AU2019378450B2 - Mixer vehicle - Google Patents

Abstract

A mixer vehicle (1) is provided with a drive device (4) which rotationally drives a mixer drum (2), a drive state detector (5c, 10b) which detects the drive state of the drive device (4), a rotation sensor (6a) as a drum rotation detector which detects the rotational speed of the mixer drum (2), and a controller (20) which outputs a drive command value to the drive device (4) so that the rotational speed of the mixer drum (2) is a target rotational speed. The controller (20) has an abnormality determination unit (21) which, when the difference between the rotational speed of the mixer drum (2) and the target rotational speed is greater than or equal to a predetermined reference value, identifies the location of an abnormality on the basis of a drive command value, a value detected by the rotation sensor (6a), and a value detected by the drive state detector (5c, 10b).

Description

DESCRIPTION MIXER VEHICLE TECHNICAL FIELD

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

BACKGROUND ART

[0002] JP2016-84105A discloses a mixer vehicle including a controller for

controlling a drum driving device so that a rotation number of a mixer drum

becomes a target rotation number.

SUMMARY OF INVENTION

[0003] In an ordinary mixer vehicle as described in JP2016-84105A, when

an abnormality occurs in a rotation number control of the mixer drum and the

rotation number of the mixer drum cannot be controlled to the target rotation

number, the quality of fresh concrete loaded on the mixer drum deteriorates.

Therefore, it is necessary to identify a failure portion immediately in order to

carry out repairs quickly when the abnormality occurs in the rotation number

control of the mixer drum in the mixer vehicle.

[0004] According to one aspect of the present invention, a mixer vehicle

including a mixer drum capable of loading fresh concrete is provided. The

mixer vehicle includes: a driving device configured to rotate the mixer drum; a

driving state detector configured to detect a driving state of the driving device;

a drum rotation detector configured to detect a rotation number of the mixer

drum; and a controller configured to output a driving command value to the

driving device so that the rotation number of the mixer drum becomes a target

rotation number, wherein the controller includes an abnormality determination unit configured to determine an abnormality portion on the basis of the driving command value, a detected value detected by the drum rotation detector, and a detected value detected by the driving state detector, when a difference value between a rotation number of the mixer drum and a target rotation number is equal to or larger than a predetermined reference value.

[0005] In some embodiments, the driving device may include a hydraulic

pump driven by a driving source and configured to discharge a working fluid;

and a hydraulic motor operated by the working fluid supplied from the

hydraulic pump and configured to rotate the mixer drum. The driving state

detector may include a pump rotation detector configured to detect the

rotation number of the hydraulic pump; and a supplying pressure detector

configured to detect a pressure of the working fluid supplied from the

hydraulic pump to the hydraulic motor. The driving command value may be a

supplying command value for instructing the supply of the working fluid from

the hydraulic pump to the hydraulic motor. The abnormality determination

unit may determine the abnormality portion on the basis of the supplying

command value, the detected value detected by the drum rotation detector, a

detected value detected by the pump rotation detector, and a detected value

detected by the supplying pressure detector.

BRIEF DESCRIPTION OF DRAWINGS

[0006] FIG. 1A is a plan view of a mixer vehicle according to an embodiment

of the present invention.

FIG. 1B is a side view of the mixer vehicle.

FIG. 2 is a block diagram illustrating a hardware configuration of a device

for driving a mixer drum of the mixer vehicle.

FIG. 3A is a part of a flowchart illustrating a process procedure in

identifying a failure portion in the mixer vehicle according to the embodiment

of the present invention.

FIG. 3B is a flowchart illustrating a processing procedure following the

flowchart shown in Fig. 3A.

DESCRIPTION OF EMBODIMENTS

[0007] An embodiment of the present invention will be described below with

reference to the drawings.

[0008] Referring to FIG. 1A, FIG. 1B, and FIG. 2, the entire configuration of

a mixer vehicle 1 according to the embodiment of the present invention will be

described. FIG. 1A is a plan view of the mixer vehicle 1, FIG. 1B is a side view

of the mixer vehicle 1, and FIG. 2 is a block diagram showing the hardware

configuration of the device for driving a mixer drum 2 of the mixer vehicle 1.

[0009] The mixer vehicle 1 is a vehicle for transporting so-called fresh

concrete such as mortar, ready-mixed concrete, or the like charged into the

mixer drum 2. In the following description, a case where the mixer vehicle 1

loads ready-mixed concrete as a load will be described.

[0010] As shown in the FIG. 1A and the FIG. 1B, the mixer vehicle 1 is a

vehicle including a cab 11 and a frame 3, and includes a mixer drum 2

mounted on the frame 3 and capable of mounting a ready-mixed concrete, a

driving device 4 that rotationally drives the mixer drum 2, and a controller 20

that controls rotation of the mixer drum 2. In the FIG. 1B, the driving device

4 and the like are not illustrated.

[0011] The mixer drum 2 is a bottomed cylindrical container mounted to

rotate on the frame 3, an opening 2a to be used to charge and discharge the

ready-mixed concrete is provided at the rear end. The mixer drum 2 is

mounted so as to be inclined so that the rotation axis 0 thereof becomes

gradually higher from the front portion toward the rear portion of the vehicle.

In the mixer drum 2, a drum blade (not shown) is spirally disposed along the

inner wall surface of the drum, and the drum blade rotates together with the

mixer drum 2, thereby the ready-mixed concrete loaded in the mixer drum 2 is

agitated or the like.

[0012] A hopper 16 is provided at a rear upper portion of the opening 2a of

the mixer drum 2. The ready-mixed concrete charged into the mixer vehicle 1

in the ready-mixed concrete plant is guided to the opening 2a by the hopper 16.

A flow guide 17 and a chute 18 are provided at a rear lower portion of the

opening 2a of the mixer drum 2. The ready-mixed concrete discharged from

the opening 2a is guided to the chute 18 by the flow guide 17, and discharged

in a predetermined direction by the chute 18.

[0013] The mixer drum 2 is rotationally driven via a driving device 4 by an

engine 10 as a power source that is mounted on the mixer vehicle 1 and used

for travelling. The driving device 4 is a hydraulic device that is driven by the

rotation of the engine 10 and rotationally drives the mixer drum 2 by the fluid

pressure of the working fluid.

[0014] As shown in FIG. 2, the engine 10 has a throttle valve 10a for

adjusting the output and the rotation number of the engine 10. The opening

degree of the throttle valve 10a is controlled by the controller 20 via an

actuator (not shown) when the driving device 4 is driven by the engine 10.

Further, the engine 10 is provided with a rotation sensor 1Ob that detects the

rotation number of the engine 10 and outputs a signal corresponding to the

detected rotation number to the controller 20. Since the rotation number of the

engine 10 detected by the rotation sensor 10b correlates with the rotation

number of an oil pump 5 described below, the rotation sensor 1Ob corresponds

to a pump rotation detector that detects the rotation number of the oil pump 5.

[0015] The rotation number of the engine 10 when driving the driving

device 4 is controlled by the controller 20 via the throttle valve 10a so that the

rotation number detected by the rotation sensor 1Ob becomes a predetermined

rotation number. The rotation sensor 10b may detect the rotation number of

the PTO shaft 9 and the drive shaft 8, which are input shaft of the driving

device 4, or may detect the rotation number of the oil pump 5, which will be

described later.

[0016] Rotations of the engine 10 are transmitted to the driving device 4 via

a PTO shaft 9 (PTO: Power take-off) which constantly extracts power from the

engine 10, and a drive shaft 8 (see FIG. 2) which connects the PTO shaft 9 and

the driving device 4.

[0017] The driving device 4 includes the oil pump 5 as a hydraulic pump

driven by an engine 10 to discharge working oil as a working fluid, and an oil

motor 6 as a hydraulic motor driven by the working oil supplied from the oil

pump 5 to drive the mixer drum 2 to rotate. In the driving device 4, other

incompressible fluid may be used as the working fluid instead of the working

oil.

[0018] The oil pump 5 is a swash plate type axial piston pump in which the

discharge amount is changed in accordance with the tilt angle of a swash plate

(not shown), and includes a control valve 5a for controlling the supply of the working oil from the oil pump 5 to the oil motor 6, a tilt angle adjusting mechanism 5b as a discharge amount adjusting mechanism for adjusting the discharge amount of the oil pump 5 by changing the tilt angle of the swash plate, a pressure sensor Sc as a supplying pressure detector for detecting the pressure of the working oil supplied to the oil motor 6, and a load sensing mechanism 5d for adjusting the tilt angle of the swash plate so that the differential pressure between the pressure of the working oil flowing into the oil motor 6 and the pressure of the working oil discharged from the oil pump 5 becomes a predetermined value.

[0019] The oil pump 5 is rotationally driven by power constantly extracted

from the engine 10 via the PTO shaft 9. The drive source for rotationally

driving the oil pump 5 is not limited to the engine 10 for driving, and may be an

auxiliary engine or an electric motor that is not used for travelling.

[0020] The control valve Sa is an electromagnetic three-position switching

valve having a first position that the working oil is provided from oil pump 5 to

oil motor 6 so that the mixer drum 2 is rotated to a agitating direction as a

regular rotation direction, a second position that the working oil is provided

from the oil pump 5 to the oil motor 6 so that the mixer drum 2 is rotated to a

discharge direction as a reverse rotation direction, and a blocking position that

the working oil is blocked to provide from the oil pump 5 to the oil motor 6.

[0021] The control valve Sa includes a first solenoid (not shown) that make

to move the position of the control valve Sa from the blocking position to the

first position, and a second solenoid (not shown) that make to move the

position of the control valve Sa from the blocking position to the second

position.

[0022] The position of the control valve Sa is changed according to the value of the driving current supplied to each solenoid from the controller 20. For example, the position of the control valve 5a gradually changes from blocking position to first position as the driving current supplied to the first solenoid increases. As the position of the control valve 5a is displaced from the blocking position to the first position, a resistance provided to the working oil passing through the control valve 5a gradually decreases, and as a result, the amount of the working oil supplied from the oil pump 5 to the oil motor 6 gradually increases. In other words, it is possible to adjust the amount of the working oil flowing from the oil pump 5 to the oil motor 6 by controlling the current supplied to the first solenoid of the control valve 5a. The control valve

5a can be of a type that gradually changes its position from the first position to

the blocking position as the driving current supplied to the first solenoid

increases.

[0023] The tilt angle adjusting mechanism 5b includes a hydraulic actuator,

which is not illustrated in the figure, that changes the tilt angle of the swash

plate. The tilt angle adjusting mechanism 5b changes the tilt angle of the

swash plate according to the pressure of the working oil that is led to the

hydraulic actuator from the load sensing mechanism 5d described below. The

discharge amount of the oil pump 5 is changed according to the change in the

tilt angle of the swash plate.

[0024] The pressure sensor Sc outputs a signal corresponding to the

detected pressure of the working oil to the controller 20. The pressure sensor

Sc may be installed on the oil motor 6 to detect the pressure of the working oil

supplied from the oil pump 5 to the oil motor 6. Thus, the pressure sensor Sc

senses the pressure of the working oil in the driving device 4.

[0025] The load sensing mechanism 5d controls the tilt angle of the swash plate of the oil pump 5 so that the differential pressure between the load pressure, which is the pressure of the working oil flowing into the oil motor 6, and the discharge pressure, which is the pressure of the working oil discharged from the oil pump 5, becomes a predetermined value. The load sensing mechanism 5d includes a spool valve (not shown) that has surfaces in which the pressure of the working oil supplied to the oil motor 6 and the pressure of the working oil discharged from the oil pump 5 act in opposition to each other. The load sensing mechanism 5d controls the discharge pressure of the oil pump 5 by changing the pressure of the working oil led to the hydraulic actuator of the tilt angle adjusting mechanism 5b that changes the tilt angle of the swash plate according to displacement of the spool valve.

[0026] In this way, the oil pump 5 changes the discharge amount according

to the tilt angle of the swash plate and changes the discharge direction by the

control valve Sa. The oil pump 5 is not limited to the above-mentioned type of

pump, and any type of pump may be used as long as the discharge capacity is

variable. Also the oil pump 5 may be a swash plate type axial piston pump in

which the discharge amount and the discharge direction are changed in

accordance with the tilt angle of the swash plate.

[0027] The oil motor 6 is a swash plate type axial piston motor in which the

capacity is changed in accordance with the tilt angle of a swash plate (not

shown), and includes a rotation sensor 6a that detects a rotation direction and

a rotation number of an output shaft (not shown) of the oil motor 6, and an tilt

angle adjusting mechanism 6b for configured to adjust a tilt angle of the swash

plate.

[0028] The rotation sensor 6a output signals corresponding to the detected

rotation direction and rotation number of the output shaft to the controller 20.

Since the rotation number of the oil motor 6 detected by the rotation sensor 6a

is correlated to the rotation number of the mixer drum 2, the rotation sensor

6a corresponds to a drum rotation detector that detects the rotation number of

the mixer drum 2. The rotation sensor 6a may be used to detect the rotation

number of the mixer drum 2.

[0029] The tilt angle adjusting mechanism 6b includes a hydraulic actuator

(not shown) for changing the tilt angle of the swash plate, and a solenoid valve

(not shown) for controlling the hydraulic pressure guided to the hydraulic

actuator. The tilt angle of the swash plate is changed according to the current

value supplied to the solenoid valve from the controller 20, and the

displacement of the oil motor 6 is changed.

[0030] It should be noted that the oil motor 6 may be a swash plate type

axial piston motor in which the capacity is switched to two stages: a small

capacity for high-speed rotation and a large capacity for normal rotation.

[0031]

In the driving device 4 configured as described above, the oil motor 6 is rotated

by the working oil discharged from the oil pump 5 which is supplied to the oil

motor 6, and the rotation number of the oil motor 6 is changed in accordance

with the amount of oil supplied and the tilt angle of the swash plate of the oil

motor 6. The rotation direction of the oil motor 6 is switched by switching the

position of the control valve 5a provided in the oil pump 5.

[0032] An output shaft of the driving device 4, that is, an output shaft of the

oil motor 6 is connected to a rotation shaft 0 of the mixer drum 2 via a

reduction gear 7. Therefore, it is possible to increase or decrease the rotation

number of the mixer drum 2 by increasing or decreasing the rotation number

of the oil motor 6, and by switching the rotation direction of the oil motor 6, it is possible to switch the rotation direction of the mixer drum 2 between the agitating direction which is the regular rotation direction and the discharging direction which is the reverse rotation direction.

[0033] When the mixer drum 2 is rotationally driven in the agitating

direction, the ready-mixed concrete in the mixer drum 2 moves forward while

being agitated by the drum blade. On the other hand, when the mixer drum 2

is rotationally driven in the discharge direction, the ready-mixed concrete in

the mixer drum 2 moves backward while being agitated by the drum blade.

[0034] By rotating the mixer drum 2 in the discharging direction which is

the opposite direction to the agitating direction in this manner, the

ready-mixed concrete can be discharged from the opening 2a of the mixer

drum 2. The ready-mixed concrete discharged from the mixer drum 2 is

guided to a predetermined position via a flow guide 17 and a chute 18.

[0035] In addition, when the ready-mixed concrete is charged into the

mixer drum 2 via the hopper 16, the mixer drum 2 is rotated in the agitating

direction at a higher speed than that at the time of agitation, so that the

charged ready-mixed concrete is quickly moved to the front of the mixer drum

2.

[0036] The controller 20 is composed of a microcomputer including a CPU

(Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access

Memory), an I/O interface (Input/Output Interface), and the like. The RAM

stores data in the processing of the CPU, the ROM stores a control program of

the CPU and the like in advance, and the I/O interface is used for

input/output of information to/from a connected device. The operation of the

driving device 4 is controlled by operating the CPU, the RAM, and the like in

accordance with a program stored in the ROM.

[0037] As described above, the rotation sensor 6a of the oil motor 6, the

rotation sensor 1Ob as a driving state detector to detect the driving state of the

driving device 4, and the pressure sensor Sc are connected to the controller 20.

The detected values detected by these sensors are input to the controller 20.

Further, as described above, a solenoid valve of the tilt angle adjusting

mechanism 6b, the first and second solenoid of the control valve Sa, and the

throttle valve 10a are connected to the controller 20, and the commands for

operating these are output from the controller 20.

[0038] Further, an operation device 22 to operate the driving of the mixer

drum 2, a display device 23 to display the driving state of the mixer drum 2, an

abnormality in the driving device 4 and so forth, and a communication device

24 to enable communication with an external facility such as the ready-mixed

concrete plant are connected to the controller 20.

[0039] The operation device 22 is provided with switches such as an

operation switch (not shown) to change the rotation direction and rotation

speed of the mixer drum 2, an automatic mixing switch to automatically stir

and rotate the mixer drum 2, and an emergency stop switch to stop the

rotation of the mixer drum 2 in case of emergency. The operation device 22 is

provided at a plurality parts of the vehicle, such as in the cabin 11 where the

operator mainly operates, and at the rear of the vehicle.

[0040] The display device 23, together with the operation device 22, is

provided at a plurality parts of the vehicle, such as in cabin 11 and the rear of

the vehicle. The display device 23 may be integrated with the operation device

22

[0041] The communication device 24 is a wireless communication part

corresponding to a wireless LAN such as Wi-Fi or a mobile telephone communication network such as third-generation mobile communication (3G), and so forth. The work states and failure portions of the mixer vehicle 1 are transmitted successively via the communication device 24 to the ready-mixed concrete plant, a vehicle maintenance factory and other external facility. The communication device 24 may be provided inside the controller 20, and may be provided in a part which is exposed to the outside of the vehicle separately from the controller20 in order to improve the communication status with external facility. And also, the communication device 24 may not be provided.

[0042] When the various switches of the operation device 22 are operated

by the operator, the controller 20 controls each mechanism that constitutes

the driving device 4, such as the tilt angle of the swash plate of the oil motor 6

and the control valve 5a provided in the oil pump 5, so that the rotating state of

the mixer drum 2 becomes the state corresponding to the operated switch.

[0043] For example, when the automatic mixing switch in the operation

device 22 is operated by the operator, the controller 20 outputs a driving

command value to the driving device 4 so that the actual rotation number of

the mixer drum 2 converted from the detected value detected by the rotation

sensor 6a provided in the oil motor 6 becomes the predetermined target

rotation number. Also, the controller 20 controls the driving state of the

driving device 4 by increasing or decreasing the rotation number of the engine

10 via the throttle valve 10a of the engine 10.

[0044] The driving command value output from the controller 20 is a

supplying command value that commands the supply of the working oil from

the oil pump 5 to the oil motor 6 and a capacity command value that increases

or decreases the capacity of the oil motor 6. Specifically, the current value

supplied from the controller 20 to the first and second solenoid of the control valve 5a provided in the oil pump 5 corresponds to the supplying command value, and the current value supplied to the tilt angle adjusting mechanism of the oil motor 6 corresponds to the capacity command value.

[0045] The controller 20 informs that there is an abnormality in the control

that the rotation number control is not being performed properly via the

display device 23 to the operator, when a difference value between the actual

rotation number of the mixer drum2 and the target rotation number is equal to

or larger than a predetermined reference value.

[0046] Here, after the abnormality of the rotation number control is

informed, even if the mixer vehicle 1 is moved to the vehicle maintenance

factory, it needs to confirm a rotating state of the mixer drum2 in a

predetermined condition at the vehicle maintenance factory, and identifying

the failure portion causing the abnormality of the control. Therefore, it may

take a long time to identify the failure portion at the vehicle maintenance

factory. And there is a risk that the mixer vehicle 1 may become unusable for

a long time.

[0047] In order to avoid such a situation, in one of the embodiment of the

controller 20 of the mixer vehicle 1 includes an abnormality determination unit

21 that automatically determines the failure portion causing the abnormality

when the difference value between the rotation number of the mixer drum 2

and the target rotation number is equal to or larger than the predetermined

reference value of difference. The abnormality determination unit 21 shows

the specific function of the controller 20 as a virtual unit, and does not mean

that it physically exists. For example, the determination described below that

are made in the abnormality determination unit 21 are mainly made by the

CPU, and the reference values described below that are used in the determinations of the abnormality determination unit 21 are mainly stored in the ROM.

[0048] Hereinafter, referring to the flow chart of FIG. 3A and FIG. 3B, a

process of determination of an abnormality portion performed by the

abnormality determination unit 21 of the controller 20 will be described.

[0049] First of all, in Step S11, when the mixer drum 2 is rotated to the

agitating direction, it is determined whether the difference value in the rotation

number between the actual rotation number of the mixer drum 2 converted

from the detected value detected by the rotation sensor 6a of the oil motor 6

and the target rotation number of the mixer drum 2 is equal to or larger than

the predetermined reference value of difference.

[0050] When the difference value in the rotation number is equal to or

larger than the reference value of difference, it is determined that the

abnormality has occurred in the rotation number control of the mixer drum2,

and the process proceeds to Step S12 to start determination of the failure

portion by the abnormality determination unit 21. When the difference value

in the rotation number is less than the reference value of difference, it is

determined that the rotation number control of the mixer drum2 is working

properly, and the process ends once. The determination of whether there is

the abnormality in the rotation number control of the mixer drum 2 by the

controller 20 can also be made based on the duration or frequency of a state

which the difference value exceeds the reference value of difference instead of

based on the magnitude of the difference value in the rotation number.

[0051] In Step S12, it is determined whether the current value supplied

from the controller 20 to the first solenoid of the control valve 5a provided in

the oil pump 5 is less than or equal to the reference current value as a predetermined reference command value.

[0052] Here, when the actual rotation number of the mixer drum 2

converted from the detected value detected by the rotation sensor 6a of the oil

motor 6 continues to be higher than the target rotation number of the mixer

drum 2, the controller 20 reduces the amount of the working oil supplied from

the oil pump 5 to the oil motor 6 in order to reduce the rotation number of the

mixer drum 2. Specifically, the controller 20 sets the current value supplied

to the first solenoid of the control valve 5a provided in the oil pump 5 to zero,

and sets the position of the control valve 5a to the blocking position.

[0053] On the other hand, when the actual rotation number of the mixer

drum 2 converted from the detected value detected by the rotation sensor 6a of

the oil motor 6 continues to be lower than the target rotation number of the

mixer drum 2, the controller 20 increases the amount of the working oil

supplied from the oil pump 5 to the oil motor 6 in order to increase the rotation

number of the mixer drum 2. Specifically, the controller 20 sets the current

value supplied to the first solenoid of the control valve 5a provided in the oil

pump 5 to maximum value, and sets the position of the control valve 5a to the

first position.

[0054] In other words, in Step S12, it is determined whether the actual

rotation number of the mixer drum2 is lower or higher than the target rotation

number based on the current value supplied from the controller20 to the first

solenoid of the control valve 5a. Specifically, when the current value is less

than or equal to the reference current value, it is determined that the actual

rotation number of the mixer drum 2 is higher than the target rotation number,

and when the current value is larger than the reference current value, it is

determined that the actual rotation number of the mixer drum2 is lower than the target rotation number. The reference current value used for determination in Step S12 should be less than the maximum value, for example, the reference current value can be set to zero.

[0055] In Step S12, when the current value supplied from the controller 20

to the first solenoid of the control valve 5a is equal to or less than the reference

current value, for example, it is determined that the current value is zero, the

process proceeds to Step S13.

[0056] In Step S13, it is determined whether the detected value detected by

the pressure sensor 5c, which detects the pressure of the working oil supplied

to the oil motor 6, is equal to or larger than the first reference value.

[0057] Here, when the current value supplied from the controller 20 to the

first solenoid of the control valve 5a is zero, the amount of the working oil

supplied from the oil pump 5 to the oil motor 6 should be zero, which means

the detected value detected by the pressure sensor 5c should be zero. On the

other hand, when the detected value detected by the pressure sensor 5c is of a

certain magnitude and the rotation number of the mixer drum 2 exceeds the

target rotation number, it means that the working oil is being supplied from

the oil pump 5 to the oil motor 6 contrary to the command from the controller

20.

[0058] Therefore, in Step S13, when it is determined that the detected value

detected by the pressure sensor 5c is equal to or larger than the first reference

value, the process proceeds to Step S14, it is determined that the cause of the

abnormality in the rotation number control of the mixer drum 2 is that the

working oil supply from the oil pump 5 to the oil motor 6 cannot be blocked

due to the malfunction of the control valve 5a provided in the oil pump 5. The

first reference value used for determination in Step S13 is set to a value larger than zero, and is a value that clearly indicates that working oil is being supplied from the oil pump 5 to the oil motor 6.

[0059] When the failure portion is identified in Step S14, the process

proceeds to Step S15 and displays on the display device 23 that the rotation

number control of the mixer drum 2 is abnormal due to the failure of the

control valve 5a provided in the oil pump 5, and the controller 20 issues an

alarm sound.

[0060] On the other hand, when it is determined in Step S13 that the

detected value detected by the pressure sensor Sc is less than the first

reference value, that is, the working oil is not supplied from the oil pump 5 to

the oil motor 6, it is understood that the control valve Sa provided in the oil

pump 5 blocks flowing the working oil from the oil pump 5 to the oil motor 6.

Then, if the working oil is not supplied from the oil pump 5 to the oil motor 6,

the oil motor 6 will not be driven, and the mixer drum 2 driven by the oil motor

6 will naturally not be rotating. Nevertheless, the fact that the rotation number

of the mixer drum 2 exceeds the target rotation number means that the

rotation sensor 6a of the oil motor 6, which detects the rotation number

correlated to the rotation number of the mixer drum 2, is outputting the

abnormally high value.

[0061] Therefore, when the detected value detected by the pressure sensor

Sc is determined to be less than the first reference value in Step S13, the

process proceeds to Step S16 and it is identified that the cause of the

abnormality in the rotation number control of the mixer drum 2 is the output

abnormality in the rotation sensor 6a.

[0062] In Step 16, when the failure portion is identified, the process

proceeds to Step S15 and displays on the display device 23 that there is the abnormality in the rotation number control of the mixer drum 2 due to the failure of the rotation sensor 6a, and also issues the alarm sound.

[0063] On the other hand, in Step S12, when it is determined that the

current value supplied from the controller 20 to the first solenoid of the control

valve 5a is a value that exceeds the reference current value, for example, the

maximum current value, the process proceeds to Step S17.

[0064] In Step S17, it is determined whether the rotation number of the oil

pump 5 is zero, that is, whether the oil pump 5 is stopped, based on the

detected value detected by the rotation sensor 10b of the engine10 for

detecting the rotation number correlated to the rotation number of the oil

pump 5.

[0065] Here, when the detected value detected by the rotation sensor 1Ob is

zero, it can be conceivable that the oil pump 5 is not actually rotating or the

rotation number of the oil pump 5 is not detected normally. Therefore, in

Step S17, when the detected value detected by the rotation sensor 10b is

determined to be zero, the process proceeds to Step S18, it is identified the

reason for the oil pump 5 is determined not to rotate.

[0066] In Step S18, it is determined whether the detected value detected by

the pressure sensor Sc for detecting the pressure of the working oil supplied to

the oil motor 6 is equal to or larger than the second reference value.

[0067] If the detected value detected by the pressure sensor Sc is of a

certain magnitude, the oil pump 5 should be in a state of discharging the

working oil, that is, in a state of being rotating. Nevertheless, the fact that the

rotation number of the oil pump 5 is zero means that the rotation of the oil

pump 5 has not been detected normally. On the other hand, if the detected

value detected by the pressure sensor Sc is zero, it means that the oil pump 5 is actually stopped, that is, the engine10 that drives the oil pump 5 to rotate is stopped.

[0068] Therefore, in Step S18, when it is determined that the detected value

detected by the pressure sensor Sc is equal to or larger than the second

reference value, the process proceeds to Step S19, and it is identified that the

reason for the rotation number of the abnormal mixer drum 2 is an

abnormality in rotation sensor1Ob system. The abnormality in rotation sensor

10b system is, for example, a malfunction of the rotation sensor 10b itself, a

disconnection of a harness connecting the rotation sensor 10b and the

controller 20, or the like.

[0069] On the other hand, in Step S18, when it is determined that detected

value detected by the pressure sensor Sc is less than the second reference

value, the process proceeds to Step S20, and it is identified that the reason for

the abnormality in the rotation number control of the mixer drum 2 is the

stoppage of the engine10 and not the failure of the driving device 4.

[0070] The second reference value used for the determination in Step S18 is

a value larger than zero and is set to a value at which the working oil is

determined to be discharged obviously from the oil pump 5. The second

reference value may be the same value as the first reference value.

[0071] When the failure portion is identified in Step S19, the process

proceeds to Step S21, it is determined whether the rotation number of the

mixer drum 2 is zero, that is, whether the mixer drum 2 is stopped, based on

the detected value detected by the rotation sensor 6a of the oil motor 6 that

detects the rotation number correlated to the rotation number of the mixer

drum 2.

[0072] If the detected value detected by the pressure sensor Sc is of a certain magnitude, it should be in a state in which the working oil is supplied to the oil motor 6, that is, the mixer drum 2 is rotating by the oil motor 6.

Nevertheless, the fact that the rotation number of the mixer drum 2 is zero

means that the rotation of the mixer drum 2 is not detected normally.

[0073] Therefore, in Step S21, when it is determined that the rotation

number of the mixer drum 2 is zero, the process proceeds to Step S22, and it is

identified that the reason for the abnormality in the rotation number control of

the mixer drum 2 is the abnormality in the rotation sensor 6a system of the oil

motor 6 in addition to the abnormality in the rotation sensor1Ob system of the

engine10 identified in Step S19. The abnormality in rotation sensor 6a system

is, for example, a malfunction of the rotation sensor 6a itself, a disconnection

of a harness connecting the rotation sensor 6a and the controller 20, or the

like.

[0074] On the other hand, when it is determined in Step S21 that the

rotation number of the mixer drum 2 is not zero, the rotation of the mixer

drum 2 is detected normally, and it is identified that the reason for the

abnormality in the rotation number control of the mixer drum 2 is only the

abnormality in the rotation sensor 10b system of the engine 10 identified in

Step S19.

[0075] In Step S22, when the failure portion is identified, the process

proceeds to Step S15, and the controller 20 displays on the display device 23

that the abnormality has occurred in the rotation number control of the mixer

drum 2 due to the abnormality in the rotation sensor 1Ob system and the

rotation sensor 6a system, and issues the alarm sound.

[0076] Further, in Step S21, when it is determined that the rotation

number of the mixer drum 2 is not zero, the process proceeds to Step S15, and the controller 20 displays on the display device 23 that the abnormality has occurred in the rotation number control of the mixer drum 2 due to the abnormality in the rotation sensor 10b system only, and issues the alarm sound.

[0077] Also, when it is identified that there is no failure in the driving device

4 in Step S20, the process proceeds to Step S15, the controller 20 displays on

the display device 23 that the abnormality has occurred in the rotation

number control of the mixer drum 2 due to the stoppage of the engine10, and

issues the alarm sound.

[0078] On the other hand, in Step S17, when it is determined that the oil

pump 5 of the rotation number is not zero, that is, the oil pump 5 is rotating,

the process proceeds to Step S23.

[0079] In Step S23, it is determined whether the detected value detected by

the pressure sensor Sc for detecting the pressure of the working oil supplied to

the oil motor 6 is equal to or larger than a third reference value.

[0080] When the detected value detected by the pressure sensor Sc is less

than the third reference value, for example, approximately zero, it means that

the oil pump 5 is in a condition where the discharge amount cannot be

increased even though the oil pump 5 is rotating.

[0081] Therefore, in Step S23, when it is determined that the detected value

detected by the pressure sensor Sc is less than the third reference value, the

process proceeds to Step S25, and it is identified that the reason for the

abnormal rotation number control of the mixer drum 2 is that the discharge

amount of the oil pump 5 cannot be increased due to the malfunction of the oil

pump 5. The malfunction of the oil pump 5 is, for example, sticking of the

swash plate, damage to the seal member, defective switching of the control valve 5a, or the like.

[0082] The third reference value used for the determination in Step S23 is a

value larger than zero and is set to a value at which the working oil is

determined to be discharged clearly from the oil pump 5. The third reference

value may be the same value as the first reference value or the second

reference value.

[0083] On the other hand, in Step S23, when it is determined that the

detected value detected by the pressure sensor Sc is equal to or larger than the

third reference value, and that a certain amount of the working oil discharged

from the oil pump 5, the process proceeds to Step S24, it is determined

whether the rotation number of the mixer drum 2 is zero, that is, whether the

mixer drum 2 is stopped, based on the detected value detected by the rotation

sensor 6a of the oil motor 6 that detects the rotation number correlated to the

rotation number of the mixer drum 2.

[0084] If the detected value detected by the pressure sensor Sc is of a

certain magnitude, it should be in a state in which the working oil is supplied

to the oil motor 6, that is, the mixer drum 2 is rotating by the oil motor 6.

Nevertheless, the fact that the rotation number of the mixer drum 2 is zero

means that the rotation of the mixer drum 2 is not detected normally.

[0085] Therefore, in Step S24, when it is determined that the rotation

number of the mixer drum 2 is zero, the process proceeds to Step S26, and it is

identified that the reason for the abnormality in the rotation number control of

the mixer drum 2 is the abnormality in the rotation sensor 6a system of the oil

motor 6. The abnormality in rotation sensor 6a system is, for example, the

malfunction of the rotation sensor 6a itself, the disconnection of the harness

connecting the rotation sensor 6a and the controller 20, or the like.

[0086] On the other hand, in Step S24, when the rotation number of the

mixer drum 2 is determined not to be zero, the process proceeds to Step S27.

[0087] In the case of proceeding to Step S27, the rotation number of the

mixer drum 2 is low and does not reach the target rotation number even

though the oil pump 5 is rotating. Therefore, there is a high possibility that

there is some abnormality in the oil pump 5 and sufficient working oil is not

being supplied from the oil pump 5 to the oil motor 6 that drives the mixer

drum 2.

[0088] For further identify the failure portion of the oil pump 5, in Step S27,

it is determined whether a fluctuation range of the detected value detected by

the pressure sensor 5c, which detects the pressure of the working oil supplied

to the oil motor 6, is equal to or larger than a predetermined reference range

value.

[0089] The discharge pressure of the oil pump 5 is likely to change due to

delay in the operation of the swash plate caused by abrasion of parts that

affect the operation of the swash plate, such as the cradle bushing that

supports the swash plate rotatably and the hydraulic actuator that changes

the tilt angle of the swash plate. Further, if the spool valve of the load sensing

mechanism 5d fails to operate properly due to sliding failure or other reasons,

the discharge pressure of the oil pump 5 becomes lower than normal, and the

oil pump 5 will not be able to supply enough working oil to the oil motor 6.

[0090] Therefore, in Step S27, when it is determined that the fluctuation

range of the detected value detected by the pressure sensor 5c is equal to or

larger than the reference range value, the process proceeds to Step S28, it is

identified that the cause of the abnormality in the rotation number control of

the mixer drum 2 is the abnormality in the part related to the tilt angle adjusting mechanism 5b of the oil pump 5, and when it is determined that the fluctuation range of the detected value detected by the pressure sensor Sc is less than the reference range value, the process proceeds to Step S29, it is identified that the cause of the abnormality in the rotation number control of the mixer drum 2 is the abnormality in the part related to load sensing mechanism 5d of the oil pump 5.

[0091] When the failure portion is identified in Step S25, Step S26, Step

S28 and Step S29, the process proceeds to Step S15 and displays the failure

portion identified in each step on the display device 23, and also issues the

alarm sound.

[0092] In this way, since the failure portion is identified before the mixer

vehicle 1 enters the vehicle maintenance factory, there is no need for the

vehicle maintenance factory to carry out confirmation work to identify the

failure portion. Therefore, the mixer vehicle 1 can be repaired quickly. As a

result, the period during which the mixer vehicle 1 cannot be used will be

shortened, and it is possible to prevent the utilization rate of mixer vehicle 1

from decreasing.

[0093] Further, since the parts that need to be replaced are identified by

determining the abnormality portion, the repair cost can be reduced and the

replacement time can be shortened compared to replacing the whole of the

driving device 4.

[0094] Further, the controller 20 displays the information on the display

device 23 and transmits the identification number of the mixer vehicle 1 and

failure details to external facilities such as the ready-mixed concrete plant and

the vehicle maintenance factory via the communication device 24. At the

vehicle maintenance factory that received the failure information, it is possible to prepare replacement parts quickly and prepare to accept the vehicle, so that the mixer vehicle 1 can be repaired even more quickly. Furthermore, the ready-mixed concrete plant will be able to deliver the ready-mixed concrete to the concrete casting site by a replacement vehicle by knowing the breakdown of the mixer vehicle 1.

[0095] According to the above embodiment, it achieves the effects shown

below.

[0096] In the mixer vehicle 1 with the above configuration, the controller 20

includes the abnormality determination unit 21 that determines the failure

portion on the basis of the current value supplied from the controller 20 to the

first solenoid of the control valve 5a provided in the oil pump 5, the detected

value detected by the rotation sensor 6a, the detected value detected by the

rotation sensor 1Ob, and the detected value detected by the pressure sensor Sc,

when the difference value between the rotation number of the mixer drum 2

and the target rotation number is equal to or larger than the predetermined

reference value. In this way, when the abnormality occurs in the rotation

number control of the mixer drum 2, the abnormality determination unit 21 of

the controller 20 automatically determines the abnormality portion.

Therefore, the failure portion can be quickly identified without doing any work

to identify the failure portion at the vehicle maintenance factory or the like.

[0097] Further, it is possible to repair the mixer vehicle 1 quickly by the

failure portion is identified before the mixer vehicle 1 enters the vehicle

maintenance factory. As a result, the period during which the mixer vehicle 1

cannot be used will be shortened, and it is possible to prevent the utilization

rate of mixer vehicle 1 from decreasing.

[0098] It will be described below a modification of the embodiment of the present invention.

[0099] In the above embodiment, after Step S12 of determining whether the

current value supplied from controller 20 to the first solenoid of the control

valve 5a provided in the oil pump 5 is equal to or less than the reference

current value, Step S17 of determining whether the rotation number of the oil

pump 5 is zero, is performed. Alternatively, Step S17 may be performed prior

toStepS12. In this case, the Steps after Step S23 will be performed when the

determination in Step S12 is denied.

[0100] In addition, in the above embodiment, in order to determine whether

the actual rotation number of the mixer drum 2 is in a state higher than the

target rotation number by exceeding the reference difference and is in a state

lower than the target rotation number by exceeding the reference difference, in

Step S12, it is determined that the current value supplied from the controller

20 to the first solenoid of the control valve 5a is equal to or less than the

reference current value.

[0101] In addition, in the above embodiment, the oil pump 5 is the swash

plate type axial piston pump. The oil pump 5 is not limited thereto and may be

any pump as long as the discharge capacity is variable, for example, a vane

pump in which the discharge capacity is variable. In this case, the

mechanism for rotating cam ring in which the vane is in sliding contact

corresponds to the discharge amount adjusting mechanism, the current value

supplied to drive the actuator or the like for displacing the cam ring

corresponds to the supplying command value.

[0102] Configurations, operations, and effects of the embodiment of the

present invention configured as described above will be collectively described

below.

[0103] The mixer vehicle 1 includes the driving device 4 configured to rotate

the mixer drum 2, the driving state detector Sc, 1Ob configured to detect the

driving state of the driving device 4, the rotation sensor 6a as the drum

rotation detector configured to detect the rotation number of the mixer drum 2,

the controller 20 configured to output the driving command value to the

driving device 4 so that the rotation number of the mixer drum 2 becomes the

target rotation number. The controller 20 includes the abnormality

determination unit 21 configured to determine the abnormality portion on the

basis of the driving command value, the detected value detected by the

rotation sensor 6a, and the detected value detected by the driving state

detector Sc, 1Ob, when the difference value between the rotation number of the

mixer drum 2 and the target rotation number is equal to or larger than the

predetermined reference value.

[0104] In this configuration, the controller 20 includes the abnormality

determination unit 21 which determine the abnormality portion on the basis of

the driving command value, the detected value detected by the rotation sensor

6a, and the detected value detected by the driving state detector Sc, 1Ob, when

the difference value between the rotation number of the mixer drum 2 and the

target rotation number is equal to or larger than the predetermined reference

value. In this way, when the abnormality occurs in the rotation number

control of the mixer drum 2, the abnormality determination unit 21 of the

controller 20 automatically determines the abnormality portion. Therefore,

the failure portion can be quickly identified without carrying out confirmation

work to identify the failure portion at the vehicle maintenance factory or the

like. Further, the failure portion is identified before the mixer vehicle 1 enters

the vehicle maintenance factory, which allows the mixer vehicle 1 to be repaired quickly. As a result, the period during which the mixer vehicle 1 cannot be used will be shortened, and it is possible to prevent the utilization rate of mixer vehicle 1 from decreasing.

[0105] In addition, the driving device 4 includes the oil pump 5 driven by

the engine 10 as the driving source and configured to discharge the working oil,

the oil motor 6 operated by the working oil supplied from the oil pump 5 and

configured to rotate the mixer drum 2. The driving state detector includes the

rotation sensor 10b as the pump rotation detector configured to detect the

rotation number of the oil pump 5, and the pressure sensor Sc configured to

detect the pressure of the working oil supplied from the oil pump 5 to the oil

motor 6. The driving command value is the supplying command value for

instructing the supply of the working oil from the oil pump 5 to the oil motor 6.

The abnormality determination unit 21 determines the abnormality portion on

the basis of the supplying command value, the detected value detected by the

rotation sensor 6a, the detected value detected by the rotation sensor 1Ob, and

the detected value detected by the pressure sensor Sc.

[0106] In this configuration, the controller 20 includes the abnormality

determination unit 21 which determine the abnormality portion on the basis of

the supplying command value for instructing the supply of the working oil

from the oil pump 5 to the oil motor 6, the detected value detected by the

rotation sensor 6a, the detected value detected by the rotation sensor 1Ob, and

the detected value detected by the pressure sensor Sc, when the difference

value between the rotation number of the mixer drum 2 and the target rotation

number is equal to or larger than the predetermined reference value. In this

way, when the abnormality occurs in the rotation number control of the mixer

drum 2, the abnormality determination unit 21 of the controller 20 automatically determines the abnormality portion. Therefore, the failure portion can be quickly identified without doing any work to identify the failure portion at the vehicle maintenance factory or the like.

[0107] In addition, in a case in which the supplying command value is

equal to or less than the predetermined reference command value (reference

current value), when the detected value detected by the pressure sensor Sc is

equal to or larger than the first reference value, the abnormality determination

unit 21 determines that there is the abnormality in the oil pump 5, and when

the detected value detected by the pressure sensor Sc is less than the first

reference value, the abnormality determination unit 21 determines that there

is the abnormality in the rotation sensor 6a.

[0108] In addition, in a case in which the rotation sensor 1Ob detects that

the oil pump 5 is not rotated, when the detected value detected by the pressure

sensor Sc is equal to or larger than the second reference value, the abnormality

determination unit 21 determines that there is the abnormality in the rotation

sensor 1Ob, and when the detected value detected by the pressure sensor Sc is

less than the second reference value, the abnormality determination unit 21

determines that the engine 10 is stopped.

[0109] In addition, in a case in which the supplying command value is

larger than the predetermined reference command value (reference current

value) and the oil pump 5 is detected to be rotating by the rotation sensor 1Ob,

when the detected value detected by the pressure sensor Sc is equal to or

larger than the third reference value and the mixer drum 2 is detected to be not

rotating by the rotation sensor 6a, the abnormality determination unit 21

determines that there is the abnormality in the rotation sensor 6a, when the

detected value detected by the pressure sensor Sc is equal to or larger than the third reference value and the mixer drum 2 is detected to be rotating by the rotation sensor 6a, the abnormality determination unit 21 determines that there is the abnormality in the oil pump 5, and when the detected value detected by the pressure sensor Sc is less than the third reference value, the abnormality determination unit 21 determines that there is the abnormality in the oil pump S.

[0110] In addition, the oil pump 5 includes the tilt angle adjusting

mechanism 5b configured to adjust the discharge amount of the oil pump 5

and the load sensing mechanism 5d configured to change the discharge

pressure of the oil pump 5 in response to load of the oil motor 6. In a case in

which: the supplying command value is larger than the predetermined

reference command value (reference current value); the oil pump 5 is detected

to be rotating by the rotation sensor 10b; the detected value detected by the

pressure sensor Sc is equal to or larger than the third reference value; and the

mixer drum 2 is detected to be rotating by the rotation sensor 6a, when the

fluctuation range of the detected value detected by the pressure sensor Sc is

equal to or larger than the reference range, the abnormality determination unit

21 determines that there is the abnormality in the tilt angle adjusting

mechanism 5b of the oil pump 5, and when the fluctuation range of the

detected value detected by the pressure sensor Sc is less than the reference

range, the abnormality determination unit 21 determines that there is the

abnormality in the load sensing mechanism 5d of the oil pump S.

[0111] In those configurations, the abnormality determination unit 21 of

the controller 20 determines the abnormality portion on the basis of the

supplying command value for instructing the supply of the working oil from

the oil pump 5 to the oil motor 6, the detected value detected by the rotation sensor 6a, the detected value detected by the rotation sensor 1Ob, and the detected value detected by the pressure sensor Sc. In this way, when the abnormality occurs in the rotation number control of the mixer drum 2, the abnormality determination unit 21 of the controller 20 automatically determines the abnormality portion, which allows the mixer vehicle 1 to be repaired quickly. Further, since the parts that need to be replaced are identified by determining the abnormality portion, the repair cost can be reduced and the replacement time can be shortened compared to replacing the whole of the driving device 4.

[0112] Although the embodiments of the present invention have been

described in the above, the above-mentioned embodiments merely illustrate a

part of application examples of the present invention, and the technical scope

of the present invention is not intended to be limited to the specific

configurations of the above-described embodiments.

[0113] This application claims priority based on Japanese Patent

Application No. 2018-215555 filed with the Japan Patent Office on November

16, 2018, the entire contents of which are incorporated into this specification

by reference.

[0114] Throughout this specification and the claims which follow, unless

the context requires otherwise, the word "comprise", and variations such as

"comprises" or "comprising", will be understood to imply the inclusion of a

stated integer or step or group of integers or steps but not the exclusion of any

other integer or step or group of integers or steps.

[0115] The reference in this specification to any prior publication (or

information derived from it), or to any matter which is known, is not, and

should not be taken as, an acknowledgement or admission or any form of suggestion that that prior publication (or information derived from it) or known matter forms part of the common general knowledge in the field of endeavour to which this specification relates.

Claims (6)

1. A mixer vehicle comprising a mixer drum capable of loading fresh

concrete, comprising:

a driving device configured to rotate the mixer drum;

a driving state detector configured to detect a driving state of the driving

device;

a drum rotation detector configured to detect a rotation number of the

mixer drum; and

a controller configured to output a driving command value to the driving

device so that the rotation number of the mixer drum becomes a target rotation

number, wherein

the controller includes an abnormality determination unit configured to

determine an abnormality portion on the basis of the driving command value,

a detected value detected by the drum rotation detector, and a detected value

detected by the driving state detector, when a difference value between the

rotation number of the mixer drum and the target rotation number is equal to

or larger than a predetermined reference value.

2. The mixer vehicle according to claim 1, wherein

the driving device includes

a hydraulic pump driven by a driving source and configured to discharge

a working fluid; and

a hydraulic motor operated by the working fluid supplied from the

hydraulic pump and configured to rotate the mixer drum,

the driving state detector includes a pump rotation detector configured to detect the rotation number of the hydraulic pump; and a supplying pressure detector configured to detect a pressure of the working fluid supplied from the hydraulic pump to the hydraulic motor, the driving command value is a supplying command value for instructing the supply of the working fluid from the hydraulic pump to the hydraulic motor, the abnormality determination unit determines the abnormality portion on the basis of the supplying command value, the detected value detected by the drum rotation detector, a detected value detected by the pump rotation detector, and a detected value detected by the supplying pressure detector.

3. The mixer vehicle according to claim 2, wherein

in a case in which the supplying command value is equal to or less than

a predetermined reference command value,

when the detected value detected by the supplying pressure detector is

equal to or larger than a first reference value, the abnormality determination

unit determines that there is an abnormality in the hydraulic pump, and

when the detected value detected by the supplying pressure detector is

less than the first reference value, the abnormality determination unit

determines that there is an abnormality in the drum rotation detector.

4. The mixer vehicle according to claim 2 or 3, wherein

in a case in which the pump rotation detector detects that the hydraulic

pump is not rotated,

when the detected value detected by the supplying pressure detector is equal to or larger than a second reference value, the abnormality determination unit determines that there is an abnormality in the pump rotation detector, and when the detected value detected by the supplying pressure detector is less than the second reference value, the abnormality determination unit determines that the driving source is stopped.

5. The mixer vehicle according to any one of claims 2 to 4, wherein

in a case in which the supplying command value is larger than the

predetermined reference command value and the hydraulic pump is detected

to be rotating by the pump rotation detector,

when the detected value detected by the supplying pressure detector is

equal to or larger than a third reference value and the mixer drum is detected

to be not rotating by the drum rotation detector, the abnormality

determination unit determines that there is an abnormality in the drum

rotation detector,

when the detected value detected by the supplying pressure detector is

equal to or larger than the third reference value and the mixer drum is detected

to be rotating by the drum rotation detector, the abnormality determination

unit determines that there is an abnormality in the hydraulic pump, and

when the detected value detected by the supplying pressure detector is

less than the third reference value, the abnormality determination unit

determines that there is an abnormality in the hydraulic pump.

6. The mixer vehicle according to any one of claims 2 to 5, wherein

the hydraulic pump includes a discharge amount adjusting mechanism configured to adjust a discharge amount of the hydraulic pump; and a load sensing mechanism configured to change a discharge pressure of the hydraulic pump in response to load of the hydraulic motor, and wherein in a case in which: the supplying command value is larger than the predetermined reference command value; the hydraulic pump is detected to be rotating by the pump rotation detector; the detected value detected by the supplying pressure detector is equal to or larger than the third reference value; and the mixer drum is detected to be rotating by the drum rotation detector, when a fluctuation range of the detected value detected by the supplying pressure detector is equal to or larger than a reference range, the abnormality determination unit determines that there is an abnormality in the discharge amount adjusting mechanism, and when the fluctuation range of the detected value detected by the supplying pressure detector is less than the reference range, the abnormality determination unit determines that there is an abnormality in the load sensing mechanism.