JPH0152987B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coil pattern for a frequency generator that obtains a signal with a frequency (or number of pulses) proportional to the rotational speed of an electric motor, for example.

Generally, a frequency generator is built into the electric motor,
When speed control is performed using the frequency signal from this frequency generator, there are advantages such as good control characteristics and less influence by ambient temperature. It will appear over time and cause a lot of trouble. In particular, in the magnetically variable frequency power generation system, magnetic induction noise due to the magnetic field from the motor and the magnetic field from outside such as a transformer becomes a problem.

FIG. 1 shows the stator section of a conventional frequency generator. In this case, the power generating coil 1 is placed on the insulating substrate A.
In order to cancel the induced noise magnetic flux that intersects with the area surrounded by the power generating coil 1, an induced noise eliminating coil 2 is provided in the opposite direction from both ends of the power generating coil 1.

However, even with such a configuration, the induced noise magnetic flux interlinking with the area surrounded by the power generation coil 1 and the induced noise removal coil 2 cannot be canceled. As a result, if the generated voltage of the frequency signal is small, the induced noise voltage due to the above-mentioned induced noise magnetic flux will have a negative effect on the rotation accuracy of the motor.

In order to eliminate this drawback, a layout shown in FIG. 3 has been proposed. In this example, in order to cancel the induced noise magnetic flux that intersects with the area surrounded by the generating coil 2, a first inductive noise removal coil 4 and a second inductive noise removing coil 5 are provided, and furthermore, the generating coil 3 and the second inductive noise removing coil 5 are provided. The induced noise magnetic flux that intersects with the area surrounded by the first induction noise removal coil 4 provided on the outer periphery of the power generation coil 3, and the second induction noise removal provided in the inner periphery of the power generation coil 3 and the power generation coil 3. The first induction noise removal coil 4, the power generation coil 3, and the second induction noise removal coil 5 are connected in series in this order so that the induction noise magnetic flux interlinking with the area surrounded by the coil 5 cancels each other out.

In other words, in this example, one circle is divided into two,
A method is adopted in which the phase is detected by connecting detection voltages with phases different by 180 degrees in opposite phases, and this is canceled against changes in the magnetic field that passes across the entire surface of the coil. However, in this example as well, the generator coil 3
If a magnetic path is formed in the power generation rotor that is magnetically deviated from the center of rotation or concentric circles, the cancel coil is divided into 180° sections, resulting in detection irregularities once per rotation, resulting in errors. There is a problem that components are easily generated.

The present invention has been made by focusing on these drawbacks and problems in the conventional technology, and has the effect of canceling changes in the magnetic field that passes through the entire generating coil, and also cancels the error component once per rotation. The purpose of the present invention is to provide a frequency generator with a configuration that makes it difficult to generate.

The configuration of the present invention will be described below based on one embodiment.

FIG. 3 shows the basic configuration of the present invention,
This coil pattern can be applied to any number of poles in the generator rotor magnet. Note that in the figure, the NS symbol in the virtual line area indicates the magnetic pole of the magnetic slider. Also, the section indicated by code 6 is 1
In the case of a rotary encoder, it corresponds to 360°, and in the case of a linear scale, it corresponds to from the start point 7 to the end point 8.

This coil pattern is from part a to part b,
It consists of two blocks from section c to section c, each of which is formed as a loop in the opposite direction and connected in series.

In addition, the area surrounded by the loop from part a to part b and the area surrounded by the loop from part b to part c are set to be approximately equal, and the coil section from part a to b and from part c to b are set to be approximately equal. The coil section up to approximately corresponds to the section 6 or the section from the start point 7 to the end point 8.

In the figure, the section from c to e is the first generating coil, the section from b to d is the second generating coil, the section from e to b is the first cancel coil, and the section a is the second generating coil. If the section from to part d is used as a second cancel coil, each of the first and second power generation coils faces a frequency generator rotor 11 (see Fig. 5), which is a magnet mover, which will be described later. It is formed into a rectangular shape with a pitch approximately equal to the magnetic pole (NS) spacing of the rotor 11.

These two generating coils are bent into a crank shape and inserted into each other, so that the wire elements of the two generating coils are formed in a position where the same magnetic signal can be sensed, and the two are arranged as parallel lines close to each other. has been done. Furthermore, on both sides of the entire area of both of these generating coils, there are one first and second cancel coil.
They are arranged side by side, with the first generating coil → the first generating coil.
cancel coil → second generator coil → second cancel coil, so that the first and second generator coils are electrically in phase with each other, and the first and second cancel coils are electrically in opposite phase with each other. They are connected alternately in series so that

As a result, a closed loop for one phase is formed by the first power generation coil and the first cancel coil,
A closed loop for two phases is formed by the second power generation coil and the second cancel coil, and both closed loops are formed in opposite phases (electrical phase difference of 180°).

According to the well-known power generation principle, each of the first and second power generation coils generates an alternating magnetic field generated by the magnetic poles of the multi-pole magnetized generator rotor as it crosses the power generation conductor portion of the rectangular waveform power generation coil. will generate electricity. At this time, since the first and second power generating coils are parallel lines that are close to each other and are connected in series, the power from these power generating coils is twice that of the conventional example. The generated voltage can be obtained.

If induced noise magnetic flux is linked to the component shown in the figure from outside other than the generator rotor, the areas of the closed loop for one phase and the closed loop for two phases are equal and opposite to each other, so they are mutually connected. They act to cancel each other out. Therefore, even if the induced noise magnetic flux is partially uneven, since the area is the same over the entire area, this will not cause detection unevenness.

The first and second power generation coils and the first and second cancel coils are formed on one side of the insulating substrate by printed wiring technology.

Alternatively, an insulating layer may be provided on the magnetic iron plate, and both coils may be formed on the surface of this insulating layer. In this case, a magnetic closed loop is formed with the rotor, further improving efficiency.

The example shown in FIG. 4 is an example in which the structure shown in FIG. 3 is formed on a disk 8, which is an insulating substrate.

The symbols a′, b′, c′, d′, and e′ in Fig. 4 are the third
They correspond to symbols a, b, c, d, and e in the figure, respectively.

Furthermore, the example shown in FIG. 5 is an example in which the configuration shown in FIG. 4 is applied to a brushless motor.

A disk 8 on which a coil pattern according to the present invention is formed is attached to a holder 10 fixed to a substrate 9, and a frequency generator rotor 11 is positioned opposite to the holder 10.

Since the basic configuration of the brushless motor is well known, the names of each component will be listed below.

Reference numeral 12 is a bearing, reference numeral 13 is a rotating shaft, reference numeral 14
15 is a boss, 15 is a rotor yoke, 16 is a rotor magnet, 17 is a stator core, and 18 is a drive coil.

According to the present invention, as described above, the first and second generating coils are inserted into each other, and the wire elements of the two generating coils are placed in a position where they can be sensitive to the same magnetic signal of the magnet mover. Since the first generating coil and the second generating coil are connected in series and close to each other so that they are in the same phase, the same generated voltage is generated in each two wire element. The generated voltage can be doubled compared to the conventional one. In addition, the first and second cancel coils are arranged in parallel on both sides of the entire area of the first and second generating coils, and the first and second cancel coils are electrically connected in series with opposite phases. , the induced noise generated in the cancel coil is canceled out because it is added in reverse phase, and the influence of the induced magnetic field is completely eliminated. Since the second loop consisting of the generator coil and the second cancel coil is connected in series so that the loop is in opposite phase, there is no influence from external noise, and as mentioned above,
Since twice the generated voltage can be obtained, an effect unique to the present invention is achieved in that an excellent frequency generator with an extremely high S/N ratio can be obtained. Furthermore, since the coil pattern is formed on one side, mass production is easy, and high performance encoders can be manufactured at low cost and with high reliability.

[Brief explanation of drawings]

1 and 2 are front views of a stator section of a frequency generator according to the prior art, FIG. 3 is a principle explanatory diagram of a stator section of a frequency generator according to the present invention, and FIG.
The figure is a front view of a stator section of a frequency generator formed on a disk as an embodiment of the present invention, and FIG. 5 is a sectional view of a brushless motor using the stator section of the same figure. 11...Rotor for frequency generator (as a magnet mover), parts c to e, parts c' to e'...first generating coil, parts b to d, parts b' to d' . . . Second generating coil, e section to b section, e' section to b' section... First cancel coil, a section to d section, a' section to d' section... second cancel coil.

Claims (1)

[Claims] 1. A plurality of magnetic poles are placed face-to-face on a magnetized mover, and the first and second power generation coils are inserted at a predetermined pitch into each other, and the wire elements of these two power generation coils are connected to the same magnetism of the magnet mover. The first and second cancel coils are arranged in close proximity to a position where the signal can be magnetically sensitive, and the first and second cancel coils are arranged in parallel on both sides of the entire area of each of the first and second generating coils, and the first and second cancel coils The coils are electrically in opposite phases, the first and second generating coils are electrically in phase, and the first and second cancel coils and the first and second generating coils are alternately connected in series. A coil pattern of a frequency generator characterized by connected.