JP2020066292A - Truck mixer - Google Patents

Abstract

To suppress noise during drum operation, and drive a drum under a balanced condition from viewpoints of suppression of energy consumption and improvement of work efficiency.SOLUTION: A target drum rotation speed Nt in response to operation is calculated (a step S402), a pump capacity Vp and an engine rotation speed Ne are determined by setting a motor capacity Vm at a maximum, and a drum is driven by Nt (steps S405-S411). A drive pressure P and a threshold P1 of the drum are compared (steps S413, S414), and the Ne and an idle rotation speed Nmin are compared (steps S415, S416). When P<P1 and Ne=Nmin, Nd is fixed and Vm and Vp are corrected to decrease (a step S417). When P<P1 and Ne≠Nmin, the Nd is fixed and the Vm and Ne are corrected to decrease (a step S418).SELECTED DRAWING: Figure 8

Description

  The present invention relates to a mixer car.

  The mixer truck is equipped with a drum that rotates by loading ready-mixed concrete. Some mixer vehicles of this type include a variable displacement hydraulic motor for driving a drum, and a variable displacement hydraulic pump for discharging hydraulic oil that drives the hydraulic motor (see Patent Document 1 and the like). In the case of such a configuration, the drum rotation speed can be adjusted by the capacity of the hydraulic motor, the capacity of the hydraulic pump, and the rotation speed. Since the hydraulic pump is generally driven by a vehicle engine, the rotational speed of the hydraulic pump is controlled by the engine rotational speed.

Japanese Patent No. 3756663

  In Patent Document 1, when adjusting the drum rotation speed in a low speed range, the engine is driven at an idle rotation speed, and at the same time, the capacity of the hydraulic motor is fixed at a large capacity to control the capacity of the hydraulic pump. When adjusting the drum speed in the medium speed range, the capacity of the hydraulic pump is controlled by fixing the capacity of the hydraulic motor to a small capacity while driving the engine at the idle speed. When adjusting the drum speed in the high speed range, the capacity of the hydraulic pump is maximized and the capacity of the hydraulic motor is fixed at a small capacity to control the engine speed. As described above, the device of the document has an advantage that noise is suppressed because the engine is driven at the idling speed in the low speed region and the medium speed region. However, simply driving the engine at idle speed as much as possible to adjust the drum speed leaves room for improvement in energy efficiency and work efficiency.

  An object of the present invention is to provide a mixer vehicle capable of suppressing noise during drum operation and driving the drum under a balanced condition from the viewpoint of suppressing energy consumption and improving work efficiency.

  In order to achieve the above object, the present invention provides a drum for loading concrete, a variable displacement hydraulic motor for driving the drum, and a variable displacement hydraulic pump for discharging hydraulic oil for driving the hydraulic motor. An engine for driving the hydraulic pump, and a controller for controlling the motor capacity of the hydraulic motor, the pump capacity of the hydraulic pump, and the engine speed of the engine, wherein the controller idles the engine speed. The motor capacity and the pump capacity are set so that the drive pressure of the hydraulic motor is a predetermined drive pressure and the drum rotation speed of the drum becomes a target drum rotation speed according to the operation of the operating device after setting the rotation speed. A control function of a pump control region for controlling at least one of the above, and the drive pressure is set to the predetermined drive pressure after setting the pump displacement to a predetermined displacement. One the as drum rotational speed becomes the target drum rotation speed, and a control function of engine control area for controlling at least one of the motor capacity and the engine rotational speed.

  According to the present invention, it is possible to suppress noise during operation of the drum, and it is possible to drive the drum under a balanced condition from the viewpoint of suppressing energy consumption and improving work efficiency.

A side view showing the appearance of a mixer car concerning one embodiment of the present invention. The figure which represented typically the drum drive system of the mixer vehicle which concerns on one Embodiment of this invention. 1 is a flow chart showing a control procedure for operation switching of a drum by a control device provided in a mixer vehicle according to an embodiment of the present invention. Flowchart showing details of the procedure of the automatic kneading operation (step S200 in FIG. 3) Time chart of drum rotation speed during automatic kneading operation Flowchart showing the details of the procedure of the automatic cleaning operation (step S300 in FIG. 3) Explanatory drawing of drum rotation amount during automatic cleaning operation Flowchart showing details of procedure of drum control (step S400 in FIG. 3) according to manual operation Explanatory drawing of limitation of speedup rate of drum speed Explanatory drawing of limitation of deceleration rate of drum speed Explanatory diagram of the relationship between the threshold and the motor capacity for the driving pressure of the drum Conceptual diagram of operating condition map used for manual operation

  Embodiments of the present invention will be described below with reference to the drawings.

-Mixer truck-
FIG. 1 is a side view showing an external appearance of a mixer vehicle according to an embodiment of the present invention, and FIG. 2 is a view schematically showing a drum drive system. In this specification, the left and right sides in FIG. 1 are treated as front and rear. The mixer vehicle shown in FIGS. 1 and 2 includes a vehicle body 10, a drum 20, a hopper 30, a chute 35, a hydraulic motor 40, a hydraulic pump 50, an engine 60, pressure sensors 71 and 72, rotation sensors 73 and 74, and a controller 80. And an operating device 90. In addition, the "rate of change" described in the specification of the present application refers to the magnitude of change per unit time, and the "number of revolutions" refers to the number of revolutions per unit time (for example, rpm).

  The vehicle body 10 includes a driver's cab 11 and a chassis frame 12. The cab 11 constitutes the front part of the vehicle body 10. The chassis frame 12 extends rearward from the cab 11. The engine 60 is arranged below the cab 11. The engine 60 runs the vehicle body 10 and drives the hydraulic pump 50. A parking brake 13 (FIG. 2) is provided inside the cab 11. A warning device 14 (FIG. 2) such as a buzzer or a lamp is provided inside and outside the cab 11.

  The drum 20 is a device for loading concrete or the like to stir or knead, and has a drum body 21 and two blades 22 and 23 (FIG. 7). The drum main body 21 is formed in a cylindrical shape, and the rotary shaft 24, which is in a fixed relationship with the drum main body 21, projects from one side (front) of the central axis direction of the drum main body 21, and the other end (rear) end is open. ing. The rotary shaft 24 is connected to the output shaft of the hydraulic motor 40. The hydraulic motor 40 is supported on the front portion of the chassis frame 12 via a mount 25. The rear portion of the drum body 21 is supported by the rear portion of the chassis frame 12 via a frame 26. The pedestal 26 is provided with a plurality of support rollers (not shown), and the outer peripheral surface of the drum body 21 is supported by these support rollers. The central axis of the drum main body 21 is inclined upward toward the rear, and the opening of the drum main body 21 is directed rearward and obliquely upward. When the hydraulic motor 40 is driven, the drum body 21 rotates around the central axis. The two blades 22 and 23 (FIG. 7) are formed in a spiral shape and are fixed to the inner wall surface of the drum main body 21 with a phase shift of 180 degrees.

  The hopper 30 is a member that receives concrete raw material and the like and guides it into the inside of the drum main body 21, and is narrowed from an input port that is wide open upward to a discharge port that faces the opening of the drum main body 21.

  The chute 35 is a gutter-shaped member that guides concrete or the like discharged from the drum body 21, and has a base end located below the opening of the drum body 21. The chute 35 is supported rotatably in a horizontal direction and a vertical direction around a base end portion, and by moving the tip end portion, a place for discharging concrete or the like can be moved.

  The hydraulic motor 40 rotationally drives the drum 20, is mounted on the chassis frame 12 as described above, and has an output shaft connected to the rotary shaft 24 of the drum 20 via a speed reducer (not shown). The hydraulic motor 40 is a variable displacement type and is provided with a regulator 41. By changing the tilting (motor displacement Vm) by the regulator 41, the number of rotations with respect to the supply flow rate of the hydraulic oil can be continuously switched.

  The hydraulic pump 50 discharges hydraulic oil that drives the hydraulic motor 40, and is mounted on the chassis frame 12. Like the hydraulic motor 40, the hydraulic pump 50 is also of a variable displacement type and is provided with a regulator 51. By changing the tilt (pump displacement Vp) by the regulator 51, the discharge flow rate of the hydraulic oil can be switched steplessly. The hydraulic motor 40 and the hydraulic pump 50 each include two input / output ports for hydraulic oil and are connected in a loop by two flow passages 52 to form a closed circuit. By switching the rotation direction of the hydraulic pump 50 with, for example, a gear, the circulation direction of the hydraulic oil flowing through the flow path 52 is switched, and the rotation direction of the hydraulic motor 40 and thus the rotation direction of the drum 20 are switched.

  The engine 60 is a prime mover that drives the hydraulic pump 50, and the hydraulic pump 50 is connected to a power takeoff shaft 61 of the engine 60. The engine 60 is equipped with a throttle adjuster 62 that adjusts the output. An electric motor may be used as a prime mover instead of the engine 60.

  The pressure sensors 71 and 72 are instruments for detecting the driving pressure P of the hydraulic motor 40 and thus the drum 20, and the pressure sensor 71 is installed in one flow path 52 and the pressure sensor 72 is installed in the other flow path 52. The drive pressure P detected by the pressure sensors 71, 72 is input to the control device 80, and in the control device 80, the larger value is selected as the drive pressure P of the hydraulic motor 40. For example, when the hydraulic oil is discharged from the lower input / output port of the hydraulic pump 50 in FIG. 2, the drum 20 rotates normally (kneading, etc.), and when the hydraulic oil is discharged from the upper input / output port, the drum 20 moves. Reverse (eject, etc.) The drive pressure P of the hydraulic motor 40 when the drum 20 rotates in the forward direction is detected by the pressure sensor 71, and the drive pressure P when the drum 20 rotates in the reverse direction is detected by the pressure sensor 72.

  The rotation sensor 73 is a meter that detects the engine speed Ne and is provided in the engine 60 in the present embodiment, but may be provided in the hydraulic pump 50 or the power take-out shaft 61. The rotation sensor 74 is an instrument that detects the number of rotations Nd of the drum, and in this embodiment, detects the rotation of the rotation shaft 24 of the drum body 21.

  The controller 80 has a function of driving the drum 20 by controlling the motor capacity Vm of the hydraulic motor 40, the pump capacity Vp of the hydraulic pump 50, the engine speed Ne of the engine 60, and the like. The control device 80 is a computer including a CPU, a RAM, a ROM, a memory, and the like. For example, according to a program stored in the ROM in advance, sensors such as the operating device 90, the pressure sensors 71, 72, and the rotation sensors 73, 74 The drum 20 or the like is driven according to the signal of. The control device 80 is also electrically connected to the parking brake 13 and the warning device 14. Various controls executed by the controller 80 will be described later.

  The operation device 90 is an input device for instructing the operation of the drum 20 and the like, and includes a dial 91, a stop switch 92, an automatic kneading switch 93, an automatic cleaning switch 94, an automatic stirring switch 95, and the like. Although only one operating device 90 is shown as a representative in FIG. 2, the operating device 90 is provided inside the cab 11, at a plurality of places such as the rear portion of the vehicle body 10. The operation device 90 is connected to the control device 80 by wire or wirelessly, and the operation signal output from the operation device 90 is input to the control device 80.

-Drum control (operation switching)-
FIG. 3 is a flow chart showing a control procedure of operation switching of the drum 20 by the control device 80. The procedure of the figure is started when the engine 60 is started and the control device 80 is energized.

  The control device 80 first determines whether any switch of the operation device 90 is operated. In the present embodiment, first, the control device 80 determines whether the stop switch 92 is operated (step S5), and if so, outputs a warning operation to the warning device 14 (step S501) and stops the drum 20. The state is set (step S502). In step S502, the control device 80 stops the drum 20 while maximizing the motor capacity Vm of the hydraulic motor 40 until the engine 60 stops (power is turned off), and invalidates all subsequent operations. The flow of FIG. 3 ends. In addition, when the stop switch 92 is operated, not all the subsequent operations are invalidated, but all the operations are invalidated until the operation of the drum 20 is stopped (waiting for the drum to stop), and the procedure goes to step S1. It may be a return flow. Although not shown in the flowchart of FIG. 3, the drum stop operation by the stop switch 92 is always valid while the drum 20 is operating. The stop switch 92 is operated during the operation of the drum 20, including each of the stirring operation (step S100), the kneading operation (step S200), the washing operation (step S300), and the manual operation (step S400) which will be described later. If so, the operation of the drum 20 is stopped.

  When the stop switch 92 is not operated (step S5), the control device 80 determines whether, for example, the automatic stirring switch 95 is operated (step S1). If the automatic stirring switch 95 is operated, the controller 80 executes the stirring operation (step S100), and shifts the procedure to step S600 via steps S101 to S105 (described later). When the automatic stirring switch 95 is not operated, the control device 80 determines whether the automatic kneading switch 93 is operated, for example (step S2), and if it is operated, the kneading operation is executed (step S200), and step S600. Move the procedure to. When the automatic kneading switch 93 is also not operated, the control device 80 determines whether the automatic cleaning switch 94 is operated, for example (step S3), and if it is operated, the cleaning operation is executed (step S300), and step S600. Move the procedure to. When the automatic cleaning switch 94 is not operated either, the control device 80 determines whether the dial 91 is operated, for example (step S4). If it is operated, the drum 20 is driven according to the operation of the dial 91 (step S4). (S400), the procedure moves to step S600. If the dial 91 is not operated, the control device 80 does nothing and moves the procedure to step S600.

  Here, the stirring operation is an operation of rotating the drum 20 at a low speed (normal rotation) to stir the concrete inside so that the concrete loaded on the drum 20 does not solidify while the mixer truck is running. The stirring operation is started, for example, by operating the automatic stirring switch 95 with the operating device 90 mounted in the operator's cab 11 (S100), which causes the interlock to function to operate the stop switch 92 of each operating device 90. Except for this, the operation is invalid in principle. This is for example to prevent the loaded concrete from scattering on the road due to the reverse operation of the drum 20 due to an erroneous operation.

  Therefore, in this embodiment, a certain condition is provided for releasing the interlock after the start of the stirring operation. During execution of the stirring operation, the control device 80 determines whether or not the release operation (priority operation) is performed by any of the operation devices 90 based on the operation signal (step S101). The release operation is, for example, rotating the dial 91 from the neutral position in the forward rotation direction (for example, clockwise) by a certain amount or more, and then rotating the dial 91 in the reverse rotation direction (for example, counterclockwise) to return to the neutral position. This is a predetermined procedure, which is set in advance and registered in the memory. When the release operation is not performed, the control device 80 shifts the procedure from step S101 to step S104, and sets only the stop operation to be valid for each operating device 90 in principle (step S104). Under this setting, even if a switch (for example, dial 91) other than the stop switch 92 is operated by any of the operating devices 90, the control device 80 determines that the operation is invalid and outputs a command to the corresponding operating device. There is no such thing.

  On the other hand, when any one of the releasing operations is performed, the interlock is released for the operation of the operating device 90 that has been operated. When the release operation is performed, the automatic stirring switch 95 of the operating device 90 is turned off. At that time, the control device 80 determines whether the parking brake 13 is being operated in the cab 11 (whether the brake is on) (step S102), and if it is being operated, the interface is maintained (without passing through step S103). The lock is released (step S105). All operations are valid for the operating device 90 with the interlock released, and if any operation is performed by the operating device 90 in the next cycle (immediately after return), the control device 80 responds to the corresponding operating device. Command is output.

  If the parking brake 13 is not operated even if the release operation is performed, the control device 80 instructs the warning device 14 to execute the warning operation (step S103) and then releases the interlock (step S105). In principle, the operation instruction of the drum 20 is given while the parking brake 13 is functioning, but for example, the work of discharging concrete from the drum 20 while traveling is rare. Therefore, the operation instruction of the drum 20 is allowed even when the parking brake 13 is not functioning, on condition that the warning operation is performed. In any case, during the stirring operation, the motor displacement Vm, the pump displacement Vp, and the engine speed Ne can be operated only by the operating device 90 that has been subjected to the predetermined release operation. In this embodiment, the warning operation is executed not only in steps S501 and S103 but also during the discharging operation and when various errors occur.

  After executing any one of the processes of steps S104, S105, S200, S300, S400, and S5, the control device 80 sets the engine speed Ne to 0 (zero) based on the signal from the rotation sensor 73 due to an abnormal operation such as engine stall. It is determined whether or not (step S600). If the engine speed Ne is 0, the control device 80 resets the settings of the pump capacity Vp and the motor capacity Vm (step S601) and returns the procedure to step S1. If the engine speed Ne is not 0, the settings are maintained. Then, the procedure is returned to step S1.

-Automatic kneading operation-
FIG. 4 is a flowchart showing the details of the procedure of the automatic kneading operation (step S200 in FIG. 3), and FIG. 5 is a time chart of the drum rotation speed during the automatic kneading operation.

  The procedure of FIG. 4 is executed when the automatic kneading switch 93 is operated in step S2 of FIG. 3, and the control device 80 first determines whether the operation of the automatic kneading switch 93 is valid (step S201). When the determination in step S201 is continuously performed in steps S104, S600, S1 and S2 in FIG. 3, the operation of the automatic kneading switch 93 is invalid. Therefore, the control device 80 ends the procedure of step S200 without executing the remaining procedure of FIG. 4 and moves the procedure to step S600 of FIG. When the operation of the automatic kneading switch 93 is valid, the control device 80 inputs the signals (driving pressure P) of the pressure sensors 71 and 72 (step S202). In order to obtain a stable value of the drive pressure P, a determination time T1 (for example, several seconds) set in advance by a preset determination rotation speed Nd1 (the pump displacement Vp, the motor displacement Vm, and the engine rotation speed Ne are set values). Only drive the drum 20. The control device 80 acquires the driving pressure P based on the signals of the pressure sensors 71 and 72 during that period (FIG. 5). As an example, the average value of the detection values during the determination time T1 can be calculated as the driving pressure P. The rotation speed Nd1 is, for example, about 7-8 rpm.

  Next, the control device 80 determines the kneading time T2 and the drum rotation speed Nd for the driving pressure P based on the driving pressure P (step S203). A kneading condition map (reference table) defining the relationship among the kneading time T2, the drum rotation speed Nd, and the motor capacity Vm with respect to the driving pressure P is stored in, for example, the ROM of the control device 80. In step S203, when the operation device 90 starts the kneading operation, the kneading time T2, the drum rotation speed Nd, and the motor capacity Vm are determined based on the driving pressure P according to the kneading condition map. According to the kneading condition map, for example, the higher the driving pressure P (for example, the higher the viscosity of concrete), the longer the kneading time T2 and the faster the drum rotation speed Nd is set. The drum speed Nd is determined by the motor capacity Vm, the pump capacity Vp, and the engine speed Ne. Therefore, if the drum speed Nd and the motor capacity Vm are determined by the kneading condition map, the pump capacity Vp and the engine speed Ne can be subsequently determined. If the operating conditions are met. Although the operating conditions may be uniquely determined by including the pump capacity Vp and the engine speed Ne in the kneading condition map, in the present embodiment, the motor capacity Vm is fixed to the maximum value and the engine is as low as possible. The pump capacity Vp is determined under the condition that the rotation speed Ne is selected. In the control range of the pump capacity Vp, the pump capacity Vp is maximized and the engine speed Ne higher than the idle speed Nmin is determined only when the drum speed Nd associated with the drive pressure P cannot be obtained in the kneading condition map. To do. In the present embodiment, the case where the kneading condition is determined by the kneading condition map has been described as an example, but the kneading condition may be determined from the driving pressure P using a predetermined calculation formula instead of the reference table. .

  As described above, when the kneading time T2, the motor capacity Vm, the pump capacity Vp, and the engine speed Ne are determined, the control device 80 outputs a command signal to the regulators 41 and 51 (FIG. 2) and the throttle adjuster 62 (the same). (Step S204). As a result, the drum 20 is driven at the drum rotation speed Nd according to the driving pressure P, and the kneading operation is executed. During execution of the kneading operation, the control device 80 compares the duration time T of the kneading operation with the kneading time T2 (step S205). If the kneading time T2 has not elapsed, the procedure is returned to step S204 to change the rotation speed of the drum 20. maintain. When the continuation time T reaches the kneading time T2, the control device 80 decelerates the driving speed of the drum 20 (FIG. 5) to the original rotation speed Nd0 (for example, the rotation speed of the stirring operation or the stopped state before the automatic kneading operation is performed). )) (Step S206). At the same time, the control device 80 turns off the automatic kneading switch 93 of the operating device 90. For example, a limit value ΔNlim described later can be applied to the deceleration rate of the drum rotation speed Nd in step S206. When the drum rotation speed Nd returns to the original rotation speed Nd0, the control device 80 finishes the procedure of the automatic kneading operation of FIG. 4 and moves the procedure to step S600 of FIG.

-Automatic cleaning operation-
FIG. 6 is a flowchart showing the details of the procedure of the automatic cleaning operation (step S300 in FIG. 3), and FIG. 7 is an explanatory diagram of the drum rotation amount during the automatic cleaning operation. Prior to the automatic cleaning operation described below, it is assumed that an appropriate amount of cleaning water (depending on the size of the drum 20, for example, 0.25 to 1.0 kL) is injected into the drum 20.

  The procedure of FIG. 6 is executed when the automatic cleaning switch 94 is operated in step S3 of FIG. 3, and the control device 80 first determines whether the operation of the automatic cleaning switch 94 is valid (step S301). When the determination in step S301 is executed successively to steps S104, S600, and S1-S3 in FIG. 3, the operation of the automatic cleaning switch 94 is invalid. Therefore, the control device 80 ends the procedure of step S300 without performing the remaining procedure of FIG. 6 and moves the procedure to step S600 of FIG. When the operation of the automatic cleaning switch 94 is valid, the control device 80 inputs the signals (driving pressure P) of the pressure sensors 71 and 72 (step S302). In order to obtain the stable value of the driving pressure P, the drum 20 is driven for the determination time T1 at the determination rotation speed Nd1 as in the automatic kneading operation. The rotation speed Nd1 and the determination time T1 may be set to the same values as those for the automatic kneading operation, but may be set to different values. The control device 80 acquires the driving pressure P based on the signals of the pressure sensors 71 and 72 during that period. As an example, the average value of the detection values during the determination time T1 can be calculated as the driving pressure P. At this time, the waveform of the driving pressure P is also stored in the memory or the RAM by the control device 80.

  Next, the control device 80 determines the drum rotation amount with respect to the drive pressure P based on the drive pressure P (step S303). A cleaning condition map (reference table) that defines the relationship between the drum rotation amount (the rotation amount in the feeding direction and the rotation amount in the discharging direction) with respect to the driving pressure P is stored in, for example, the ROM of the control device 80. In step S303, when the cleaning operation is started by the operation device 90, the drum rotation amount is determined based on the drive pressure P according to the cleaning condition map. According to the cleaning condition map, the higher the driving pressure P (for example, the higher the water level of the cleaning water introduced into the drum 20), the smaller the rotation amount of the drum is set. At this time, for example, the discharge direction rotation amount is 2 rotations (720 degrees), the closing direction rotation amount is 2.5 rotations (900 degrees), and the closing direction rotation amount is larger than the discharging direction rotation amount (for example, 0. It is set to be larger by 5 rotations. Further, in order to drive the drum 20, it is necessary to determine the motor capacity Vm, the pump capacity Vp, and the engine speed Ne, but if the load on the drum 20 is water, the load does not increase so much. Therefore, the motor capacity Vm is fixed to the minimum, the engine speed Ne is fixed to the idle speed Nmin, and the pump capacity Vp is determined so that the drum 20 is driven at the set speed (for example, 15 rpm) for the cleaning operation. In the present embodiment, the cleaning condition is determined by the kneading condition map as an example, but the cleaning condition may be determined from the driving pressure P by using a predetermined calculation formula instead of the reference table. .

  After determining the drum rotation amount, the motor displacement Vm, the pump displacement Vp, and the engine rotation speed Ne, the control device 80 outputs a command signal to the regulators 41 and 51 and the throttle adjuster 62 to rotate the drum 20 and set a predetermined start position. To stop (step S304). The predetermined start position is a preset rotation angle of the drum 20, and for example, an angle such that the center of gravity of one of the blades 23 is directly below the rotation center of the drum body 21 can be exemplified (FIG. 7B). The start position can be specified from the waveform of the driving pressure P acquired in step S302. For example, even after the execution of step S303, the drum body 21 is rotated to the start position (FIG. 7B) in step S304 even if the drum body 21 is out of phase with the start position as shown in FIG. 7A. .

  After that, the control device 80 outputs a command signal to the regulators 41 and 51 (FIG. 2) and the throttle adjuster (the same) according to the operating condition determined in step S303, and executes the cleaning of the drum 20 (step S305). Explaining in the previous example, the drum 20 rotates, for example, in the discharge direction (two rotations in the above example) from the start position (predetermined rotation angle), and then in the loading direction (2.5 rotations in the above example). ) Do. When this forward rotation / reverse rotation is executed once, the amount of rotation in the closing direction is large by half a rotation, so that the drum 20 is rotated 180 degrees from the start position (FIG. 7C). When this normal rotation / reverse rotation is repeatedly executed a preset number of times (several times, for example, four times), the control device 80 ends the procedure of the automatic cleaning operation of FIG. 6 and moves the procedure to step S600 of FIG. At that time, the control device 80 turns off the automatic cleaning switch 94 of the operating device 90 at the same time as ending the procedure of the automatic cleaning operation. When ending the procedure of FIG. 6, the control device 80 restores the drive speed of the drum 20 to the original rotation speed Nd0 (for example, the rotation speed of the stirring operation or the stopped state) before the execution of the automatic cleaning operation.

-Manual operation-
8 is a flowchart showing the details of the procedure of the drum control (step S400 in FIG. 3) according to the manual operation, FIG. 9 is the limitation of the speed increase rate of the drum rotation speed, and FIG. 10 is the limitation of the speed reduction rate of the drum rotation speed. FIG. FIG. 11 is an explanatory diagram of the relationship between the threshold value for the driving pressure P of the drum 20 and the motor capacity Vm, and FIG. 12 is a conceptual diagram of an operating condition map used for manual operation. The manual operation means that the operator arbitrarily adjusts the drum rotation speed Nd with the dial 91 to drive the drum 20, and the kneading work of concrete or the like and the cleaning work of the drum 20 are also performed manually using the dial 91. You can

  The procedure of FIG. 8 is executed when the dial 91 is operated in step S4 of FIG. 3, and the control device 80 first determines whether the operation of the dial 91 is valid (step S401). When the determination of step S401 is executed successively to steps S104, S600, S1 to S4 of FIG. 3, the operation of the dial 91 is invalid. Therefore, the control device 80 ends the procedure of step S400 without performing the remaining procedure of FIG. 8 and moves the procedure to step S600 of FIG. When the operation of the dial 91 is valid, the control device 80 calculates the target drum rotation speed Nt according to the operation (direction and size of the operation) of the dial 91 (step S402). In the case of this example, when the dial 91 is operated clockwise from the neutral position, the target drum rotational speed Nt in the forward rotation direction is calculated according to the size of the operation, and when the dial 91 is operated counterclockwise from the neutral position, the operation is performed. A target drum rotation speed Nt in the reverse rotation direction is calculated according to the size.

  After calculating the target drum rotation speed Nt, the control device 80 determines whether the target drum rotation speed Nt is other than 0 (zero), that is, whether the command from the dial 91 instructs to stop the drum (step S403). . When the target drum rotation speed Nt is 0, the controller 80 stops the drum 20 in a state where the motor capacity Vm of the hydraulic motor 40 is maximized, as in step S502 (FIG. 3), and the procedure of step S400 is finished and The procedure moves to step S600 of 3 (step S404). When the target drum speed Nt is other than 0, the control device 80 sets the motor capacity Vm to the maximum motor capacity and calculates the pump capacity Vp and the engine speed Ne for driving the drum 20 at the target drum speed Nt. Yes (step S405). At this time, the pump displacement Vp is set under the condition that the engine speed Ne is set as small as possible.

  Next, the control device 80 calculates the rate of change ΔNd of the drum rotation speed based on the current drum rotation speed Nd and the target drum rotation speed Nt input from the rotation sensor 74 (FIG. 1) (step S406). The rate of change ΔNd is the rate of increase when the operation of the dial 91 is to instruct to increase the speed, and is the rate of deceleration when it is to instruct to decrease the speed. The controller 80 compares the calculated change rate ΔNd (for example, absolute value) with the limit value ΔNlim (> 0) (step S407). If the change rate ΔNd is less than or equal to the limit value ΔNlim, the controller 80 sets a value (Nd = Nd + ΔNd) obtained by adding the change rate ΔNd to the current drum rotation speed Nd as the command drum rotation speed (step S408). On the other hand, when the rate of change ΔNd is larger than the limit value ΔNlim, the control device 80 sets a value (Nd = Nd + ΔNlim) obtained by adding the limit value ΔNlim to the current drum speed Nd as the command drum speed (step S409). Since the motor capacity Vm is the maximum at the time of steps S408 and S409, if the engine speed Ne set at step S405 is the idle speed Nmin, the engine speed Ne depends on the command drum speed under the condition of the idle speed Nmin. The pump capacity Vp is set. If the pump displacement Vp set in step S405 is the maximum, the engine speed Ne is set according to the command value of the drum speed under the condition of the maximum pump capacity.

  After that, the controller 80 outputs the command value set in step S408 or S409 to the regulators 41 and 51 and the throttle adjuster 62 to drive the drum 20 (step S410). After driving the drum 20, the control device 80 inputs the drum rotation speed Nd from the rotation sensor 74 and determines whether or not the drum rotation speed Nd has reached the target drum rotation speed Nt (step S411). If the drum rotation speed Nd has not reached the target drum rotation speed Nt, the controller 80 repeats the procedure of steps S410 and S411 to bring the drum rotation speed Nd close to the target drum rotation speed Nt. The operating condition when the drum rotational speed Nd is brought close to the target drum rotational speed Nt is set according to an operating condition map (FIG. 12) which is a reference table described later under the condition that the motor capacity Vm is fixed to the maximum value. In the pump control region (described later), the engine speed Ne is fixed to the idle speed Nmin and the pump capacity Vp is increased to increase the drum speed Nd. In the engine control range (described later), the pump speed Vp is fixed to the maximum value and the engine speed Ne is increased to increase the drum speed Nd. Therefore, if the dial 91 is largely operated from the stirring operation or the stopped state, the operating condition of the drum 20 shifts from the pump control range to the engine control range, and after the pump capacity Vp increases to the maximum value, the engine speed Ne is idle. It will increase from several Nmin.

  The determination in step S411 is not always necessary and can be omitted. For example, when the target value of the command value for rotating the drum rotation speed Nd at the target drum rotation speed Nt is calculated, the command output to the regulators 41 and 51 and the throttle adjuster 62 without the determination in step S411. It suffices to change each value to the target value.

  By the procedure of steps S406 to S411, when the rate of change ΔNd of the drum rotation speed according to the operation of the dial 91 exceeds the limit value ΔNlim, the rate of change ΔNd of the drum rotation speed is limited by the limit value ΔNlim. . For example, when the speed increase rate ΔNd1 (absolute value) of the drum rotation speed according to the operation of the dial 91 is equal to or less than the limit value ΔNlim, the drum speed Nd increases at the speed increase rate ΔNd1 (FIG. 9). Similarly during deceleration, when the deceleration rate ΔNd3 (absolute value) of the drum rotation speed according to the operation of the dial 91 is equal to or less than the limit value ΔNlim, the drum rotation speed Nd decreases at the deceleration rate ΔNd3 (FIG. 10). However, when the speed increase rate ΔNd2 (absolute value) of the drum rotation speed according to the operation of the dial 91 is larger than the limit value ΔNlim, the speed increase rate of the drum rotation speed Nd is limited by the limit value ΔNlim (FIG. 9). Similarly, at the time of deceleration, when the deceleration rate ΔNd4 (absolute value) of the drum rotation speed according to the operation of the dial 91 is larger than the limit value ΔNlim, the deceleration rate of the drum rotation speed Nd is limited by the limit value ΔNlim (FIG. 10). ).

  When the drum rotation speed Nd reaches the target drum rotation speed Nt through the processing of steps S406 to S411, the control device 80 inputs the drive pressure P detected by the pressure sensors 71 and 72 (step S412). Subsequently, the control device 80 compares the driving pressure P with the threshold value (steps S413 and S414), and determines the engine speed Ne or the pump capacity Vp according to the comparison result (steps S415 and S416). The threshold value based on the processing of steps S413 and S414 is a preset value (appropriate value) for the driving pressure P, and is stored in advance in the ROM, for example. This threshold may be a value without a width, but in this embodiment, it is set as a range having a lower limit P1 and an upper limit P2 as shown in FIG. In the present embodiment, as shown in the figure, the larger the motor capacity Vm, the smaller the thresholds (lower limit P1 and upper limit P2) are set.

  Here, in the control device 80, for example, an operation condition map (reference table) of the drum rotation speed Nd is stored in the ROM. As shown in FIG. 12, this operation condition map defines the relationship among the motor displacement Vm, the pump displacement Vp, the engine speed Ne and the drum speed Nd. Although schematically shown in the figure, the operating condition map is such that the horizontal axis represents the motor capacity Vm and the vertical axis represents the drum rotation speed Nd, and each operation point (Vm, Vm, Other conditions (pump capacity Vp, engine speed Ne) are set for Nd). The pump displacement Vp and the engine speed Ne are set so that the engine speed Ne is minimized (minimized) at each operating point. As a result, the operating condition map is divided into a pump control region where the engine speed Ne is constant and an engine control region where the pump displacement Vp is constant (FIG. 12). In the pump control range, the engine speed Ne is fixed to the idle speed Nmin, and the value of the pump capacity Vp is different for each operating point (if the same drum speed Nd, the pump is on the left operating point in the figure). The capacity Vp becomes smaller). In the engine control range, the pump capacity Vp is fixed at the maximum pump capacity, and the value of the engine speed Ne differs for each operating point (if the same drum speed Nd, the operating point on the left side in FIG. The number Ne becomes smaller). When the motor capacity Vm on the horizontal axis and the drum rotation speed Nd on the vertical axis are determined, the control device 80 can uniquely determine the pump capacity Vp and the engine rotation speed Ne by referring to this operation condition map. When the operating point belongs to the pump control range, by decreasing (increasing) the pump capacity Vp, the drum rotation speed Nd can be maintained even if the motor capacity Vm is decreased (increased). When the operating point belongs to the engine control range, by decreasing (increasing) the engine speed Ne, the drum speed Nd can be maintained even if the motor capacity Vm is decreased (increased). For example, when the motor displacement Vm is set to the maximum and the drum 20 is driven at a predetermined drum rotation speed Nd, at the operating point X (FIG. 12) belonging to the engine control range, the pump displacement Vp is the maximum and the engine rotation speed Ne is the idle rotation speed. The operating condition is larger than Nmin. Starting from this operating point X, the motor capacity Vm is reduced together with the engine speed Ne to keep the drum speed Nd constant and move the operating point to the left side on the map to bring it closer to the pump control range. Range A). After the engine speed Ne drops to the idle speed Nmin and the operating point X moves to the pump control range, the pump capacity Vp and the motor capacity Vm are decreased to keep the drum speed Nd constant. Further, it can be moved to the left on the map (range B in the figure). In any control range, the change rate of the drum rotation speed Ne is described with reference to FIGS. 9 and 10 by smoothly changing the motor capacity Vm between the minimum value (for example, 15 cc) and the maximum value (for example, 60 cc). Be limited as you did.

  In the present embodiment, the case in which the actuator related to the drum rotation speed Nd is controlled on the basis of the operation condition map according to the operation has been described as an example, but a predetermined calculation formula is used instead of the reference table. You can also The required engine speed Ne and the pump capacity Vp can be calculated from the product of the required rotation speed of the hydraulic motor 40 according to the dial operation amount and the current motor capacity Vm, and the drum rotation speed Nd according to the dial operation amount. Can be expressed by a calculation formula.

  As a result of the determination in steps S413 and S414, when the drive pressure P matches the threshold value (P1 ≦ P ≦ P2), the control device 80 ends the procedure of FIG. 8 and shifts the procedure to step S600 of FIG. As a result of the determination in steps S413 to S416, when the drive pressure P is smaller than the lower limit value P1 and the engine speed Ne is the idle speed Nmin (Ne = Nmin), the controller 80 maintains the drum speed Nd while maintaining the motor capacity. Vm and pump capacity Vp are reduced and corrected (step S417). When the drive pressure P is lower than the lower limit P1 and the engine speed Ne is higher than the idle speed Nmin (Ne> Nmin), the controller 80 reduces the motor capacity Vm and the engine speed Ne while maintaining the drum speed Nd. (Step S418). When the drive pressure P is larger than the upper limit P2 and the pump displacement Vp is the maximum (Vp = max), the controller 80 increases and corrects the motor displacement Vm and the engine rotation speed Ne while maintaining the drum rotation speed Nd (step S419). ). When the drive pressure P is larger than the upper limit P2 and the pump displacement Vp is smaller than the maximum (Vp <max), the controller 80 increases the motor displacement Vm and the pump displacement Vp while maintaining the drum rotation speed Nd (step S420). ). After performing the correction process in any of steps S417 to S420, the control device 80 inputs the driving pressure P from the pressure sensors 71 and 72, and the corrected driving pressure P matches the threshold value (P1 ≦ P ≦ P2). Is determined) (step S421). If the drive pressure P does not match the threshold value (P <P1, P> P2), the control device 80 returns the procedure to step S412, and the drum rotation is performed assuming that the engine speed Ne is the idle speed Nmin or more. The operating conditions are further corrected while maintaining the number Nd. If the drive pressure P matches the threshold value (P1 ≦ P ≦ P2), the controller 80 ends the procedure of FIG. 8 and moves the procedure to step S600 of FIG. As a result of the feedback control in steps S412 to S421, the drum 20 is driven at an appropriate driving pressure P while maintaining the drum rotation speed Nd designated by the dial 91 at the lowest engine rotation speed Ne.

  However, the determination in step S421 is not always necessary and can be omitted. For example, when the motor capacity Vm, the pump capacity Vp, and the engine speed Ne for matching the drive pressure P with the threshold value are calculated, the motor capacity Vm, the pump capacity Vp, and the engine speed Ne do not need to be determined in step S421. Ne may be changed to the target value.

  In the present embodiment, the case where both the motor displacement Vm and the pump displacement Vp are controlled in the pump control region (steps S417 and S420) is illustrated, but either one may be controlled. That is, a pump control region that controls at least one of the motor displacement Vm and the pump displacement Vp so that the drive pressure P becomes the predetermined drive pressure (P1-P2) and the target drum rotation speed Nt after being set to the idle rotation speed Nmin. It suffices that the control device 80 has the control function of. Similarly, the case where both the motor capacity Vm and the engine speed Ne are controlled in the engine control range (steps S418 and S419) has been illustrated, but either one may be controlled. That is, the engine control for controlling at least one of the motor capacity Vm and the engine speed Ne so that the drive pressure P becomes the predetermined drive pressure (P1-P2) and the target drum speed Nt after the pump capacity Vp is set to the maximum. It suffices that the control device 80 be provided with the control function of the range. Further, in the present embodiment, the pump displacement Vp is set to the maximum in the engine control range. However, for example, when it is desired to avoid the maximum value, the pump displacement Vp is set to a predetermined relatively large displacement. May be. Further, in the present embodiment, when the dial 91 of the operating device 90 is operated, the motor capacity Vp is set to the maximum and then the control of the pump control region is executed. In the control of the pump control region, the drum 20 is rotated at the target drum rotation speed Nt. The case where the control is switched to the engine control range when the engine cannot be driven has been illustrated. However, the motor capacity Vp is not first set to the maximum and the control value is calculated in the pump control range, but the motor capacity Vp is set to a preset relatively large predetermined value and the control value is calculated in the pump control range. It may be done.

-Effect-
(1) In the present embodiment, when the drum 20 is driven at the target drum rotation speed Nt according to the operation of the dial 91, for example, the motor capacity Vm is set to the maximum and the drum 20 is driven. In this case, since the motor capacity Vm is the maximum, the required power for driving the hydraulic motor 40 is the minimum, and the drum 20 can be driven under the condition that both the engine speed Ne and the pump capacity Vp are low. After that, while comparing the driving pressure P with a threshold value, the motor capacity Vm is reduced while maintaining the drum rotation speed Nd in a range where the driving pressure P does not become excessive. At that time, if the engine speed Ne is higher than the idle speed Nmin and there is a margin for lowering the engine speed Ne and the pump capacity Vp, the engine speed Ne is preferentially decreased. If the engine speed Ne is the idle speed Nmin and there is no allowance for lowering, the pump capacity Vp is lowered. By doing so, in driving the drum 20 at the target drum rotation speed Nt, the engine rotation speed Ne can be minimized, and noise during drum operation can be suppressed. Further, since the motor capacity Vm is automatically adjusted so that the driving pressure P is in the proper range (P1 ≦ P ≦ P2), the drum is under a balanced condition from the viewpoint of suppressing energy consumption and improving work efficiency. 20 can be driven.

  (2) The drive pressure P may exceed the threshold value depending on the response delay until the engine speed Ne, the motor capacity Vm, and the pump capacity Vp actually change from the input of the drive pressure P by the correction process (the required power of the drum 20). Can be too large). The same applies when the correction range of the operating condition per cycle is large, the load of the drum 20 is heavy, and the like. In such a case, in the present embodiment, the motor capacity Vm is increased while keeping the drum rotation speed Nd constant so that the driving pressure P falls to an appropriate value, so that more energy is consumed than necessary when driving the drum 20. Can be suppressed. When the motor displacement Vm is increased, the engine displacement Ne is corrected by the pump displacement Vp when the engine revolution Ne is at the idle revolution Nmin and the pump displacement Vp is less than the maximum, and by the engine revolution Ne when the pump displacement Vp is maximum. Therefore, the engine speed Ne can be suppressed to suppress noise. However, when the response delay of the correction control is small, or when the correction width of the operating condition per cycle is small, and the drive pressure P is not expected to exceed the threshold value in the process of lowering the motor capacity Vm, the motor capacity The process of increasing and correcting Vm can be omitted.

  (3) The drum speed Nd is determined by the motor capacity Vm, the pump capacity Vp, and the engine speed Ne, and the motor capacity Vm, the pump capacity Vp, and the engine speed Ne for driving the drum 20 at the same drum speed Nd. There are many combinations. On the other hand, in the present embodiment, the operating condition map (FIG. 12) is created, and the engine speed Ne is minimized so that the engine speed Ne becomes the minimum at the operating point on the map defined by the motor capacity Vm and the drum speed Nd. And the pump capacity Vp are set. By using this operating condition map under the condition that the motor capacity Vm is set to the maximum during the initial operation, the operating condition of the drum 20 can be uniquely determined if the target drum rotation speed Nt is determined. When the first operating point is determined on the map, the above-mentioned feedback control allows the drum 20 to be driven at the drum rotation speed Nd according to the operation under the condition of the proper driving pressure and the low noise.

  (4) As described above, the rotation direction and the number of rotations of the drum 20 are instructed according to the operation (direction and size of the operation) of the dial 91. For example, when concrete is discharged from the drum 20 or the drum 20 is stopped. In some cases, the dial 91 may be operated suddenly. As described above, the operating condition map of the drum 20 is divided into the engine control region and the pump control region, and the operating point is changed from the engine control region to the pump control region or the pump control region in the process of approaching the drum rotation speed Nd to the target drum rotation speed Nt. The control range may be shifted to the engine control range. When the operation of the dial 91 at that time is a sudden operation with a large operation amount, if the drum rotation speed Nd changes according to the operation as it is, when the operating point shifts from the engine control range to the pump control range. The drum rotation speed Nd changes discretely. This is because there is a difference in responsiveness between the engine speed Ne and the pump capacity Vp. When the drum rotation speed Nd discretely changes, if the load is heavy, a large inertial weight may be generated in the drum 20 due to a rapid speed change, and the mixer vehicle may momentarily shake greatly. Such shaking can be a psychological burden on the operator. Further, not only when the control in the engine control range is switched to the control in the pump control range (the same applies in the opposite case), the rate of change of the pump capacity Vp, even when approaching the target drum rotation speed Nt in each control range, The behavior of the vehicle associated with the sudden change in the engine speed Ne may cause anxiety for the operator.

  On the other hand, in the present embodiment, when the change rate ΔNd of the drum rotation speed Nd according to the operation of the dial 91 exceeds the limit value ΔNlim, the change rate ΔNd of the drum rotation speed Nd is limited by the limit value ΔNlim. As a result, the behavior change of the mixer vehicle due to the sudden operation of the dial 91 such as the shake of the mixer vehicle can be suppressed, and the psychological burden on the operator can be reduced. However, as long as the above-mentioned essential effect (1) is obtained, it is not always necessary to limit the rate of change ΔNd of the drum rotation speed.

  (5) In a mixer vehicle using a variable displacement hydraulic motor as a drum driving device, the hydraulic motor is generally operated when the dial is returned to the neutral position or the stop switch is pressed while driving the drum. Stop at the current capacity. For example, when the hydraulic motor stops with a relatively small capacity, when a lot of concrete is in the drum, the drum rotates (self-propelled) even though the stop weight is instructed by the weight of the unevenly distributed concrete. ) Can occur. If the hydraulic motor is in a small capacity state, the holding pressure is low, and a small amount of hydraulic oil leaks, causing the motor to rotate a lot, which makes it appear to the operator who does not know the reason that the hydraulic motor is out of order.

  Therefore, in the present embodiment, when the driving stop of the drum 20 is instructed as described above, the motor capacity Vm of the hydraulic motor 40 is forcibly maximized and the drum 20 is stopped. Since the motor capacity Vm is in the maximum state, the holding pressure for keeping the hydraulic motor 40 in the stopped state is maximum, and the amount and speed of rotation (self-propelled) of the drum 20 are the same even if the amount of leakage of hydraulic oil is the same. It can be suppressed. Therefore, it is possible to make it difficult for an operator who does not know the circumstances to mistakenly think that it is a failure. However, as long as the above effect (1) is obtained, it is not always necessary to maximize the motor capacity Vm when the drum is stopped.

  (6) The stirring operation is started, for example, by operating the automatic stirring switch 95 with the operating device 90 mounted in the operator's cab 11, but as described above, thereafter, the stop switch 92 of the operating device 90 mounted in the operator's cab 11 is operated. In principle, operations other than are invalid. This is an interlock for preventing the concrete in the drum from being discharged onto the road due to an erroneous operation, for example, while traveling while traveling while stirring. In order to release this interlock, it is generally necessary to operate a release switch (not shown) of an operating device installed in the cab. However, for example, when the operator switches the operation of the drum from the stirring operation to another operation (automatic kneading operation, manual operation, etc.) outside the vehicle when the vehicle is stopped, it is troublesome because the operator must return to the cab to cancel the stirring operation.

  Therefore, in the present embodiment, even with the operating device 90 installed outside the operator's cab 11, the interlock is released when a predetermined procedure as a releasing operation is performed during the stirring operation. Configured to. Thus, for example, when the operator switches the operation of the drum 20 from the stirring operation to the automatic kneading operation outside the vehicle when the vehicle is stopped, it is not necessary to return to the operator cab 11 one by one, and work efficiency is improved. Although the interlock can be released by the operating device 90 installed outside the operator's cab 11, the interlock is not accidentally released because an operation according to a predetermined procedure is required. However, as long as the above effect (1) is obtained, such an interlock releasing function is not always necessary.

  (7) When arriving at a construction site or the like, a mixer truck that moves while stirring is generally used to raise the drum rotation speed to mix the concrete in the drum to make it evenly mixed and then to discharge it. is there. However, the number of drum rotations and time when kneading this concrete are often due to the operator's sense, and even if the automatic kneading operation function is installed, the operating conditions are uniform regardless of the properties of the concrete in the drum, Quality is likely to be uneven.

  Therefore, in this embodiment, the operation condition of the kneading operation is set based on the driving pressure P of the drum 20 according to the kneading condition map prepared in advance. For example, when the concrete in the drum is hard and a high driving pressure P is detected, the kneading time T2 is long and the drum rotation speed Nd is set fast. On the other hand, when the water content is high and the concrete is soft, the kneading time T2 is set to be short and the drum rotation speed Nd is set to be slow. By doing so, concrete can be kneaded in a necessary and sufficient manner according to the properties, and the kneading condition can be made uniform and unevenness in quality can be suppressed.

  (8) Similar to the concrete kneading operation, in the drum cleaning operation, the drum rotation speed and time often depend on the operator's sense, and even if the automatic cleaning operation function is installed, it depends on the level of the cleaning water in the drum. No, the operating conditions are uniform, and uneven cleaning easily occurs on the drum.

  Therefore, in the present embodiment, the operating condition of the cleaning operation is set based on the driving pressure P of the drum 20 according to the previously prepared cleaning condition map. For example, when a relatively high driving pressure P is detected at a high water level in the drum, the drum rotation amount is small, and when a relatively low driving pressure P is detected at a low water level, a large drum rotation amount is set. . By doing so, the inside of the drum 20 can be uniformly washed according to the water level of the washing water. In addition, when the drum 20 is rotated in the loading direction (the direction in which concrete is transferred to the front), the drum body 21 is tilted forward as compared to the case where the drum 20 is rotated in the discharge direction (the direction in which it is transferred to the rear). Therefore, the contact pressure between the contents of the drum 20 and the blades 22 and 23 is low. Therefore, if the rotation amount is set to be the same in both rotation directions, a difference may occur in the cleaning state between the front and back surfaces of the blades 22 and 23. Therefore, in the present embodiment, by setting the rotation amount in the loading direction to be larger than the rotation amount in the ejection direction, the cleaning state of both the front and back surfaces of the blades 22 and 23 can be made uniform.

  (9) Further, in the process of the automatic cleaning operation, the cleaning operation is executed after the waveform of the driving pressure P is detected and the drum 20 is set to a predetermined start position. As a result, the number of times the blades 22 and 23 come into contact with the cleaning liquid can be made uniform each time, and even if the rotation amount is set to be small, the cleaning effect can be prevented from varying between cleaning operations, and the cleaning effect can be kept constant depending on the level of the cleaning liquid. Can be obtained.

20 ... Drum, 40 ... Hydraulic motor, 50 ... Hydraulic pump, 60 ... Engine, 80 ... Control device, 90 ... Operating device, Nd ... Drum rotation speed, Ne ... Engine rotation speed, Nmin ... Idle rotation speed, Nt ... Target drum Rotation speed, ΔNd ... Rate of change, ΔNlim ... Limit value, P ... Driving pressure, P1 ... Lower limit value (threshold value), P2 ... Upper limit value (threshold value), T1 ... Kneading time, Vm ... Motor capacity, Vp ... Pump capacity, X … Operating point

Claims (9)

A drum for loading concrete,
A variable displacement hydraulic motor that drives the drum,
A variable displacement hydraulic pump that discharges hydraulic oil that drives the hydraulic motor,
An engine for driving the hydraulic pump,
A motor displacement of the hydraulic motor, a pump displacement of the hydraulic pump, and a control device for controlling the engine speed of the engine,
The control device is
After setting the engine speed to an idle speed, the drive pressure of the hydraulic motor is a predetermined drive pressure, and the drum speed of the drum is a target drum speed according to the operation of the operating device. A control function of a pump control region for controlling at least one of a motor capacity and the pump capacity,
At least one of the motor capacity and the engine speed is controlled so that the drive pressure is the predetermined drive pressure and the drum speed is the target drum speed after setting the pump capacity to a predetermined capacity. A mixer vehicle equipped with a control function of an engine control range.   The mixer vehicle according to claim 1, wherein when the operating device is operated, the control device sets the motor capacity to a maximum and then executes control of the pump control region, and in the control of the pump control region, the target is set. A mixer vehicle that switches to control in the engine control range when the drum cannot be driven at a drum rotation speed.   The mixer car according to claim 1 or 2, wherein the predetermined capacity is the maximum capacity of the hydraulic pump.   The mixer vehicle according to any one of claims 1 to 3, wherein the control device limits the rate of change of the drum rotation speed with a limit value when the rate of change of the drum rotation speed according to an operation exceeds a limit value. car.   The mixer vehicle according to any one of claims 1 to 4, wherein the control device maximizes a motor capacity of the hydraulic motor to stop the drum.   The mixer vehicle according to any one of claims 1 to 5, wherein the control device sets the motor capacity, the pump capacity, and the engine speed to a value only when a set release operation is performed during a stirring operation. A mixer truck that controls according to the operation from the operating device.   7. The mixer vehicle according to claim 6, wherein the controller determines a kneading condition including the kneading time and the drum rotation speed based on the driving pressure when the kneading operation is started by the operating device. A mixer truck that performs a kneading operation.   The mixer vehicle according to claim 6 or 7, wherein the controller includes a cleaning amount including the rotation amount in the input direction and the rotation amount in the discharge direction based on the driving pressure when a cleaning operation start operation is performed by the operation device. A mixer vehicle that determines conditions and executes the cleaning operation.   The mixer vehicle according to claim 8, wherein the control device performs the cleaning operation after rotating the drum to a preset start position based on the waveform of the driving pressure.

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