NZ621394B2 - Mixer truck with drum rotation unevenness determination - Google Patents
Mixer truck with drum rotation unevenness determination Download PDFInfo
- Publication number
- NZ621394B2 NZ621394B2 NZ621394A NZ62139412A NZ621394B2 NZ 621394 B2 NZ621394 B2 NZ 621394B2 NZ 621394 A NZ621394 A NZ 621394A NZ 62139412 A NZ62139412 A NZ 62139412A NZ 621394 B2 NZ621394 B2 NZ 621394B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- mixer drum
- mixer
- rotation
- magnitude
- pressure
- Prior art date
Links
- 239000012530 fluid Substances 0.000 claims description 28
- 238000007599 discharging Methods 0.000 abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 24
- 238000005406 washing Methods 0.000 description 9
- 238000005259 measurement Methods 0.000 description 5
- 230000032258 transport Effects 0.000 description 2
- 230000003213 activating Effects 0.000 description 1
- 230000004913 activation Effects 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000000875 corresponding Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000000284 extract Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006011 modification reaction Methods 0.000 description 1
- 238000004642 transportation engineering Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
- B28C5/42—Apparatus specially adapted for being mounted on vehicles with provision for mixing during transport
- B28C5/4203—Details; Accessories
- B28C5/4206—Control apparatus; Drive systems, e.g. coupled to the vehicle drive-system
- B28C5/421—Drives
- B28C5/4213—Hydraulic drives
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
- B28C5/42—Apparatus specially adapted for being mounted on vehicles with provision for mixing during transport
- B28C5/4203—Details; Accessories
- B28C5/4206—Control apparatus; Drive systems, e.g. coupled to the vehicle drive-system
- B28C5/422—Controlling or measuring devices
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
- B28C5/42—Apparatus specially adapted for being mounted on vehicles with provision for mixing during transport
- B28C5/4203—Details; Accessories
- B28C5/4231—Proportioning or supplying water
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60P—VEHICLES ADAPTED FOR LOAD TRANSPORTATION OR TO TRANSPORT, TO CARRY, OR TO COMPRISE SPECIAL LOADS OR OBJECTS
- B60P3/00—Vehicles adapted to transport, to carry or to comprise special loads or objects
- B60P3/16—Vehicles adapted to transport, to carry or to comprise special loads or objects for carrying mixed concrete, e.g. having rotatable drums
Abstract
mixer truck with drum rotation drive that detects and corrects unevenness of drum is described. The mixer truck comprises: a mixer drum that can carry wet concrete; a drive device that rotatably drives the mixer drum by the pressure of an operating oil; a pressure sensor that detects the drive status of the mixer drum driven by the drive device; a controller that, after discharging the wet concrete inside the mixer drum, determines the amount of unevenness of rotation of the mixer drum, by comparing a predetermined set value and the amount of fluctuation in the drive status detected by the pressure sensor; and a notification device that, if the controller has determined that the amount of fluctuation in the drive status detected by the pressure sensor has reached the set value, notifies the driver that the amount of unevenness of rotation of the mixer drum has reached a permissible value. tus of the mixer drum driven by the drive device; a controller that, after discharging the wet concrete inside the mixer drum, determines the amount of unevenness of rotation of the mixer drum, by comparing a predetermined set value and the amount of fluctuation in the drive status detected by the pressure sensor; and a notification device that, if the controller has determined that the amount of fluctuation in the drive status detected by the pressure sensor has reached the set value, notifies the driver that the amount of unevenness of rotation of the mixer drum has reached a permissible value.
Description
Description
GS10565/PCT-860
DESCRIPTION
MIXER TRUCK WITH DRUM ROTATION UNEVENNESS
DETERMINATION
TECHNICAL FIELD
This invention relates to a mixer truck.
BACKGROUND ART
A mixer truck having a mixer drum that is capable of
carrying ready-mixed concrete is used conventionally.
JP2005-199859A discloses a mixer truck having a
washing nozzle capable of injecting washing water into a mixer drum.
In this mixer truck, ready-mixed concrete adhered to an interior of the
mixer drum is washed away by injecting the washing water through
the washing nozzle.
SUMMARY OF INVENTION
However, even when a washing function such as that of
the mixer truck described in JP2005-199859A is provided, it remains
difficult to remove the ready-mixed concrete adhered to the mixer
drum completely. Therefore, the ready-mixed concrete that could not
be removed may harden within the mixer drum. Hardened concrete
adhered to the mixer drum must be removed periodically by an
operation known as chipping, but since it is impossible to see detailed
portions of the mixer drum interior, it is difficult to determine whether
or not concrete removal is required.
This invention has been designed in consideration of the
GS10565/PCT-860
problem described above, and in one form the invention seeks to
provide a mixer truck which is capable of notifying a driver of the need
to remove hardened concrete adhered to an interior of a mixer drum.
According to one aspect of this invention, a mixer truck
having a mixer drum that is capable of carrying ready-mixed concrete
is provided. The mixer truck includes: a driving device that is
configured to drive the mixer drum to rotate using a fluid pressure of
a working fluid; a driving condition detector that is configured to
detect a driving condition of the mixer drum driven by the driving
device; a controller that is configured to determine a magnitude of
rotation unevenness in the mixer drum by comparing a magnitude of
variation in the driving condition detected by the driving condition
detector with a predetermined set value after the ready-mixed
concrete in the mixer drum has been discharged; and a notifying
device that is configured to notify a driver that the magnitude of the
rotation unevenness in the mixer drum has reached an allowable
value when the controller determines that the magnitude of the
variation in the driving condition detected by the driving condition
detector has reached the set value.
The details as well as other features and advantages of
this invention are set forth in the remainder of the specification and
are shown in the accompanying drawings.
BRIEF DESCRIPTION OF DRAWINGS
is a plan view of a mixer truck according to an
embodiment of this invention.
is a control block diagram of the mixer truck.
is a side sectional view showing a mixer drum of the
mixer truck in a condition where ready-mixed concrete is adhered
thereto.
is a front sectional view of .
is a graph illustrating an action of the mixer truck.
is a flowchart showing a routine for notifying a driver
that a magnitude of rotation unevenness in the mixer drum of the
mixer truck has reached an allowable value.
DESCRIPTION OF EMBODIMENTS
A mixer truck 100 according to an embodiment of this
invention will be described below with reference to the figures.
First, referring to FIGS. 1 and 2, an overall configuration
of the mixer truck 100 will be described.
As shown in the mixer truck 100 is a vehicle
having a driver’s cab 11 and a frame 1. The mixer truck 100 includes
a mixer drum 2 that is carried on the frame 1 to be capable of carrying
ready-mixed concrete, a driving device 4 that drives the mixer drum 2
to rotate, and a controller 10 that controls rotation of the mixer drum
2. The mixer truck 100 transports the ready-mixed concrete carried
in the mixer drum 2.
The mixer drum 2 is a closed-end cylinder-shaped
container carried rotatably on the frame 1. The mixer drum 2 is
carried such that a rotary axis thereof is oriented in a front-rear
direction of the vehicle. The mixer drum 2 is carried at a front-rear
incline so as to rise gradually toward a rear portion of the vehicle.
An opening portion is formed in a rear end of the mixer
drum 2, and the ready-mixed concrete can be introduced and
discharged through the opening portion. The mixer drum 2 is driven
to rotate using a travel engine 3 installed in the mixer truck 100 as a
power supply.
The driving device 4 is driven by rotation of the engine 3
to drive the mixer drum 2 to rotate using a fluid pressure of a working
fluid. A rotary motion of a crankshaft in the engine 3 is transmitted
to the driving device 4 by a power take-off (PTO) 9 that extracts power
from the engine 3 continuously, and a drive shaft 8 (see that
couples the power take-off 9 to the driving device 4.
As shown in the power take-off 9 is provided with
a rotation sensor 9a that detects a rotation speed thereof and outputs
a rotation speed signal corresponding to the detected rotation speed to
the controller 10. A rotation speed of the drive shaft 8 may also be
detected using the rotation sensor 9a.
Working oil is used in the driving device 4 as the working
fluid. It should be noted that another incompressible fluid may be
used as the working fluid instead of working oil. As shown in
the driving device 4 includes a hydraulic pump 5 serving as a fluid
pressure pump that is driven by the engine 3 to discharge the working
fluid, and a hydraulic motor 6 serving as a fluid pressure motor that is
driven by the hydraulic pump 5 to drive the mixer drum 2 to rotate.
The driving device 4 can rotate the mixer drum 2 normally and in
reverse, and can increase and reduce a rotation speed of the mixer
drum 2.
The hydraulic pump 5 is driven to rotate by the power
extracted continuously from the engine 3 via the power take-off 9. A
rotation speed of the hydraulic pump 5 is therefore greatly affected by
variation in the rotation speed of the engine 3 accompanying variation
in a travel condition of the vehicle. Hence, in the mixer truck 100,
operations of the hydraulic pump 5 and the hydraulic motor 6 are
controlled by the controller 10 so that the mixer drum 2 achieves a
target rotation condition in accordance with the rotation speed of the
engine 3.
The hydraulic pump 5 is a variable capacity swash
plate-type axial piston pump. A tilt angle of the hydraulic pump 5 is
switched to a normal rotation direction or a reverse rotation direction
upon reception of a control signal from the controller 10. The
hydraulic pump 5 includes a solenoid valve for adjusting the tilt angle.
By switching the solenoid valve, a discharge direction and a discharge
capacity of the hydraulic pump 5 are adjusted.
The working oil discharged from the hydraulic pump 5 is
supplied to the hydraulic motor 6 in order to rotate the hydraulic
motor 6. The mixer drum 2 is coupled to the hydraulic motor 6 via a
reduction gear 7. Hence, the mixer drum 2 rotates in accordance
with the rotation of the hydraulic motor 6.
When the mixer drum 2 is operated by the hydraulic
pump 5 to rotate normally, the ready-mixed concrete in the mixer
drum 2 is agitated. When the mixer drum 2 is operated by the
hydraulic pump 5 to rotate in reverse, on the other hand, the
ready-mixed concrete in the mixer drum 2 is discharged to the outside
through the opening portion in the rear end. The hydraulic pump 5 is
provided with a pressure sensor 5a (see serving as a pressure
detector that detects a pressure of the discharged working oil.
As shown in the pressure sensor 5a outputs a
load pressure signal to the controller 10 in accordance with the
detected pressure of the working oil. It should be noted that instead
of providing the pressure sensor 5a in the hydraulic pump 5, the
pressure sensor 5a may be provided in the hydraulic motor 6 in order
to detect the pressure of the working oil in the hydraulic motor 6.
Hence, the pressure sensor 5a detects the pressure of the working oil
in the driving device 4.
The hydraulic motor 6 is a variable capacity swash
plate-type axial piston motor. The hydraulic motor 6 is driven to
rotate upon reception of the supply of working oil discharged from the
hydraulic pump 5. The hydraulic motor 6 includes a solenoid valve
that adjusts a tilt angle of the motor upon reception of a two-speed
switch signal from the controller 10. By switching the solenoid valve,
a capacity of the hydraulic motor 6 is switched between two stages,
namely a small capacity for high speed rotation and a large capacity
for normal rotation. The hydraulic motor 6 is provided with a
rotation sensor 6a (see serving as a rotation speed detector
that detects a rotation speed thereof.
As shown in the rotation sensor 6a detects a
rotation direction and the rotation speed of the hydraulic motor 6, and
outputs a rotation direction signal and a rotation speed signal to the
controller 10.
Here, in the pressure sensor 5a that detects the
discharge pressure of the hydraulic pump 5 is used as a driving
condition detector. The pressure sensor 5a and the rotation sensor
6a that detects the rotation speed of the hydraulic motor 6 are both
used to detect a driving condition of the mixer drum 2 driven by the
driving device 4. Variation in the driving condition indicates
variation in various conditions relating to rotational driving of the
mixer drum 2 by the driving device 4, such as variation in the
discharge pressure of the hydraulic pump 5 that drives the mixer
drum 2 to rotate and variation in the rotation speed of the hydraulic
motor 6 that drives the mixer drum 2 to rotate.
Accordingly, the rotation sensor 6a may also be used as
the driving condition detector. In other words, in the mixer truck 100,
at least one of the pressure sensor 5a and the rotation sensor 6a is
used as the driving condition detector.
The controller 10 is used to control the driving device 4,
and is constituted by a microcomputer having a CPU (Central
Processing Unit), a ROM (Read-Only Memory), a RAM (Random Access
Memory), an I/O interface (Input/Output interface), and so on. The
RAM stores data used in processing executed by the CPU. A control
program for the CPU and so on are stored in the ROM in advance.
The I/O interface is used to input and output information into and
from connected devices. Control of the driving device 4 is realized by
operating the CPU, the RAM, and so on in accordance with the
program stored in the ROM.
As shown in an ignition power supply is input into
the controller 10 when a driver starts the engine 3 by operating an
ignition switch provided in the driver’s cab 11. Accordingly, a power
supply relay 21 is switched such that a main power supply from a
main battery 23 is supplied to the controller 10, and as a result, the
controller 10 is driven.
The mixer truck 100 further includes a water tank 12
storing water, a water pressure pump 13 that suctions and discharges
the water in the water tank 12, and an open/close valve 14 provided
between the water pressure pump 13 and the mixer drum 2.
The water pressure pump 13 and the open/close valve 14
are provided in a supply passage for supplying water from the water
tank 12 into the mixer drum 2. The water pressure pump 13 is
activated by an activation signal from the controller 10. The
open/close valve 14 is opened and closed by an open/close signal from
the controller 10.
The water in the water tank 12 is supplied to the mixer
drum 2 by activating the water pressure pump 13 and switching the
open/close valve 14 to an open condition. The water in the water
tank 12 can be replenished with water from an external water supply
at a plant or the like.
Next, referring to control performed in the mixer
truck 100 will be described.
The controller 10 controls the operations of the hydraulic
pump 5 and the hydraulic motor 6 in accordance with a calculated
rotation speed of the engine 3 such that the rotation direction and the
rotation speed of the mixer drum 2 correspond to the target rotation
condition. More specifically, the controller 10 ensures that the
rotation direction and the rotation speed of the mixer drum 2
correspond to the target rotation condition by calculating the
discharge direction and the discharge capacity of the hydraulic pump
and the capacity of the hydraulic motor 6, and outputting a control
signal to the hydraulic pump 5 and the two-speed switch signal to the
hydraulic motor 6.
The load pressure signal is input into the controller 10
from the hydraulic pump 5 via the pressure sensor 5a, and the
rotation direction signal and rotation speed signal are input into the
controller 10 from the hydraulic motor 6 via the rotation sensor 6a.
On the basis of these input signals, the controller 10 controls the
operations of the hydraulic pump 5 and the hydraulic motor 6.
The controller 10 includes a rotation unevenness
determination unit 15 that determines a magnitude of rotation
unevenness in the mixer drum 2 following discharge of the
ready-mixed concrete in the mixer drum 2, or in other words in a
condition where the ready-mixed concrete in the mixer drum 2 has
been completely discharged. The rotation unevenness of the mixer
drum 2 will be described in detail below with reference to FIGS. 3A to
The rotation unevenness determination unit 15
determines the magnitude of the rotation unevenness in the mixer
drum 2 by comparing a magnitude of the driving condition detected by
the driving condition detector with a set value set in advance. More
specifically, the rotation unevenness determination unit 15
determines the rotation unevenness as follows.
When the pressure sensor 5a is used as the driving
condition detector, the rotation unevenness determination unit 15
determines the magnitude of the rotation unevenness in the mixer
drum 2 by comparing a magnitude of variation in the discharge
pressure of the hydraulic pump 5, detected by the pressure sensor 5a,
with a predetermined set value.
The set value used at this time is a set pressure variation
width, which is set in advance on the basis of an allowable value of the
magnitude of the rotation unevenness in the mixer drum 2, and serves
as a magnitude of variation in the working oil pressure detected by the
pressure sensor 5a. The rotation unevenness determination unit 15
determines whether or not the magnitude of the pressure variation
detected by the pressure sensor 5a as the mixer drum 2 rotates has
reached the set pressure variation width.
When the rotation sensor 6a is used as the driving
condition detector, on the other hand, the rotation unevenness
determination unit 15 determines the magnitude of the rotation
unevenness in the mixer drum 2 by comparing a magnitude of
variation in the rotation speed of the hydraulic motor 6, detected by
the rotation sensor 6a, with a set value set in advance.
The set value used at this time is a set rotation speed
variation width, which is set in advance on the basis of the allowable
value of the magnitude of the rotation unevenness in the mixer drum
2, and serves as the magnitude of the variation in the rotation speed of
the hydraulic motor 6 detected by the rotation sensor 6a. The
rotation unevenness determination unit 15 determines whether or not
the magnitude of the rotation speed variation detected by the rotation
sensor 6a as the mixer drum 2 rotates has reached the set rotation
speed variation width.
A parking brake 31, an operating device 32 for operating
the mixer drum 2, and a notifying device 35 for providing the driver
with notifications are disposed in the driver’s cab 11.
The parking brake 31 is provided with a detector that
detects a lever position of the parking brake 31. When the parking
brake 31 is engaged, a stop signal is output to the controller 10 from
the detector.
The operating device 32 is provided with a knob type
operating switch 32a for switching the rotation direction and rotation
speed of the mixer drum 2, a stop switch 32b for stopping the mixer
drum 2 from rotating in an emergency, an automatic agitation switch
32c for automatically rotating the mixer drum 2 for the purpose of
agitation, and an adhesion determination mode switch 32d for
determining whether or not hardened concrete adhered to the mixer
drum 2 has reached an allowable value.
Command signals are output to the controller 10 from
the operating device 32 on the basis of operations performed on the
respective switches 32a to 32d by the driver. On the basis of the
command signals, the controller 10 determines the target rotation
condition, or more specifically the rotation direction and the rotation
speed, of the mixer drum 2.
A rotation operation of the mixer drum 2 will now be
described. When the automatic agitation switch 32c is ON, the stop
signal has not been output from the parking brake 31, and a vehicle
speed is equal to or higher than a predetermined speed, the controller
determines that the vehicle is traveling. Accordingly, the
controller 10 rotates the mixer drum 2 automatically for the purpose
of agitation, thereby preventing discharge of the ready-mixed concrete
and maintaining a quality of the ready-mixed concrete.
When the automatic agitation switch 32c is OFF, on the
other hand, the controller 10 can operate the operating device 32 to
rotate the mixer drum 2 in reverse even while the vehicle travels. In
so doing, the ready-mixed concrete in the mixer drum 2 can be
discharged to the outside while the vehicle travels at an extremely low
speed, whereby the ready-mixed concrete can be supplied to an
elongated groove or the like, for example. The controller 10 can also
operate the operating device 32 to rotate the mixer drum 2 in reverse
when the stop signal has been output from the parking brake 31,
whereby the ready-mixed concrete in the mixer drum 2 can be
discharged to the outside.
The notifying device 35 notifies the driver that the
magnitude of the rotation unevenness in the mixer drum 2 has
reached the allowable value on the basis of the determination made by
the rotation unevenness determination unit 15 when the magnitude of
the variation in the discharge pressure of the hydraulic pump 5
reaches the set value. The notifying device 35 is a buzzer that
notifies the driver using sound, a lamp that notifies the driver visually,
or the like.
A rear portion operating device 38 with which the mixer
drum 2 can be operated from the exterior of the mixer truck 100 is
disposed on the rear portion of the mixer truck 100. Similarly to the
operating device 32, the rear portion operating device 38 includes a
knob type operating switch 38a for switching the rotation direction
and rotation speed of the mixer drum 2, and a stop switch 38b for
stopping the mixer drum 2 from rotating in an emergency. A
command signal is output to the controller 10 from the rear portion
operating device 38 on the basis of an operation of the rear portion
operating device 38 by the driver.
The mixer truck 100 is further provided with an
automatic washing/mixing operating device 39 with which an
automatic washing operation and a ready-mixed concrete mixing
operation can be performed inside the mixer drum 2 from the exterior
of the mixer truck 100.
Next, referring to FIGS. 3A and 3B, adhesion of concrete
40 to the mixer drum 2 will be described.
As shown in blades 2a formed in a double spiral
shape are provided in the mixer drum 2, and an opening portion 2b is
formed in a rear end portion of the mixer drum 2. Therefore, when
the mixer drum 2 is operated to rotate in reverse, the ready-mixed
concrete in the mixer drum 2 can be discharged to the outside through
the opening portion 2b.
The driver, after completely discharging the ready-mixed
concrete in the mixer drum 2 by operating the mixer drum 2 to rotate
in reverse, washes the interior of the mixer drum 2 by introducing
water. Automatic washing may be performed by controlling the
supply of water to the mixer drum 2 from the water tank 12 and the
rotation of the mixer drum 2 using the controller 10 shown in
However, it is difficult to see into the corners of the
interior of the mixer drum 2 through the opening portion 2b. As
shown in , the ready-mixed concrete adheres to an inner
periphery of the mixer drum 2, and it may therefore be impossible to
see the adhered ready-mixed concrete through the opening portion 2b.
Hence, as shown in , ready-mixed concrete may remain
adhered behind the blades 2a and so on even after the interior of the
mixer drum 2 has been washed.
The ready-mixed concrete adhered to the mixer drum 2
hardens over time to form the concrete 40. When the concrete 40 is
adhered to the mixer drum 2, a capacity of the mixer drum 2 decreases,
leading to a reduction in an amount of ready-mixed concrete that can
be carried in the mixer drum 2. Further, the hardened concrete 40
may narrow a passage for discharging the ready-mixed concrete,
thereby obstructing discharge of the ready-mixed concrete.
Therefore, the hardened concrete 40 adhered to the mixer drum 2
must be removed periodically by performing an operation known as
chipping, in which the concrete 40 is scraped away manually.
Conventionally, the concrete 40 is removed on the basis
of the elapse of time, for example once every several months, or a
number of ready-mixed concrete transportation operations. These
methods are not based on the actual amount of hardened concrete 40
in the mixer drum 2. Therefore, a removal operation may be
performed even though the amount of hardened concrete 40 in the
mixer drum 2 is small, or the mixer drum 2 may continue to be used
even though the amount of hardened concrete 40 in the mixer drum 2
is large. Hence, in the mixer truck 100 according to this invention,
the driver is notified of the need to remove the concrete 40 on the basis
of the magnitude of the rotation unevenness in the mixer drum 2.
When ready-mixed concrete adheres to the mixer drum 2
and hardens, further ready-mixed concrete adheres to the hardened
concrete 40 and likewise hardens. The concrete 40 therefore adheres
to the mixer drum 2 and hardens in specific parts thereof rather than
over the entire periphery. Hence, when the mixer drum 2 is rotated
in a condition where the hardened concrete 40 is adhered thereto,
rotation unevenness occurs in the mixer drum 2.
Next, rotation unevenness in the mixer drum 2 will be
described with reference to
In an abscissa shows time [s], and an ordinate
shows the discharge pressure [Pa] of the hydraulic pump 5, detected
by the pressure sensor 5a.
As shown in when the ready-mixed concrete
adheres to the interior of the mixer drum 2 and hardens, variation
occurs in the discharge pressure of the hydraulic pump 5. More
specifically, when the mixer drum 2 is rotated such that a part in
which the concrete 40 has hardened ascends, a load increases,
leading to an increase in the discharge pressure of the hydraulic pump
. When the part in which the concrete 40 has hardened passes top
dead center and begins to descend, on the other hand, the load
decreases, leading to a reduction in the discharge pressure of the
hydraulic pump 5.
The magnitude of the variation in the discharge pressure
of the hydraulic pump 5 increases as the amount of hardened concrete
40 in the mixer drum 2 increases. In the mixer truck 100, therefore,
a determination as to whether or not the amount of hardened concrete
in the mixer drum 2 has reached an allowable value is made on the
basis of the magnitude of the variation in the discharge pressure of
the hydraulic pump 5.
A case in which the rotation sensor 6a is used as the
driving condition detector is as follows.
When the ready-mixed concrete adheres to the interior of
the mixer drum 2 and hardens, variation occurs in the rotation speed
of the rotation sensor 6a. More specifically, when the part in which
the concrete 40 has hardened passes a lowermost position and starts
to ascend, the load increases, leading to a reduction in the rotation
speed of the hydraulic motor 6. When the part in which the concrete
40 has hardened passes an uppermost position and starts to descend,
on the other hand, the load decreases, leading to an increase in the
rotation speed of the hydraulic motor 6.
The magnitude of the variation in the rotation speed of
the hydraulic motor 6 increases as the amount of hardened concrete
40 in the mixer drum 2 increases. In the mixer truck 100, therefore,
the determination as to whether or not the amount of hardened
concrete in the mixer drum 2 has reached the allowable value is made
on the basis of the magnitude of the variation in the rotation speed of
the hydraulic motor 6.
Next, referring to a routine executed in the mixer
truck 100 by the controller 10 to notify the driver that the magnitude
of the rotation unevenness in the mixer drum 2 has reached the
allowable value will be described. The controller 10 executes this
routine repeatedly at fixed time intervals of ten milliseconds, for
example, while the engine 3 is operative. Here, only a case in which
the pressure sensor 5a is used as the driving condition detector will be
described, but similar control is executed in a case where the rotation
sensor 6a is used as the driving condition detector.
The driver, after completely discharging the ready-mixed
concrete in the mixer drum 2, washes the interior of the mixer drum 2
by introducing water. After completely discharging the washing
water, the driver operates the adhesion determination mode switch
32d. In the mixer truck 100, therefore, a determination as to
whether or not a magnitude of variation in the driving condition of the
mixer drum 2 has reached an allowable value is made in a condition
where the ready-mixed concrete in the mixer drum 2 has been
completely discharged.
In a step S1, the controller 10 determines whether or not
the adhesion determination mode switch 32d has been operated.
When it is determined in the step S1 that the adhesion determination
mode switch 32d has been operated, the routine advances to a step
In the step S2, the controller 10 switches the mixer drum
2 to measurement rotation. Here, measurement rotation is rotation
at a rotation speed where the rotation unevenness in the mixer drum
2 becomes apparent. The rotation speed of the mixer drum 2 during
measurement rotation is set at a higher rotation speed than a rotation
speed employed during agitation rotation. In so doing, a time
required to measure the rotation unevenness in the mixer drum 2 can
be shortened. It should be noted that the rotation speed of the mixer
drum 2 during measurement rotation may be identical to or lower than
the rotation speed employed during agitation rotation. The rotation
unevenness in the mixer drum 2 can also be measured in these cases.
In a step S3, the rotation unevenness determination unit
determines whether or not the magnitude of the variation in the
discharge pressure of the hydraulic pump 5, detected by the pressure
sensor 5a, has reached the set pressure variation width. In so doing,
the controller 10 can determine whether or not removal of the
ready-mixed concrete adhered to the mixer drum 2 is required.
When it is determined in the step S3 that the magnitude
of the variation in the discharge pressure of the hydraulic pump 5 has
reached the set pressure variation width, the routine advances to a
step S4. When it is determined in the step S3 that the magnitude of
the variation in the discharge pressure of the hydraulic pump 5 has
not reached the set pressure variation width, on the other hand, the
routine returns.
In the step S4, the controller 10 notifies the driver from
the notifying device 35 that the magnitude of the variation in the
discharge pressure of the hydraulic pump 5 has reached the set
pressure variation width, and therefore that the magnitude of the
rotation unevenness in the mixer drum 2 has reached the allowable
value. As a result, the driver is notified of the need to remove the
ready-mixed concrete adhered to the mixer drum 2.
Hence, in the mixer truck 100, the driver is notified of the
need to remove the concrete 40 on the basis of the magnitude of the
rotation unevenness in the mixer drum 2. As a result, situations in
which a removal operation is performed even though the amount of
hardened concrete 40 in the mixer drum 2 is small or the mixer drum
2 continues to be used even though the amount of hardened concrete
40 in the mixer drum 2 is large can be prevented.
In a step S5, the rotation speed of the mixer drum 2 is
switched from measurement rotation to agitation rotation. Once the
mixer drum 2 has been switched to agitation rotation, the
determination as to whether or not the magnitude of the rotation
unevenness in the mixer drum 2 has reached the allowable value is
terminated, and the routine is returned.
According to the embodiment described above, following
effects are obtained.
When the magnitude of the variation in the driving
condition of the mixer drum 2 reaches the preset set value, the driver
is notified from the notifying device 35 that the rotation unevenness of
the mixer drum 2 has reached the allowable value. The magnitude of
the variation in the driving condition of the mixer drum 2 increases as
the amount of ready-mixed concrete adhered to the mixer drum 2
increases. Therefore, by determining whether or not the magnitude
of the variation in the driving condition of the mixer drum 2 has
reached the allowable value after the ready-mixed concrete in the
mixer drum 2 has been completely discharged, a determination can be
made as to whether or not the concrete 40 adhered to the mixer drum
2 needs to be removed. As a result, notification of the need to remove
the concrete 40 adhered to the mixer drum can be provided.
Although the invention has been described above with
reference to certain embodiments, the invention is not limited to the
embodiments described above. Modifications and variations of the
embodiments described above will occur to those skilled in the art,
within the scope of the claims.
This application claims priority based on Japanese
Patent Application No. 2011-191520 filed with the Japan Patent Office
on September 2, 2011, the entire contents of which are incorporated
into this specification.
INDUSTRIAL APPLICABILITY
This invention can be applied to a mixer truck that
transports ready-mixed concrete.
The embodiments of this invention in which an exclusive
property or privilege is claimed are defined as follows:
Claims (4)
1. A mixer truck having a mixer drum that is capable of carrying ready-mixed concrete, comprising: a driving device that is configured to drive the mixer drum to rotate using a fluid pressure of a working fluid; a driving condition detector that is configured to detect a driving condition of the mixer drum driven by the driving device; a controller that is configured to determine a magnitude of rotation unevenness in the mixer drum by comparing a magnitude of variation in the driving condition detected by the driving condition detector with a predetermined set value after the ready-mixed concrete in the mixer drum has been discharged; and a notifying device that is configured to notify a driver that the magnitude of the rotation unevenness in the mixer drum has reached an allowable value when the controller determines that the magnitude of the variation in the driving condition detected by the driving condition detector has reached the set value.
2. The mixer truck as defined in Claim 1, wherein the driving condition detector is a pressure detector that is configured to detect a pressure of the working fluid in the driving device, the set value is a set pressure variation width, which is set in advance on the basis of the allowable value of the magnitude of the rotation unevenness in the mixer drum and serves as the magnitude of the variation in the working oil pressure detected by the pressure detector, and the controller determines whether or not the magnitude of the variation in the pressure, detected by the pressure detector as the mixer drum rotates, has reached the set pressure variation width.
3. The mixer truck as defined in Claim 2, wherein the driving device includes: a fluid pressure pump that is configured to discharge the working fluid; and a fluid pressure motor that is configured to be driven by the working fluid discharged by the fluid pressure pump in order to drive the mixer drum to rotate, and the pressure detector is configured to detect a discharge pressure of the fluid pressure pump or a fluid pressure in the fluid pressure motor.
4. The mixer truck as defined in Claim 1, wherein the driving device includes: a fluid pressure pump that is configured to discharge the working fluid; and a fluid pressure motor that is configured to be driven by the working fluid discharged by the fluid pressure pump in order to drive the mixer drum to rotate, the driving condition detector is a rotation speed detector that is configured to detect a rotation speed of the fluid pressure motor, the set value is a set rotation speed variation width, which is set in advance on the basis of the allowable value of the magnitude of the rotation unevenness in the mixer drum and serves as a magnitude of variation in the rotation speed of the fluid pressure motor, detected by the rotation speed detector, and the controller determines whether or not the magnitude of the variation in the rotation speed, detected by the rotation speed detector as the mixer drum rotates, has reached the set rotation speed variation width.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2011-191520 | 2011-09-02 | ||
JP2011191520A JP5785825B2 (en) | 2011-09-02 | 2011-09-02 | Mixer truck |
PCT/JP2012/071670 WO2013031759A1 (en) | 2011-09-02 | 2012-08-28 | Mixer truck |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ621394A NZ621394A (en) | 2015-10-30 |
NZ621394B2 true NZ621394B2 (en) | 2016-02-02 |
Family
ID=
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