JPS62213541A - Brushless servo motor with frequency generating coil - Google Patents

Abstract

PURPOSE:To reduce the cost of a brushless servo motor by using an FG coil also for detecting a rotating phase, and inputting the FG voltage to a servo circuit and a driving circuit, thereby omitting the number of parts. CONSTITUTION:The frequency generating voltage of an FG coil 9 is energized at the moment that part of a power source V is determined at starting time. This voltage is input through an amplifier 21 or a servo circuit 24, a speed control amplifier 25 and an amplifier 23 to driving circuits 27, 28. After a motor is started, the coil 9 starts frequency generating in response to the rotation of the motor. The rotating phase is detected by the positional relationship between the coil 9 and a magnetic sensor 26b, and the circuits 27, 28 generate continuous driving torques. Thereafter, a 2-phase brushless motor is operated by two phase sensors made of the sensor 26b and the coil 9.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention is applied to a small frequency power generation coil and a 1-inch brushless servo motor, and can be used in all kinds of machines that require precise rotation by servo control.

[Conventional technology]

Conventionally, there has been a device of this type as shown in FIG.

First, the configuration of the motor section will be explained.

In FIG. 6, Ia is a rotor, which includes an annular drive magnet (not shown) and a magnet yoke (not shown) in which different magnetic poles are alternately magnetized with an equal magnetization pitch. It is made up of. 5a, 5b
is a two-phase drive coil, and the drive coil 5 a +
5b is arranged with an electrical angle of π/2. Reference numeral 9 denotes a full-circumference integral type frequency power generation coil (hereinafter referred to as FC coil), in which a large number of power generation line elements (not shown) are arranged at intervals approximately equal to the magnetization pitch of the drive magnet, and each power generation line They are connected in series so that the generated voltages are added together. The FG coil outputs an alternating current voltage (hereinafter referred to as FG electric voltage) with a frequency proportional to the rotational speed of the rotor 1a, and the FG lightning voltage is generated due to some local magnetization unevenness in the drive magnet. However, the sum of the voltages generated in each of the power generation line elements is smooth and contains only a small error.

Next, the operation will be explained while showing the configuration of each block.

The FGilft pressure F is amplified by an amplifier 20 to become a speed signal S, which is manually inputted to a servo circuit 24 as a feedback signal. The servo circuit performs signal processing such as comparing the speed signal S with a prescribed speed signal, and outputs a speed control signal E. The speed control signal E is supplied to the speed control amplifier 26.
The signals are amplified and input to amplifiers 21 and 23, respectively.

On the other hand, two magnetic sensors 26a, 2 made of Hall elements etc.
6b is the driving coil 5a,
The outputs of the rj & air sensors 26 a + 26 b are amplified by amplifiers 20 and 22 to become phase signals Pa and Pb, which are output to the amplifiers 21 .
23 along with the speed nlj 'II signal.

Now, when the power is turned on, the electronic circuit such as the servo circuit and the magnetic sensors 26a, 26b are energized, and the magnetic sensors 26a, 26b supply a drive current corresponding to the phase of the rotor 1a to the drive coils 5a, 5b. . The drive coil 6 a +5b generates a drive torque to the drive magnet, so the rotor la rotates. Thereafter, the rotor la continues to rotate by the well-known operation of a brushless motor using a magnetic sensor.

As the drive magnet rotates, the FG coil 9
As a result, a magnetic flux change occurs on the FG voltage with a frequency proportional to the rotational speed of the motor, and the FG lightning voltage is increased by the increase II! iii input to the device 20.

Thereafter, the speed of the rotor Ia is controlled by a well-known operation such as a servo motor using an FG coil, and the rotor Ia continues to rotate.

(Problems to be Solved by the Invention) In conventional brushless motors, two or more magnetic sensors for rotational phase detection are used.

This is because one magnetic sensor only detects the strength of the magnetic flux generated from the magnetic poles of the drive magnet.
This is because although the distance from the magnetic pole can be detected, the direction of the magnetic pole, that is, the rotational phase of the drive magnet cannot be detected, resulting in a dead point where commutation is not possible.

When a Hall element or the like is used as a magnetic sensor, there is a problem in the component cost of the Hall element itself, and there is also the disadvantage that it is necessary to constantly supply Ft power to the Hall element while the motor is operating. There was also.

The present invention has been made to eliminate the drawbacks of the conventional motors as described above, and the conventional brushless motor uses a magnetic sensor made of a Hall element, etc.; By using one piece for the FG coil, supplying the FG lightning voltage to the servo circuit and the drive circuit, and using it for both rotational speed control and drive current commutation, the number of parts can be omitted and costs can be reduced. The purpose of the present invention is to provide a brushless motor with a possible frequency generating coil.

[Means for solving problems]

In order to solve the problems mentioned above in the present invention, in a brushless servo motor with a frequency power generation coil, an FG lightning voltage servo circuit and a driving One of the magnetic sensors consisting of a plurality of Hall elements was omitted because each circuit was manually operated.

[Effect]

A magnetic sensor receiving the magnetic flux generated from the ff1ill magnet generates a phase signal of the rotor having the drive magnet. Further, when the drive magnet is rotating, the drive magnet causes a change in magnetic flux to the FG coil, thereby generating an FG voltage. and said′
flj, the air sensor and the FG coil each generate phase signals with a phase difference depending on their mounting position 1α, so the FG coil also generates the phase signal of the rotor in the same manner as the magnetic sensor. Occur.

The FG voltage is input to the servo circuit as a speed signal and to the drive circuit as a phase signal, and is used for controlling the rotational speed of the rotor and commutating the drive current.

〔Effect of the invention〕

In the present invention, a rotor having a drive magnet formed of an annular multi-pole magnet in which N and S magnetic poles are adjacent to each other and a plurality of poles are provided at regular intervals has a drive coil, a plurality of magnetic sensors, and a frequency generating coil arranged in the rotor. The rotor is rotatably supported by a stator having a substrate installed therein, detects the rotational phase of the rotor based on the output of the magnetic sensor, and supplies a commutated drive current to the drive coil according to the phase. In the brushless servo motor with a frequency power generation coil, which includes a drive circuit and whose rotational speed is controlled by the output of the FG coil, the FG coil also serves as one of the plurality of magnetic sensors, and the FG coil Since the rotational speed is controlled by the output of the rotor and the rotational phase of the rotor is detected by the magnetic sensor including the FC coil, one magnetic sensor can be omitted. or,
If the omitted magnetic sensor is a Hall element,
Compared to before omitting it, the power consumption can be saved.

Furthermore, when the FC coil is of the all-circumference integral type, the output of the all-circumference integral type FG coil is less affected by errors such as uneven magnetization of the drive magnet than the output of a conventional magnetic sensor. , more stable motor rotation can be obtained.

〔Example〕

Hereinafter, the present invention will be explained in detail using the drawings.

However, in each figure, things with the same effect are expressed with the same symbols.
l of explanation! Avoid duplication.

1 to 5 show embodiments of the present invention,
Fig. 1 is a sectional view of essential parts of a brushless servo motor with a frequency generating coil (hereinafter referred to as this device), Fig. 2 is a plan view showing the relationship between the full-circumference integral type FG coil and the drive magnet, and Fig. 3 FIG. 4 is a plan view showing the relationship between the drive coil and the drive magnet, and FIG. FIG. 5 is a sectional view of a main part showing another embodiment in which the positional relationship between the FG coil and the drive coil on the printed circuit board is changed.

First, the configuration of this device will be explained with reference to FIGS. 1 to 3.

1 to 3, 1 is a rotor, and a shaft 2 has a magnetic yoke 3 and a drive magnet 4 coaxially connected thereto. The driving magnet 4 is an annular magnet that is divided and magnetized at equal magnetization pitches, and is attached to the magnet yoke 3.

A stator 10 rotatably supports the rotor 1, and a printed circuit board 13 on which an FG coil 9, drive coils 5&, 5b, and a magnetic sensor 26b are arranged is fixed to the stator yoke 12 with adhesive screws. As shown in FIG. 2, the power generation line elements 8 facing the radial blade are arranged all around the circumference at the same pitch as the magnetization pitch of the drive magnet 4, and the sum of these generated M1Ti pressures is A printed pattern is formed so as to be connected in series to form a well-known all-circumference integral type FG coil 9. Moreover, since the motor of this embodiment is a two-phase motor, as shown in FIG.
The drive coils of two circuits (drive coil 5I) (not hatched in the figure) are aligned with the electrical angle π/2 on the printed circuit board 13. It is located at h.

Note that the symbols N and S in FIGS. 2 and 3 indicate the magnetization mode of the drive magnet 4.

Next, the operation of this device will be explained with reference to FIG.

In Fig. 4, when the DC power supply indicated by ■ is turned on, a part of the power supply voltage is applied to the point shown in the figure only at an instant corresponding to the time constant determined by the product of the values of the resistor R and the capacitor C. In addition to inputting the instantaneous current from the point to the amplifier 21, a signal obtained by amplifying the instantaneous current via the servo circuit 24 and the speed control amplifier 25 is also input to the amplifier 21.

By means of assisting startup as described above, at the time of startup, there is no output generated in the FC coil 9, but a part of the power source V is used to increase the frequency generated voltage of the FG coil 9 only at a predetermined moment. , so the increase @
@21 or via the servo circuit 2°4, the speed control amplifier 25, and the amplifier 23, the drive circuits 27 and 28 can be started by manually inputting some kind of signal.

On the other hand, even when the rotor l is in a stopped state, the magnetic sensor 26b generates the phase signal pb due to the magnetic sensing action of a Hall element or the like. The phase signal pb is amplified by the amplifier 22 and inputted to the amplifier 23. The speed control signal E is also input to the amplifier 23, whereby the output of the amplifier 23 is input to the drive circuit 28 so as to obtain a drive N flow with rotational speed control. In the drive circuit 28, a known commutation operation is performed using a conventional brushless motor, and a drive T! is applied to the drive coil 5b. The flow is supplied,
A driving torque is generated for the driving magnet 4 of the rotor 1.

After starting as described above, the PG coil 9 also starts generating power at a frequency corresponding to the rotation of the motor, so that the phase signal ph can be obtained continuously. Furthermore, due to the positional relationship in which the FG coil 9 and the magnetic sensor 26b are arranged, the phase signals Ph and pb generated by them are π
/2 phase difference, and the phase signal ph and pb
The complementary actions of the two drive circuits 27, 28 perform well-known operations to detect a complete rotational phase and generate a continuous drive torque by the drive circuits 27,28.

Thereafter, the two phase sensors consisting of the magnetic sensor 26b and the FG coil 9 operate as a well-known two-phase brushless motor, so the motor of this device continues to rotate smoothly.

In addition, as another embodiment, as shown in FIG.
A printed circuit board 13 for arranging the drive magnet 4 is provided between the drive coil 15 and the drive magnet 4, and the surface facing the drive magnet 4 of both surfaces of the printed circuit board 13 (side A in the figure) ) or the surface on which the drive coil is attached (8 surfaces in the figure).
The coil may be formed using a printed baton.

In general, the present invention is applicable not only to a two-phase type motor having a drive coil made up of two circuits as shown in the above embodiment, but also to a multi-phase brushless servo motor such as a three-phase type motor.

[Brief explanation of drawings]

1 to 5 are diagrams showing embodiments of the present invention, in which FIG. 1 is a sectional view of the main part of the device, FIG. 2 is a plan view showing the relationship between the FG coil and the drive magnet, and FIG. The figure is a plan view showing the relationship between the drive coil and the drive magnet, Figure 4 is a block diagram of a square circuit equipped with means to assist in starting the device, and Figure 5 is a main part showing another embodiment. FIG. Figure 6 shows the conventional example...' Figure 1 Figure 5 Figure 4'cgJ

Claims (2)

[Claims] (1) A rotor having a drive magnet consisting of an annular multi-pole magnet in which N and S magnetic poles are adjacent to each other and a plurality of poles are provided at a prescribed interval (hereinafter referred to as magnetization pitch) is connected to a drive coil, a plurality of magnetic Sensor and frequency power generation coil (hereinafter referred to as FG)
The rotor is rotatably supported by a stator having a substrate on which a coil (referred to as a coil) is disposed, and the rotational phase of the rotor is detected by the output of the magnetic sensor, and a drive current commutated according to the phase is transmitted to the drive coil. In the brushless servo motor with a frequency generating coil, the FG coil also serves as one of the plurality of magnetic sensors. A brushless servo motor with a frequency generating coil, characterized in that the rotational speed is controlled by the output of the FG coil, and the rotational phase of the rotor is detected by a magnetic sensor including the FG coil. (2) The brushless servo motor with a frequency power generation coil according to claim 1, wherein a full-circumference integral type is used as the FG coil.