JP3337038B2 - Motor control method for bread maker - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor torque control and abnormality display device for a bread maker.

[0002]

2. Description of the Related Art In a conventional bread maker, the rotation of an AC motor is transmitted to a pulley by a belt, a stirring blade is attached to a pulley shaft, and the power of the AC motor is turned on and off by a switch. It was the place where it was attached.

[0003]

However, if the torque of the motor is too large, the tension of the belt becomes a problem.
If the belt is cut or the torque is too small, the motor is locked, an overcurrent flows and heat is generated, and the thermal fuse is cut. The present invention has been made in view of the above circumstances.

[0004]

According to the present invention, the rotation of a motor is transmitted via a pulley and a belt to a drive shaft on which a stirring blade is attached, and the dough in a container is kneaded by the rotation of the stirring blade. In the bread machine, it is determined whether the current value of the motor is abnormal or the rotation speed of the pulley is equal to or lower than a normal value (S1). If Yes, the voltage of the motor is increased, and then the rotation speed of the pulley is 0. It is determined whether or not the motor current value is not abnormal (S5). If the current value of the motor is higher than a specified value, a motor lock abnormality is displayed. This is a motor control method for a bread maker, wherein when the motor current value is not abnormally high, an error indication of running out of belt is displayed.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a block diagram showing one embodiment of the present invention, FIG. 2 is a flowchart showing one embodiment of the present invention,
FIG. 3 is a circuit diagram showing one embodiment of the present invention, and FIGS. 4 to 6 are diagrams showing shapes and positions of reflectors or ferrites attached to the surfaces of pulleys showing one embodiment of the present invention.

In the figure, 1 is an AC motor, 2 is a pulley on the driven side, 3 is a belt, 4 is a pulley on the driving side, 6
Is a switching circuit, 6a is a relay IC, 7 is a motor voltage control circuit, 8 is a microcomputer, and 12 is a CT (current transformer). In FIG. 1, the rotation of the AC motor 1 causes the shaft 21 to rotate at a predetermined rotation speed via the belt 3 stretched over the pulleys 4 and 2. For example, when a stirring blade of a bread maker is attached to the pulley shaft 21, the operation of kneading the dough in the container is performed. Reference numeral 22 denotes a rotation detection sensor which applies a reflection to a pulley and detects it with a photo sensor, or attaches a ferrite to a pulley and detects rotation with a magnetoelectric conversion element and a Hall IC. Amplify after detection A /
D-converted and input to the microcomputer 8. FIG.
In the circuit shown in FIG.
2A illustrates the case where 2a is used.

[0007] For simplicity, only one reflector or ferrite to be attached to the pulley 2 for detection by the rotation detection sensor 22 is sufficient as shown in FIG. 5, but if it is attached in a semicircular shape as shown in FIG. A square wave having a ratio of 50% can be obtained, and the rotation number can be easily detected by sequentially increasing the angle θ as shown in FIG.

On the other hand, the current of the AC motor 1 is detected via a current transformer 12 (FIG. 3) or the like, and is input to an A / D conversion circuit 15 through a circuit 12a. input. Similarly, the voltage is detected and input to the A / D conversion circuit 15 through the circuit 13a.
D-converted and input to the microcomputer 8. If the torque of the pulley shaft 21 becomes abnormally large, the current value becomes abnormally large, and the number of revolutions also decreases.
(FIG. 1) is operated to increase the voltage by + α, increase the voltage to a predetermined voltage, and increase the torque of the AC motor according to the torque of the pulley shaft 21. In the circuit diagram shown in FIG. 3, a relay IC is used as the switching circuit 6a.
Is boosted to 120V.

As shown in FIG. 1, a control signal from a microcomputer 8 is input to a motor voltage control circuit 7, and a multi-stage switching circuit 6 is operated by a switching signal output from the control signal to input the signal to the AC motor 1. The voltage can be increased to a predetermined value. The flowchart shown in FIG. 2 shows the above case. As described above, when the motor voltage is increased to a predetermined value, when the AC motor 1 is locked or when the belt 3 is broken, the abnormal indications 10 and 11 are displayed. However, the motor may be stopped by operating the voltage control circuit 7 and turning off the switching circuit 6 in response to the abnormality display signal. However, the stop circuit is not shown in the circuit diagram shown in FIG. As shown in FIG. 1, the motor can be stopped by using the motor voltage control circuit 7 and the switching circuit 6.

Next, the program written in the ROM will be described with reference to the flowchart of FIG. First,
In step S1, it is determined whether the current value of the AC motor 1 is abnormal or the rotation speed of the pulley 2 is equal to or lower than a normal value. If YES, the voltage of the AC motor 1 is increased by + α in step S2, and NO If there is, the process returns to step S1. Next, it is determined whether or not the motor voltage is MAX in step S3. If YES, it is determined in step S4 whether or not the rotation speed of the pulley 2 is 0. If NO, the process returns to step S1.

If the rotational speed of the pulley 2 is 0 in step S4, it is determined in step S5 that the current value of the AC motor 1 is abnormal, as indicated by an arrow of YES. If NO (the pulley 2 is rotating), the process proceeds to step S5. Return to S1. If the current value is abnormally higher than the specified value in step S5, a motor lock abnormality display is made with YES, and if the current value is not abnormally high, a belt break abnormality display is made with NO.

[0012]

According to the present invention described in detail above, the following effects can be obtained. By controlling the voltage applied to the motor, the torque can be temporarily increased even when the motor torque is small.

Further, by detecting the number of rotations of the pulley and the current of the motor, it is possible to detect a belt break when the motor torque is too large and a motor lock when the torque is too small, and display them separately. .

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a flowchart showing an embodiment of the present invention.

FIG. 3 is a circuit diagram showing one embodiment of the present invention.

FIG. 4 is a view showing a shape and a position of a reflector or a ferrite attached to a surface of a pulley according to an embodiment of the present invention.

FIG. 5 is a view showing a shape and a position of a reflector or a ferrite attached to a surface of a pulley according to the embodiment of the present invention.

FIG. 6 is a view showing a shape and a position of a reflector or a ferrite attached to a surface of a pulley according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 AC motor 2, 4 Pulley 3 Belt 6, 6a Switching circuit 7 Motor voltage control circuit 8 Microcomputer 10, 11 Error display 12 CT 21 Pulley shaft 22 Rotation detection sensor

Claims (1)

(57) [Claims] 1. The rotation of a motor is controlled via a pulley and a belt.
To the drive shaft on which the stirring blade is attached,
Bread making that rotates the dough in the container by rotation
Machine has abnormal motor current value, or
It is determined whether the rotation speed of the pulley is equal to or less than a normal value (S1), and Y
If it is es, after boosting the motor voltage, pulley
It is determined whether or not the number of rotations is 0 (S4), and here also, Yes
If any, check whether the motor current value is normal.
(S5), if the motor current value is higher than specified
Displays the motor lock error and the motor current value is abnormal
If it is not too high, display an error display indicating that the belt has run out.
A motor control method for a bread maker.