WO2015181703A1

WO2015181703A1 - Electrical machine with continuous geometry and constant torque operation

Info

Publication number: WO2015181703A1
Application number: PCT/IB2015/053862
Authority: WO
Inventors: David Haitin
Original assignee: Serby Ag
Priority date: 2014-05-25
Filing date: 2015-05-25
Publication date: 2015-12-03

Abstract

An electrical machine operates at uninterrupted constant current and is provided in rotary and linear configurations in which magnets and windings are continuous rings or cylinders around the stator or rotor - plunger. The machine is designed so that the field lines are perpendicular to the active segments of the current conducting coils and variations on a slot rotor or stator are provided for the rotary motor, and a cylinder is provided for the linear motor.

Description

ELECTRICAL MACHINE WITH CONTINUOUS GEOMETRY AND CONSTANT

TORQUE OPERATION

RELATED APPLICATION/S

This application claims the benefit of priority under 35 USC § 119(e) of U.S.

Provisional Patent Application No. 62/002,874 filed May 25, 2014, the contents of which are incorporated herein by reference in their entirety.

FIELD AND BACKGROUND OF THE INVENTION

The present invention, in some embodiments thereof, relates to an electrical machine and, more particularly, but not exclusively, to an electrical machine with a continuous geometry, and includes both electrical motors and generators.

Conventional electric motors

One can find a large variety of motor structures and designs in which the specific design dictates the optimal rotational speed in RPM as well as the rated output power. Motors may be defined according to two main types - the most common type (1) makes use of magnetic forces while the less common type (2) normally found in low power applications, makes use of the Lorenz force. With both conventional motor types, torque and power consumption are RPM dependent.

High output power type 1 motors generally comprise multiple iron core coils to provide high magnetic force but also high induction electro-magnets, while the direction of the current is switched or toggled one or more times during a full rotor rotation cycle.

Low output power type 2 motors are normally coreless and comprise multiple permanent magnetic poles. The current direction is switched or toggled one or more times during a full rotor rotation cycle.

The output power of an electric motor is proportional to its static force (Newton) multiplied by the radius of the rotor (Torque - Newton/meter) multiplied by angular velocity (RPM). With conventional motors, static force, torque and power consumption are all RPM dependent.

Conventional motors are designed and are limited to a specifically designed efficient and safe RPM range. At very slow angular velocity the motor may be damaged, and therefore a controlled soft start is required. At high RPM losses rapidly increase until their effect is greater than that of the increase in torque.

Conventional motor operation is based on a phase or pole switching sequence. The switching leads to the following disadvantages:

- Coil current, which creates the static force, is RPM dependent, while a relatively narrow RPM range allows efficient power production.

- The high induction coils under multiple phase current switching, delays current development (impedance) so that higher voltage is required meaning higher energy consumption.

- A rotation cycle comprises angular intervals without any force, as well as certain intervals having an opposite force residue. The result is a slight decrease in the static rotational force.

- Heat losses due to eddy currents are induced within the core.

Conventional AC motors are normally synchronous, so that the RPM is equal to the relatively low input frequency (mains). In addition, a brushless AC motor comprises an additional expensive starting mechanism, which remains active until the motor reaches the rated RPM. In addition velocity control of large AC motors is complicated and expensive (over 35% of the motor itself) and has to be based on frequency conversion (inverter units).

US Patent 3,315,106 describes a disk-shaped electric motor in which the rotors are disk shaped. The stators are made of surrounding magnet assemblies, and each magnet assembly comprises at least two oppositely magnetized sections, the maximum flux in the rotor being produced by arranging like poles of the two magnets opposite one another and providing a sub-divided coil winding on a cylindrical surface surrounding the rotor shaft substantially outside the magnetic field. As a result, the flux passes radially through the coils and the output torque becomes large. The arrangement has small dimensions in the longitudinal direction of the rotor.

SUMMARY OF THE INVENTION

An electrical machine may be operated at constant current and is provided in rotary and linear configurations in which magnets and windings are continuous rings or cylinders around the stator or rotor - plunger. Field lines are designed to cut the windings of the coils at right angles, leading to variations of a slot rotor for a rotary machine and a cylinder construction for a linear motor.

The disadvantages discussed in the background may be minimized when both current and magnetic field are constant and continuous at any RPM. A continuous geometry for coils and magnets as rings around the axis of rotation is provided.

According to an aspect of some embodiments of the present invention there is provided an electrical machine comprising a stator and a rotor, the stator and the rotor both arranged around a central axis, one of the stator and the rotor comprising at least one magnet and the other of the stator and the rotor comprising at least one coil, the at least one magnet and the at least one coil respectively forming rings, the rings being continuous around the central axis, wherein the at least one magnet and at least one coil overlie each other to provide field lines from the at least one magnet that cut front windings of the coil perpendicularly.

In an embodiment, the rotor comprises a disk extending into a slot within the stator.

In an embodiment, the coil comprises a substantially flat ring-shaped coil arranged on the disk, and the at least one magnet comprises a first ring magnet on an upper side of the slot and a second ring magnet on a lower side of the slot.

In an embodiment, identical magnetic poles face each other across the slot. An embodiment may include soft iron between the first magnet and a motor housing and between the second magnet and a motor housing.

In an embodiment, the substantially flat ring-shaped coil comprises an iron core.

In an embodiment, the iron core comprises an upper iron layer and a lower iron layer with a non-ferrous layer in between the upper iron layer and the lower iron layer.

In an embodiment, the substantially flat ring-shaped coil has an inner and an outer circumference, and comprises laterally placed iron shields on the inner and outer circumferences.

In an embodiment, the at least one magnet comprises a substantially flat ring- shaped magnet arranged on the disk, and the at least one coil comprises a first ring shaped coil on an upper side of the slot and a second ring shaped coil on a lower side of the slot. In an embodiment, the substantially flat ring-shaped magnet has an inner and an outer circumference, and comprises laterally placed iron shields on the inner and outer circumferences.

In an embodiment, the substantially flat ring-shaped coil comprises an iron core. In an embodiment, the iron core comprises an upper iron layer and a lower iron layer with a non-ferrous layer in between the upper iron layer and the lower iron layer.

In an embodiment, the stator comprises a pipe and the rotor comprises a cylinder travelling within the pipe.

An embodiment may provide a linear motor wherein the stator comprises a hollow tube and the rotor comprises a plunger linearly mobile along the hollow tube to move in reciprocal motion.

According to a second aspect of the present invention there is provided a linear motor comprising a hollow tube stator and a plunger linearly mobile along the hollow tube to move in reciprocal motion, one of the stator and the plunger carrying a magnet and the other of the stator and the plunger carrying a coil, the one of the magnet and the coil being carried by the stator being a continuous cylinder along a circumference and a depth of the stator, wherein the magnet and the coil overlie each other to provide field lines from the at least one magnet that cut front windings of the coil perpendicularly.

In an embodiment, the stator comprises a central tube coaxial with the hollow tube, and the plunger comprises a cylinder linearly mobile along a slot defined between the central tube and the hollow tube.

In an embodiment, the central tube comprises a cylindrical magnet arranged around an iron core and the hollow tube comprises a cylindrical magnet surrounded by an iron cylinder.

According to a third aspect of the present invention there may be provided a stator and a rotor, the stator and the rotor both arranged around a central axis, the rotor comprising a disk, one of the stator and the rotor comprising at least one ring of magnets and the other of the stator and the rotor comprising at least one ring of coils, the rings being co-radial and continuous around the central axis, thereby to provide field lines from the at least one magnet that cut front windings of the coil perpendicularly.

In an embodiment, the coils are substantially flat coils located on the disk. The stator may have an upper part and a lower part and a slot in between the upper part and the lower part. The rotor may extend into the slot.

In an embodiment, the magnets are located on both upper and lower parts of the stator.

According to a fourth aspect of the present invention there is provided a method of operating the electrical machine or linear motor comprising supplying the machine with a constant current, and/or maintaining the constant current over changes in angular or linear velocity and independently of mechanical load.

Unless otherwise defined, all technical and/or scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of embodiments of the invention, exemplary methods and/or materials are described below. In case of conflict, the patent specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and are not intended to be necessarily limiting.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Some embodiments of the invention are herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of embodiments of the invention. In this regard, the description taken with the drawings makes apparent to those skilled in the art how embodiments of the invention may be practiced.

In the drawings:

Fig. 1 is a simplified schematic diagram that illustrates a cross section of an electric motor diagram comprising a flat shape magnetic ring rotor and two parallel Iron core stator coils, according to an embodiment of the present invention;

Fig. 2 is a view from above of the embodiment of Fig. 1;

Fig. 3 is a simplified schematic diagram that illustrates a cross section of an electric motor diagram comprising a flat shape magnetic ring rotor and two parallel Magnet core stator coils according to an embodiment of the present invention;

Fig. 4 is a view from above of the embodiment of Fig. 3; Fig. 5 is a simplified schematic diagram that illustrates a motor diagram in cross section, the motor comprising two flat ring shaped magnet stators and a wound rotor with Iron core rotor in between according to an embodiment of the present invention; Fig. 6 is a view from above of the embodiment of Fig. 5;

Fig. 7 is a simplified schematic diagram that illustrates an electric motor comprising a radially cylindrical ring magnet having an internal void and a rotor with windings and a core traveling through the void, according to an embodiment of the present invention; Fig. 8 is a view from above of the embodiment of Fig. 7;

Fig. 9 is a simplified schematic diagram that illustrates a longitudinal cross section of a linear electric motor having magnetic pistons with moving coils and a crankshaft mechanism, according to an embodiment of the present invention;

Fig. 10 is a simplified schematic diagram that illustrates a variation of the linear motor of Fig. 9;

Fig. 11 is a simplified schematic diagram that illustrates a further variation of the linear motor of Fig. 9, comprising two magnet layers having a moving coil in between, according to an embodiment of the present invention;

Fig. 12 is a transverse cross-sectional view of the cylinder of the variation of Fig. 11; Fig. 13 is a simplified schematic diagram that illustrates an electric generator, according to an embodiment of the present invention; and

Fig. 14 is a simplified schematic diagram that illustrates a variation of the generator of Fig. 12 according to an embodiment of the present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

The present invention, in some embodiments thereof, relates to an electrical machine and, more particularly, but not exclusively, to an electrical machine with a continuous geometry of magnets and coils around an axis of rotation, and includes both electrical motors and generators.

An electrical machine operates at constant current and is provided in rotary and linear configurations in which magnets and windings are continuous rings or cylinders around the stator or rotor - plunger. The machine is designed so that the field lines are perpendicular to the active winding coils and thus variations on a slot rotor are suggested for the rotary motor, and a cylinder construction is suggested for the linear motor.

Contrary to conventional motors, machines of the present embodiments produce a constant torque and consume a constant input power while both are angular velocity (RPM) independent. The present embodiments make use of the Lorenz force within a unipolar and homogenous magnetic field environment and are based on a manipulation of field strength (density) and perpendicularity in order to maximize field strength and perpendicularity affecting active current conductors while minimizing the same for all parasitic conductors. That is to say the design is such that field lines may meet the front coil conductors at right angles, and this feature unites the rotary machines, linear machines and rotary generators of the various embodiments herein.

In addition due to a continuous operating mode the present embodiments perform efficiently at any RPM, and contrary to known unipolar limited power applications the present embodiments may be scalable for a large range of output power.

A feature of the present embodiments is a constant and continuous current at relative low power consumption. Current that produces a constant and continuous tangential static force between a rotor and stator elements - an uninterrupted current and static force having no phase and/or current switching. Thus the current and static force are independent of angular velocity (RPM) enabling an unlimited high and efficient RPM as well as a safe stall situation.

The continuous operation electrical machine of the present embodiments may produce a constant static force and torque by means of a large quantity of current conductors perpendicular to a unipolar homogeneous and continuous magnetic field (flux). An efficient implementation is made possible due to the relative absence of impedance as well as iron core losses, which is the outcome of continuous operation with no phase or current switching within a full axial rotation.

In addition the present embodiments provide a manipulation of the magnetic field strength (density) and perpendicularity in order to maximize field strength and perpendicularity affecting the active current conductors while minimizing the same for all parasitic conductors. Considered in greater detail, the continuous tangential static force created between the homogeneous magnetic field and the plurality of perpendicular current conductors is a function of the field strength or density (Tesla) multiplied by the sum of the length of the conductors multiplied by the current (Ampere) in the conductors, which may be kept constant and uniform. Furthermore, due to a relative low Ohmic resistance and the lack of inductive impedance, the supply voltage is relative low, meaning relative low energy consumption.

Furthermore, current conductors perpendicular to the magnetic field are affected by a constant and uninterrupted Laplace force. The Laplace force is derived from the Lorenz force, and affects fast moving electrons within current conducting wires, forces that create a relatively large radial angular torque, a torque that pulls or pushes the current conductors as well as the magnetic source itself, thus creating a circular axial rotation in accordance with the "right hand" rule. The force direction is perpendicular to both the magnetic field and the current conductors - meaning a clock wise (CW) or counter clock wise (CCW) tangential static force and torque on the motor's axis, according to the continuous current direction within the uniform current conductors.

Force direction is maintained while symmetrically inverting in accordance with both field polarity and current direction.

The continuous operation method provides an additional source of efficiency - The static force is produced all the time and over a relative large area, given the diameter of the interaction surface of the magnetic/conductors, in contrast with narrow and alternating segments, the phases or poles, in conventional motors. Furthermore, even at high RPM the continuous method does not suffer negative effects such as a slow buildup of current and force, dead angles/zones of the rotor, and an opposite force residue acting against a smooth continuous rotation.

The continuous operation method provides additional properties compared with conventional motors - Velocity control is relative simple and inexpensive as current is constant and is not affected by varying RPM nor by varying mechanical load nor by varying source frequency of AC motors. Furthermore, heat dissipation of the continuous operation motor is relative low thus requires minimal cooling accessories.

The motor torque (Newton/meter) may be a function of the constant and continuous static force (Newton) multiplied by the radius (distance) of the interaction surface, and is the interaction between the magnetic field and the current conductors. In contrast with conventional motors, the torque may be constant and does not decrease as the RPM increases.

The constant torque multiplied by a relative high angular velocity (RPM) may provide an efficient output power.

Furthermore, the relative long current conductors may be separated into parallel connected segments reducing motor resistance and thus the required supply voltage.

The present embodiments may be scalable for a large range of efficient output power, e.g. from 0.1 horsepower (HP) to several thousand HP.

In an embodiment, higher power demands may be met using one or more power modules wherein each of the modules comprise multiple uniform velocity serially connected and packed motors.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not necessarily limited in its application to the details of construction and the arrangement of the components and/or methods set forth in the following description and/or illustrated in the drawings and/or the Examples. The invention is capable of other embodiments or of being practiced or carried out in various ways.

Referring now to the drawings, Figure 1 is a simplified schematic diagram showing a cross section of a stator and a rotor of an electrical machine. Both the stator and rotor are arranged around a central axis. Between the stator and rotor there are magnets and coils and the magnets and coils are arranged in continuous rings around the axis of rotation. The magnet or magnets may be arranged to provide a magnetic field which meets the foremost turns of the coil at right angles, hereinafter referred to as perpendicularity.

The following embodiments are based on the above discussed principles of a unipolar field, field manipulations, continuous operation, Laplace static force, tangential force direction, angular torque, output power and input power consumption.

Reference is now made to Fig 1, which is a simplified schematic diagram showing a cross-section of a rotor and stator of a disk-shaped electrical motor according to one embodiment of the present invention. The rotor in Fig. 1 is a disk that rotates in a slot between upper and lower stator parts. Cross section 8 illustrates rotational axis 10 and top and bottom motor housing plates 11, 12, and a magnetic rotor 20 comprising a flat ring shape homogeneous magnet 22, and a containment cylinder made of inner 7 and outer 8 pipes which serve as centripetal force protection. The magnet is continuous around the rotor but may in practice be constructed out of sections. The ring rotor is attached to a circular rotor plate 80 via a plurality of connection screws 70.

The magnetic rotor revolves as a disk in a slit between two parallel flat ring shape stator cores attached to the motor housing, having current conductor windings. The coils are indicated as 50, and 51 and are made up of current conductors. The coils are flat so that the field lines from the rotor cross the active facing length of the windings marked 'a' in the figure at the perpendicular. The stator cores are made of soft iron which may enable field manipulations. The cores may comprise one or more layers, and a three layer core implementation is described herein by way of example. Inwardly facing first layers 30 and 31 are soft iron layers which significantly increase the density and the perpendicularity of the unipolar homogenous magnetic field affecting the longitudinal active segments (a) of the top and bottom current conductors of the coils 50 and 51. An optional middle non-ferromagnetic layer 32, 33, for example made of alumina, may be provided, and third, outer soft iron layer 40,41 may shield outer longitudinal segments (b) of the top and bottom current conductors 50,51. Thus the two outer longitudinal winding segments (b) which are parasitic wire segments are affected by a significantly non-perpendicular and much weaker magnetic field preventing the parasitic wires from generating significant opposite force over the (b) segments.

In addition, the short parasitic segments (c, d) of the windings are also affected by a weak and non-perpendicular magnetic field, and are in any event particularly short.

With the magnetic rotor implementation of Fig. 1, the motor apparatus is brushless.

The Laplace force produced by both (a) segments is a tangential static force. With reference to Fig. 2, which is a view from above of the rotor and stator of Fig. 1, the static force multiplied by the interaction radius/distance 81 between the magnet and conductor rings and the axis produces an angular torque that is constant and continuous at any rotor angle and at any RPM including a stall situation. The constant torque may bring the rotor to any angular velocity while the only limitation is the centrifugal force.

The constant and un-interrupted torque together with a high RPM may produce a relative high and efficient output power measurable in Watts.

A combination of continuous operation, without current or phase switching, a constant and un-interrupted current, the general lack of impedance and eddy currents, and the relatively low Ohmic resistance, leads to an improved efficiency.

Reference is now made to Fig. 3, which illustrates an alternative embodiment of the present invention, in which magnetic field enhancers 130 and 131 are added to the stators. Fig.3 illustrates an implementation comprising a rotational axis 10, motor housing plates 11,12, and a magnetic rotor 20 made of a flat ring shape homogeneous magnet, as before. The ring magnetic rotor may comprise inner 7 and outer 8 pipes used as centripetal force protection and is continuous although it may be constructed in segments as above. The ring rotor is attached to a circular rotor plate 80 via connection screws 70.

The magnetic rotor revolves between two parallel flat ring shape stator cores attached to the motor housing, having a plurality of current conductor windings 50,51. The stator cores comprise ring shape magnets 130 and 131, which serve as field enhancers and may increase the active magnetic fields, meaning the density and perpendicularity of the unipolar field affecting the active inner longitudinal segments (a) of the top and bottom current conductor windings 50, and 51.

In addition soft iron plates 40 and 41 are attached at the back of the magnet cores enhancing the flux density of the opposite active pole. The iron plate may be made of multiple layers, as discussed in Fig. 1 above, to provide improved shielding to decrease the density and perpendicularity of the magnetic field that affects the parasitic opposite facing longitudinal winding segments (b) of the top and bottom current conductor winding coils 50,51. The shielding may prevent or at least reduce the production of an opposite force in the (b) segments. Plate 40,41 may comprise a middle non-ferromagnetic layer, for example an alumina layer. In addition, the short parasitic winding segments (c,d) may also merely be affected by a weak and non-perpendicular magnetic field. As with the embodiment of Fig. 1, the present embodiment of a magnetic rotor provides a brushless apparatus.

Reference is now made to Fig. 4, which is a top view of the embodiment of Fig. 3. The Laplace force produced by both (a) segments is a tangential static force. The static force multiplied by the magnet to conductor interaction radius 81 produces an angular torque, a torque that is constant and continuous at any rotor angle and at any RPM including a stall situation. The constant torque may bring the rotor to any angular velocity and the only limitation is the centrifugal force.

The constant and un-interrupted torque together with a high RPM produces a relative high and efficient output power as measured in Watts or Horsepower.

The combination of continuous operation, having no current or phase switching, constant and un-interrupted current, lack of impedance and eddy currents, and the relative low Ohmic resistance, combine to improve efficiency of the machine.

Reference is now made to Fig. 5, which illustrates a third embodiment of the present invention. Fig. 5 is a simplified diagram showing in cross section an embodiment of the constant toque motor in which the winding is in the rotor and the magnets are in the stator.

The embodiment of Fig. 5 comprises a rotational axis 10, upper and lower motor housing plates 11 and 12, and a ring shape iron core rotor 40 having current conductor windings 50. Two parallel flat shape ring magnets 26 and 27 have a first pole 74, 75, facing the rotor and a second pole 24, 25 facing outwardly. The magnets 26 and 27 are attached to the motor housing via soft iron plates 35 and 36 and connection screws 72 and 73 to provide a stator. The iron plates 35 and 36 serve to enhance flux density at the opposite active pole 74 and 75, that is the pole of the magnet facing the rotor. The polarity of each magnet is arranged so as to push against the oppositely facing magnet. In the present example two south poles face each other.

The Iron ring rotor is attached to a circular rotor plate 80 via connection screws

70.

The rotor windings may have a soft iron core 42 which in turn may comprise layers as discussed above. The core 42 may increase the density and the perpendicularity of the unidirectional magnetic field affecting active segments (a,b) of the current conductor windings 50. In addition soft iron plates 60 and 61 may be provided on the radial ends of the windings to provide shielding for the horizontal magnetic flux between magnets 20 and 21 so as to prevent the flux from affecting the short parasitic coil segments (c,d).

In the embodiment of Fig. 5, the parasitic conductors are much shorter, thus improving efficiency. However more magnetic volume is required than for the previous embodiments and electric brushes are required. In addition, heat must be dissipated from the rotor element, typically via design of rotor plate 80.

Reference is now made to Fig. 6, which is a view from above of the rotor and stator of the embodiment of Fig. 5. The Laplace force produced by active segments (a,b) is a tangential static force. The static force multiplied by the magnet/conductors interaction distance/radius 81 produces a rotational torque which is constant and continuous at any rotor angle and at any RPM including a stall situation. The constant torque may bring the rotor to any angular velocity while the only limitation is the centrifugal force.

The constant and un-interrupted torque together with a high RPM produces a relative high and efficient output power in Watts or Horsepower.

The combination of continuous operation, meaning no current or phase switching, the constant and un-interrupted current, the lack of impedance and eddy currents, and the relative low Ohmic resistance, may provide improved efficiency over prior art machines.

Reference is now made to Fig. 7, which is a simplified cross sectional diagram showing an alternative embodiment of the present invention in which rotor windings form a cylindrical ring around the rotor and the stator comprises a hollow pipe within which the ring travels.

The embodiment of Fig. 7 comprises motor housing plates 181 and 182 and a rotational axis 180. The motor comprises a radial cylindrical magnet 110, which is radially magnetized and covered with a soft iron layer 120, which serves to increase the inner magnetic field. Magnet 110 may be manufactured from cylindrical and radial segments fastened together to form a full 360 degrees cylindrical magnet.

Magnet 110 may be hollow, that is pipe shaped, and the inside rotor core 132 travels through the pipe inner rotor core 133 comprises windings of current conductors 140 and is connected to the motor axis 180 via a circular rotor plate 150 and connection screws 70. Slot 183 in the magnet 110 allows for the rotor plate 150. In addition radial Iron layer 120 connects the radial magnet 110 to housing plates 181 and 182 via connection screws 71 and 72.

In addition, an iron shield 160 may be provided at slot 183 to protect the short conductors in the vicinity of magnet slot 183 from an opposite magnetic field.

The embodiment of Fig. 7 may minimize parasitic conductance, thus improving efficiency. Electric brushes are required, and heat may be dissipated from rotor element 130.

Figure 8 is a simplified schematic view from above of the rotor and stator of Fig.

7.

The radial and condensed magnetic field (flux) inside the cylindrical magnet may produce a tangential Laplace static force, meaning that every point, meaning electron, within the rotating conductors 140 having a minimal parasitic length, is affected by a strong and perpendicular field, meaning a maximal tangential static force around the cylindrical structure.

The static force as above, multiplied by the magnet and conductor interaction radius produces a rotational torque, which may be constant and continuous irrespective of the rotor angle and at any RPM including a stall situation. The constant torque may bring the rotor to any angular velocity while the only limitation is the centrifugal force.

The constant torque together with a high RPM produces a relative high and efficient output power in Watts or Horsepower.

The combination of continuous operation, that is no current or phase switching, the constant current, the lack of impedance and eddy currents, and the relative low Ohmic resistance, combine to provide improved efficiency.

Reference is now made to Fig. 9, which is a simplified schematic diagram illustrating a further embodiment of a constant torque electric motor according to the present invention. The embodiment of Fig. 9 is a linear embodiment in which the motor generates linear motion. As illustrated, the linear motor is converted to rotary motion but the motor may be utilized in other ways suitable for linear motors as well.

The embodiment of Fig. 9 comprises a cylindrical magnetic piston, or alternatively multiple magnetic pistons arranged in series or at V shape or at any preferred orientation. The linear pistons movement is converted into angular rotation using a conventional crankshaft mechanism implemented in any combustion engine. More particularly, the linear motor comprises a hollow tube stator and a plunger linearly mobile along the hollow tube. As the plunger moves up and down in reciprocating motion, the motion can be transferred via a cam and levers to provide rotary motion if required. Either the stator or the plunger carries a magnet and the other of the stator and plunger carries a coil. The magnet or coil on the stator may be a continuous cylinder along both the circumference and depth of the stator. The magnet is arranged to provide a magnetic field which meets the foremost turns of the coil at right angles.

Considered in further detail, Fig 9 illustrates cylindrical magnet 210 mounted to a motor housing 100. Moving coil 230 moves up and down inside the cylindrical magnet and is shown in four successive positions a - uppermost, b - half way down descending, c - fully descended and d - half way up ascending. Coil 230 is connected to shaft 231, and linear bearing 250 is a cylindrical mounted pipe which holds shaft 231 steady below the magnet. Connection rod bearing 260 connects shaft 231 to connection rod 270. Rotation is caused of crankshaft 290, which is held by crankshaft bearing 291. Brushes 240 provide electricity for the coil 230. The brushes and bearings are held by brush and bearing support 241.

Reference is now made to Fig. 10, which is a simplified schematic diagram showing an alternative configuration of the linear motor of Fig. 9. In Fig. 10, coil 330 is mounted to the motor housing 100 while magnet 310 moves inside a mounted cylindrical pipe 350. That is to say coil 330 is mounted via shaft 331 to coil mounting support 340 and is stationary. Magnet 310 is shown in four successive positions, a - fully raised, b - half way descending, c - fully descended and d - half way rising. The magnet 310 is a hollow cylinder that surrounds the static winding or mounted coil 330 and the magnet is in turn wrapped in a soft iron outer casing 320. The magnet 310 is connected to shaft 332. Connection rod bearing 360 connects shaft 332 to connection rod 370. Rotation is caused of crankshaft 390, which is held by crankshaft bearing 391. There is no need for brushes as the winding is static.

Reference is now made to Fig 11, which is a simplified schematic cross- sectional diagram which illustrates an embodiment in which two cylindrical magnet layers 410 and 411 are mounted to a motor housing 100 while coil 430 shaped as a ring, moves in between the two cylindrical magnet layers. Fig. 12 is a view from above of the embodiment of Fig. 11.

Housing 100 supports soft outer iron cylinder 420 and inner iron core 421. The core is wrapped with magnet inner layer 411 and outside of the magnet inner layer is a space for the cylindrical coil or winding 430 is able to travel up and down. Forming the outer cylindrical wall of the space is outer magnet 410 and beyond the outer magnet 410 is the soft iron outer cylinder 420.

Brush and bearing support 441 holds bearing 450 which supports coil rod 431. Coil brushes 440 supply electricity to the coil 430. Connection rod 470 is pivotally connected to the base of coil rods 43 land connects to crankshaft bearing 491 to rotate crankshaft 490.

Due to the inner and outer cylinder layers, the coil is affected by a stronger magnetic field and thus produces a stronger static force.

In the embodiments of Figs 9, 10 and 11, the magnets are covered with a soft Iron layer, 220, 320, 420, 421, thus increasing field density at the active magnetic side of the coil. In addition the cylindrical magnets may be radially magnetized, for example with the south pole along the inner side against the coil and the north pole away from the coil along the outer side.

With the moving coils implementations, an electric brush 240, 440 and a brush mounting support 241, 441 is required in order to supply the constant current to the moving coil.

In the linear piston implementations of Figs 9, 10 and 11, the current conductors may be constantly active and may produce static force without parasitic conductance.

Linear bearing 250, 450 may maintain a defined distance between a piston moving part and a mounted part.

A linear static force, a constant Laplace force, is produced, while the magnetic field or flux inside or outside the cylindrical magnet is radial and condensed. Thus every point, or electron, within the current conductors is affected by a strong and perpendicular field, meaning a maximal static force at every linear position.

The piston's constant static force is converted into a rotational torque which is constant and continuous at any RPM including a stall situation. The constant torque may allow the motor apparatus to operate at any RPM speed, the only limitation being the centrifugal force.

In each of the embodiments of Figs 9 to 11, the coil 230, 330, or 430 has relative low induction, and with the continuous operation mode, impedance is zero and the current is constant.

With pistons, current may be inverted at the two ends of the linear motion, but due to the coreless coil and overall low induction, the small impedance has a minimal effect on current buildup.

Reference is now made to Fig. 13, which is a simplified schematic diagram illustrating an electrical generator operative according to the present embodiments.

Fig. 13 shows an electrical machine, for use as a generator, and which comprises a stator and a rotor. The stator and rotor are both arranged around a central axis, and the rotor is typically a disk. Either the stator or the rotor has one or more rings of magnets, the other of the two having one or more rings of coils. The rings on the stator and rotor are co-radial and are continuous around the central axis. The field lines from the magnets cross the facing windings of the coils at right angles. In greater detail, the electric generator implementation of the present embodiments comprises housing plates 511 and 512, a rotational axis 510 and a circular rotor plate 520 comprising a plurality of flat coils 521. In greater detail, rotor plate 520 comprises one or more concentric rings 522, 523, each having a plurality of flat coreless coils 521 wound on a thin pipe and having a relative low resistance and induction. Coreless coils are preferred for eliminating eddy current losses.

The implementation also comprises stator 525. The stator likewise includes one or more concentric rings 526, 527 of permanent magnets 530 mounted within housing plate 511 or 512 and arranged as an even number of alternating polarity units.

The magnet rings 526 and 527 are arranged at the same radius as the rotating coil rings 522 and 523, and a defined minimal gap between coils and magnets is provided. An exemplary value for the minimal gap may be less than 1 mm.

The coils may be grouped or wired together in parallel and/or in series for the production of a required voltage and current. The generator implementation is relatively efficient and relatively light weight due to strong and fast magnetic field changes that simultaneously affect multiple coils, for example over +/-0.3 Tesla cycles at a rate of over 4KHz.

Thus, the low mass rotor and coils can reach a relative high and efficient rotational velocity in RPM, and electric brushes are required.

The embodiment of Fig. 13 can be varied by placing the magnets on the rotor and the coils on the stator, to produce a brushless version of the generator.

Reference is now made to Fig. 14, which shows an alternative embodiment of an electrical generator according to the present embodiments. The embodiment of Fig. 14 uses fewer coils than that of Fig. 13 and thus uses less weight for the power generated and takes up less space. The generator may comprise a rotational axis 610, housing plates 611 and 612, and a circular rotor plate 620 comprising a plurality of flat coils 621 arranged in one or more concentric rings 622 and 623 of different radii.

In greater detail, rotor 620 comprises one or more concentric rings 622 and 623, each having multiple flat coreless coils 621 wound on a thin pipe and having a relative low resistance and induction. Coreless coils are preferred for eliminating or reducing eddy current losses.

The implementation may comprise stator 631 having a double sided sequence of permanent magnets 630 also arranged in one or more concentric rings 632 and 633. The stator may be mounted within housing plates 611 and 612 and arranged as an even number of alternating polarity units.

The magnet rings 632 and 633 are arranged at the same circular diameter as the rotating coil rings 622 and 623, and may have a defined minimal gap between the coils and the magnets, for example being less than 1 mm.

The coils may be grouped or wired together in parallel or in series for the production of a required voltage and current.

The generator implementation is relatively efficient and relatively light weight due to strong and fast magnetic field changes that simultaneously affect multiple coils, for example over +/-0.6 Tesla cycles at a rate of over 4KHz.

Thus, the low mass rotor and coils can reach a relative high and efficient rotational velocity in RPM, and electric brushes are required. The embodiment of Fig. 14 can be varied by placing the magnets on the rotor and the coils on the stator, to produce a brushless version of the generator.

An application for a light weight generator is a bicycle or like vehicle. For example, a small generator can be placed on a bicycle, where pedal power turns the rotor, or on any other kind of vehicle, where the motor turns the rotor. In either case, the penalty due to weight of the generator for the amount of electricity to be generated is lower than for conventional generators.

It is expected that during the life of a patent maturing from this application many relevant electrical machine designs will be developed and the scopes of the corresponding terms are intended to include all such new technologies a priori.

As used herein the term "about" refers to ± 10 %.

The terms "comprises", "comprising", "includes", "including", "having" and their conjugates mean "including but not limited to".

The term "consisting of means "including and limited to".

As used herein, the singular form "a", "an" and "the" include plural references unless the context clearly dictates otherwise.

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment, and the above description is to be construed as if this combination were explicitly written. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention, and the above description is to be construed as if these separate embodiments were explicitly written. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is inoperative without those elements.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.

Claims

WHAT IS CLAIMED IS:

1. An electrical machine comprising a stator and a rotor, said stator and said rotor both arranged around a central axis, one of the stator and the rotor comprising at least one magnet and the other of the stator and the rotor comprising at least one coil, said at least one magnet and said at least one coil respectively forming rings, the rings being continuous around said central axis, wherein the at least one magnet and at least one coil overlie each other to provide field lines from said at least one magnet that cut front windings of said coil perpendicularly.

2. The electrical machine of claim 1, wherein said rotor comprises a disk extending into a slot within said stator.

3. The electrical machine of claim 2, wherein said coil comprises a substantially flat ring-shaped coil arranged on said disk, and said at least one magnet comprises a first ring magnet on an upper side of said slot and a second ring magnet on a lower side of said slot.

4. The electrical machine of claim 3, wherein identical magnetic poles face each other across said slot.

5. The electrical machine of claim 3, further comprising soft iron between said first magnet and a motor housing and between said second magnet and a motor housing.

6. The electrical machine of claim 3, wherein said substantially flat ring- shaped coil comprises an iron core.

7. The electrical machine of claim 6, wherein said iron core comprises an upper iron layer and a lower iron layer with a non-ferrous layer in between said upper iron layer and said lower iron layer.

8. The electrical machine of claim 3, wherein said substantially flat ring- shaped coil has an inner and an outer circumference, and comprises laterally placed iron shields on said inner and outer circumferences.

9. The electrical machine of claim 2, wherein said at least one magnet comprises a substantially flat ring-shaped magnet arranged on said disk, and said at least one coil comprises a first ring shaped coil on an upper side of said slot and a second ring shaped coil on a lower side of said slot.

10. The electrical machine of claim 9, wherein said substantially flat ring- shaped magnet has an inner and an outer circumference, and comprises laterally placed iron shields on said inner and outer circumferences.

11. The electrical machine of claim 9, wherein said substantially flat ring- shaped coil comprises an iron core.

12. The electrical machine of claim 11, wherein said iron core comprises an upper iron layer and a lower iron layer with a non-ferrous layer in between said upper iron layer and said lower iron layer.

13. The electrical machine of claim 1, wherein said stator comprises a pipe and said rotor comprises a cylinder travelling within said pipe.

14. The electrical machine of claim 1, being a linear motor wherein said stator comprises a hollow tube and said rotor comprises a plunger linearly mobile along said hollow tube to move in reciprocal motion.

15. A linear motor comprising a hollow tube stator and a plunger linearly mobile along said hollow tube to move in reciprocal motion, one of said stator and said plunger carrying a magnet and the other of said stator and said plunger carrying a coil, the one of said magnet and said coil being carried by said stator being a continuous cylinder along a circumference and a depth of said stator, wherein the magnet and the coil overlie each other to provide field lines from said at least one magnet that cut front windings of said coil perpendicularly.

16. The linear motor of claim 15, wherein said stator comprises a central tube coaxial with said hollow tube, and said plunger comprises a cylinder linearly mobile along a slot defined between said central tube and said hollow tube.

17. The linear motor of claim 16, wherein said central tube comprises a cylindrical magnet arranged around an iron core and said hollow tube comprises a cylindrical magnet surrounded by an iron cylinder.

18. An electrical machine comprising a stator and a rotor, said stator and said rotor both arranged around a central axis, the rotor comprising a disk, one of the stator and the rotor comprising at least one ring of magnets and the other of the stator and the rotor comprising at least one ring of coils, the rings being co-radial and continuous around said central axis, thereby to provide field lines from said at least one magnet that cut front windings of said coil perpendicularly.

19. The electrical machine of claim 18, wherein said coils are substantially flat coils located on said disk.

20. The electrical machine of claim 18, said stator having an upper part and a lower part and a slot in between said upper part and said lower part, and wherein said rotor extends into said slot.

21. The electrical machine of claim 20, wherein said magnets are located on both upper and lower parts of said stator.

22. A method of operating the electrical machine of claim 1, comprising supplying said machine with a constant current.

23. The method of claim 22 comprising maintaining said constant current over changes in angular velocity and independently of mechanical load.

24. A method of operating the linear motor of claim 15 comprising supplying said machine with constant current.

25. The method of claim 24, comprising maintaining said constant current over changes in velocity and independently of mechanical load.