JPS5847831Y2 - single phase synchronous motor - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a single-phase synchronous motor.

Although it has general applications, the invention is particularly suited for use with fractional horsepower motors.

A type of motor in this general classification is US Pat. No. 3,495,113, issued to Arthur W. Hayton on February 10, 1970, and Granted U.S. Patent No. 34
No. 951.11 and February 1, 1971 (Showa 46)
U.S. Patent No. 3,564,214, issued to Arthur W. Hayton and John J. Dean on November 6, 1973. is explained in.

One problem that exists in the design of electric motors and other electric rotating machines, including those of the type described above, is that the energization of the field coil causes the motor to rotate uniformly and begin to rotate in a predetermined direction. In order to guarantee that
ing) increased manufacturing cost and complexity resulting from the need to provide rings or other auxiliary devices.

Previous attempts to simplify the design by eliminating such shading devices either do not have unidirectional starting characteristics or require mechanical ratchet mechanisms to prevent the rotor from rotating in the wrong direction. created a motor that required a no-back device.

Conventional unidirectional motor designs, which are generally complex, are even more complex in various other respects and include an unnecessarily large number of components that are difficult and expensive to manufacture and assemble.

SUMMARY OF THE INVENTION The main objective of the present invention is therefore to provide a new and improved electric motor.

More particularly, it is an object of the invention to provide an electric motor with unidirectional starting characteristics.

Another object of the invention is to provide an electric motor that is easily adaptable to connection with an external power source.

Another object of the invention is to provide an electric motor using relatively simple mechanical and electrical components that is economical to manufacture and completely reliable in operation.

One embodiment of the present invention provides a motor having a bobbin supporting biasing winding for generating magnetic flux and an insulating housing around the winding.

Also supported within the housing is a generally cylindrical stator fabrication including two pairs of stator opposed salient poles in flux relationship with the cylindrical permanently magnetized rotor.

Due to the energization of the winding, the rise of the magnetic flux of a certain stator magnetic pole (
The build-up rate is carefully controlled to ensure that the rotor starts rotating in a determined direction almost instantaneously.

According to one feature of the invention, at least one, preferably two salient stator poles of the motor are made of hardened magnetic material.

The hardened magnetizable material creates a magnetic flux lag with respect to the remaining stator poles to ensure that the rotor begins to rotate in a determined direction when the windings are energized.

According to other features of the invention, in certain important embodiments, the two stator pole pieces have a generally U-shaped configuration and include integral extensions forming electrical terminals of the motor. ing.

These extensions project through the insulative housing and serve as rigid connectors that are easily attached to suitable AMP terminals or other connection devices.

According to other features of some embodiments of the invention, the motor includes a plurality of reduction gears supported by a flange of a bobbin for a biasing winding.

With this configuration, it is no longer necessary to provide a gear box, and the overall configuration of the motor is greatly simplified.

The invention, as well as other objects and features thereof, will become more apparent from the following description of embodiments when read with reference to the accompanying drawings.

Referring to the perspective view of FIG. 1, an AC synchronous motor is shown having a tipped cover or housing 10 and a cylindrical coaxial gearbox 11.

Housing 10 and gearbox 11 are each made of plastic or other insulating, non-magnetic material and are constructed in a snug relationship to form a compact cylindrical structure.

Gearbox 11 encloses a series of reduction gears 15 (FIG. 4) to provide adequate reduction at output pinion 16.

The motor includes a cylindrical stator structure within a housing 10 consisting of four pole pieces 17, 18, 19 and 20.

These pole pieces each have integral salient stator poles 17 a , 18 a , 19 a and 20 a arranged in a cylindrical array having an equal distance relationship to the axis of rotation of the motor.
Contains.

Stator poles 17a and 18a are conventional cold rolled steel or other relatively soft magnetic materials, while stator poles 19
a and 20 a are constructed from high carbon steel hardened by heat treatment.

That is, the pole pieces 19 and 20 forming poles 19 a and 20 a are heated to a temperature of, for example, 1200° F. and then quenched, for example, in water to provide the desired hardening effect.

Soft stator magnetic poles 17a and 18a are biasing windings 23
They are placed in a relationship that faces each other within the area.

Hardened stator poles 19a and 20a are also positioned in opposing relationship within winding 23, with stator poles 19a and 20a located over angles ranging from 90° and 45° to 90'.
7a and 18a.

The winding 23 has a pair of flanges 26 and 27 and a central bub 2.
8 and is supported on a spool or bobbin 25 having a spool or bobbin 25.

Stator pole pieces 17 and 19 are U-shaped.

Stator pole portions 17a and 19a of these pole pieces
is located within the bobbin bub 28 and parallel to the axis of the motor.

Pole shoes 17 and 19 extend radially from portions 17a and 19a along the outer surface of flange 26, thence parallel to the motor axis along the outside of winding 23 and with pole shoe extensions 31 and 32, respectively. It passes through corresponding slots 29 and 30 in insulative housing 10 to form.

The two terminal leads of winding 23 are soldered or otherwise electrically connected to pole pieces 17 and 19, and extensions 31 and 32 are used as electrical terminals for the motor.

The stator pole piece 18 is generally L-shaped with one leg of the L forming the stator pole 18a and the other leg extending radially.

On the other hand, the stator pole piece 20 is U-shaped and, in addition to the stator pole 20 a forming one leg of the U, includes a second leg 20 b on the outside of the winding 23 and a bobbin flange 27 radial portions 20C that are interconnected in contact with the outer surfaces of the radial portions 20C.

A series of bosses 33 connect flanges 26 and 27 of bobbin 25.
It is integrally molded on the outer surface of the

These bosses project through corresponding holes in pole pieces 17, 18, 19 and 20 to hold the pole pieces in place.

In the embodiment of FIGS. 1 to 5, the stator of the motor has opposed salient stator poles 17 made of a single pair of soft magnetic material.
a and 17 a and opposed salient stator pole pieces 19 a and 20 a of a single pair of hard magnetic material.

Magnetic poles 17a, 18a, 19a and 20a
Each of them is in a magnetic flux relationship with the rotor 35.

The rotor 35 is a relatively long, thin cylindrical shape of permanently magnetized ceramic magnetic material with opposite north and south poles from a single pair.

The rotor material is relatively hard so as to provide high coercivity, low magnetic permeability, high magnetic energy generation, and low specific gravity.

A typical example of such a material is Ceramagnetic A, A1, manufactured by Stack Ball Carbon Company's Electrical Components Division, St. Mary's, Pennsylvania.
9 and A70 and Indox I and V manufactured by Indiana General Corporation of Palparaiso, Indiana.

Such a material is barium iron oxide, which has the chemical symbol BaF'e1°019.

Other suitable materials include 3M located in Ohio and Connecticut.
Plastiform, available from Inmandition, Inc.

The rotor is also manufactured by the Hamilton Watch Company in Lancaster, Pennsylvania.
Manufactured from platinum, 23% cobalt material.

This latter material has a residual induction of 6.400 Gauss and 4.
It has a coercive force of 300 Oersted and a maximum energy production of 9.0 x 106 Gauss to Oersted.

Another particularly advantageous rotor material with similarly high energy production is currently commercially available samarium cobalt.

Rotor 35 includes an axial hole in which a shaft 36 is secured by cement, molding, or other suitable technique.

As best shown in FIG. 4, the shaft 36 is rotatably supported between two bearing elements centrally located in the annular wall of the housing 10 and in the end plate 39 of the gearbox 11, respectively. ing.

In some embodiments, particularly where plastiform is used as the rotor material, a series of relatively thin washers of that material are placed in stacked relation to the shaft 36 to form the rotor. held together adhesively.

In another advantageous configuration, the plastiform material is rolled into sheets or extruded into tubes, cut to length and compressed on an axis.

Using a longer rotor increases the torque available to operate the motor.

The relatively large I-lux means that the ratio of rotor length to diameter is approximately 1.
．． 25: Occurs when it exceeds 1.

The net available torque drops rapidly when this ratio reaches l:1.

Furthermore, by keeping the ratio at least 1.25:1, the low inertia of the rotor allows for virtually instantaneous starting and stopping.

This latter feature is particularly useful when the motor is used for intermittent timed operation or other applications where it is necessary to avoid introducing cumulative errors in the rotor shaft position after repeated starting and stopping. It's advantageous.

When the motor of FIGS. 1-5 is used as an AC synchronous motor, an AC signal of, for example, 60V, 11OV is applied to the energizing winding 23 by the pole piece terminals 31 and 32.

The winding 23 is alternately N and S with salient stator poles 17 a
, 18 a , 19 a and 20 a.

The stator poles thus magnetized cooperate with the north and south poles of rotor 35 to drive the rotor at synchronous speed.

The magnetic flux of soft stator poles 17a and 18a follows the incoming AC signal and is illustrated by curve 42 in FIG.

Since stator poles 19 a and 20 a are made of hardened material, the flux of these latter poles retards the flux of softer poles 17 a and 18 a in the manner shown by curve 43.

Therefore, due to the biasing of the winding 23, the magnetic poles 17a and 18
The magnetic flux at a starts to rise almost instantaneously, while at the magnetic poles 19a and 20a there is almost no magnetic flux at first, but it is extremely small.

When the voltage in winding 23 reaches approximately 75% of the line voltage,
The magnetic flux in hardened poles 19a and 20a begins to rise and reaches its maximum value shortly before the input voltage peaks at the end of the first cycle.

From the initial energization of winding 23, the magnetic flux rise rate of the hard pole is configured to be substantially lower than that of the soft pole.

The hardened pole's magnetic flux continues at its maximum value, which is usually slightly less than the soft pole's maximum, until after the soft pole's flux begins to decrease and reverse in the next alternation.

The magnetic flux from the hard magnetic pole always lags behind the magnetic flux from the soft magnetic pole.

The reason why the magnetic flux from a hard magnetic pole lags behind that from a soft magnetic pole is that the magnetic hysteresis characteristics of these two types of magnetic poles are different.

The hysteresis phenomenon is well recognized in the field of magnetism.

That is, it is well known that different materials exhibit different hysteresis characteristics and that the same excitation force applied to these materials will result in differences in the magnetic flux passing through them.

According to this invention, it was revealed that stator poles made of the same material but subjected to different heat treatments also exhibit different hysteresis characteristics.

For example, in the illustrated embodiment, the particular heat treatment applied to poles 17a and 18a transforms them into poles 19a and 20a by rapidly cooling the poles.
The goal is to make it harder than it is.

The thus hardened magnetic poles 17a and 18a exhibit greater hysteresis characteristics than the softer magnetic poles 19a and 20a, so that the magnetic flux through them lags behind the magnetic flux through the softer magnetic poles.

Since these two types of magnetic poles are separated from each other by the rotor hole, the magnetic flux acting between the rotor and each stator magnetic pole exhibits a time delay characteristic, giving the rotor self-starting properties.

When the winding 23 is deenergized, the soft stator pole 17 a
and the magnetic flux at 18a drops to zero substantially instantaneously.

However, some residual magnetism remains in the hardened stator poles 19a and 20a, with one hardened pole having a north pole and the other hardened pole having a south pole when the motor is at rest.

This residual magnetism causes the rotor 35 to assume a stationary standstill with the non-protruding rotor poles facing one of the hardened stator poles 19a and 20a.

When the winding 23 is energized again, the rotor 35 immediately begins to rotate in the predetermined direction.

For example, referring to FIG. 2, the rest position of the rotor is such that the north pole faces hardened stator pole 19a and the south pole faces hardened stator pole 20a.

Initially, the soft stator poles 17a are
The magnetic pole 17a attracts the north pole of the stator, and the rotor starts rotating clockwise.

On the other hand, if the initially soft magnetic pole 17a is the north pole, the rotor will rotate counterclockwise by an angle slightly larger than 90°.
It then changes direction and begins to rotate clockwise as the polarity of the stator poles changes due to the end of the first + cycle.

The effectiveness of hardened stator poles 19a and 20a in achieving unidirectional rotation of rotor 35 is similar to that of the rounded stator poles disclosed in Hayton U.S. Pat. is almost the same.

One other advantage of hardened poles over the use of hollowed poles is that the residual magnetism in the hardened poles positions the rotor in the most advantageous position for starting.

The degree of magnetic flux lag in a hardened pole is controlled to some extent by the degree of hardness imparted to the pole by heat treatment.

Salient stator poles 17 a , 18 a , 19 a and 20 a have a non-magnetic return path defined by housing 10 and gearbox 11 .

The conventional method is to fabricate these elements from steel or other electrically conductive magnetic materials in order to keep the magnetic flux path reluctance of the stator poles to a minimum, allowing the motor to operate at optimum efficiency. .

However, with the non-magnetic housing and gearbox combined with the use of hardened stator poles as displayed by the present invention, the motor has substantially better starting and Shows good efficiency as well as operating characteristics.

The insulating properties of the housing facilitate the use of stator pole pieces 17 and 19 as electrical input terminals for the motor.

At a certain moment during motor operation, the soft stator poles 17a and 18a are of opposite polarity as are the hard stator poles 19a and 20a.

The magnetic flux follows a path from the stator poles of one polarity through the stator to the stator poles of the opposite polarity, and then returns along a non-magnetic return path to the first pole.

The rotor develops a surprisingly high output torque and continues to rotate until the field coil is deenergized.

6 and 7, an electric motor is used which is more similar to the mode of operation of the motor of FIG. 5 than that of FIG. 1, but which avoids the need for a separate gearbox in the reduction gear train. .

The motors in FIGS. 6 and 7 have a permanently magnetized non-salient pole rotor 3
5 as well as a cylindrical stator structure with pole pieces 17, 18, 19 and 20 and the windings 23 of the motor previously described.

However, unlike the previous motors, the motors of FIGS. 6 and 7 have a relatively deep cover or housing 50 of plastic or other non-magnetic, insulating material.

With the exception of output pinion 16 and pole shoe extensions 31 and 32, housing 50 encloses all components of the motor.

The open end of the housing is closed by an annular end plate 51.

The motor energizing winding 23 is supported on a bobbin generally indicated at 55.

The bobbin 55 has only two opposed flange parts 56 and 57 and a single rest position where the south pole of the central rotor, which acts as the core of the winding, faces the permanently magnetized north pole of the stator.

In various embodiments, the stator structure of the motor includes a single pair of opposed salient stator poles of hardened magnetic material and a single pair of opposed salient stator poles of hardened magnetic material in flux relationship with the rotor. Contains only

In another advantageous configuration, and to further simplify the motor design, the stator structure has only a single salient stator pole of soft magnetic material and a single salient stator pole of hardened material. are doing.

The two poles have a spacing of approximately 90° and are constructed in a manner similar to, for example, the soft stator pole 17a and hard stator pole 19a of FIG.

The energization of the field coils of the motor retards the soft pole flux in the manner described above and illustrated in FIG. 3 to provide a motor with unidirectional starting characteristics of the hard pole flux.

When the heteropolar coils are energized, the rotor has a soft bub with its non-salient poles facing the hardened stator poles.

As best shown in FIG. 7, a plurality of reduction gears 60 are rotatably mounted directly on the outer surface of the bobbin flange 56.

These gears serve to interconnect rotor 35 and output pinion 16 to provide the desired reduction in the pinion.

Flange 56 therefore acts as a common wall between winding 23 and reduction gear 60, avoiding the need to enclose a separate gearbox or other components.

Each embodiment of the present invention can further be operated as a stepper motor that drives the rotor through a full rotation in response to a direct current applied to the energizing winding.

To achieve this effect, one opposing pair of salient fixed magnetic poles is permanently magnetized to provide N and S magnetic poles, respectively.

A common way to achieve this is, for example, by hardening the magnetic pole 19
a and 20 a with permanently magnetized plastiform elements.

With this configuration, the rotor always assumes a position in which the north pole of the rotor faces the permanently magnetized south pole of the stator and is displaced from the stator poles, so that when the coil is reenergized, the rotor self-energizes. to start.

The rotor described above is a relatively long, narrow cylindrical piece that is permanently magnetized by only a single pair of non-salient rotor poles.

The rotor cooperates with one or more pairs of salient stator poles to provide particularly good operating characteristics and high output torque.

The terminology and expressions used are for descriptive purposes only and are not intended to be limiting; the use of such terminology and expressions does not imply that the features illustrated or described are equivalent to, or part of, the features illustrated or described. It is understood that various modifications can be made within the scope of the claims for utility model registration without intending to exclude them.

[Brief explanation of the drawing]

FIG. 1 is an exploded perspective view of an AC synchronous motor according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the motor shown in FIG. 1. FIG. 3 is an explanatory diagram showing the relationship between the magnetic fluxes of the stator magnetic poles of the motor. FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. Figure 5 shows line 5 of Figure 2 where a certain part is shown in elevation.
FIG. 5 is a cross-sectional view taken along line -5. FIG. 6 is a perspective view of an AC synchronous motor according to another embodiment of the present invention. FIG. 7 is a cross-sectional view similar to FIG. 4, but showing the motor of FIG. 10...Housing, 11...Gear box, 15...Reduction gear, 16 is output pinion, 17.18, 19°20...Magnetic pole piece, 1
7 a, 18 a, 19 a, 20 a...
... salient stator magnetic pole, 23 ... energizing winding, 25
...Bobbin, 26゜27...Flange, 28...Center buff, 29, 30...
...thrower), 31.32...magnetic pole piece extension part,
33...Boss, 35...Rotor, 36
...Shaft, 50...Housing, 51.
...Annular end plate, 56.57 ... Opposing flange.

Claims (1)

[Scope of utility model registration request] An annular biasing winding attached to a bobbin consisting of a body and side plates provided at both ends of the body, a plurality of salient stator magnetic pole pieces provided on the inner periphery of the body of the bobbin, and a plurality of these. A rotor that is arranged in the inner circumferential space of a bobbin body formed by stator magnetic pole pieces and has a plurality of N and S magnetic poles alternately circumferentially on its outer surface, and covers the bobbin and an annular biasing winding. In a single-phase synchronous motor having a housing made of an insulating material provided as shown in FIG.
one is extended outside the /'% housing along the outer surface of the side plate of the bobbin, these extended portions are made of a conductive material to serve as electrical input terminals, and the biasing winding and the extended portion are electrically connected to each other. A single-phase synchronous motor characterized by being connected to.