JPS5947941B2 - Rotational speed signal detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a rotational speed signal detector for an electric motor using a permanent magnet as a rotor. The present invention relates to an extremely simple and economical speed detector that uses a magnetic pole array magnetized on the other circumferential surface to detect a rotational speed signal.

The present invention will be described below with reference to drawings of embodiments.

1 to 5 show an embodiment of the present invention, in which 1
is a cylindrical rotor magnet made of isotropic magnetic material, and its inner circumferential surface is sequentially magnetized with a magnetic pole array 1A of n-poles in the circumferential direction, and its outer circumferential surface is m'(
The magnetic pole array 1B having m>n) poles is sequentially magnetized.

2 is a magnet support to which the rotor magnet 2 is fixed; 3 is a bearing portion 9A of the support base 9 to which the magnet support 2 is fixed.
The rotor magnet 1 is rotatably supported by the rotary shaft 3.

A stator 4 is fixed to the stator mounting portion 9B of the support base 9, and is opposed to the n-pole magnetic pole array 1A of the rotor magnet 1.

This stator 4 has an n-pole magnetic pole array 1A of the rotor magnet 1.
The rotor magnet 1 has a winding 4A that acts on the rotor magnet 1 to apply rotational force to the rotor magnet 1.

Reference numeral 5 denotes a ring-shaped detection coil that faces the m-pole magnetic pole array 1B of the rotor magnet 1 at a constant interval, and a detection winding element is disposed at an angular position corresponding to each of the m-pole magnetic pole pitches. It has 5A.

As shown in FIG. 5, this ring-shaped detection coil 5 is mounted on a flexible strip-shaped insulation sheet 10.
A plurality of conductor foils 11A are provided as A, and these conductor foils 11
The connecting conductor 11B is formed into a continuous wavy shape, and a conductor foil 11C serving as an output terminal 5B is provided at both ends of the connecting conductor 11B.

The above-mentioned detection coil 5 is manufactured by forming a conductor foil for the detection winding on the insulating sheet 10 by etching, or by forming a conductor foil for the detection winding by die stamping. It will be done.

Reference numeral 6 denotes a detecting coil support for supporting the detecting coil 5 in a ring shape at a constant interval with respect to the magnetic pole array 1B of the rotor magnet 10 m poles. It consists of an outer ring 6A made of synthetic resin that is fixed so that .

Here, the detection coil 5 is adhered to the outer periphery of the inner circumferential ring 6B constituting the support body 6 to maintain a ring-like shape, and is fixed at a constant level with respect to the m-pole magnetic pole array 1B of the rotor magnet 1. They are facing each other with a distance between them.

Further, as shown in FIG. 4, the output terminal 5B of the detection coil 5 passes through a through hole 12 provided in the outer ring 6B and connects to the conductor foil 7A of the wire-wound substrate 7 attached to the support base 9. They are connected with solder 13.

Similarly, the stator winding 4A is also soldered to the conductor foil 7A of the winding processing board 7 with its lead wire 14.

The direction of the magnetic flux required to generate the rotational force of the rotor magnet 10 is determined from the magnetic pole N magnetized on the inner circumference of the rotor magnet 1 (N pole → air gap → stator convex → stator → fixed Similarly, the direction of the magnetic flux necessary to generate the rotation speed signal of the rotor magnet 1 is determined by the m-pole magnetization on the outer periphery of the rotor magnet 1. From the magnetic pole N pole, (N pole → air gap → supporting ring → detection coil → supporting ring → air gap →
It is designed to make a complete circuit through the passageway of the south pole.

The rotational speed signal detector configured as described above has the following advantages.

([) To detect the rotational speed signal, no separate rotor is specifically required.

That is, the magnetic flux of the n-pole of one cylindrical surface of the rotor magnet 1 is used for generating rotational force, and the magnetic flux of the m-pole of the other cylindrical surface is used for generating speed signals. They share a permanent magnet.

Therefore, the rotational speed signal detector has not only a simple configuration but also is extremely economical.

(il) In order to detect the rotational speed signal, since the rotor magnet 1 is magnetized in the radial direction (in this embodiment, the outer peripheral surface) for the rotational speed signal, the detection coil 5 may be arranged in the radial direction. Therefore, in the mass production of this type of detector, if the inner and outer circumferential surfaces of the rotor magnet 1 are polished to a predetermined precision, the runout on the inner and outer circumferences can be suppressed to a fairly precise level. can.

Therefore, the detection coil 5 together with the support 6 can be brought quite close to the rotor magnet 1, and variations in detection signals can be suppressed during mass production.

610 The detection coil 5 has a configuration in which a support body 6 is sandwiched with the circumferential opposing surface of the rotor magnet 1. In such a configuration, the material of the support body 6 may be any non-magnetic material, and is generally made of resin. It is possible to use a thinly formed or drawn thin metal plate.

In particular, copper plates and aluminum plates can be made extremely thin and have a strong structure, making them lightweight, inexpensive, and extremely useful as such constituent materials.

Here, although the detector uses electromagnetic phenomena, it is as if the inner ring 6B that constitutes the support 6 is used to obtain electrical output.
However, since the detection frequency required for the application is in the range of several Hz to several 100 Hz, a metal material such as copper or aluminum is used as the material for the inner ring 6B of the support 6. It can be used extensively to greatly improve mechanical precision.

In addition, when using a metal material as described above for the inner circumferential ring 6B of the support body 6, it is necessary to eliminate interference at a relatively high frequency (several KHz or more) that enters the detection coil 5 from the outside. I can do it.

In other words, since the metal material on the circumferential surface of the inner ring 6B causes eddy current loss at these relatively high frequencies, the structure is essentially extremely resistant to high frequency induction or electromagnetic interference through space. I can do it.

Qv) The magnetic flux source of the detection signal is located on the outer circumferential side of the rotor magnet 1, and therefore m can be much larger than the number n of magnetic poles of the magnetic flux source necessary for generating rotational force.

In other words, although the embodiment shows a configuration in which n=16 and m=72, this is only shown to facilitate understanding through illustrations, and the value of m is the size of the outer diameter of the rotor magnet 1. Determined by the size D and the minimum magnetic pole width of the magnetizing device, the outer diameter is 90~
10011t77! Even for a rotor magnet of m'=200~5
It is also possible to set it to 00.

Therefore, since the output frequency as a rotation speed signal can be set high, when controlling the current in the stator winding using the output signal, the ripple frequency of the current to be controlled can be set high as well. Therefore, the gain of the speed control feedback system can be set high.

Therefore, changes in rotational speed with respect to changes in load torque can be minimized, and the start-up characteristics at startup or the response characteristics of the speed control system due to disturbance load fluctuations can be greatly improved.

In the above embodiment, the inner ring 6B of the support 6 is made of a metal material, but the inner ring 6B may be made of a resin material, and the detection coil 5 is made of a metal material. In addition to being attached to the outer circumferential surface of the ring, it may be inserted and supported within the gap between the inner circumferential ring 6B and the outer circumferential ring 6A.

In addition to supporting the detection coil 5 with a support 6 having a double structure of an inner circumferential ring 6B and an outer circumferential ring 6A, the detection coil 5 may be supported simply by bonding or the like on the inner circumferential surface of the outer circumferential ring 6A. You can do it like this.

As described above, according to the present invention 1/fi, the peripheral surface of the rotor magnet is magnetized and used for detecting the rotation speed signal, so that a simple and economical rotation speed detector can be obtained. In addition, the dimensional accuracy of each component of the rotation speed detector can be easily maintained, variations in output signals can be kept small, and the structure can be made resistant to high frequency induction or interference with electromagnetic waves. It is possible to obtain effects such as being able to obtain a considerably large output frequency per force/rotational speed, and when applied to this kind of rotational speed signal detector, extremely remarkable effects can be obtained.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an example of the configuration of the rotational speed signal detector of the present invention, FIG. 2 is a partially cutaway front sectional view of the same detector, and FIG.
The figures are a cross-sectional view taken along the line xx' of FIG. 2, FIG. 4 is an enlarged cross-sectional view of a main part of the detector, and FIG. 5 is a plan view of a detection coil of the detector. 1...Rotor magnet, IA, IB...Magnetic pole row, 4...Stator, 4A...Stator winding, 5
...Detection coil, 5A...Detection winding element, 6...Support, 6A...Outer ring,
6B... Inner ring, 10... Insulating sheet, 11A. 11B, 11C... Conductor foil.

Claims (1)

[Claims] 1. A magnetic pole array of n poles is magnetized in the circumferential direction on one cylindrical circumferential surface, and m pole arrays are magnetized in the circumferential direction on the other cylindrical circumferential surface (where m>
a cylindrical rotor magnet magnetized with a magnetic pole array of n), and a stator winding for applying rotational force to the rotor magnet fixed opposite to the n-pole magnetic pole array of the rotor magnet. a stator including a stator, a detection coil having each detection winding element at an angular position corresponding to each magnetic pole pitch of m poles of the rotor magnet, and connecting these in a wavy manner; The detection is performed in a radial direction with respect to each of the m-pole magnetic pole rows of the rotor magnet, and the detection coil is opposed to the m-pole magnetic pole row of the rotor magnet on its circumferential surface with a constant gap. A support body for supporting the coil in a ring shape,
The n-pole magnetic pole array of the rotor magnet is used to generate rotational force by the action of the stator, and the m-pole magnetic pole array of the rotor magnet is rotated by a detection coil supported in a ring shape by the support. A rotation speed signal detector configured to obtain a speed signal. 2. The detection coil is a flexible insulating sheet with multiple conductor layers as a detection winding element and a connecting conductor layer for connecting these conductor layers, and a coil formed in a wave shape with these conductor layers. The rotational speed signal detector according to claim 1, characterized in that: 3 Claims characterized in that the detection coil is provided on the outer peripheral surface of the inner ring of a support having a double structure of an outer ring made of a non-magnetic material and an inner ring made of a non-magnetic metal material. The rotational speed signal detector according to item 2. 4. The rotational speed signal detector according to claim 2, wherein the detection coil is sandwiched between each ring of a support having a double structure of an outer circumferential ring and an inner circumferential ring made of a non-magnetic material. 5. The rotational speed signal detector according to claim 2, wherein the detection coil is provided on the inner peripheral surface of the ring-shaped support. 6. The rotational speed signal detector according to claim 1, characterized in that an isodirectional magnet material is used as the rotor magnet.