JPS59176679A - Motor-driven fan - Google Patents

Abstract

PURPOSE:To incorporate a circuit part in a motor by IC-implementation and obtain a simplified, small-sized structure by integrating a pulse signal proportional to the rotating speed of the motor by a capacitor and detecting the rotating state of a fan. CONSTITUTION:The output of a position detecting element 2 such as a Hall element is used as a signal source, and the pulse signal of frequency proportional to the rotating speed of the DC brushless motor 4 is obtained by a converting circuit 14 and integrated by the capacitor C. Then, the rotating state of the motor 4 is detected from the output of the capacitor C. Thus, said DC brushless motor uses one Hall element, commutating circuit succeeding thereto, and winding conductor for only one phase and is driven by a full-wave current to continue to rotate by the composition of reluctance torque by the opposite positions of recessed parts provided to a rotor magnetic pole and a stator iron core, thus realizing the simple constitution. Further, the circuit part is IC-implemented and incorporated in the motor and its structure is simplified and reduced in size to maintain high performance.

Description

[Detailed description of the invention] The invention of this application relates to a small electric fan.

In particular, the present invention relates to a sensor-based electric fan used for cooling electronic devices such as small computers and their terminal devices.

These electric fans are becoming increasingly smaller and thinner, but since these fans often cool important parts of electronic devices, if a fan malfunctions, the entire device may stop functioning. This often leads to malfunctions, so when a fan malfunctions, it is necessary to detect it as soon as possible to prevent malfunctions of the entire device.

This type of fan that has been used conventionally will be explained. These fans are actually fan drive motors (hereinafter simply referred to as fan motors) that employ AC induction motors or DO motors with brush commutators. Therefore, in order to obtain a fan failure detection output, a special device must be provided, and in the case of an AC fan motor, a DC power source for the sensor is required in addition to the AC power source to configure the sensor. In addition, in order to obtain a detection output, there are some that require a detection magnet or a detection magnet or optical sensor, etc. to be attached to the professional cover or pentu IJ-, but these fans with sensors are cumbersome because they require special work for each fan. Not only that, but it cannot be used in common with devices that do not have a sensor, and since detection is performed using parts different from the fan motor and fan, there are various defects such as reliability problems. did.

The invention of the present application has been devised to eliminate the defects of the conventional example, and its gist is that, in a fan motor that employs a DC brushless motor, the output of a position detection element, such as a Hall element, is used as a signal source. The converter circuit obtains a frequency/ξ pulse signal proportional to the number of rotations of the motor, integrates the pulse signal in a capacitor, and the output of this capacitor makes it possible to detect the fan's rotation state. The circuit section with this configuration is made into an IC and built into the motor, simplifying the structure and downsizing it. Examples according to the present invention will be described below. The fan and motor according to the present invention use a DCC brushless motor,
A magnet is used for the rotor, a Hall element is used to detect the position of the rotor, an amplifier section is used to amplify the output of the Hall element,
The drive stage is equipped with a logic circuit that controls a power amplifier ( ) ξ power amplifier, and uses an o-to-124 stage to apply rotational force to the coil and rotor using logic output.

To explain the history in detail, as shown in Fig. 1, the Hall element 2
detects the magnetic field of the permanent magnet of the rotor 6 of the DC planless motor 4, leads this output to the logic circuit 12 with the Hall amplifier A1, outputs the outputs Lout 1 and 2, and outputs the Power amplifier A2 as a driver
+ A3 is activated, and an alternating current is passed through the stator winding 8 to generate torque.

In other words, the single-phase/less motor is driven by a single-phase full-wave system that generates torque by alternating the winding current in accordance with changes in the relative position of the single-phase winding and rotor magnetic poles.

In the case of single-phase drive, the Hall output voltage decreases near the point where the polarity of the magnetic field applied to the Hall element changes, making it impossible to obtain sufficient Hall output for switching the transistor, and preventing normal current from flowing through the stator winding. However, in the DC brushless motor according to the present invention, the winding conductor is distributed over a wide range in the air gap on the surface of the magnetic pole. This problem is solved by widening the torque generation range.

Further, as shown in FIG. 1, for polarity switching, a pair of recesses 10 are locally provided in the inner diameter gap surface of the stator core 5.
A gradient is provided in the nog-meance of the air gap to generate reluctance torque to stop the rotor 6 at a position away from the rotor polarity switching point, so that the rotor always stops at a position where starting torque is generated. has been done.

As described above, the DO bra/less motor according to the present invention uses only one Hall element, a commutation circuit following it, and a winding conductor for one phase, is driven by a single-phase full-wave current, and is driven by a single-phase full-wave current. It has a simple structure in which rotation is sustained by the combination of reluctance torque depending on the relative position of the recess provided in the stator core, and the circuit section is integrated into the motor, making the structure simple and compact. Demonstrates high performance retention.

Next, the fan motor rotation detection circuit and its detection function according to the present invention will be explained.

In the present invention, a brushless motor is used, and the circuit detects the rotational position of the rotor using a Hall element, and is equipped with a Ronok stage that drives each ξ power amplifier, so the rotation of the 7-amp motor can be easily detected. I can do it. That is, as shown in the voltage waveform diagram of FIG.
Obtain all and Lout2. However, the reference voltage sv is
A three-person comparator as the conversion circuit 14 is constructed at a point slightly below the midpoint between outl and Lout2, and is compared with the reference voltage SV to obtain a signal Fau I.

In the actual expansion i example of the present invention, this output is V FLTH=4.5~5.4V ~’FLTL=0.8V MAX.

jp = 10μs Outflow current = 10mA NIN.

It is said that

This output is connected to capacitor C as shown in Figure 1.
9.1ttI;' can suppress the output of Fault c. That is, when the fan motor is driven and the fan is rotating, an output of pault Q is output, but when the fan stops rotating or the number of rotations decreases irritatingly, VFLTO decreases.

Therefore, before the 77 malfunctions, that is, the rotation stops or the rotation speed decreases significantly, causing abnormal heat generation or malfunction in the equipment, the FaulLQ output is used to detect the problem, and the signal is used to switch modes such as shutting off the power or stopping the operation. is possible. In the invention of this application, all of these elements are integrated into ICs, and the extra effort of setting up the attached circuits etc. is eliminated, and
It is also possible to house these inside the fan motor and make the output lead h into a drawer structure.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram of an embodiment of the present invention, and FIG. 2 is a voltage waveform diagram of the valley (Φ') according to the present invention.

Claims (1)

[Claims] A DC brushless fan motor includes a conversion circuit that uses the output of the fan motor's rotational position detection element as a signal source and converts it into a frequency ξ pulse signal proportional to the motor's rotational speed, and a capacitor that integrates the output ξ pulse signal. An electric fan characterized in that the rotating state of the fan is detected by the output of a capacitor.