle according to claim 1, wherein the control device performs horizontal control to control the operation of the support mechanism so that the vehicle body is in a horizontal position based on detection information from the tilt state detection means.

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