JPH0119585Y2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field The present invention relates to a commutatorless motor, in which the magnetic poles of a drive magnet and the magnetic poles of a pick-up magnet are configured to be continuous in the axial direction. It is an object of the present invention to provide a commutatorless motor that can form magnetic poles at the same time and that can be assembled in a shorter time and easier than conventional motors.

Conventional technology As a motor that drives the rotating drum of a VTR,
Axial field type commutatorless motors are often used. The rotor of this device has a ring-shaped drive magnet in which a plurality of magnetic poles are formed in the circumferential direction with N and S poles magnetized in the axial direction, and a plurality of ring-shaped drive magnets for extracting signals for detecting the phase of the video head. A pick-up magnet is provided.

In conventional motors, a pre-magnetized pick-up magnet is generally provided, for example, on the outside of the rotor yoke, independently of the magnetic poles of the drive magnet.

Problems that the invention aims to solve However, pick-up magnets are generally minute, and if they are pre-magnetized like conventional pick-up magnets, they will adhere to other magnetic materials etc. during assembly. It had some drawbacks that made it difficult to handle. In addition, this device had the disadvantage that the pick-up magnet and the drive magnet had to be magnetized separately, which required a lot of time to manufacture and could not be constructed at low cost. The present invention eliminates the above-mentioned drawbacks, and an embodiment thereof will be described below with reference to the drawings.

Means for Solving the Problems In the motor of the present invention, the fixed pick-up coil is arranged so as to face the surface of the rotor-side drive magnet opposite to the stator-side drive coil, and the pick-up coil The net is protruded from the surface of the drive magnet facing the fixed pick-up coil, and the polarity of the surface of the pick-up magnet facing the fixed pick-up coil is the same as the polarity of the surface of the drive magnet in contact with the pick-up magnet. The rotor is provided with a rotor in which the magnetic poles of the drive magnet and the magnetic poles of the pick-up magnet are magnetized in the axial direction.

Function In the present invention, the pick-up magnet is arranged so that the polarity of the surface of the pick-up magnet facing the fixed pick-up coil and the polarity of the surface of the drive magnet in contact with the pick-up magnet are the same as the polarity of the surface of the drive magnet. The structure is such that it is magnetized in the axial direction. This results in
When forming magnetic poles in pick-up magnets and drive magnets, by simply stacking the magnetic material to become the drive magnet and the magnetic material to become the pick-up magnet in the axial direction and applying a magnetic field once in the axial direction, both magnetism can be achieved. The magnetic poles can be formed on the body at the same time, and it can be assembled and manufactured easily and in a short time.

Embodiment FIG. 1 shows a sectional view of an embodiment of the non-commutator motor according to the present invention applied to a drum motor of a VTR. In the figure, reference numeral 1 denotes an upper rotating drum to which video heads 2a and 2b are attached. A rotor portion 3, which will be described later, is fixed to the lower part of the rotating shaft 1a of the drum 1, and is supported by a bearing 4.

Reference numeral 5 denotes a lower fixed drum, which is fixed below the rotating drum 1, and a stator section 6 is attached to the lower side of the lower fixed drum so as to face the rotor section 3. The stator section 6 generally includes a cup-shaped motor base 7, a stator yoke 8 fixed to the bottom thereof, a rubber elastic coil holder 9 attached to the stator yoke 8, and a drive for the rotor section 3 supported by the coil holder 9. It is composed of a flat drive coil 11 and the like provided opposite to the magnet 10.

As shown in FIGS. 2A and 2B, the rotor portion 3 is roughly as follows.
It is composed of a rotor yoke 12, a drive magnet 10, a bearing 4, and pickup magnets 13a and 13b. Reference numeral 14 denotes a pick-up coil, which is fixed at a position opposite to the rotation locus of the pick-up magnets 13a, 13b.

When manufacturing the rotor section 3, holes 12a and 12b are formed in the rotor yoke at positions 180 degrees opposite to the surface of an unmagnetized ring-shaped magnetic body 10' (which will later become the drive magnet 10). 12, and unmagnetized cylindrical magnetic bodies 13a', 13b' (these will later become pick-up magnets 13a, 13b) are fitted into the holes 12a, 12b, and bonded to the magnetic body 10'. . next,
These are attached to a magnetic field generator so that the polarities adjacent to each other in the circumferential direction are different from each other over the entire 360° circumferential direction of the magnetic body 10′, and the polarities facing 180° are different from each other. Apply a magnetic field in the axial direction so that it is polarized.

As a result, the magnetic body 10' has N,
The drive magnet 10 is formed by alternately forming, for example, 10 magnetic poles with different polarities in the circumferential direction, with the S pole magnetized. At the same time, the magnetic material 13
N and S poles are magnetized in the axial direction of a' and 13b', forming pick-up magnets 13a and 13b. Here, pick up magnet 1
A sectional view taken along a straight line passing through the centers of 3a and 13b is as shown in Figure B, and as is clear from Figure B, the surface of the pickup magnet 13a (the surface facing the pickup coil 14) and the drive magnet 10 are The surface of the magnetic pole 10a (the surface adjacent to the back surface of the pick-up magnet 13a) is the S pole, and the back surface of the pick-up magnet 13a (the surface adjacent to the surface of the magnetic pole 10a of the drive magnet 10) and the magnetic pole of the drive magnet 10 are the S-pole. 10a
The back surface (the surface facing the coil holder 9) of each is magnetized to the N pole, while the pick-up magnet 1
3b (the surface facing the pick-up coil 14) and the surface of the magnetic pole 10b of the drive magnet 10 (the surface adjacent to the back surface of the pick-up magnet 13b) are N poles, and the pick-up magnet 1
3b (the magnetic pole 10 of the drive magnet 10)
b) and the back surface of the magnetic pole 10b of the drive magnet 10 (the surface facing the coil holder 9) are each magnetized to the S pole.

This is because the magnetic field generator is manufactured so as to connect the magnetic body 10' and the magnetic bodies 13a' and 13b', and when magnetizing, the magnetic flux that promotes the magnetization of the magnetic body 10' is transmitted to the magnetic bodies 13a', 13a' and 13b'.
By forming a magnetic path passing through 13b', simultaneous magnetization becomes possible. In general, a magnetic substance can be regarded as a collection of very small magnets (molecular magnet), and the simultaneous magnetization described above is thought to be caused by magnetization by this molecular magnet. In this direction, N and S poles as shown in FIG. 2 are formed.

In this case, positions facing each other by 180 degrees in the circumferential direction are magnetized to have different polarities, so the surface magnetic poles of the pick-up magnets 13a and 13b have different polarities, and this pick-up magnet 1
3a and 13b alternately oppose the pickup coil 14 in FIG. 1 as the rotating drum 1 in FIG. 1 rotates, whereby phase detection signals of positive pulses and negative pulses are extracted.

Note that the number of pick-up magnets is not limited to two, and may be larger than this.
Further, the respective surface magnetic poles are not limited to different polarities, but may be of the same polarity.

Alternatively, the pick-up magnet may be partially embedded within the drive magnet.

Effects of the invention As mentioned above, the commutatorless motor according to the invention has the following advantages:
The fixed pick-up coil is arranged so as to face the surface of the drive magnet opposite to the stator-side drive coil, and the pick-up magnet is protruded from the surface of the drive magnet that faces the fixed pick-up coil. and,
The magnetic poles of the drive magnet and the pick-up magnet are aligned in the axial direction so that the polarity of the surface of the pick-up magnet facing the fixed pick-up coil is the same as the polarity of the surface of the drive magnet that is in contact with the pick-up magnet. Since it has a magnetized rotor, when forming magnetic poles on both magnets, the magnetic material that will become the drive magnet and the magnetic material that will become the pick-up magnet are overlapped in the axial direction and once in the axial direction. Just by applying a magnetic field, magnetic poles can be formed on both magnetic materials at the same time, and as a result, the magnets do not adhere to other magnetic materials during assembly, unlike conventional methods in which both magnets with magnetic poles formed in advance are assembled. There are no such inconveniences, it is easy to handle, easy to assemble, and can be manufactured in a shorter time and at a lower cost than the conventional method in which both magnetic materials are magnetized separately. .

[Brief explanation of drawings]

FIG. 1 is a sectional view of an embodiment of the motor of the present invention applied to a drum motor for a VTR, and FIGS. 2A and 2B are a perspective view and a sectional view of the essential parts of an embodiment of the motor of the present invention, respectively. 3... Rotor section, 1... Drive magnet,
10a, 10b...Magnetic pole, 10', 13a', 13
b'...Magnetic material, 12...Rotor yoke, 12a,
12b...hole, 13a, 13b...pickup magnet, 14...pickup coil.

Claims (1)

[Scope of Claim for Utility Model Registration] A rotor-side drive magnet, in which a plurality of axially magnetized magnetic poles are arranged circumferentially so that the magnetic poles are alternately different, is arranged axially upwardly facing a stator-side drive coil. and a rotor-side pick-up magnet for detecting the rotational phase is disposed axially upwardly facing a fixed pick-up coil in its rotation locus, the fixed pick-up coil is connected to the rotor-side drive The magnet is arranged so as to face the surface opposite to the stator-side drive coil, and the rotor-side pick-up magnet is arranged on the surface of the rotor-side drive magnet that faces the fixed pick-up coil. protrudingly provided, and such that the polarity of the surface of the rotor-side pickup magnet facing the fixed pickup coil is the same as the polarity of the surface of the rotor-side drive magnet that is in contact with the rotor-side pickup magnet; A commutatorless motor comprising a rotor in which the magnetic poles of the rotor-side drive magnet and the magnetic poles of the rotor-side pickup magnet are magnetized in the axial direction.