JPS6325903Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a non-commutator motor that is attached to, for example, a rotating field type non-commutator motor and generates a speed signal with a frequency corresponding to the number of rotations of the motor.

A conventional motor of this type is shown in FIG. Figure a is a plan view, and figure b is a sectional view taken along line A-A' in figure a. However, the motor shaft, bearing, and bearing support plate are omitted from FIG.

In the figure, 1 is a stator plate made of a soft magnetic material, 2 is a rotor disc made of a soft magnetic material, and a concave-convex gear is cut on the outer periphery for generating a speed signal. 3 is a flywheel, 4 and 5 are speed detection plates made of soft magnetic material, and concave and convex gears for generating speed signals having the same pitch as the gears on the rotor disk 2 are opposed to the gears on the rotor disk 2, respectively. It has been cut. Reference numeral 6 indicates a motor shaft, and 7 and 8 indicate excitation bar-shaped magnets (hereinafter referred to as FG magnets) that create a magnetic path for generating a speed signal.These magnets are located at the same position from the motor shaft. The magnetomotive forces of are equal. However, the polarities of FG magnets 7 and 8 are opposite to each other, and magnet 7 has an S pole while magnet 8 has an S pole.
is arranged so that the N pole is in contact with the stator plate 1. 9 and 10 are speed detection coils for converting speed signals appearing as magnetic flux changes into voltage;
11 is an armature coil of the motor disposed on the stator plate 1, and 12 is a rotor field magnet facing the armature coil 11, which is magnetized into a plurality of poles. 13 is a bearing, 14 is a bearing support plate, and 15 is a thrust bearing. In Figure b, the dashed line indicates the magnetic path, and the arrows indicate the flow of magnetic flux.

Next, the speed detection operation in a conventional commutatorless motor will be explained.

As shown in FIG. 1, two speed detection plates 4 and 5 are arranged on the rotor disk 2 with a certain gap between them, and between these two speed detection plates 4 and 5 and the stator plate 1. FG magnets 7 and 8 having magnetomotive forces of equal magnitude and opposite sign are respectively arranged. To detect the rotational speed of the motor, the FG magnets 7 and 8 are used as magnetomotive force to detect the stator plate, the speed detection plates 4 and 5, and the rotor disc 2.
The magnetic path shown by the dashed line passing through is used.

In other words, when the motor rotates, the magnetic resistance between the rotor disk 2 and the speed detection plates 4 and 5 is increased by the uneven gear teeth cut on both the rotor disk 2 and the speed detection plates 4 and 5. The magnetic flux that changes periodically and interlinks the speed detection coils 9 and 10 becomes denser and denser, and this change appears as a voltage change at the output terminals of the speed detection coils 9 and 10. Since the frequency of this voltage change is proportional to the rotational speed of the motor, this can be used as a speed signal.

By the way, in the structure shown in FIG. 1, since a soft magnetic material such as a steel plate is generally used for the bearing support plate 14 from the viewpoint of strength and cost, the magnetic flux generated by the FG magnets 7 and 8 as magnetomotive force is transferred to the rotor. In addition to the magnetic path passing through the disc 2, a magnetic path also passes through the bearing support plate 14. The magnetic path for speed signal detection at this time constitutes a closed loop of magnetic path as shown by the dashed-dotted line in Figure 1b, and the magnetic circuit diagram of the magnetic path at this time is as shown in Figure 2. .

In Fig. 2, RF ₁ and RF ₂ are speed detection plates 4 and 5.
The magnetic resistance between the speed detection plates 4 and 5 and the rotor disk 2 changes periodically due to the unevenness of the gears cut into both the speed detection plates 4 and 5 and the rotor disk 2, respectively. By the way, both resistance values are equal. So RF ₁ =
Let RF ₂ = RF. R ₁₁ and R ₁₂ are speed detection plates 4 and 5
and the bearing support plate 14 with their respective magnetic resistances,
The two resistance values are equal. So R ₁₁ = R ₁₂ =
Let's set it as R ₁ .

Rm ₁ and Rm ₂ are the respective internal magnetic resistances of the FG magnets 7 and 8, and the two resistance values are equal. Therefore
Let Rm ₁ = Rm ₂ = Rm. F ₁₁ and F ₁₂ are magnetomotive forces of the FG magnet 6 and are equal. Therefore, let F ₁₁ = F ₁₂ = F ₁ . 9 and 10 are coils for speed detection.

The flow of magnetic flux in the magnetic circuit diagram of FIG. 2 is in the direction of the arrow in the figure. As can be seen from the flow of magnetic flux, the magnetic path passing through the magnetic resistances R ₁₁ and R ₁₂ is connected in parallel to the magnetic path passing through the magnetic resistances RF ₁ and RF ₂ . Changes in interlinking magnetic flux are caused by magnetic resistance RF ₁ , RF ₂ and magnetic resistance R ₁₁ ,
Parallel combined resistance of R ₁₂ x = {(2RFR ₁ )/(RF+
R ₁ )} is caused by a change Δx=2Δ{(RFR ₁ )/(RF+R ₁ )}. Here, since the magnetic resistance value R ₁ is constant in one device, ΔR ₁ =
It is 0. Therefore, the change in parallel resistance is Δx=
{(2R ₁ ² )/(RF+R ₁ ) ² }ΔRF. Therefore, when the motor becomes thinner and the gap between the speed detection plates 4 and 5 and the bearing support plate 14 becomes smaller, and the resistance value R ₁ of the magnetic resistances R ₁₁ and R ₁₂ becomes smaller, the above-mentioned Since the change in parallel resistance Δx also becomes smaller synergistically, the change in the magnetic flux that interlinks the speed detection coils 9 and 10 also becomes smaller, and the output level of the speed signal obtained from the speed detection coils 9 and 10 increases. The drawback was that the width was significantly reduced.

This idea was made in order to improve the drawbacks of the conventional ones as mentioned above, and an FG auxiliary magnet is placed between the speed detection plate and the bearing support plate to give the speed detection plate a magnetomotive force of the same polarity as the FG magnet. It is an object of the present invention to provide a commutatorless motor that prevents the adverse effects of the parallel magnetic path by arranging the parallel magnetic paths.

Hereinafter, the commutatorless motor of this invention will be explained with reference to the drawings.

In FIG. 3, the same reference numerals as in FIG. 1 indicate the same or corresponding parts, and the same operations as those described above are performed.
16 and 17 are FG auxiliary magnets, and speed detection plates 4 and 5
The FG magnets 7 and 8 are arranged so that the poles of the same polarity as the magnetic poles on the detection plate 4 side are in contact with each other. Note that the electromotive forces of these two FG auxiliary magnets 16 and 17 are equal. Therefore, in the speed generator of the present invention, a closed loop of magnetic path as indicated by the dashed line in FIG. 3 is formed, and the magnetic flux flows in the direction of the arrow in the figure.
The magnetic circuit diagram of the magnetic path at this time is as shown in FIG.

In the figure, RF ₁ , RF ₂ , Rm ₁ , Rm ₂ , F ₁₁ ,
F ₁₂ , 9, and 10 indicate the same or corresponding parts as the same reference numerals in FIG. R ₂₁ and R ₂₂ are FG auxiliary magnets 16,
17 and the bearing support plate 14, the resistance values are equal. So R ₂₁ = R ₂₂ = R ₂
far. Rm′ ₁ and Rm′ ₂ are FG auxiliary magnets 16 and 17
The resistance value is the same for each internal magnetic resistance. Therefore, let Rm′ ₁ = Rm′ ₂ = Rm′. _F21 , _F22
is the magnetomotive force of the FG auxiliary magnets 16 and 17, and both are equal. Therefore, let F ₂₁ = F ₂₂ = F ₂ . Fourth
The arrows in the figure indicate the flow direction of magnetic flux.

As can be seen from the direction in which the magnetic flux flows in FIGS. 3 and 4, since the FG auxiliary magnets 16 and 17 are arranged between the speed detection plates 4 and 5 and the bearing support plate 14 with the above polarity, The magnetic path of the speed generator of the present invention includes a speed detection plate 4 which uses both FG magnets 7 and 8 as magnetomotive force, passes through the rotor disk 2, the speed detection plate 5, the FG magnet 8, and the stator plate 1 to the FG magnet. 7,
The closed loop of the magnetic path toward the speed detection plate 4 and the FG auxiliary magnets 16 and 17 serve as magnetomotive force.From the speed detection plate 4, the rotor disk 2, the speed detection plate 5, the FG auxiliary magnet 17,
Two closed loops are formed independently, including a closed loop of a magnetic path passing through the bearing support plate 14 to the FG auxiliary magnet 16 and the speed detection plate 4.

Therefore, the magnetic flux linked to the speed detection coils 9, 10 using the closed-loop FG magnets 7, 8 as magnetomotive force does not go around to the bearing support plate 14 side, but instead passes through the speed detection plate which is cut to form a speed signal. 4, 5 and the respective magnetic resistances RF ₁ , RF ₂ between the gears of the rotor disk 2
Therefore, regardless of the magnitude of the resistance value R ₂ of the magnetic resistance R ₂₁ , R ₂₂ between the speed detection plates 4, 5 and the bearing support plate 14, the speed detection coils 9, 10 transmit the closed loop speed. It is possible to obtain a speed signal with an output level that depends only on the change in magnetic resistance (ΔRF) due to the uneven gear between the detection plates 4 and 5 and the rotor disk 2. In addition, two FG magnets 7,
By making the magnetomotive forces of 8 have equal amounts and different signs, and by making the magnetomotive forces of the two FG auxiliary magnets 16 and 17 have equal amounts and different signs, the stator plate 1, rotor disk 2, and bearing support In order to keep all the plates 14 at zero magnetic potential, the FG magnets 7 and 8 and the FG auxiliary magnets 16 and 17
This does not create magnetic flux unevenness in the field magnetic field.

As described above, according to this invention, a second permanent magnet is provided between the speed detection plate and the bearing support plate, which gives the speed detection plate a magnetomotive force of the same polarity as the first permanent magnet, so that the speed detection coil The magnetic flux interlinking with the bearing support plate is no longer adversely affected by the magnetic flux passing through the bearing support plate, which has the effect of preventing the speed signal level from decreasing due to thinning.

[Brief explanation of the drawing]

Figure a in Figure 1 is a plan view of a conventional speed generator with the motor shaft, bearing, and bearing support plate removed, Figure b in Figure 1 is a side sectional view of the conventional speed generator, and Figure 2 is a side sectional view of the conventional speed generator. FIG. 3 is a side sectional view of the speed generator of the present invention, and FIG. 4 is an explanatory diagram of the magnetic circuit of the speed generator of the present invention. 1... Stator plate, 2... Rotor disc, 3...
Rotor flywheel, 4, 5...speed detection plate,
6... Motor shaft, 7, 8... FG magnet, 9, 10
... Speed detection coil, 11 ... Armature coil,
12...Rotor field magnet, 13...Bearing, 14...
... Bearing support plate, 15 ... Thrust bearing, 16,1
7...FG auxiliary magnet. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A rotating shaft supported by a stator plate and a bearing support plate that face each other, a rotor disk that is attached to the rotating shaft between the stator plate and the bearing support plate and has an uneven outer periphery, and a rotor field that is attached to this rotor disk. a magnet, an armature coil disposed on the stator plate facing the rotor field magnet, an armature coil disposed opposite to the outer periphery of the rotor disc between the stator plate and the bearing support plate, and an armature coil disposed on the outer circumference of the rotor disk between the stator plate and the bearing support plate; a speed detection plate having an uneven surface, a first permanent magnet disposed between the speed detection plate and the stator plate, and generating a magnetic flux flowing between the rotor disk and the speed detection plate;
The magnetic flux flowing between the rotor disk and the speed detecting plate is directed in the same direction as the magnetic flux generated by the first permanent magnet. A second permanent magnet generated in
and a non-commutator motor, comprising a speed detection coil that is provided in a magnetic flux path through which the first permanent magnet flows and generates a speed signal based on changes in the magnetic flux.