AU2015264984B2

AU2015264984B2 - Mixer vehicle, control device, and rotation control method for mixer drum

Info

Publication number: AU2015264984B2
Application number: AU2015264984A
Authority: AU
Inventors: Shinsuke TAKINO; Takahiro Yoshida
Original assignee: KYB Corp
Current assignee: KYB Corp
Priority date: 2014-05-30
Filing date: 2015-05-19
Publication date: 2018-06-07
Anticipated expiration: 2035-05-19
Also published as: NZ726458A; JP6410480B2; JP2015224015A; WO2015182433A1; AU2015264984A1

Abstract

[Problem] To appropriately process ready-mixed concrete in a mixer drum even when vehicle failure has occurred. [Solution] In a rotation control method for a mixer drum according to one embodiment of the present technology, a mixer drum (1) is rotated, during idling stopping of a mixer vehicle (100), in a direction in which ready-mixed concrete is stirred, said rotation being accomplished by driving an electric motor (22) using a first output using power stored in a second battery (21). During an input operation by an operator on an operation unit (8) that is mounted in the mixer vehicle (100), the mixer drum (1) is rotated in a direction in which the ready-mixed concrete is discharged, said rotation being accomplished by driving the electric motor (22) using a second output using power stored in the second battery (21).

Description

DESCRIPTION

MIXER VEHICLE, CONTROL DEVICE, AND ROTATION CONTROL METHOD FOR MIXER DRUM

Technical Field [0001] The present invention relates to a mixer vehicle including an idling stop function for stopping an engine at a time the vehicle is stopping, a control apparatus mounted on the mixer vehicle, and a rotation control method for a mixer drum.

Background Art [0002] For reducing noises and improving fuel efficiency, there is known an idling stop function for vehicles, for stopping engines at a time the vehicles are stopping at a red light or the like. At present, the idling stop function is mounted mainly on normal vehicles such as a passenger car. In recent years, an idling stop system for specialized vehicles such as a construction vehicle is being developed.

[0003] For example, mixer vehicles that convey ready-mixed concrete to construction sites have mixer drums that constantly need to be rotated until the ready-mixed concrete is discharged. As a drive source thereof, an engine for mixer vehicles is generally used. Specifically, by transmitting rotative power of the engine to a hydraulic pump and supplying a hydraulic oil discharged from the hydraulic pump to a hydraulic motor to drive the motor, a mixer drum is rotary driven by the rotation of the hydraulic motor. Therefore, there has been a need to improve mixer vehicles of the related art from an environmental aspect, which involves improvements in engine noises when a construction site is near a residential district, exhaust gas in the case of a construction in a tunnel, exhaust gas and noises during idling while stopping at a red light or in a traffic jam, and the like .

[0004] In this regard, in recent years, there is proposed a mixer vehicle capable of rotating a drum even during an engine stop. For example, Patent Document 1 discloses a mixer vehicle including a power generator apparatus driven by an engine, an electric storage apparatus that stores outputs of the power generator apparatus, an electric motor driven by power stored in the electric storage apparatus, a second hydraulic pump driven by outputs of the electric motor, and a control apparatus capable of detecting a vehicle stop and driving, based on a selection operation by an operator, a hydraulic motor by the electric motor and the second hydraulic pump at a time the engine is stopped to rotate a drum.

[0005] Patent Document 1: Japanese Patent

Application Laid-open No. 2003-301802 Summary of Invention

Problem to be solved by the Invention [0006] However, in the mixer vehicle disclosed in Patent Document 1 above, there has been a problem that when there is a failure in the control apparatus that detects a stop of a vehicle, the mixer drum cannot be rotated even when an operator is operating it.

Moreover, when a vehicle failure such as an engine trouble occurs, there is a limit in rotating the mixer drum only by power of a secondary battery to continue mixing ready-mixed concrete. Therefore, some kind of countermeasure needs to be taken.

[0007] In view of the circumstances as described above, the present invention aims at providing a mixer vehicle, a control apparatus, and a rotation control method for a mixer drum, with which ready-mixed concrete in a mixer drum can be processed appropriately even when a vehicle failure occurs.

Means for solving the Problem [0008] According to an embodiment of the present invention, there is provided a mixer vehicle including a vehicle body section, a first drive circuit, and a second drive circuit.

The vehicle body section includes a power generator that generates power by power of an engine, a first control section that generates an idling stop signal and controls the engine, a mixer drum, and an operation section that generates an operation signal based on an input operation made by an operator.

The first drive circuit includes a hydraulic motor that rotates the mixer drum, and a first hydraulic pump that is driven by power of the engine and supplies a fluid to the hydraulic motor.

The second drive circuit includes a secondary battery that stores outputs of the power generator, an electric motor that is driven by power stored in the secondary battery, a second hydraulic pump that is driven by the electric motor and supplies a fluid to the hydraulic motor, and a second control section.

The second control section executes a first control mode when the idling stop signal is received from the first control section and a second control mode when the first control section failure occurs and the operation signal is received, the first control mode involving rotating the mixer drum in a first direction by power stored in the secondary battery, the second control mode involving rotating the mixer drum in a second direction opposite to the first direction by power stored in the secondary battery.

[0009] The mixer vehicle rotates the mixer drum by the first drive circuit during drive by an engine, such as while a vehicle is moving. On the other hand, the mixer vehicle rotates the mixer drum by the second drive circuit at a time of an idling stop, such as while a vehicle is stopping. Specifically, in the second drive circuit, upon receiving the idling stop signal from the first control section, the second control section executes the first control mode so as to rotate the mixer drum in the direction in which the contents such as ready-mixed concrete are stirred in the mixer drum (first direction).

[0010] On the other hand, upon receiving the operation signal generated based on the input operation with respect to the operation section, the second control section executes the second control mode so as to rotate the mixer drum in the second direction opposite to the first direction. The second direction is typically a direction in which the contents are discharged from the mixer drum.

[0011] Therefore, in the mixer vehicle, even when a failure occurs in the engine, the first control section, or the like, the contents of the mixer drum can be discharged by power stored in the secondary battery based on an input operation made by the operator via the operation section. As a result, as an emergency measure using limited power of the secondary battery, ready-mixed concrete in the mixer drum can be processed appropriately.

[0012] The discharge destination of the contents of the mixer drum when executing the second control mode is not limited in particular, and an example thereof is a mixer drum of another mixer vehicle.

[0013] The second control section may drive the electric motor by a first output in the first control mode and drive the electric motor by a second output larger than the first output in the second control mode. With this structure, the contents of the mixer drum can be discharged efficiently.

[0014] The second drive circuit may further include a normally-open-type switch device connected between the secondary battery and the electric motor, and the second control section may close the switch device in the second control mode. As the switch device, a contactor, a relay, an electromagnetic switch, and the like are applicable. With the structure described above, the secondary battery and the electric motor can be directly connected via the switch device in the second control mode. As a result, since the mixer drum can be rotated with relatively-large power stored in the secondary battery, contents thereof can be discharged efficiently.

[0015] The mixer vehicle may further include a switch valve provided between the second hydraulic pump and the hydraulic motor. The switch valve is capable of switching states between a first state where a flow channel for rotating the mixer drum in the first direction is formed and a second state where a flow channel for rotating the mixer drum in the second direction is formed. With this structure, the second control section can appropriately make switches between the flow channels respectively corresponding to the first control mode and the second control mode. It should be noted that the switch valve may be provided either in the first drive circuit or the second drive circuit.

[0016] The vehicle body section may further include an electric storage apparatus that stores outputs of the power generator. In this case, the second control section may use either the power stored in the electric storage apparatus or power stored in the secondary battery as a power source for activating the second control section. Typically, the second control section uses the electric storage apparatus as the power source in the first control mode. On the other hand, in the second control mode, when the second control section judges whether a charge amount of the electric storage apparatus is a predetermined value or less and the charge amount is judged to be the predetermined value or less, the secondary battery is used as the power source. With this structure, even when a vehicle failure occurs, the power source for the second control section can be secured.

[0017] According to an embodiment of the present invention, there is provided a control apparatus mounted on a mixer vehicle including a power generator that generates power by power of an engine, a control section that generates an idling stop signal and controls the engine, a hydraulic motor that rotates a mixer drum, a secondary battery that stores outputs of the power generator, an electric motor that is driven by power stored in the secondary battery, a hydraulic pump that is driven by the electric motor and supplies a fluid to the hydraulic motor, and an operation section that generates an operation signal based on an input operation made by an operator, the control apparatus including a first reception section, a second reception section, and a controller.

The first reception section is capable of receiving the idling stop signal from the control section.

The second reception section is capable of receiving the operation signal.

The controller executes a first control mode when the idling stop signal is received and a second control mode when the first control section failure occurs and the operation signal is received. The first control mode involves rotating the mixer drum in a first direction by power stored in the secondary battery. The second control mode involves rotating the mixer drum in a second direction opposite to the first direction by power stored in the secondary battery.

[0018] According to an embodiment of the present invention, there is provided a rotation control method for a mixer drum, including rotating, by driving an electric motor by power stored in a secondary battery that stores outputs of a power generator driven by an engine based on a first output at a time a mixer vehicle is at an idling stop, the mixer drum in a direction in which contents of the mixer drum are stirred.

By driving the electric motor by power stored in the secondary battery based on a second output at a time an input operation is made by an operator using an operation section mounted on the mixer vehicle when the first control section failure occurs, the mixer drum is rotated in a direction in which the contents are discharged.

Effects of the Invention [0019] According to the present invention, even when a vehicle failure occurs, ready-mixed concrete in a mixer drum can be processed appropriately.

Brief Description of Drawings [0020] [Fig. 1] A schematic side view of a mixer vehicle according to an embodiment of the present invention .

[Fig. 2] A schematic structural diagram showing a drive circuit of a mixer drum in the mixer vehicle.

[Fig. 3] A block diagram showing a structure of a second control section in the mixer vehicle.

[Fig. 4] A flowchart for explaining a control method of a second drive circuit for the second control section.

[Fig. 5] A block diagram showing a schematic structure of the second control section according to a second embodiment of the present invention.

[Fig. 6] A flowchart for explaining an operation example in a second control mode, that is executed by the second control section.

Modes for Carrying Out the Invention [0021] Hereinafter, embodiments of the present invention will be described with reference to the drawings .

[0022] <First embodiment>

Fig. 1 is a schematic side view of a mixer vehicle according to an embodiment of the present invention. Fig. 2 is a schematic structural diagram showing a drive circuit of a mixer drum in the mixer vehicle.

[0023] (Overall structure of mixer vehicle)

As shown in Fig. 1, the mixer vehicle 100 includes a mixer drum 1 that conveys mortar, ready-mixed concrete, and the like (hereinafter, referred to as "ready-mixed concrete") from ready-mixed concrete plants to construction sites. The mixer drum 1 is rotatably set on a mount 2 of the mixer vehicle 100.

For preventing quality deterioration and coagulation of ready-mixed concrete while conveying ready-mixed concrete, the mixer vehicle 100 causes the mixer drum 1 to positively rotate so as to stir the ready-mixed concrete with a plurality of spiral blades attached inside the mixer drum 1. The mixer vehicle 100 also causes the mixer drum 1 to rotate negatively so as to discharge the ready-mixed concrete in the mixer drum 1 and supply the ready-mixed concrete to concrete placement positions.

[0024] As shown in Fig. 2, the mixer vehicle 100 includes a vehicle body section 10. The vehicle body section 10 includes the mixer drum 1, the mount 2 (see Fig. 1), an engine 3, a power generator 4, a first battery 5, a first control section 6, a cabin 7 (see Fig. 1), and an operation section 8.

[0025] The engine 3 is a power source of the mixer vehicle 100 and is constituted of an internal-combustion engine such as a gasoline engine and a diesel engine. The power generator 4 generates power by rotative power of the engine and supplies the generated power to the first battery 5 and a second battery 21 to be described later.

[0026] The number of power generators 4 is not limited to one, and a plurality of power generators 4 may be provided. In this case, the first battery 5 and the second battery 21 may be charged by the plurality of power generators, or the power generator may be allocated to each battery.

[0027] The first battery 5 constitutes an "electric storage apparatus" that stores outputs (power) of the power generator 4 and is used as a power source of an electric component system of the vehicle body section 10. Used as the first battery 5 is, for example, a rated-24V lead battery in which 12 2V unit cells are connected in series .

[0028] The first control section 6 is typically constituted of a computer and electrically controls electric component members of the mixer vehicle 100 in addition to ignition control of the engine 3.

[0029] Moreover, the first control section 6 executes an idling stop function for stopping drive of the engine 3 under predetermined conditions at a time the mixer vehicle 100 stops at a red light or the like. The predetermined conditions are set as appropriate. Typically, operation conditions of an accelerator pedal, a brake pedal, an emergency brake (handbrake), and the like are referenced. In executing the idling stop function, the first control section 6 transmits an idling stop signal SI (see Fig. 3) to a second drive circuit 52. On the other hand, it is also possible to structure the first control section 6 so as not to generate the idling stop signal SI when judged that the engine cannot be driven normally due to an engine trouble and the like.

[0030] The operation section 8 generates an operation signal S2 (see Fig. 3) according to an input operation made by an operator (e.g., driver). The operation section 8 is used to activate the second drive circuit 52 and temporarily drive the mixer drum 1 at a time of an emergency where a vehicle failure such as an engine trouble has occurred as will be described later. The operation signal S2 is directly transmitted to the second drive circuit 52 without passing through the first control section 6. In other words, even when some kind of failure occurs in the first control section 6, the operation signal S2 is positively transmitted to the second drive circuit 52.

[0031] Typically, the operation section 8 is constituted of an appropriate switch mechanism such as a button switch, a toggle switch, and a lever switch.

The operation signal S2 is not particularly limited as long as it can electrically detect an input operation with respect to the operation section 8 in the second drive circuit 52, and a signal potential thereof is also not limited. For example, the signal potential may be a predetermined bias potential or a ground potential. When a potential source is necessary for generating the operation signal S2, the potential source may be the first battery 5, the second battery 21, or a dedicated battery.

[0032] The operation section 8 is typically provided inside the cabin 7 (driver's seat), but the present invention is not limited thereto, and the operation section 8 may be provided outside the cabin 7 (e.g., predetermined position on mount 2).

[0033] In the mixer vehicle 100, the mixer drum 1 constantly needs to be rotated until the ready-mixed concrete is discharged. In this regard, the mixer vehicle 100 includes, as drive circuits of the mixer drum 1, a first drive circuit 51 that is operated during drive by an engine and the second drive circuit 52 that is operated during an engine stop.

[0034] The first drive circuit 51 uses the engine 3 of the mixer vehicle 100 as its drive source. The first drive circuit 51 transmits rotative power of the engine 3 to a first hydraulic pump 11 (first hydraulic pump) via a PTO (Power Take Off), supplies the hydraulic oil (fluid) discharged from the first hydraulic pump 11 to a hydraulic motor 12 (hydraulic motor) to drive the hydraulic motor 12, and rotationally drives the mixer drum 1 by rotations of the hydraulic motor 12.

[0035] The second drive circuit 52 uses an electric motor 22 as its drive source. The second drive circuit 52 drives the electric motor 22 by discharge power of the second battery 21 and transmits rotative power of the electric motor 22 to a second hydraulic pump 23 (second hydraulic pump). The second hydraulic pump 23 supplies a hydraulic oil to the hydraulic motor 12 to drive the hydraulic motor 12 and rotationally drives the mixer drum 1 by rotations of the hydraulic motor 12 .

[0036] (First drive circuit)

Next, the first drive circuit 51 will be described in detail.

[0037] The first drive circuit 51 includes the first hydraulic pump 11, the hydraulic motor 12, and a first control valve 13. The first control valve 13 is provided between the first hydraulic pump 11 and the hydraulic motor 12, and a hydraulic circuit 14 is structured between the hydraulic motor 12 and the first control valve 13.

[0038] The first hydraulic pump 11 is driven by power of the engine 3 and supplies a hydraulic oil to the hydraulic motor 12. Being supplied with the hydraulic oil from the first hydraulic pump 11, the hydraulic motor 12 rotates the mixer drum 1.

[0039] The first control valve 13 supplies the hydraulic oil from the first hydraulic pump 11 to the hydraulic circuit 14 and shuts off the supply, and also switches a hydraulic oil supply direction in the hydraulic circuit 14. The first control valve 13 is constituted of a 3-position 4-port electromagnetic switch valve including A, B, and C positions. Those positions are switched based on control signals transmitted from the first control section 6.

[0040] Specifically, the first control valve 13 is switched to the A position when the mixer drum 1 is rotated in a positive direction (first direction) and switched to the C position when the mixer drum 1 is rotated in an opposite direction (second direction).

The first control valve 13 is switched to the A position when the ready-mixed concrete in the mixer drum 1 is stirred and switched to the C position when the ready-mixed concrete is discharged from the mixer drum 1. In addition, the first control valve 13 is switched to the B position when the supply of the hydraulic oil from the first hydraulic pump 11 to the hydraulic motor 12 is shut off.

[0041] It should be noted that although not shown in the figure, in the hydraulic circuit 14, a relief valve that opens when a hydraulic pressure of a predetermined level or more is caused, a check valve that restricts the hydraulic oil supply direction, and the like may be provided at appropriate positions. Moreover, although not shown in the figure, a reducer may be provided between the hydraulic motor 12 and the mixer drum 1.

[0042] (Second drive circuit)

The second drive circuit 52 includes the second battery 21, the electric motor 22, the second hydraulic pump 23, a second control valve 24, and a second control section 25.

[0043] The second drive circuit 52 may have a single unit structure. In this case, the second drive circuit 52 is provided at an appropriate position on the mount 2 between the cabin 7 and the hydraulic motor 12 as shown in Fig. 1, for example.

[0044] The second battery 21 constitutes a "secondary battery" that stores outputs (power) of the power generator 4 and is used as a power source of the electric motor 22. The second battery 21 is not particularly limited as long as it is a secondary battery capable of charging and discharging. In this embodiment, a rated-25.9V lithium ion battery in which 7 3.7V unit cells are connected in series is used as the second battery 21.

[0045] The electric motor 22 is driven by power stored in the second battery 21 and is constituted of a DC motor, for example. As will be described later, when the second control section 25 receives the idling stop signal SI or when the second control section 25 receives the operation signal S2 from the operation section 8, the electric motor 22 is driven by power stored in the second battery 21.

[0046] The second hydraulic pump 23 is driven by the electric motor 22. The second hydraulic pump 23 sucks an operating oil accumulated in a tank 26 and supplies the hydraulic oil to the hydraulic circuit 14. The hydraulic oil amount to be discharged from the second hydraulic pump 23 is controlled based on outputs of the electric motor 22 (rpm).

[0047] The second control valve 24 is constituted as a "switch valve" provided between the second hydraulic pump 23 and the hydraulic circuit 14. The second control valve 24 makes switches between supply of the hydraulic oil from the second hydraulic pump 23 to the hydraulic circuit 14 and shutoff of the supply of the hydraulic oil. In this embodiment, the second control valve 24 is constituted of a 3-position 4-port electromagnetic switch valve including D, E, and F positions. In this embodiment, those positions are switched based on control signals transmitted from the second control section 25. It should be noted that the second control valve 24 may be switched not only by control signals from the second control section 25 but also by manual operations of an operator .

[0048] The second control valve 24 is switched to the D position during drive by the engine 3 and shuts off supply from the second hydraulic pump 23 to the hydraulic circuit 14. On the other hand, the second control valve 24 is switched to the E position when the second control section 25 receives an idling stop signal as will be described later. The E position constitutes a "first state" where a flow channel for rotating the mixer drum 1 in the positive direction is formed, and enables the hydraulic oil to circulate between the hydraulic circuit 14 and the tank 26 in the direction in which the hydraulic motor 12 is rotated in the positive direction.

[0049] Further, the second control valve 24 is switched to the F position when the second control section 25 receives an operation signal as will be described later. The F position constitutes a "second state" where a flow channel for rotating the mixer drum 1 in the opposite direction is formed, and enables the hydraulic oil to circulate between the hydraulic circuit 14 and the tank 26 in the direction in which the hydraulic motor 12 is rotated in the opposite direction.

[0050] The second control section 25 controls drive of the second drive circuit 52. The second control section 25 includes a first control mode and a second control mode.

[0051] Upon receiving the idling stop signal SI from the first control section 6, the second control section 25 executes the first control mode for rotating the mixer drum 1 in the positive direction (stirring direction) by power stored in the second battery 21. On the other hand, upon receiving the operation signal S2 from the operation section 8, the second control section 25 executes the second control mode for rotating the mixer drum 1 in the opposite direction (discharge direction) by power stored in the second battery 21.

[0052] Fig. 3 is a block diagram showing the structure of the second control section 25.

[0053] The second control section 25 includes a reception section 251, a controller 252, an output adjustment section 253, and a contactor 254. The second control section 25 is structured as a control apparatus that controls operations of the second drive circuit 52. In this embodiment, the second control section 25 is driven using the first battery 5 as its power source .

[0054] The reception section 251 is electrically connected to the first control section 6 and the operation section 8 and is capable of receiving the idling stop signal SI and the operation signal S2.

Although the reception section 251 is connected to the first control section 6 by wires herein, the reception section 251 may be connected wirelessly.

[0055] In this embodiment, the reception section 251 includes functions as a first reception section that receives the idling stop signal SI and a second reception section that receives the operation signal S2. Of course, the reception section 251 may be divided into the first reception section and the second reception section.

[0056] The controller 252 is typically constituted of a computer and is electrically connected to the first battery 5, the reception section 251, the output adjustment section 253, the contactor 254, and the second control valve 24.

[0057] Upon receiving the idling stop signal SI via the reception section 251, the controller 252 executes the first control mode described above. Upon receiving the operation signal S2 via the reception section 251, the controller 252 executes the second control mode described above .

[0058] As described above, the operation section 8 is used for temporarily driving the mixer drum 1 when a vehicle failure such as an engine trouble occurs. Therefore, while the reception section 251 typically receives one of the idling stop signal SI and the operation signal S2, when both signals are received, the reception of the operation signal S2 may be invalidated so that the idling stop signal is received preferentially. Such a judgment may be executed by the controller 252 or may be executed by the reception section 251.

[0059] The output adjustment section 253 is provided between the second battery 21 and the electric motor 22. In the first control mode, the output adjustment section 253 adjusts a discharge output (voltage) of the second battery 21 to a predetermined voltage and outputs the voltage to the electric motor 22 under control of the controller 252.

[0060] In this embodiment, the output adjustment section 253 includes a plurality of switching devices such as an FET (Field Effect Transistor) and performs a pulse width modulation (PWM) on the discharge output (voltage) of the second battery 21 by a predetermined duty ratio determined by the controller 252.

[0061] The predetermined voltage is not particularly limited and is typically set to an appropriate value with which power requisite for rotating the mixer drum 1 by a desired rpm can be output during an idling stop.

[0062] The rpm of the mixer drum 1 during an idling stop is not particularly limited and may be set to an rpm lower than that while moving, for example. In this embodiment, the mixer drum 1 is rotated by a first rpm (e.g., 2 rotations/min) during drive by an engine and by a second rpm (e.g., 0.8 to 1 rotation/min) at an idling stop.

[0063] The contactor 254 is constituted of a normally-open-type switch device connected in parallel with the output adjustment section 253 between the second battery 21 and the electric motor 22. The contactor 254 closes under control of the controller 252 in the second control mode and supplies power stored in the second battery 21 to the electric motor 22 via the output adjustment section 253.

[0064] Depending on whether the idling stop signal 51 or the operation signal S2 has been received, the controller 252 controls the operations of the second control valve 24, the output adjustment section 253, and the contactor 254. Fig. 4 is a flowchart for explaining a control method of the second drive circuit 52 for the controller 252.

[0065] Upon receiving the idling stop signal SI via the reception section 251, the controller 252 switches the second control valve 24 to the E position. Then, the controller 252 modulates power stored in the second battery 21 to the predetermined voltage described above via the output adjustment section 253 and supplies the modulated voltage to the electric motor 22 (ST101, ST102, ST103).

[0066] Upon receiving the operation signal S2 via the reception section 251, the controller 252 switches the second control valve 24 to the F position. Then, the controller 252 closes the contactor 254 and supplies the power stored in the second battery 21 as it is to the electric motor 22 (ST104, ST105, ST106).

[0067] On the other hand, when neither the idling stop signal SI nor the operation signal S2 is received, the controller 252 switches the second control valve 24 to the D position. Then, the controller 252 stops discharge of the second battery 21 via the output adjustment section 253 and shuts off power supply to the electric motor 22 (ST107, ST108). At this time, of course, the controller 252 maintains the open state (OFF state) of the contactor 254.

[0068] (Operations of mixer vehicle)

Next, typical operations of the mixer vehicle 100 will be described.

[0069] The mixer vehicle 100 in which ready-mixed concrete is loaded in the mixer drum 1 stirs the ready-mixed concrete in the mixer drum 1 while rotating the mixer drum 1 at a predetermined rpm in the positive direction until reaching a concrete placement site from a concrete plant.

[0070] Here, while the mixer vehicle 100 is moving, the first control valve 13 is at the A position and the second control valve 24 is at the D position as shown in Fig. 2. As a result, the mixer drum 1 is rotated by the first rpm in the positive direction by the first drive circuit 51 that uses the engine 3 as its drive source. Moreover, while the mixer vehicle 100 is moving, the first battery 5 and the second battery 21 are charged by the power generator 4.

[0071] On the other hand, upon detecting a predetermined condition for executing a predetermined idling stop function at a time the mixer vehicle 100 stops at a red light, by a traffic jam, or the like (e.g., operation of handbrake), the first control section 6 executes the idling stop function and stops the drive of the engine 3. The first control section 6 also transmits an idling stop signal SI to the second control section 25 and switches the first control valve 13 from the A position to the B position.

[0072] By receiving the idling stop signal SI from the first control section 6, the second control section 25 executes the first control mode to switch the second control valve 24 to the E position and drive the electric motor 22 at a predetermined voltage while using the second battery 21 as a power source (ST101 to ST103). The second hydraulic pump 23 discharges a hydraulic oil corresponding to the rpm of the electric motor 22 to the hydraulic circuit 14. The hydraulic motor 12 is driven by the hydraulic oil discharged from the second hydraulic pump 23 and causes the mixer drum 1 to rotate by the second rpm in the positive direction. As a result, the drive source of the mixer drum 1 is switched from the first drive circuit 51 to the second drive circuit 52.

[0073] Then, when the first control section 6 detects a movement operation of the mixer vehicle 100 by the driver, the first control section 6 switches the first control valve 13 to the A position and stops outputting the idling stop signal SI. Accordingly, the second control section 25 switches the second control valve 24 to the D position and stops discharge of the second battery 21 to stop the drive of the electric motor 22 (ST107, ST108). As a result, the drive source of the mixer drum 1 is switched from the second drive circuit 52 to the first drive circuit 51.

[0074] Here, when some kind of failure such as an engine trouble and a vehicle body trouble occurs in the engine 3 or the first control section 6, there is a fear that the rotation of the mixer drum 1 will stop and the loaded ready-mixed concrete will coagulate. Further, since there is a limit in continuing stirring the ready-mixed concrete while rotating the mixer drum 1 only by power stored in the second battery 21, some kind of measure needs to be taken for preventing the coagulation of ready-mixed concrete.

[0075] In this regard, in this embodiment, when a vehicle failure such as an engine trouble occurs, the mixer drum 1 can be rotated in the opposite direction by an input operation made to the operation section 8 by the operator.

[0076] Specifically, when the second control section 25 receives the operation signal S2 generated by an input operation to the operation section 8, the controller 252 executes the second control mode to switch the second control valve 24 to the F position and close the contactor 254 (ST104 to ST106). As a result, power is supplied from the second battery 21 to the electric motor 22, and the mixer drum 1 can thus be rotated in the opposite direction.

[0077] According to this embodiment, since the ready-mixed concrete loaded in the mixer drum 1 can be discharged from the mixer drum 1 by an input operation made to the operation section 8 by the operator, a large amount of ready-mixed concrete loaded in the mixer drum 1 can be prevented from coagulating. Consequently, as an emergency measure using limited power of the second battery 21, ready-mixed concrete in the mixer drum 1 can be processed appropriately.

[0078] As a typical discharge destination of ready- mixed concrete, a mixer drum of another mixer vehicle is favorable. Accordingly, it becomes possible to convey the ready-mixed concrete by the mixer drum of another mixer vehicle to construction sites or ready-mixed concrete plants.

[0079] Further, in the second control mode, the second battery 21 and the electric motor 22 are directly connected via the contactor 254. Therefore, the output of the electric motor 22 can be made larger than that in the first control mode for supplying power from the second battery 21 to the electric motor 22 via the output adjustment section 253. As a result, even when a rotation load during discharge is larger than that during stirring, the mixer drum 1 can be rotated stably with relatively-large power. Therefore, the ready-mixed concrete can be discharged efficiently.

[0080] Furthermore, in this embodiment, since the switch of the second control valve 24 is controlled by the second control section 25, even when some kind of failure occurs in the first control section 6, the second control mode can be executed stably and appropriately.

[0081] <Second embodiment>

Fig. 5 is a block diagram showing a schematic structure of a second control section according to a second embodiment of the present invention.

Hereinafter, structures different from those of the first embodiment will mainly be described. In addition, the same structures as the first embodiment are denoted by the same reference numerals, and descriptions thereof will be omitted or simplified.

[0082] A second control section 35 of this embodiment includes the reception section 251, the controller 252, the output adjustment section 253, the contactor 254, a detection section 255, and a switch unit 256.

[0083] The reception section 251, the output adjustment section 253, and the contactor 254 have the same structures as those of the first embodiment, so descriptions thereof will be omitted herein.

[0084] The detection section 255 is capable of detecting a charge amount (SOC: State of Charge) of the first battery 5. The charge amount is a remaining battery amount that expresses the full charge state (or initial capacity) of the first battery 5 as 100%. The charge amount may be measured by a current integration or may be judged based on I-V property data of the first battery 5 that has been acquired in advance.

[0085] The switch unit 256 is connected to the first battery 5 and the second battery 21 and is capable of switching the power source of the second control section 35 from the first battery 5 to the second battery 21 under control of the controller 252.

[0086] As in the first embodiment above, the controller 252 controls the second control valve 24, the output adjustment section 253, and the contactor 254 according to the first or second control mode based on the idling stop signal SI or the operation signal S2 received via the reception section 251.

[0087] The controller 252 also judges the charge amount (SOC) of the first battery 5 via the detection section 255 and controls the switch unit 256 to switch the power source of the controller 252 from the first battery 5 to the second battery 21 based on the judgment result.

[0088] Specifically, in this embodiment, while the second control section 35 uses the first battery 5 as the power source in the first control mode, in the second control mode, when the second control section 35 judges that, upon judging whether the charge amount (SOC) of the first battery 5 is a predetermined value or less, the charge amount is the predetermined value or less, the second control section 35 uses the second battery 21 as the power source. As a result, even when a vehicle failure occurs, the power source for the second control section 35 can be secured.

[0089] Fig. 6 is a flowchart for explaining an operation example of the controller 252 in the second control mode.

[0090] Upon receiving the operation signal S2, the controller 252 judges whether the second battery 21 is being charged by the power generator 4 (ST201). This judgment can be executed based on a temporal change of the charge amount (SOC) of the second battery 21, for example. When judged that the second battery 21 is being charged, it can be assumed that the power generator 4 is operating normally. Therefore, execution of the second control mode is stopped. The processing as described above becomes particularly effective when the operation section 8 is erroneously operated during drive by the engine or the like.

[0091] On the other hand, when judged that the second battery 21 is not being charged by the power generator 4, it can be assumed that some kind of trouble has occurred in the engine 3 or the power generator 4. Therefore, the controller 252 executes the second control mode by the same procedure as in the first embodiment (ST202, ST105 and ST106 in Fig. 4).

[0092] At this time, the controller 252 judges whether the charge amount (SOC) of the first battery 5 is a predetermined value or more based on the output of the detection section 255. When the charge amount is judged to be a predetermined value or more, the controller 252 closes the contactor 254 and executes the second control mode (ST203, 202).

[0093] On the other hand, when judging that the charge amount (SOC) of the first battery 5 is smaller than the predetermined value, the controller 252 switches the power source of the second control section 35 from the first battery 5 to the second battery 21 via the switch unit 256 (ST204) . As a result, even when the charge amount (SOC) of the first battery 5 is low, the power source for the second control section 35 can be secured.

[0094] The charge amount (SOC) of the first battery 5 as a reference for switching the power source can be set to an arbitrary value with which the second control section 35 cannot be operated appropriately. For example, in this embodiment, the charge amount is set such that, when the remaining voltage of the first battery 5 is smaller than 18V, the power source of the second control section 25 is switched from the first battery 5 to the second battery 21.

[0095] It should be noted that in switching the power source to the second battery 21, the controller 252 may reference the charge amount (SOC) of the second battery 21. In such a case, when the charge amount (SOC) of the second battery 21 is smaller than the predetermined value, the switch of the power source may be canceled for securing the power source requisite for temporarily driving the mixer drum 1.

[0096] Heretofore, the embodiments of the present invention have been described. However, the present invention is not limited to the embodiments above and can of course be variously modified without departing from the gist of the present invention.

[0097] For example, in the embodiments above, at the time the second control section 25 executes the second control mode, the power stored in the second battery 21 is supplied to the electric motor 22 via the contactor 254 while bypassing the output adjustment section 253. Alternatively, at the time the operation signal S2 is received, the controller 252 may consecutively supply power to the electric motor 22 without performing an output modulation on the power of the second battery 21 by the output adjustment section 253 . Also by such a method, the electric motor 22 can be driven by a larger output than in the first control mode.

[0098] Furthermore, in the embodiments above, a lithium ion battery is used as the second battery 21 in the second drive circuit 52. However, other secondary batteries such as a nickel-hydrogen storage battery and a lead storage battery may be used instead.

Claims

Claims [1] A mixer vehicle, comprising: a vehicle body section including a power generator that generates power by power of an engine, a first control section that generates an idling stop signal and controls the engine, a mixer drum, and an operation section that generates an operation signal based on an input operation made by an operator; a first drive circuit including a hydraulic motor that rotates the mixer drum, and a first hydraulic pump that is driven by power of the engine and supplies a fluid to the hydraulic motor; and a second drive circuit including a battery that stores outputs of the power generator, an electric motor that is driven by power stored in the battery, a second hydraulic pump that is driven by the electric motor and supplies a fluid to the hydraulic motor, and a second control section that executes a first control mode when the idling stop signal is received from the first control section and a second control mode when the first control section failure occurs the and operation signal is received, the first control mode involving rotating the mixer drum in a first direction by power stored in the battery, the second control mode involving rotating the mixer drum in a second direction opposite to the first direction by power stored in the battery.
[2] The mixer vehicle according to claim 1, wherein the second control section drives the electric motor by a first output in the first control mode and drives the electric motor by a second output larger than the first output in the second control mode .
[3] The mixer vehicle according to claim 2, wherein the second drive circuit further includes a normally-open-type switch device connected between the secondary battery and the electric motor, and the second control section closes the switch device in the second control mode.
[4] The mixer vehicle according to claim 1, further comprising a switch valve that is capable of switching states between a first state where a flow channel for rotating the mixer drum in the first direction is formed and a second state where a flow channel for rotating the mixer drum in the second direction is formed, the switch valve being provided between the second hydraulic pump and the hydraulic motor.
[5] The mixer vehicle according to claim 1, wherein the vehicle body section further includes an electric storage apparatus that stores outputs of the power generator, and the second control section uses the electric storage apparatus as a power source in the first control mode and uses, in the second control mode, when the second control section judges whether a charge amount of the electric storage apparatus is a predetermined value or less and the charge amount is judged to be the predetermined value or less, the battery as the power source.
[6] A control apparatus mounted on a mixer vehicle including a power generator that generates power by power of an engine, a control section that generates an idling stop signal and controls the engine, a hydraulic motor that rotates a mixer drum, a battery that stores outputs of the power generator, an electric motor that is driven by power stored in the battery, a hydraulic pump that is driven by the electric motor and supplies a fluid to the hydraulic motor, and an operation section that generates an operation signal based on an input operation made by an operator, the control apparatus comprising: a first reception section capable of receiving the idling stop signal from the control section; a second reception section capable of receiving the operation signal; and a controller that executes a first control mode when the idling stop signal is received and a second control mode when control section failure occurs and the operation signal is received, the first control mode involving rotating the mixer drum in a first direction by power stored in the battery, the second control mode involving rotating the mixer drum in a second direction opposite to the first direction by power stored in the battery.
[7] A rotation control method for a mixer drum, comprising: rotating, by driving an electric motor by power stored in a battery that stores outputs of a power generator driven by an engine based on a first output when an idling stop signal is received from a control section, the mixer drum in a direction in which contents of the mixer drum are stirred; and rotating, by driving the electric motor by power stored in the battery based on a second output at a time an input operation is made by an operator using an operation section mounted on the mixer vehicle when control section failure occurs, the mixer drum in a direction in which the contents are discharged.