MXPA99010201A - A motor - Google Patents

Abstract

A motor comprising two or more rotors (20, 30) rotated by means of a common power supply (6), each rotor (20, 30) having a plurality of poles (22, 32) and being associated with a stator (16, 26) having a plurality of poles (18, 28), wherein the arrangement of rotor poles (22, 32) and stator poles (18, 28) is different for each rotor (20, 30) so that the rotors (20, 30) rotate at different speeds when the common power supply (6) is applied.

Description

MOTOR DESCRIPTION OF THE INVENTION The invention relates to a motor. Many developments have been made over the years in engines, particularly those engines that are used in household items. However, it is generally believed that the trend of improvements in relation to universal engines is coming to an end. Therefore, it is an object of the present invention to provide a motor that is suitable for providing the appropriate power to various parts of a household appliance and that also has scope for improvements beyond the potential of known universal motors. Household items such as vacuum cleaners usually include a universal motor adapted to activate the fan used to create the suction through which air is drawn into the vacuum cleaner. When the vacuum cleaner is a straight vacuum cleaner, a brush bar is usually mounted in a rotating fashion on the dirty air inlet located on the head of the vacuum cleaner. The brush bar is rotated through a driving belt extending between the motor and the brush bar. There are many disadvantages to this arrangement, one of which is the vulnerability of the same driving band. Other advantages include the fact that, in most cases, the drive belt engages with a portion of the outer surface of the brush bar, which means that the brush bristles can not be located in that area. It is also advantageous to have some kind of mechanism to prevent the brush bar from rotating against a carpet that will be guided if, for some reason, the engine is left running while the cleaner remains fixed, for example, while cleaning above the floor. In a cylinder vacuum, the dirty air inlet is located at the end of a hose, therefore a driving belt for the main motor of the vacuum cleaner is impractical, and the activation of the brush bar directly through an engine secondary universal has practical difficulties, it has been proposed "tube" pneumatically operated brushes, but they are usually efficient and reduce the energy wats available for the collection of dirt and dust by the head of the vacuum cleaner. Therefore, it is an object of the invention to provide a motor suitable for use in a vacuum having a drive brush bar, which reduces or eliminates the problems defined above. According to the invention, an engine according to the aspects of claim 1 is provided. Preferred aspects of the invention are set forth in the subsidiary claims. The provision of at least two rotors in the engine has been identified as an economical and compact way to activate the two separate features of a household item such as a vacuum cleaner at different speeds. Making use of a common stator and the same winding or windings or a common power supply to activate two separate rotors is clearly advantageous in an environment where consumers demand lightweight, small items. A number of alternative embodiments of the invention will now be described by way of example with reference to the accompanying drawings in which: Figure 1 is a schematic view of a primary and secondary motor arrangement; Figures 2a-2d are sectional and transverse views of the brush bar thus incorporating the secondary motor of Figure 1; Figures 3a-3d are sectional and cross-sectional views of a second brush bar incorporating a secondary motor as shown in Figure 1; Figures 4a-4g are schematic cross-sectional views of several alternative engines according to the present invention; Figures 5a and 5b are schematic cross-sectional views of the alternative motor arrangements according to the invention; Figure 6 is a schematic cross-sectional view of an engine according to the present invention; Figure 7 is a further cross-sectional view of an engine according to the present invention; Figure 8 is a schematic sectional view of an additional motor according to the invention; and Figure 9 shows an arrangement in which a motor and a generator are coupled together. Figure 1 shows a 4/2 primary, 2-phase switched reluctance motor, 2, a 24/16, two-phase switched reluctance motor, secondary, 4 and a power supply circuit, which is connected to the primary motor 12. Other types of switched reluctance motors (for example, single-phase, three-phase, four-phase, etc.) can be used for any motor, if desired. The arrangement shown is perceived as being particularly suitable for activating the fan and the brush bar of a vacuum cleaner, although in no way is it the only application observed. In common with the known switched reluctance motors, the primary motor 2 comprises a stator 16 with four projecting poles 18a-18d. The opposite poles 18a and 18b each support a similar armature winding + A, -A forming a first phase. The opposite poles 18c and 18d adapt respective armature windings respectively + B, -B, which represent a second phase. A rotor 20 is rotatably mounted on a shaft 21 within the stator 16 and comprises opposite poles 22. The rotor 20 is formed from rolled steel in the axial direction. The energy is supplied to the motor 2 from a main supply 6, which is rectified through a bridge rectifier 8. A capacitor 10 is provided to moderate the bridge output. Each of the armature winding pairs A, B is fed through a respective asymmetric mid-bridge 12, 14. Each middle bridge 12, 14 relates to one of the two respective phases. In this regard, the middle bridge 2 supplies the windings A and the middle bridge 14 supplies the windings B. For continuous operation, the current is applied to each of the stator phases in turn at a speed that is dependent on and determined by the variation of the rotor position with time. The time control of the asymmetric half-bridges 12, 14 is determined by reference to the rotor positions of the primary and / or secondary motors through sensors either optical or Hall effect or any other suitable means. The primary reluctance motor 2 also includes two additional winding pairs: C and D. A winding of the pair of windings C are fitted on each of the projecting poles 18a and 18b. A winding of the winding pair B is adapted on each of the projecting poles 18c and 18d. The respective pairs of the windings A and C on one side and B and D on the other each operate in a transformer form. The current induced in the winder pairs C and D by the winding pairs A and B is supplied to the secondary reluctance motor 4. For the convenience of the assembly inside the brush bar of the vacuum cleaner, this motor is structurally inverse to the motor 2. That is, the rotor 30 is located radially outside the stator 26, which is located on a fixed axis 34. The radially internal surface of the brush bar 36 is fixed directly on the radially outer surface of the rotor 30 and secured instead through tabs 37. A closer reference to Figure 1 will reveal that the stator 26 comprises 16 poles 32. The rotor 30 comprises 24 poles 28 radially inwardly directed. The poles 32 located on the stator 26 are arranged in pairs, each pair being surrounded by a respective winder. The same windings are in pairs circumferentially and then these pairs of windings are in pairs in pairs with a similar pair of windings located on the radially opposite side of the stator. For example, the poles 32a and 32b are provided with a winding B. Circumferentially adjacent poles 32c and 32d are provided with a second winding D. The radially opposed poles 32e-32h are arranged in a similar fashion. The spacing between the poles 32a-32h is such that it allows its simultaneous radial correspondence with rotor poles 28, as the picture shows. However, the poles associated with the windings D are radially deviated from the coils associated with the windings C, so that the radial correspondence with the rotor poles can not be achieved by the poles associated with the coils C at the same time as the poles. poles associated with coils D. Therefore, a two-phase structure is presented. The number of poles provided in the secondary switched reluctance motor 2 ensures a moderate rotation of the brush bar 36. The power supply to the primary reluctance motor 4 is typically driven at a frequency of the order of 1.25 kHz per phase (if will use a 4/4 individual phase switched reluctance motor as the primary switching frequency of approximately 2.5 kHz could be comparable). The secondary reluctance motor can be switched to the same high frequency (or reduced ratio by disconnecting the secondary windings of the pole number). As a consequence of this frequency magnitude, there is no need to provide a high level of flow development in the coil armature of the primary motor (or an intermediate transformer, if the voltage is staggered outside the primary motor). Since the voltage to the secondary motor 4 is stepped and isolated from the voltage of the primary motor 2, the power supply to the secondary motor is very safe. Actually, the supply is so secure that the energy can be fed through the hose to the suction head of a cylinder vacuum without the risk of compromising safety. The supply of energy to the primary motor 2 through the power supply circuit causes the primary rotor 22 to rotate inside the stator 16. The current flowing inside the coils A and B induces the current in the coils C, D, which in turn cause the secondary rotor 30 to rotate around the secondary stator 36. The number of poles present on each stator 16, 36 and rotor 22, 30 determines the relative speeds of rotation; in this example, the secondary rotor 30 will rotate to one twelfth of the speed of the primary rotor 22 Switches 38 are provided in order to allow electrical connection to the windings C, D that will be interrupted The switches can be operated manually or activated in a Automatic in response to the conditions of the device where the motor is located For example, it may be desirable to switch the brush bar of a vacuum under certain circumstances and the operation of the switches 38 can achieve this. The switches can be made to open in the case that the handle of the vacuum cleaner is placed in the straight position through a simple electronic circuit system, which will be readily available to one skilled in the art. Switches can also be operated intermittently, for example, during the start of the brush bar, so that the rotation of the brush bar can be accelerated in a controlled and reliable way Using a switched reluctance motor as the secondary motor 4, important advantages arise Due to the lack of switching brushes, no carbon dust is generated by the wear of the brush In addition, the motor has a life relatively long and its speed is not limited by the need to maintain a reasonable brush life. The use of a switched reluctance motor as the primary motor allows a switched reluctance motor to be used as the secondary motor with relative ease. Figures 2a-2d show the secondary motor 2 of Figure 1, located inside a vacuum brush bar 36, in more detail. Figure 2a is a section. The views 2b-2d are cross sections taken along lines I to III in Figure 2a, respectively. Referring to Figure 2a, it will be seen that the brush bar 36 and the rotor 28 are mounted together via bearings 40 on the arrow 34 that supports the stator 26. The arrow 34 is mounted at each end to a housing 42 of vacuum. From the cross section of Figure 2c, it will be seen that the arrow 34 includes 4 axial grooves 42 located at circumferential intervals (e.g., 90 °). Each slot 42 adapts a cable for the supply of current from the primary motor 2 to the secondary motor 4. Figures 3a-3d show a variation of the arrangement of Figure 2. Figure 3a is a section and Figures 3b to 3d they are cross sections taken along lines I to III of Figure 3a, respectively. In this design, the arrow 34 is hollow and the wires for supplying current to the windings of the secondary motor run inside the arrow, as will be seen more clearly in the cross section of Figure 3c. Although the above arrangements have a large number of poles in the secondary motor than in the primary motor, this is not necessary. The primary motor may have an equal or greater number of poles relative to the secondary motor if circumstances require. For example, in a washing machine, a primary motor used as a direct drive can operate at approximately 0-2000 rpm and activate a secondary motor for a high speed water pump operating at 0-10,000 rpm. In such a case, it may be appropriate for the primary motor to have a greater number of poles than the secondary motor. In the case of the mentioned example, the primary motor will have a pole arrangement capable of driving the secondary motor at 5 times the speed of the primary motor. Figure 4 illustrates various embodiments of the invention, in each of which one or more windings are used to activate more than one rotor of a single motor. Figure 4a illustrates an embodiment having similarities to the arrangements illustrated in Figures 1 to 3. The engine 500 has a stator 502 which carries a winding A and 24 external poles 504. Mounted rotatably radially outwardly of the stator 502 is found an external 506 engine, also carrying 24 poles 508. A plurality of tongues 510 is disposed between the outer rotor 506 and the inner surface of a brush bar cylinder 512 of a vacuum cleaner. This arrangement can be used to cause rotation of the brush bar 512 in the same manner as described in relation to the previous Figures. The main difference between the motor illustrated in Figure 4a and the previously illustrated motors is the provision of four internal poles 514 in the stator 502. Radially inward of the stator 502 is mounted a second internal motor 516 having four equi-spaced poles 518. The inner rotor 516 is rotatably mounted about a central shaft 520. It will be appreciated that, simultaneously with the rotation of outer rotor 506, when energy is applied to winding A, internal rotor 516 will also rotate. However, the rotation speed of the internal rotor 516 will be six times the rotation speed of the external rotor 526 due to the difference in the number of poles provided on each rotor and the associated stator. It will also be appreciated that this principle can be applied to many alternative arrangements and many more alternative variations are possible. Figures 4b, c, d, e and f each show, schematically, different arrangements of an individual switched reluctance motor having a common winding or a group of windings driving two separate rotors. In each case, the number of poles carried by each rotor is different. It will be appreciated that the number of poles on each rotor can also be varied. Figure 4g schematically illustrates a two-phase switched reluctance motor having two windings instead of one and also activating two separate rotors. An advantage of activating two separate rotors through a winding or group of windings is that the volume occupied by the motor will be reduced and the associated mass, therefore, will also be reduced. The rotors of an engine according to the invention can either rotate uni-contra or multi-directionally.

In the case of a switched reluctance motor, the initial direction of rotation is usually determined by the initial position of the rotor poles relative to the stator poles and / or the phase switching sequences when a current pulse is applied to the windings. Considering the motors shown in Figure 4, it is possible to obtain a rotation either uni or directional counter by locating the rotors in suitable respective orientations relative to the stator before the application of a current pulse. Figures 5a and 5b show a motor where magnets 550 are provided to stop the rotors when the drive current is terminated, so that the rotors will be in a position suitable for counter-directional rotation when a current is applied afterwards. In this regard, Figure 5a shows an engine with different speed outputs in an initial stopping position prior to the application of a driving current. Figure 5b shows the direction of rotation of the respective rotors after the winding is energized. It will be seen from the figure that the two rotors rotate in respectively opposite directions. It will be seen that the magnets are strategically placed in order to align each of the poles of the rotors so that they are closer to a particular pole than to an adjacent pole. Therefore, when the coil is energized, each rotor pole moves towards the nearest stator pole, thus determining the direction of rotation. Naturally, a mechanism for adjusting the position of the magnets can be provided, in order to change the direction of rotation of a particular motor. An alternative for multi-phase switched reluctance motors having more than one rotor is to arrange the phase sequences in such a way as to produce either a uni or a directional counter rotation in the rotors. It is also possible to control the direction of rotation by providing asymmetric air gaps between the rotor and stator poles. The above motor arrangements allow for counter-directional rotation elements without a prohibitive increase in mechanical cost or complexity. The engine arrangements can also provide important additional advantages as follows. First, the angular angular momentum can be canceled or reduced. This leads to the minimization of the acceleration / retardation torques in the motor as well as in the article or product to which it is fixed. In addition, net gyroscopic effects can be canceled or reduced. This leads to the minimization of gyroscopic forces in the engine and / or the article or product when subjected to general movement. Said motor arrangements also allow a reduction of acoustic and mechanical vibrations through various methods including cancellation of overlap.

An engine having directional rotors, as described above, can provide important advantages when used in a vacuum to rotate motorized dual cyclones or multiple cyclones. More specifically, the motor can be used to activate the impellers inside internal and external fins, directly. In addition, if desired, the air flows through the internal and external cyclones that can be connected in series, resulting in a potential load that matches the outputs of the motor and thus a simplification or reduction of the power electronics and / or mechanical complexity. In the case of switched reluctance motors, the switching times of the primary and / or additional windings can be controlled using the position sensor information on the primary and / or additional rotors. If desired, the positional information of the rotors can be combined (for example, through a microprocessor, logical construction or physical combination of the sensors) to give the desired characteristics of operation for the engine and / or the product / article that they use inside or in combination with. This allows a potential simplification of the electronic energy circuit system and thus a potential reduction in the total cost, size and weight of the product / article. Figures 6 and 7 show variations of the winding structure for a single phase dual output motor, as shown in Figure 4a, for example. In each of Figures 6 and 7, the stator 502 is provided with two winding groups. In this regard, a first winding 550 is wound around the poles 518 radially inwardly and a second winding 560 is wound around the radially outward poles 504. Figure 7 shows an arrangement broadly similar to Figure 6, however , there is some radial overlap between the radially internal windings 550 and the radially outer windings 560. This arrangement allows for significant reductions in size for a given number of winding turns. In vacuum cleaner applications, it is possible to provide more impeller to extract air through the vacuum cleaner. Typically, and in accordance with a mode shown in Figure 8, a first impeller 570 may be disposed upstream of the bag (not shown), which separates dirt and dust from the air flow, while a second impeller 572 may be disposed downstream of it. The first impeller 570 can be rotated more slowly than the second impeller 572, but it can be larger in size to accommodate the passage of larger dust particles. The second impeller 572 can be made relatively smaller, since it only looks for finer dust particles. This facilitates a high operating speed that also improves the operation of the vacuum cleaner. In addition, the ratio of the rotor speeds can be configured to compensate the fan / rotor inertia ratios thus allowing net zero reduced gyroscopic forces. A third motor outlet can be provided to rotate a brush bar.

Looking at Figure 8 in more detail, the motor arrangement comprises a central mechanical support 574 supporting an axially central stator 576 provided with laminated poles 590. The poles 590 are provided with windings 578. A pair of axially aligned rotors 580, 581 are provided. on respective axial sides of the stator 576. The impellers 570, 572 are provided on the axial sides of the rotors 580, 581 away from the support 574. The impellers 570, 572 and the rotors 580, 581 are mounted on a central arrow 582, the which is integrally formed with the support 574. Stop magnets 584 are provided to locate the poles 586 of each rotor 580, 581 closer to the poles that are respectively on circumferentially opposite sides of the midpoint between any given adjacent pair of stator poles 590. This has the effect of causing the rotors 580, 581 to rotate in opposite directions when the windings 578 are energized. To ensure that the impellers 570, 572 draw air from opposite sides of the motor arrangement, each impeller 570, 572 has fins 588, which are oriented in the opposite direction to those of the other impeller. In this way, the air can be extracted from the dirty air intake of the vacuum cleaner through the impeller 570, expelled from there to the dirt and dust collection bag where the air is cleaned, and then removed from the bag towards the output of clean air through the impeller 572. Another application of the invention is the variation of the ratio of the speeds of a motor and a generator. An example of this type of application is the variation of the speeds of the turbine and the compressor in the turbocharger in an internal combustion engine in an automotive vehicle as illustrated in Figure 9. This can be achieved in practice through the use of a switched reluctance motor 610 to activate the compressor 612 and a switched reluctance generator 614 to absorb the energy of the turbine 616. The speed of the compressor 612 can be synchronized to a whole multiple of the speed of the turbine 616 and to the combination of the relations of the motor / generator poles, so that the input energy by "stroke" of the generator 614 can be directly transformed to the output power by "stroke" of the motor 610. Said variable ratio of turbocharger has many advantages over a standard turbo-charger ratio unit, including improved engine power and efficiency, a reduced turbo delay, a high a reliability combined with compact component size and robust construction. The arrangement is not expensive to manufacture and can be linked to any engine management system. It also provides the opportunity for a vehicle alternator to be removed from being redundant. Many other modifications and variations will be suggested by themselves to those skilled in the art with reference to the foregoing description which is given by way of example only and is not intended to limit the scope of the invention, being determined by the appended claims.

Claims (15)

1. - An engine comprising two or more rotors rotating through a common power supply, each rotor having a plurality of poles and being associated with a common stator having a plurality of poles, wherein the arrangement of poles of rotor and poles Stator is different for each rotor, so that the rotors rotate at different speeds when a common power supply is applied.

2. An engine according to claim 1, wherein the number of stator poles is equal for each rotor, but the number of rotor poles is different.

3. An engine according to any of the preceding claims, wherein means are provided for causing at least one of the rotors to rotate in a direction opposite to the direction of rotation of the remaining rotor or rotors.

4. An engine according to claim 3, wherein said means comprise magnets that are located in such positions that allow the rotors, when fixed, to rotate in mutually opposite directions locating each rotor pole very close to one of the predetermined stator poles of the two adjacent stator poles.

5. An engine according to any of the preceding claims, wherein the first rotor and the second rotor each operate as a switched reluctance motor.

6 -. 6 - An engine according to any of claims 1 to 4, wherein a first rotor and a second rotor each operates as a stepped motor.

7. An engine according to any of claims 1 to 4, wherein the first rotor operates as a switched reluctance rotor and a second rotor operates as a stepped motor.

8. An engine according to any of the preceding claims, wherein the motor is adapted for use in a vacuum cleaner.

9. An engine according to claim 8, wherein one of the rotors is adapted to activate the impeller of the vacuum cleaner.

10. An engine according to claim 9, wherein a second rotor is adapted to activate a second impeller of the vacuum cleaner.

11. An engine according to any of claims 8 to 10, wherein one of the rotors is adapted to activate a brush bar of the vacuum cleaner.

12. An engine according to any of claims 1 to 7, wherein the second rotor is part of a switched reluctance generator.

13. An engine according to claim 12, wherein the first rotor is used to drive the compressor of a turbocharger and the switched reluctance generator is adapted to absorb the energy of the turbine.

14. A motor substantially as described above with reference to any of the modalities shown in the attached drawings.

15. A vacuum cleaner incorporating an engine according to any of the preceding claims.