JPH04165951A - Brushless motor - Google Patents

Abstract

PURPOSE:To see that the signal line is not affected by the radiant noise from a power source line thereby generating a more accurate detection signal so as to elevate various properties of a brushless motor by leading out the signal line in the direction opposed to the power source line. CONSTITUTION:During operation of a brushless motor 2, for the current flowing in a power source line 29, the changeover of the direction or ON/OFF of current application are performed repeatedly, so the radiant noise resulting from that occurs from the power source line 29. On the other hand, a detector 25 is constituted of a low-voltage circuit, so the current value transmitted by the signal line 28 is small, and it is subject to the influence of the external noise. In this case, the signal line is led out from the direction opposite to the power source line 29. Hereby, the effect to the signal line 28 by the radiant noise of the power source line 29 can be removed, so the drop of the various properties of a motor 2, caused by the divergence of the conduction period by the occurrence of an error signal, commutation error, etc., can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to prevention of malfunctions and deterioration of various characteristics due to noise in a brushless motor.

[Conventional technology]

Conventionally, the drawing out of signal lines from the power source ItfA and the position detection device in a brushless motor was disclosed in Japanese Patent Application Laid-open No. 1986-
As described in No. 257754, in order to facilitate wiring to connected control circuits, etc., the drawers are drawn out in the same direction or in the vicinity.

[Problem to be solved by the invention]

The above-mentioned prior art does not take into account the influence of radiation noise from the power line on the signal line, and the signal line is wired near the power line that supplies power to the brushless motor, so the current flowing through it is large. Furthermore, there is a fear that the signal line may be affected by radiation noise generated from the power line where the current direction is changed, causing an erroneous signal to be generated.

An object of the present invention is to improve various characteristics of a brushless motor by preventing signal lines from being affected by radiation noise from power supply lines and generating more accurate detection signals.

[Means to solve the problem]

In order to achieve the above purpose, by pulling out the signal line in the direction opposite to the power line,
Since it can be placed as far away as possible, the influence of radiation noise from the power supply line can be minimized, and the generation of erroneous signals can be prevented.

〔Example〕

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

FIG. 1 shows the overall configuration of an electric blower and its control device using an embodiment of the present invention. In the figure, an electric blower 1 is composed of an electric motor 2 and a blower 3.

The electric motor 2 is a brushless motor, and includes a stator 22. A rotor 239 having a permanent magnet 24 houses a detection device w25 for detecting the magnetic pole position of the rotor 23, and a signal from the detection device 25 is sent to the control device 4 via a signal line 28.
0. Electricity is supplied to the stator winding 22b from the control device 40 through the power line 29.

The stator winding 22b is composed of three-phase windings, and as shown in FIG.
Power supply to each winding is controlled by the output signals of 5a, 4.5b, and 45c. During operation of the (brushless motor 2), the direction of the current flowing through the power line 29 is switched or the current ON/FF is repeated, and radiation noise is generated from the power line 29 due to this.

On the other hand, since the detection device 25 is constituted by a low voltage circuit, the current value transmitted through the signal line 28 is small and is easily affected by external noise.

Therefore, if the signal line 28 is near the power line 29,
Noise from the power supply line 29 may generate an erroneous signal on the signal line 28 . For example, the graph shown in FIG.
(using a Hall IC) represents the output signal (for three phases). Since the (brushless motor) 2 in this embodiment uses a two-pole rotor 23, H (same potential as the power supply potential) and L (O potential) are repeated at 180° pitch.

Of these signals, the control device 40 determines whether the signal is high or low.
The energization to the stator winding 22b is controlled based on the timings of the A part) and the falling part (B part).

Here, when influenced by external noise, the potential of the signal may be reversed midway as shown in FIG. 4. In this case, a shift in energization timing or a commutation error occurs, which causes deterioration of various characteristics of the electric motor (brushless motor) 2.

In the present invention, the signal line 28 is drawn out from the direction opposite to the power line 29 in order to minimize the influence of radiation noise generated by the power line 29 on the signal line 28 .

As a result, the influence on the signal line 28 is small, and
The deterioration of characteristics as described above can be prevented.

〔Effect of the invention〕

According to the present invention, it is possible to eliminate the influence of the radiation noise of the power supply line 29 on the signal line 28, so that the deterioration of various characteristics of the motor 2 due to deviations in energization timing due to generation of erroneous signals, commutation errors, etc. It can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of an electric blower and an overall configuration diagram of a control circuit according to an embodiment of the present invention, and FIG. 2 is a perspective view of a magnetic pole detection device.
3 and 4 are output signal diagrams of the magnetic pole detection device. 22 stator, 22b stator winding, 23 rotor,
24 Permanent magnet, 28 Signal line, 29 Power line, 40.
- Control device, 45... Detection device, 45a. 45b, 45cm detection element.

Claims (2)

[Claims] 1. In a brushless motor having a detection device that detects the rotational position of a rotor made of a permanent magnet, a power supply line connected to a stator winding and a signal line connected to the detection device are pulled out from opposite directions to the outside. A brushless motor characterized by: 2. In claim 1, the rotor, stator, and detection device are housed in a housing, and the power supply line and the signal line are arranged to pass through holes provided at opposing positions on the outer periphery of the housing. A brushless motor characterized by: