JPS6016187B2 - high flux electric motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to highly efficient magnetic devices and circuits.

In particular, the present invention relates to high flux electric motors with magnetic circuits for reducing leakage of magnetic flux through magnetically permeable materials. In a magnetic circuit that has a magnetomotive force source such as an electromagnet or a permanent magnet, it is recognized that some amount of leakage magnetic flux occurs.Leakage magnetic flux appears in various forms, and its form is caused by magnetic members (for example, one part of the stator). It depends on various factors, such as the shape of the magnetic field, the influence of magnetic fields other than the magnetic field, the strength of the magnetic field, and the degree of proximity between the magnetic member and the magnetic field.

Taking motors as an example, magnetic flux leakage typically occurs on the sides of the magnetic poles and near the fixed windings. However, in a magnetic field outside the magnetic field, it is natural that it is desirable to send as much of the magnetic flux generated by the magnetic source as possible to the opposite magnetic pole or magnetic flux return path via the magnetic pole face, air gap, and rotor. Magnetic flux that does not follow the path just described, that is, leakage flux, does not interact with the current in the armature and therefore does not contribute to the generation of torque in the motor. Therefore, from this point of view, the torque generated by the motor is directly related to the degree of magnetic transmission between the magnetic force source and the air gap. The same applies to electromagnetic equipment other than motors, such as moving saddle pole relays and transducers. Various attempts have been made to increase the magnetic flux density of magnetic circuits in motors and other electromagnetic devices.

For example, the magnetic poles or pole pieces of a motor with multiple magnetic poles are generally tapered radially inward, so that the area of the surface of the pole piece near the rotor (called the pole face) is reduced. It is smaller than the radially outer surface of the same pole piece, and the magnetic flux density in the pole piece becomes relatively higher in the portion closer to the rotor. Typically, the magnetic field strength is increased to compensate for magnetic flux leakage from the pole piece, or the pole piece itself is magnetically isolated from nearby magnetically permeable materials. . Gourd material with low magnetic permeability is placed to block the magnetic field, but it not only takes up space, but is also a passive method, and does not itself contribute to increasing magnetic flux density.

Other conventional methods simply change the shape of the magnetic pole piece to prevent concentration of the magnetic field, which causes leakage magnetic flux.
In some conventional stators for two-pole electric motors, strong permanent magnets are attached to a pair of flat surfaces of the magnetic pole pieces near the outer periphery of the stator and facing each other at an obtuse angle.

However, the purpose of this is to ensure as many lines of magnetic force as possible on the wide magnetic pole surface of the radially thin magnetic pole piece. The magnetic pole axis of the added magnet intersects the rotation axis of the motor, and in this respect the relationship between the magnet and the motor is completely conventional. That is, as conventionally seen in this type of motor, the magnetic pole axes of the individually provided magnetic sources (for example, field coils) are arranged to approximately coincide with a radial line passing through the rotational axis of the motor. In addition, in the above-mentioned two-pole motor stator, one independent magnetomotive force source (magnet)
They are structurally unique in that they share one magnetic pole piece. This tends to realign the magnetic field lines along the mid-axis of the pole piece, but does not prevent large amounts of flux from escaping from any unshielded sides of the pole piece. . Furthermore, because the angle between the sides of the pole piece covered with permanent magnets is quite large, the degree of tapering of the surface castle is extremely small, and therefore the magnetic flux density can be increased and strengthened at the pole face. Have difficulty. Although the conventional motor having the above-described structure improves the transmission of magnetic flux from the magnetomotive force source to the rotor, a considerable amount of leakage magnetic flux still occurs.

For this reason, the increase in magnetic flux density in the effective air gap between the magnetic pole face and the rotor is extremely limited, and from a structural standpoint, a fairly large area is required to mount the magnet as a source of magnetomotive force. is a drawback. In some cases, it may not be possible to secure a magnet mounting surface due to the overall size of the motor.
Even in conventional motors and other magnetic equipment, where the magnetic transmission efficiency in the stator magnetic circuit has reached a somewhat satisfactory level, the magnetic flux leaking from the magnetic elements reaches a considerable level. There is a limit to the absolute magnetic strength possible.

According to the present invention, since magnetic flux loss is significantly reduced,
As will be explained in detail later, the strength of the required magnetic field can be increased to a value exceeding the magnetic flux density of a normal single supermagnetic force source, and in particular, a magnetic flux density of 20,000 Gauss or more can be achieved. Furthermore, the present invention can easily increase the magnetic operation efficiency of inexpensive magnetic-related equipment without incurring any expense. That is, according to the present invention, it is possible to dramatically increase the magnetic flux density in magnetic equipment, particularly in the stator of an electric motor, using a small and inexpensive supermagnetic force source. From the viewpoint of magnetic circuit design, it is possible to assume that the magnetic flux loss due to leakage of magnetic flux from magnetic components is zero in the stator magnetic circuit of the motor of the present invention.

Therefore, it can be said that there is no need to include or consider the factor of magnetic flux loss when designing. Specifically, the high magnetic flux electric motor according to the present invention includes at least a pair of polygonal magnetic pole pieces made of a magnetically permeable material disposed around a rotor, a magnetomotive force source that covers the side surface of each magnetic pole piece, and a magnetomotive force source that covers a side surface of each magnetic pole piece. in contact with a magnetic source,
It includes a ferromagnetic housing that establishes a magnetic circuit passing through each magnetomotive force source via at least one pair of magnetic pole pieces and a rotor.

Each magnetic pole piece has at least four magnetic pole piece sides and a magnetic pole face facing the rotor with an effective air gap, and the area ratio of the magnetic pole piece side surfaces to the magnetic pole face is 1.5 or more, preferably 2. It is 0 or more. At least two of the pole piece sides are located substantially opposite the pole face, and the other two pole piece sides sandwiching the pole face are tapered toward the pole face to concentrate magnetic flux across the pole face. Sloped, with at least 2 of the 4 sides
are formed so that the angles they form with each other are obtuse angles. On the other hand, a magnetomotive force source is a magnetomotive force source that covers each side of one or more identical magnetic pole pieces having a plurality of magnetic pole axes extending in different directions. The average magnetic pole axes of the magnetomotive force sources covering each side of each magnetic pole piece intersect with each other inside each magnetic pole piece, and are opposed to each other with respect to the rotor. The magnetic pole faces of each matching pole piece are given opposite polarities. here,
The term "portion covered by a supermagnetic force source" means a portion where a magnetomotive force source for forcing magnetic flux into the inside of the magnetically permeable member is installed. A magnetomotive force source is composed of independent, distinct or numerous magnetic segments, which have average magnetic pole axes that are approximately perpendicular to the surface of the magnetically permeable member and intersect at one or several locations within it. are doing.

Therefore, physically, even a single source of magnetomotive force can be viewed as a composite magnetic field with magnetic flux extending in multiple directions.
The magnetic pole axis of the magnetic flux establishes at least one magnetic field having a component perpendicular to the composite magnetic field. To further generalize the present invention, the magnetic fields of independent magnetic segments interact with each other to control the magnetic vector of the composite magnetic field in the effective gap of the magnetically permeable member to be oriented in a predetermined direction, and The segments are arranged so that the magnetic flux can be directed only from the portion of the magnetically permeable member facing the effective air gap.

Under the influence of the composite magnetic field or the total magnetic field, the net magnetic flux gradient vector extends parallel to a predetermined axis that is the magnetic flux passing axis in the magnetic circuit. The deflection (leakage) magnetic vector is almost completely neutralized by the opposing magnetic vector components emanating from the individual magnetomotive force sources. In any case, in order to increase the magnetic flux passing efficiency in the magnetic circuit and improve the magnetic efficiency of the entire circuit, it is desirable to match the magnetic resistance of the magnetomotive force source to the magnetic resistance of the load, that is, the magnetic path.

In the stator magnetic circuit of the present invention, a large number of magnetomotive force sources are arranged so that the magnetic flux they emit can prevent magnetic flux leakage in the magnetic circuit, and in this case, the magnetic resistance of each magnetomotive force source is It is chosen to be equal to the reluctance of the load excited by the magnetic source. In the high-flux motor of the present invention, pole pieces with angularly related inclined sides serve as magnetically permeable members of the stator magnetic circuit.

Parts of at least two sides of the pole piece are covered with a magnetomotive force source, such as a permanent magnet plate, and the magnetic flux crossing the effective air gap between the pole piece and the rotor is caused by this magnetomotive force source. Forms a magnetic vector with orthogonal components.
The area of the pole piece portion covered by the magnetomotive force source is at least 1.5 mm larger than the surface area of the effective air gap. It is more than a sound. Also,
In the present invention, a single magnetomotive force source or a plurality of magnetomotive force sources may be used to form magnetic fields having at least three different directions of development that intersect with each other.

This form is a common configuration of the magnetic circuit of the present invention, and the entire surface of the magnetic pole piece except for the effective air gap portion is covered by the magnetomotive force source. Referring to the attached drawings below,
Some embodiments of the invention will now be described in detail.

First, FIG. 1 shows a motor incorporating a magnetic stator circuit according to the present invention for passing extremely high-density magnetic flux through the air gap between the rotor and the stator. A motor employing this magnetic stator circuit will be able to generate unexpectedly large torques for a given armature current, as will be explained in more detail below. In the following, the present invention will be explained using a DC motor as an example, but the scope of application of the present invention is not simply limited to a specific electromagnetic device or a motor magnetic circuit, but is applicable to all types of magnetic circuits and electromagnetic devices. It has wide applicability. The DC motor shown in FIG. 1 is a simple one having a two-pole rotating armature and is housed inside a housing 10.

The housing 10' includes vertical magnetic flux road plates 12, 14 and horizontal magnetic flux road plates 15, 16 which provide a return path for magnetic flux, which will be described later.
, as well as a magnetic-like frame 18. Note that these components may be made of steel, for example. In order to simplify the explanation, explanations of the structure of the armature, the state of electrical wiring, and other matters not directly related to the present invention will be omitted. Armature 2 attached to shaft 21
0 is encased inside the housing 10, but the armature may be of any known type. When installed inside the housing 10, the armature 20 rotates within the space secured between the two salient pole pieces 22, 24. Since the motor of the present invention is intended to be operated under extremely high magnetic flux density, the pole piece 2
2,24' magnetic materials with high values of magnetic saturation, e.g.
Preferably, it is made of annealed ferromagnetic alloy C-1018. The salient pole piece 24 has four side faces 25, 25', 27, 27' and a pole face 29, and the salient pole piece 24 has four side faces 25, 25', 27, 27' and a pole face 29.
6, 26', 28, 28', and a magnetic pole face 30.

Of these, each side 25, 25' and 26, 26'
are inclined in a direction in which they approach each other as they go radially inward, so that they have a tapered shape. A high-density magnetic flux for driving the armature 20 passes through the magnetic pole faces 29 and 3. Then, the armature 20 and the magnetic pole faces 29 and 30
An air gap is created between the magnetic pole piece 22,
This will be referred to as an "effective void" to distinguish it from voids that occur in connection with other surfaces of 24. The actual effective air gap in the high-performance outer sheath to which the present invention is applied is several hundredths of a centimeter, but is exaggerated in the accompanying drawings for clarity. Magnetic pole face 29 in the magnetic pole piece 22
Main field magnets 32 and 32' are bonded to the two opposite sides 27 and 27' so as to cover almost the entire surface thereof, and the two opposite sides 28 of the magnetic pole face 30 of the magnetic pole piece 24 , 28', main field magnets 34, 34' are arranged so as to cover almost the entire surface thereof.

The main field magnets 32, 32', 34, 34' form a magnetic field that passes through and couples through the pole pieces 22, 24, the armature 20, the vertical flux road plates 12, 14, and the horizontal flux road plates 15, 16. The magnetic path of the magnetic field formed by the main field magnets 32, 32', 34, 34' is indicated by dotted lines 35. In addition,
The main field magnets 32, 32', 34, 34' are Alnico No.
81B is suitable, and they are arranged in the magnetic relationship shown in FIG. As is clear from what has been described so far, the illustrated motor is a DC motor, and the magnetic flux density within the effective air gap is
, 26' are tapered.

That is, since the surface area of the magnetic pole faces 29, 30 of the magnetic pole pieces 22, 24 is significantly smaller than the surface area of the flat surfaces 27, 27', 28, 28' in contact with the main field magnets 32, 32', 34, 34', The number of lines of magnetic force passing per unit area of the magnetic pole faces 29, 30 is greater than the number of lines of magnetic force passing per unit area of the planes 27, 28. In conventional motors, the maximum flux density that can be achieved in the effective air gap is not significantly affected by the flux losses in the pole pieces 22, 244 as well as in the magnetic path outside the armature. The reality is that it is inevitable.

For example, the magnetic flux loss in the pole pieces 22, 24 is such that the magnetic flux passing through the pole pieces 25, 25', 26, 26'
Leaking from the armature 2 to the opposite side, and from both sides 25
, 25', 26, 26' towards the housing 01 made of magnetic material. This magnetic flux loss greatly limits the magnetic efficiency of the motor magnetic circuit. It is this type of flux loss that the present invention seeks to, and indeed does, significantly reduce. According to the invention, the single or multiple magnetomotive force sources for exciting the effective air gap are capable of causing the magnetically permeable pole piece to radiate all the magnetic flux passing through the pole piece from the pole faces 29, 30. It will be placed in

This allows the magnetic flux to be concentrated in a specific area of the magnetic circuit. In order to achieve this objective, the magnetic pole axis of the magnetomotive force source is arranged so that the magnetomotive force source can have a magnetic field component perpendicular to the direction of passage of the desired composite magnetic flux. In the magnetic circuit of the motor shown in FIG. 1, cross-field magnets 36, 37, 38, 39 are arranged close to each side surface 25, 25', 26, 26' of the magnetic pole pieces 22, 24 to achieve this purpose. has been reached.

The average magnetic pole axis of the auxiliary magnets 36 to 39 is the same as the magnetic pole pieces 22 and 2.
Main field magnets 32, 32', 34, 34 passing through the inside of 4
' is arranged so as to intersect with the average magnetic pole axis of '. Therefore, the magnetic field generated by the auxiliary magnets 36 to 39 includes the main field magnet 3.
Includes magnetic flux components that perpendicularly intersect with the magnetic flux that exits from 2, 32', 34, and 34' and extends radially inward toward the effective air gap. Basically, the magnetic pole axes of the auxiliary magnets 36-39 are oriented to prevent magnetic flux from leaking to the outside from the main field magnets 32, 32', 34, 34'. For this reason, the magnetic field of the auxiliary magnets 36 to 399 (cross magnetic field =
cross field) and main field magnets 32, 32', 34, 3
4' interact with each other to generate magnetic pole pieces 22, 2.
The magnetic flux emitted from the magnetic pole surfaces 29 and 30 of No. 4 is increased. In connection with this point, it should be noted that in reality, one of the magnetic pole faces 29 and 30 of the two magnetic pole pieces 22 and 24 becomes a magnetic flux emitting surface, and the other becomes a magnetic flux incident surface that receives the emitted magnetic flux. Looking at the effects of the auxiliary magnets 36 to 39 theoretically, the main field magnets 32, 32', 34, and 34' cause the magnetic pole pieces 22,
It can be said that the magnetic region formed inside the magnetic field 24 is rotated or modified. The auxiliary magnets 36 to 39, which are the sources of supermagnetic force of the cross magnetic field, are arranged separately and individually in a state of large inclination with respect to the normal magnetic path of the magnetic pole pieces 22 and 24, so that an effective cross magnetic field can be established. In addition to the auxiliary magnet, another magnetic material is additionally installed. These are magnetic flux path blocks made of soft iron and indicated by reference numerals 40 and 41 in FIG. The magnetic flux path blocks 40, 41 form a magnetic flux return path, thereby magnetically coupling the auxiliary magnets 36-39 together. Due to the magnetic coupling of the auxiliary magnets 36 to 39 by the magnetic flux path blocks 40 and 41, the magnetic pole piece 22
, 24 as a common magnetic path, and the magnetic pole faces 29, 301
Two separate magnetic circuits are formed which serve to increase the magnetic flux density in the core. By making the return flux paths of the auxiliary magnets 36 to 39 for cross magnetic fields with materials with low magnetic resistance, smaller auxiliary magnets 36 to 39 can be used, and proper alignment, especially alignment, can be achieved at the load point (mainly the effective air gap) and the auxiliary magnets. It becomes possible to obtain the magnetomotive force. The magnetic flux paths of the crossed magnetic fields are indicated by dotted lines 43. It should be noted here that all the outer circumferential surfaces of the magnetic pole pieces 22, 24 except for the magnetic pole faces 29, 37 are The fact is that we are surrounded.

This is one feature that contributes to the realization of the objective of the present invention, which is to significantly reduce magnetic flux leakage. magnetic pole pieces 22, 24
Auxiliary magnets or sources of magnetomotive force are arranged not only on the outer circumferential surface but also on both end surfaces of the magnetic pole surface 29, which literally faces the effective air gap.
If the entire outer surface of the magnetic pole piece except for 30 is surrounded by a magnetomotive force source, the pole faces 29 and 30 will be subjected to repulsive effects of opposing magnetic fields from all directions, creating an ideal state in which there is virtually no leakage of magnetic flux. comes closer to. Furthermore, in the high magnetic flux electric motor according to the present invention, the area ratio of the side surface of one magnetic pole piece to the magnetic pole surface is 1.
The basis of the configuration in which the number is 5 or more will be explained based on the embodiment shown in FIG.

Since the angle between the two pole piece side surfaces 27 and 27' located on opposite sides of the magnetic pole face 29 of the magnetic pole piece 22 is an obtuse angle, the maximum angle is 90°. The remaining magnetic pole piece side surfaces 25 and 25' sandwiching the magnetic pole piece 29 are tapered toward the magnetic pole surface, but assuming the ultimate state that satisfies this condition, they are parallel to each other. Assuming that the length of each side of the magnetic pole piece side surfaces 27 and 27' is "1", the intersection of the average magnetic pole axes of each main field magnet 32 and 32' is formed inside the magnetic pole piece 22.
In the extreme state, the magnetic pole single side surfaces 25, 25' are infinitely "
This is when the value is close to 0. In this case, the length of the magnetic pole surface 29 is "2" in terms of straight line distance, and the ratio between this and the sum of the opposing magnetic pole side surfaces 27 and 27', "111=2", is "2/2".
"Zo 2" becomes about ノ 2. However, since the two pole piece sides 25, 25' taper toward the pole face, the actual length of the pole face 29 is at most 1. It's a milk shop degree.
In this case, the ratio of the magnetic pole piece side surface covered with the magnet to the magnetic pole surface is 2/1.3=1.5, which is the basis for limitation in the present invention. Another important feature of the invention is the total magnetomotive force source surrounding the pole pieces 22, 34, i.e. the main field magnets 32, 32', 34, 34'.
, is the setting of the relationship between the average magnet axes of the auxiliary magnets 36 to 39.

In the present invention, these magnetic pole axes are arranged in a mutually interacting relationship inside the magnetic pole pieces 22 and 24, and the magnetic field formed by each magnetomotive force source is at least perpendicular to the composite magnetic flux (total magnetic flux). Contains magnetic flux component. Here, the composite magnetic flux or total magnetic flux is a general term for the magnetic flux that passes through the magnetic pole pieces and toward the effective air gap, and this composite magnetic flux connects the center of the rotation axis of the motor and the center of the pair of magnetic pole pieces 22 and 24 at any position. parallel to the connecting line. Each magnetomotive force source 32, 32'
, 34, 34', and 36 to 39 contribute to forming the total magnetic flux inside the magnetic pole pieces 22, 24, but some of them prevent the magnetic flux from leaking from other than the designated points of the main magnetic circuit. It works to prevent. The reluctance of such a portion is such that the main reluctance is substantially matched to the reluctance in the effective air gap of the main magnetic circuit. FIG. 3 shows the approximate arrangement of the magnetomotive force sources 32, 32', 36, 37 associated with one of the pole pieces 22.

As is clear from this, the cross magnetic field auxiliary magnets 36, 3
7, the average magnetic pole axes 42, 44 of each main field magnet 32, 32'
They intersect with the average magnetic pole axes 46 and 46', respectively. Here, the "average magnetic pole axis" refers to the average magnetic field line of a magnetomotive force source that passes through the center of the magnetomotive force source when it is not affected by external magnetic materials or external magnetic fields. It means a line parallel to the direction. for example,
The average magnetic pole axis of a Hiromi magnet is an axis parallel to the vertical axis connecting the north and south poles of the Hiromi magnet. The arrangement of the magnetomotive force sources shown in FIG. 3 is basically the same as that shown in FIG. 1, but with some modifications.

That is, the auxiliary magnets 36 and 37 for the crossed magnetic poles are composed of a plurality of segment magnets. That is, the auxiliary magnet 3
6 is composed of segment magnets 36a and 36b, and the auxiliary magnet 37 is composed of segment magnets 37a and 37b.
Among the segment magnets constituting each auxiliary magnet, the magnetomotive force of the segment magnets 36b, 37b that are closer to the magnetic pole surface 29, which is the magnetic flux emitting surface of the magnetic pole piece 22, is the same as that of the segment magnets 36a, 37a that are farther from the magnetic pole surface 29. Stronger than magnetomotive force. In this way, by setting the magnetic flux density of the auxiliary magnets 36 and 37 to be high in the region where the magnetic flux density is higher due to the main field magnet 32 and the magnetic resistance of the magnetic path is also increased, the crossover formed The effectiveness of the magnetic field is recognized, and an increase in cost due to the use of strong magnetic material throughout the auxiliary magnets 36, 37 as a source of magnetomotive force of the cross magnetic field can be avoided. In FIG. 3, the path of the magnetic flux generated by the stronger segment magnets 36b, 37b is indicated by a dotted line 45. This magnetic flux path 45 also has magnetic flux paths 43 and 3.
5, the magnetic pole piece 22 and the magnetic pole face 29 are shared as a supply path. Magnetic materials suitable for the cross-field magnets 36 to 39 include Indox 1A, Indox V, and barium ferrite V.

The type of magnetic material used depends on the configuration of the magnetomotive force source and the strength of the magnetic field required to counteract the drop in the magnetomotive force in the effective air gap beneath it. When designing the magnetic circuit of the present invention, generally speaking, first the required magnetomotive force at the flux emitting surface is determined, at least one magnetomotive force source (e.g., the main field magnet) is selected, and its magnetic resistance is loaded. The design generally assumes that there is no or little leakage of magnetic flux by matching the magnetic reluctance at the sides (mainly the effective air gap). The strength of the magnetomotive force of the cross-field auxiliary magnet is determined in relation to the magnetomotive force drop in the effective air gap, and it is desirable that its magnetic resistance closely match the magnetic resistance in the effective air gap. Once these parameters are determined, it becomes possible to calculate the length and thickness of each magnet, the area of both sides of the pole piece, and its inclination angle while taking into account the given dimensional restrictions. As stated above, by matching the magnetic reluctance of each magnet to that in the effective air gap, the intended effects of the present invention are more significantly exhibited.

The magnetic flux generated by the main field magnets 32, 32', 34, and 34', which are connected to the effective air gap through the magnetic pole pieces 22 and 24 made of black iron, passes through the effective air gap. By additionally arranging auxiliary magnets 36 to 39 on both sides of the pieces 22 and 24, the magnetic flux passage characteristics can be significantly improved. However, when such an auxiliary magnetomotive force source is added to the magnetic circuit, the matching state of magnetic resistance between the already set main field magnets 32, 32', 34, 34' and the effective air gap is disrupted, and the main field Magnet 32, 32'34
, 34', there will be a mismatch between this and the effective air gap reluctance. If the added auxiliary magnet does not contribute to increasing the magnetic flux density in the effective air gap, it is sufficient to simply adjust the magnetic resistance of the main field magnet to be approximately equal to the magnetic resistance of the effective air gap. If the addition of a magnet results in an increase in the magnetic flux density in the effective air gap, then
This point must be taken into consideration when designing the magnetic circuit. The use of multiple magnetomotive force sources with reluctances matched to those of the active air gap to increase the magnetic flux density in the active air gap and to prevent flux leakage is another feature of the invention. FIG. 6 shows a simple equivalent circuit of the high magnetic flux density magnetic circuit of the present invention.

In the equivalent magnetic circuit shown in FIG. 6, Fo and F are the main field magnets 32, 32', 34, and 34', respectively, in the barrier state.
and shows the magnetomotive force of the auxiliary magnets 36 to 39. It has already been explained that in the actual magnetic circuit, the main field magnet and the auxiliary magnet each have a return flux path made of a piece of soft iron. Ro, R
．． represent the Thevenin's internal magnetic reluctance in the Wang Kai magnet, the auxiliary magnet, and the auxiliary magnet, respectively, R3 and R4 represent the total magnetic reluctance of the magnetic flux path passing through the iron piece, and RL represents the magnetic reluctance of the magnetic flux path outside the iron piece. (However, effective voids are excluded). The magnetic flux leakage at the pole piece is the auxiliary magnetomotive force F
, so the load reluctance is mainly accounted for by the effective air gap reluctance Rg. The leakage magnetic resistance RL may be ignored. Since the magnetic permeability of the soft iron pieces forming the return magnetic path is high, these magnetic resistances R3,
R4 is extremely small compared to the load magnetic resistance. Therefore,
The magnetic resistance of the iron piece (return magnetic flux path) can also be almost ignored. This can be achieved by minimizing leakage of magnetic flux, optimizing the operating conditions of the magnetic circuit, and maximizing magnetic effectiveness by matching the relationship between the magnetomotive force source and the load. The design of the magnetic circuit of the invention is simple.

If a preliminary design is made with the above points in mind, it often becomes the final design. However, it is also possible to modify the preliminary design based on experiments or current calculations, taking into account the unavoidable slight residual magnetic flux leakage, the non-linear characteristics of the ferromagnetic magnetomotive force source and the return flux path, etc. It is. For convenience of explanation below, other parameters in the magnetic equivalent circuit are listed below.

= Area of the surface perpendicular to the magnetic flux of the main field magnet A, = Area of the surface perpendicular to the magnetic flux of the auxiliary magnet L = Length (thickness) parallel to the magnetic flux of the main field magnet L = Parallel to the magnetic flux of the auxiliary magnet Length (thickness) Fg = Magnetomotive force drop in the effective air gap Lg = Length parallel to the magnetic flux of the effective air gap Ag = Area of the surface perpendicular to the magnetic flux of the effective air gap.

=Low magnetic flux in the magnetic flux path of the main field magnet. = Magnetic flux Bg in the magnetic flux path of the auxiliary magnet = Magnetic flux density in the effective air gap If we choose conditions under which each magnetomotive force source can independently overcome the magnetic resistance in the air gap area of Ag/2, each The load on the magnetic source is ice g (the actual load Rg is obtained by combining the members of love g).

In order to maximize the magnetic efficiency of the magnetic circuit of the present invention, as mentioned previously, it is necessary to match the internal reluctance of each magnetomotive force source to the reluctance of the load it encounters.

Therefore, in the embodiment of the present invention, R of the magnetic resistance R of the supermagnetic force sources Fo, F is made equal to the wave g. Further, the magnetomotive force of the main magnetomotive force source Fo must be equal to twice the magnetomotive force in the effective air gap. That is, F.

= is g=200 (2Rg) {1) Therefore, the following relationship becomes clear. ingredient.

=Science t2'Rg=Magazine [3' Here, the Buddha in the air is 1 in the c bag unit system.

Therefore, F.

Bonito calculation)・Chopsticks t4’F.

=2kgLg Also, F.

= LH. =L. day, (5}
BgLg=Half [6' Here, Ho, H, are the magnetic field strengths of the main supermagnetic force source and the auxiliary magnetomotive force source, respectively.

The magnetic resistance per cubic centimeter of magnetic material is R
When m is assumed, the magnetic resistance of the main magnetomotive force source and the auxiliary magnetomotive force source is expressed by the following equation.

R.

= empty; -R. 2R trick; {7' Magnetic flux obtained by main field magnet and auxiliary magnet? o,? 1 is ○, respectively.

= &, A small ○, = B, A, {81 So 20 Puo=Fo= is gL 2? ,R,=F.

= WageL'9' Substituting the above formulas [7) and '8} into formula '9), ARmoL=B, Rm, L, = BgLg[IQ
BRm from '61 type and '10 type.

=School day. (11) BRml=2 From this equation (11), it is possible to find the operating point of any magnetic material.

FIG. 7 shows the magnetic field strength on days when the relationship between magnetic flux density and unit magnetic resistance Rm is constant.

It is displayed on a logarithmic graph in relation to. Also shown is the relationship between how the unit magnetoresistance of various magnetic materials changes depending on the magnetic flux density of the magnetic field. Once the size of the effective air gap and the required value of magnetic flux density are determined, the magnetic field strength Ho can be calculated from the above-mentioned formula. Therefore,
Determine the operating point of each magnetic material from the chart in Figure 7, and since Ro = R, = next g in the above example, determine the size according to the {7- formula for matching the magnetic resistance with the load. be able to. These analyzes are intended to determine how much each auxiliary supermagnetic force source (auxiliary magnet) should contribute to achieving the total magnetic flux density in the effective air gap, and remain relevant even when multiple auxiliary magnets are used. FIG. 2 shows a motor incorporating a stator magnetic circuit according to an embodiment of the present invention, which can reduce magnetic flux losses to a maximum extent.

Broadly speaking, the magnetic circuit employs a pole piece having an arcuate profile and a plurality of magnetomotive force sources that create separate magnetic fields with intersecting pole axes within the pole piece.

FIG. 2 shows an example of implementing the above magnetic circuit, in which the magnetic pole pieces 50, 52 have substantially cylindrical side surfaces 53,
54, and the cylindrical side surfaces 53, 54 are magnetomotive force sources 55, 5
6 is substantially completely surrounded by. magnetic pole piece 50,
52 is the short axis along line 5-5 in FIG.
It may have an elliptical cross-section with the major axis along a line perpendicular to the line, or it may have a completely circular cross-section. The magnetomotive force sources 55, 56 surrounding the cylindrical side faces 53, 54 of the pole pieces 50, 52 are each composed of a plurality of closely spaced magnet segments 55a, 56a. Each magnet segment 5 that constitutes the magnetomotive force sources 55 and 56
The average magnetic pole axis of 5a, 56a is the cylindrical side surface 53 of the magnetic pole piece.
54, and each average flux axis 57 is preferably arranged to intersect the average pole axis of at least one other magnet segment, as shown in FIG. More generally, each magnet segment is installed on the cylindrical side of the pole piece, and must be positioned in such a way as to prevent leakage of magnetic flux at the location where it is installed. In FIG. 4, the cylindrical side surface 5 of the magnetic pole piece 50 is
3 as a dotted line and some of the magnet segments 55a disposed around it as solid lines to illustrate the relationship between the average magnetic pole axes 57 of these magnet segments.

Each magnet segment 55a is arranged so that the groove properties match along the direction perpendicular to the cylindrical side surface 53. In other words, the N poles of each magnet segment 55a all face inward in the opposite direction. As shown in the figure, if the cross-sectional shape of the magnetic pole piece 50 is elliptical, the size of the entire magnetic circuit can be reduced, but as already mentioned, it may be completely circular or other arcuate shapes. . In the magnetic circuit shown in FIG. 2, magnet segments 55a and 5 forming supermagnetic force sources 55 and 56
6a itself is almost completely surrounded by the ferromagnetic housing 58.

In order to eliminate eddy loss, the ferromagnetic housing 58 preferably has a laminated structure or a split structure, and is preferably fixed and held together by six shaft-shaped fasteners. Ferromagnetic housing 5
8 also acts as a return path for the magnetic flux, and this housing and magnet segments 55a and 56a are connected to the rotor 5.
1 so that a closed magnetic flux path can be formed through the magnetic flux path.

According to such an arrangement, a nearly ideal state is realized in which the lines of magnetic force are directed toward the magnetic pole surface in any part of the magnetic field. The magnetomotive force source 55 is composed of a cylindrical molded magnet, which is composed of countless minute magnet segments each forming a separate magnetic field, and in which the magnetic flux exits at right angles to the magnet surface at any point of the magnet. Good too. Fifth
What is shown in the figure is a modification of the embodiment of FIG.

In this case, both end faces 64, 65 of the pole pieces 50, 52 are almost completely covered by the end magnets 63, 62. The average magnetic pole axis 67 of the end magnets 62 and 63 corresponds to both end surfaces 64 of the magnetic pole pieces,
65 is approximately perpendicular to the angle. In addition, the magnetic path of the magnetic field generated by the end magnets 62 and 63 for cross magnetic field is the chain line loop 66.
It is shown as A particularly remarkable feature of the present invention is that the magnetic flux density at the magnetic pole face of the magnetic pole piece is higher than the magnetic flux density of the main magnetomotive force source (main field magnet).

That is, by using a strong auxiliary magnetomotive force source (auxiliary magnet) that forms a cross magnetic field, the magnetic flux density at the magnetic pole face is increased to a value higher than that of the main field magnet. Another notable feature of the invention is that the magnetic flux of the main supermagnetic force source is directed in a predetermined direction. This prevents magnetic flux from leaking from the pole pieces and, in conjunction with providing a suitable flux return path, eliminates the influence of stray magnetic fields on the motor. FIG. 8 shows another motor to which the magnetic circuit of the present invention is applied.

The general structure of this motor is the same as that shown in FIGS. 1 and 2, except for the use of polygonal pole pieces 70, 71. The polygonal pole pieces 70, 71 have five flat outer surfaces 72 on which a magnetomotive force source 75 is placed. These pole pieces are generally surrounded by a monolithic motor housing 73, and the inner shape of this housing 73 is that of the polygonal pole pieces 70,
It is designed to provide a space 74 for accommodating the magnetomotive force source 75 attached to the outer surface of the magnet 71. Each outer surface 7
2 extends over a range of about 61° from the center of the pole pieces 70, 71, and only the magnetic pole face facing the rotor 77 extends over a range of about 550°.

The magnetomotive force source 75 installed on the outer surface 72 of the magnetic pole pieces 70, 71 is a permanent magnet, and the magnetic strength per unit volume of each permanent magnet is determined by the magnetic force between the magnetic pole surface of the magnetic pole piece and the rotor 77. They are selected in consideration of achieving a predetermined magnetic flux density in the effective air gap.

The magnetic resistance of each permanent magnet 75 is matched to the magnetic resistance of the effective air gap that each permanent magnet 75 has. For example, each permanent magnet 75 has a magnetic reluctance five times greater than the effective air gap magnetic reluctance Rg. Note that end magnets may be arranged on the end faces of the magnetic pole pieces 70, 71 as in the case of FIGS. 1 and 2. As described above, the present invention includes at least one pair of magnetic pole pieces made of a magnetically permeable material and having a polygonal cross section around the rotor, and the magnetic pole pieces have at least four side surfaces and a magnetic pole facing the rotor. at least two of the side surfaces are located on substantially opposite sides with respect to the magnetic pole surface, and the adjacent magnetic pole piece side surfaces are configured to form an obtuse angle with each other. It is characterized by

In this respect, according to the embodiment shown in FIG.
One magnetic pole piece 7 has five side surfaces 72 and a concave curved magnetic pole surface facing the rotor 77, the magnetic pole piece side surface is located on the opposite side with respect to the magnetic pole surface, and the magnetic pole piece side surface is located on the opposite side with respect to the magnetic pole surface. ,
The angle between the side surfaces of adjacent magnetic pole pieces is an obtuse angle. According to such a configuration, the side surface of the magnetic pole piece, that is, the magnetomotive force source installation surface, can be configured to be much larger than the magnetic pole surface, and the magnetic force source can be arranged from the magnetic pole surface of one magnetic pole piece to the other magnetic pole piece through the rotor. The density of the magnetic flux due to the magnetomotive force source directed toward the magnetic pole surface can be designed to be extremely high in the area between the effective magnetic pole surface and the rotor. In Figure 9,
A typical four pole high performance motor incorporating the magnetic circuit of the present invention is illustrated.

In this motor, extremely large torque can be obtained by the strong magnetic fields emitted from each of the four magnetic pole pieces 110 interacting with the rotor 111. Also, almost all of the magnetic flux in this motor, perhaps about two-thirds, is created by the interpole magnets 113. Each interpolar magnet 113 is arranged so that its pole axis is approximately perpendicular to the adjacent side surface of the pole piece. For this reason, the two magnets 115 and 116 attached to the side surface of the magnetic pole piece facing the effective air gap 117
This causes some magnetic flux to be generated. The angle between the two magnetic pole side surfaces covered by these two magnets 115 and 116 is an obtuse angle, but the angle between these magnetic pole side surfaces and another adjacent magnetic pole side surface is an obtuse angle. In the motor shown in Figures 9 and 10, the outer surfaces of the motor pole pieces are substantially completely surrounded by magnetomotive force sources, and the pole axis of each supermagnetic force source is perpendicular to the direction of the resultant magnetic flux in the effective air gap. Contains ingredients.

Further, the magnetic pole axis of the magnet 113 intersects with the magnetic pole axes of the other magnets 115 and 116 inside the magnetic pole piece 110.
Furthermore, the space between the magnetic poles is wide enough to accommodate the brush holder 119 that slidably holds the brush 120. The end face of the motor housing 122 is sealed by a bell-shaped end frame. In addition, motor housing 1
The interior of 22 is shaped to accommodate the magnetic stator and forms a flux return path for the magnetic circuit including the pole pieces. As explained above, the stator magnetic circuit incorporated in the electric motor of the present invention has a simple structure, yet can emit high-density magnetic flux toward the effective air gap, and has high magnetic transmission efficiency to the rotor. Are better.

In particular, by incorporating low-strength, inexpensive magnets into the stator magnetic circuit to form a cross-magnetic field, the magnetic flux generated by the main supermagnetic force source can be efficiently and concentratedly transmitted to the rotor through the effective air gap. As a result, the generation of leakage magnetic flux and the generation of unnecessary magnetic fields associated with it are significantly reduced. The motor incorporating the magnetic circuit of the present invention is suitable as a drive source for a magnetic tape in equipment that requires quick and agile start/stop operations, such as a tape recorder.

The torque of a motor is directly related to the magnetic flux density, and by using the magnetic circuit having a high magnetic flux density of the present invention, the acceleration and deceleration of a rotated body can be significantly increased.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the main parts of a motor incorporating a stator magnetic circuit according to an embodiment of the present invention, and FIG. 2 is a front view of a motor incorporating a stator magnetic circuit according to another embodiment of the present invention. Figure 3 is a partial diagram schematically showing the structure of the stator magnetic poles in the motor shown in Figure 1, and Figure 4 shows the relationship between the magnetic pole axes of the stator magnetic poles outside the motor shown in Figure 2. 5 is a sectional view taken along line 5-5 in FIG. 2, FIG. 6 is an equivalent circuit diagram of a typical stator magnetic circuit according to the present invention, and FIG. 8 is a graph showing the magnetic properties of typical magnetic materials and data available for designing the stator magnetic circuit of the present invention. FIG. 8 is a graph showing a motor incorporating a magnetic circuit according to another embodiment of the present invention. FIG. 9 is a perspective view showing a four-pole motor incorporating the magnetic circuit of the present invention with a part missing. FIG.
FIG. 2 is a cross-sectional view taken along line 12-12 in the figure. 10... Motor housing, 12, 14... Vertical magnetic plate, 15, 16... Horizontal magnetic plate, 18...
・End frame, 20...Rotor, 21...
Rotating shaft, 22, 24...Magnetic pole piece, 25,
26... Side surfaces of magnetic pole pieces, 32, 34...
・Main field magnet, 36, 37, 38, 39... Auxiliary magnet for cross magnetic field, 40, 41... Magnetic block, 5
0,52...Magnetic pole piece, 51...Rotor, 5
5,56... Source of magnetomotive force. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10

Claims (1)

[Claims] 1 At least one pair of polygonal magnetic pole pieces made of a magnetically permeable material is provided around the rotor, each of said magnetic pole pieces having at least four
and a magnetic pole face facing the rotor with an effective air gap, and an area ratio of the magnetic pole piece side surface to the magnetic pole face is 1.5 or more, and the magnetic pole piece side surface At least two of the magnetic pole faces are substantially located on opposite sides of the magnetic pole face, and the other two magnetic pole piece side faces sandwiching the magnetic pole face are tapered toward the magnetic pole face in order to concentrate magnetic flux crossing the magnetic pole face. and at least two of the four side surfaces are formed so that the angles formed between them are obtuse angles,
a magnetomotive force source covering each side surface of each magnetic pole piece of each of the magnetic pole pieces, the magnetomotive force sources covering each side surface of the same magnetic pole piece have the same polarity, and the magnetomotive force source is The average magnetic pole axes of the magnetomotive force sources that cover each side of each magnetic pole piece intersect with each other inside each magnetic pole piece, and the average magnetic pole axes of the magnetomotive force sources that cover each side surface of each magnetic pole piece intersect with each other in the interior of each magnetic pole piece. The magnetic pole faces of the respective magnetic pole pieces facing each other are given opposite polarities, are in contact with the plurality of magnetomotive force sources, and pass through each magnetomotive force source via the at least one pair of magnetic pole pieces and the rotor. A high magnetic flux electric motor characterized by having a ferromagnetic housing that establishes a magnetic circuit.