JPS6039001B2 - electric drive - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electric drive device for driving a mixing drum of a concrete mixer vehicle using a variable speed electric motor.

In conventional concrete IJ mixer vehicles, oil is produced by driving a hydraulic pump using the engine for running the wheels as a power source to generate rotational driving force for the mixing drum, which is a storage container for mixed concrete to be transported or mixed. A hydraulic drive device is used that drives a hydraulic motor using pressure.

In general, in this type of vehicle marrow, the rotational speed of the mixing drum during mixing and transporting mixed concrete is required to be driven at a relatively low speed in order to mix the contained concrete well and to save driving power. At the same time, at the time of discharging the contained concrete to the outside, it is necessary to generate sufficient centrifugal force and drive at a relatively high speed in order to efficiently discharge the concrete. It is necessary for the operator to be able to adjust the amount appropriately. On the other hand, in conventional hydraulic drive devices using a hydraulic pump and a hydraulic motor, the operator operates the rotation speed adjustment lever of the hydraulic motor to adjust the rotation speed of the mixing drum and adjust the discharge amount. There is a problem in that when the engine rotation speed changes, the rotation speed of the hydraulic motor changes even if the rotation speed adjustment lever is fixed at a constant position. In other words, when wheels are run to transport or mix bran concrete, the engine is operated at various engine speeds depending on wheel running conditions such as running speed, and the hydraulic motor's speed changes accordingly. . In general, the rotation speed of the hydraulic motor must be set so that sufficient mixing function can be obtained even when the engine is idling, so when the engine speed is high such as when driving at high speed, the mixing drum is hydraulically driven as the rotation increases. The horsepower consumption of the equipment increases, creating the problem of energy waste.

Therefore, in the first aspect of the present invention, a variable speed electric motor is operated using a battery as a power source, and a speed setting device of a rotation speed adjusting device for driving a mixing drum with the electric motor and adjusting the rotational speed of the electric motor is manually set. It is an object of the present invention to provide a mixing drum driving device in which the rotational speed of the mixing drum can be adjusted to a desired value, and the battery is charged by a charging device including a generator driven by a traveling engine. That is.

Furthermore, in general, regarding the rotation direction of the mixing drum,
Regarding the above-mentioned concrete storage and mixing function, it is necessary to be able to set the drum rotation speed to a desired value within the range of a few revolutions per minute to more than ten revolutions per minute. Then, for the function of discharging concrete from the drum, it is necessary to be able to set the desired rotational speed in the opposite rotational direction to the storage and mixing functions and within the same range of drum rotational speeds. Therefore, in the second aspect of the present invention, the variable speed electric motor is configured to be capable of forward and reverse rotation using a rotation direction switching device, so that the variable speed motor can be rotated in the forward and reverse directions by simple electrical means without using a complicated mechanical rotation direction switching device. It is an object of the present invention to provide a mixing drum driving device capable of switching the mixing drum.

The electric drive device according to the present invention will be described in detail using the electrical connection diagram shown in FIG. 1 as an example.

Reference numeral 1 denotes a battery, which in this example also serves as a power source for the starting motor of the car shrine.

2 is a key switch.

3 is an electric motor that generates driving force for the mixing drum.

In this example, a DC shunt motor is used, and power is transmitted between the armature and the mixing drum via a gear. Reference numeral 4 denotes an electric control circuit, which has a function of controlling the speed of the DC shunt motor.

A speed detector 5 detects the rotational speed of the electric motor 3.

6 is a generator that charges the battery, and the engine drives a three-phase alternating current generator, with a built-in diode for converting the generated alternating current output to direct current.

A voltage regulator 7 controls the output voltage of the generator 6 to be constant.

Reference numeral 8 denotes a rotation direction changeover switch for the electric motor 3, which in this example reverses the polarity of the excitation coil of the electric motor 3.

In the above configuration, the inductor 51 is engaged with the armature 31 of the electric motor 3, and its rotation is controlled by the electromagnetic pickup 5.
2, a pulse signal with a repetition frequency proportional to the rotational speed is obtained.

When the power switch 41 is turned on, the electrical control circuit 4 enters the operating state and the contact 42' of the relay 42 is also closed, and the voltage of the battery 1 is applied to the positive end of the armature 31 and exciting coil 32 of the motor 3. Ru. The pulse signal from the speed detector 5 is converted by a speed voltage generator 43 into a speed voltage VN in which a slight triangular wave ripple voltage is superimposed on a DC voltage corresponding to the pulse repetition frequency.

Further, a set voltage Vs is determined by adjusting the potentiometer 44' of the speed transformer 44, and a comparator 45 compares this set voltage Vs with the speed voltage VN including the ripple voltage to generate an error signal. . This error signal is amplified by the current amplification circuit 46, the excitation current of the motor 3 is controlled, and the motor rotation speed is adjusted. Outside of operation, the potentiometer 44' of the setting device 44 is adjusted in accordance with the desired drum rotation speed to determine the set voltage Vs.

Regarding this, the basic control operation for the motor rotation speed is that when the drum rotation speed is lower than the set rotation speed, VN<Vs
, and accordingly, the conduction time of the transistor 46' becomes relatively longer than the cutoff time, and the phase of the transistor 46'' is reversed, and the cutoff time becomes relatively longer than the cutoff time. Therefore, the effective value of the excitation current flowing through the excitation coil 32 of the electric motor 3 is added, and the rotation speed of the armature 31 is controlled in the direction of increasing.On the other hand, when the drum rotation speed becomes higher than the set rotation speed, VN>Vs and vice versa. The magnetic current of the conductor 3 decreases and the motor rotation speed decreases.The rotation speed of the mixing drum is adjusted to the operator's desired rotation speed accordingly.The rotation direction switch 8 is closed as indicated by the solid line. When switching from the state to the open state of the line,
Since the direction of the excitation current is reversed, the armature 31 is reversed, and the mixing drum connected with the gear rotates in the reverse direction.

In the example shown in FIG. 1 described above, the armature 31 of the electric motor
We have explained an example of a closed-loop control method in which the rotation speed of the motor is detected as a pulse frequency by a speed detector, an error with respect to the set rotation speed is detected, and the motor excitation current is controlled.
As shown in the figure, by inserting a variable resistor 33 in series with the excitation coil 32 of the electric motor 3 for driving the mixing drum, and engaging this variable resistor with the speed setting knob, the operator can rotate the electric motor by operating this knob. The number of drum rotations can be controlled and the drum rotation speed can be adjusted to a desired value.

However, since the method in Figure 2 is an open-loop control method, the motor rotation speed fluctuates under the influence of load torque, battery voltage, etc., and although it is less accurate than the closed-loop control method in Figure 1, it is simpler. It is also cost effective. In FIG. 2, 1 is a battery, 41 is a power switch, 6 is a battery charging generator, 7 is a known voltage regulator for adjusting the voltage of the generator 6, 71 is a voltage control relay, 72 is a lamp relay, and 73 is a charge lamp.

The rotational direction of the mixing drum may be determined by a switch similar to the example shown in FIG. 1, or by a known mechanical rotational direction switching device. As described above, in the first aspect of the present invention, in order to drive the mixing drum of a concrete mixer truck, a variable remote electric motor is operated using the car's battery as a power source, and the rotational force generated by the electric motor is used to drive the mixing drum of a concrete mixer truck. The battery is charged by a generator that is driven by a driving engine and generates DC output, so that even if the engine rotation speed varies, the mixing drum rotation speed remains constant. This has the excellent effect of not only being able to maintain a nearly constant rotation speed without directly affecting the rotation speed, but also saving the driving energy of the mixing drum.

Furthermore, in the second aspect of the present invention, since the rotational direction of the electric motor can be electrically switched, there is an excellent effect that the rotational direction of the mixing drum can be switched with a simple configuration.

[Brief explanation of drawings]

FIG. 1 is an electrical wiring diagram showing one embodiment of the device of the present invention, and FIG. 2 is an electrical wiring diagram showing another embodiment of the device of the invention. DESCRIPTION OF SYMBOLS 1... Battery, 3... Electric motor, 4... Electrical control circuit, 5... Speed detector, 6... Generator, 8...
・Rotation direction selector switch, 43...speed voltage generator,
44...Speed setter, 45...Comparator, 46...
Current amplification circuit. Figure 2 Figure 1

Claims (1)

[Claims] 1. In a concrete mixer vehicle equipped with a mixing drum, a charging device including a generator driven by a traveling engine, a battery charged by the charging device, and a battery using the battery as a power source. An electric drive device comprising a variable speed electric motor and a rotational speed adjusting device for the variable speed electric motor, and driving the mixing drum by the rotational force of the variable speed electric motor. 2. In a concrete mixer vehicle equipped with a mixing drum, a charging device including a generator driven by a driving engine, a battery charged by the charging device, and a reversible variable speed electric motor using the battery as a power source, An electric drive device comprising a rotation speed adjusting device and a rotation direction switching device for the reversible variable speed electric motor, and driving the mixing drum by the rotational force of the variable speed electric motor.