Patent Description:
In particular said brushed electric motor can be used in environments with risk of fire or explosion or in presence of potentially explosive or flammable fluids.

Existing brushed electric motors do not allow the use in such conditions as the brushes create sparks and therefore can determine the onset of a fire or explosion.

<CIT> discloses a fluid pump having an electric brushed motor.

For such applications brushless motors are used, namely the motor known with the English term "brushless" which, however, are more complicated to realize and also have on average greater costs in comparison to brushed motors.

In fact brushless motors have a construction and functioning completely different with respect to brushed electric motor, consequently the difference is not only the absence of the brushes.

Aim of the present invention is to provide a brushed electric motor which can be used in environments with risk of fire or explosion or in presence of potentially explosive or flammable fluids and which at the same time can have high performance characteristics of the electric motor itself.

Another aim is to provide a brushed electric motor which has a reduced volume and a reduced number of components.

Still another aim is to have a brushed electric motor which has a low noise level and which is economic.

Further aim is to have a brushed electric motor which is economically advantageous.

These aims according to the present invention are achieved by providing a brushed electric motor as described in claim <NUM>.

Further features of the invention are highlighted by the subsequent claims.

Features and advantages of a brushed electric motor according to the present invention will become more evident from the following exemplary and non-limiting description, with reference to the attached schematic drawings in which:.

With reference to the figures, a brushed electric motor <NUM> is shown, that is equipped with sliding contacts, in particular with a direct current, in particular usable in environments with risk of fire or explosion and/or in presence of potentially explosive or flammable fluids.

According to the present invention said brushed electric motor <NUM> comprises at least one filler element <NUM> made with a polymer based material which is positioned internally to said brushed electric motor <NUM>, for minimizing the free volume within said brushed electric motor <NUM> itself, and in particular for avoid a reduction in size of the entire brushed electric motor <NUM> itself, and for allowing at the same time to maintain high power and great performance characteristics of said brushed electric motor <NUM>, so advantageously minimizing the possibility of triggering of a burst or fire, in other terms by minimizing the probability of triggering a deflagration or a combustion in the case of use of said brushed electric motor <NUM> in environments with risk of fire or explosion or in presence of potentially explosive or flammable fluids.

In particular said at least one filler element <NUM> permits to reduce the free volume within said brushed electric motor <NUM> below a predetermined volume, in particular lower than <NUM><NUM>, below which the probability of fire and/or explosion of a determined fluid is drastically reduced, and at the same time it permits to maintain high performance characteristics of said brushed electric motor <NUM> and also permits to convert the existing brushed electric motors for use the same for applications in presence of flammable fluids or explosives.

In particular said brushed electric motor <NUM> comprises two brushes and an external case <NUM> preferably metallic and having an internal cavity <NUM> within which said at least one filler element <NUM> is inserted, and also said brushed electric motor <NUM> comprises a rotor <NUM>, having a first inner end <NUM> and a second outer end <NUM>, which is inserted within said external case <NUM>.

This allows to further reduce the risk of explosion or fire, as said external case <NUM> allows in part to absorb any possible electric strokes through a grounding electric connection, of which said brushed electric motor <NUM> is preferably provided.

Another advantage is that existing brushed motors can be converted, by inserting in the same said at least one filler element <NUM>, for use of the same with fluids which are at risk of a fire or explosion without necessarily using a different type of electric motor of the type known with the term "brushless", which does not have such kind of problems as they do not generate sparks or electric discharges during its operation, being in fact brushless.

Preferably said at least one filler element <NUM> is also vibration-damping and soundproof, that is it contributes to the attenuation of noise and vibrations produced by said brushed electric motor <NUM>.

Advantageously, this allows the use of a brushed electric motor <NUM> by also minimizing noise emissions.

According to the invention said brushed electric motor <NUM> comprises a printed circuit board <NUM>, which is inserted within said external case <NUM>, and in particular within said internal cavity <NUM>.

According to the invention said at least one filler element <NUM> has an housing <NUM> for said printed circuit board <NUM> for avoid the so-called "tracking" problem, hence for avoiding short circuits due to dusts produced by the brushes which can be positioned on said electric circuit or on contacts of the components present on said printed circuit board <NUM> and in particular in the presence of high humidity.

Preferably said brushed electric motor <NUM> comprises two brush holders <NUM> which are preferably mounted on said printed circuit board <NUM> and in particular which are integrated with said printed circuit board <NUM>.

Preferably said housing <NUM> for said printed circuit board <NUM> has two housings for enclosing said two brush holders <NUM> and at least partially enclose said two brushes for prevent the passage of predetermined conductive dusts in particular due to rubbing of said two brushes on a first inner end <NUM> of said rotor <NUM> and for allow to the portion of said two brushes projecting inside the same to contact said first internal end <NUM> of said rotor <NUM>.

Preferably said rotor <NUM> is of the completely automatic wound type and is preferably provided with <NUM> polar sections with a <NUM> blade collector.

Advantageously in particular in the case of a direct current <NUM> v motor, lower electromagnetic emissions, lower noise emissions are obtained and is obtained a lower sparking of the brushes with a longer life of the same, by advantageously reducing also the "tracking" phenomenon of the dusts, and accompanied by an increased useful life of said brushed electric motor <NUM>.

Preferably said brushed electric motor <NUM> comprises an electric noise suppression device <NUM>, such as in particular, a high pass filter preferably of the passive type, preferably of the type known by the English term EMC, which is inserted inside said external case <NUM>, wherein preferably said electric noise suppressor device <NUM> is connected to said two brushes of said brushed electric motor <NUM> for attenuate frequencies higher than the frequency of the electricity network and in particular frequencies between <NUM> and <NUM>, for attenuate electromagnetic interferences and for obtain an electromagnetic compatibility of said brushed electric motor <NUM>.

Advantageously this allows to reduce the encumbrance, and allows to protect said electric noise suppression device <NUM> from external agents and in particular from environments with high humidity or with oxidizing or corrosive agents.

Advantageously this also allows to reduce the number of components as it is avoided an additional box or outer casing for housing said electric noise suppression device <NUM> and the related assembly, with a consequent reduction of production costs.

Preferably said electric noise suppression device <NUM>, and in particular said high pass filter is mounted on said printed circuit board <NUM>.

Advantageously this allows to reduce the overall dimensions, and to protect said electric noise suppression device <NUM> from external agents.

Preferably said printed circuit board <NUM> also comprises an electric circuit and a number of components connected together, a part of which makes said electric noise suppression device <NUM>.

Also preferably said printed circuit board <NUM> also includes said two brush holders <NUM>, for integrate in a single element all the electric components of said brushed electric motor <NUM>.

Preferably said at least one filler element <NUM> comprises a second housing for said electric noise suppression device <NUM>, for avoiding the so-called "tracking" problem, hence for avoid short circuits due to the dusts produced by the brushes which can be positioned on said electric circuit or on the contacts of the components on said printed circuit board <NUM>.

Preferably said printed circuit board <NUM> comprises a central through hole, inside which an innermost end <NUM> of said rotor <NUM> is preferably inserted, and also said two brushes are mounted on said printed circuit board <NUM> and also said two brushes include corresponding ends protruding inside said through hole and are preferably diametrically opposed one to another with respect to said central through hole.

In particular said housing <NUM> for said printed circuit board <NUM> reproduces as a negative, in particular on a side of said at least one filler element <NUM>, the shape of said printed circuit board <NUM>, preferably of said printed circuit board <NUM> and preferably also of its components, for completely cover the same and for prevent the positioning of dust or other agents on said printed circuit board <NUM>, and also it advantageously permits an easy replacement of said printed circuit board <NUM> or other components on the same.

Preferably said printed circuit board <NUM> comprises two filters, each of which comprises an inductor and a capacitor, each filter of said two filters is connected to a correspondent brush of said two brushes.

Preferably said printed circuit board <NUM> comprises a third capacitor, a diodes bridge rectifier having two input poles and two output poles, wherein said two output poles are connected to said two brushes, furthermore said two input poles are mutually connected by said third capacitor, not shown, which is so connected in parallel respect to the same.

Preferably said printed circuit board <NUM> comprises a thermal protection element which is connected in series to an input pole of said diodes bridge rectifier, in particular said thermal protection element is able to interrupt the connection to the input pole of said diodes bridge rectifier in the event that the operative temperature is greater than a maximum predetermined admissible temperature for said diodes bridge rectifier.

In particular said thermal protection element comprises a memory shape metallic strip made with to different metals, which bend itself in the case of an operative temperature greater than a maximum predetermined admissible temperature.

Preferably said housing <NUM> comprises a plurality of traces or housings for each component of which said printed circuit board <NUM> is provided.

Preferably said housing <NUM> of said at least one filler element permits to insert and completely enclose at least a first face of said printed circuit board <NUM>.

Preferably said housing <NUM> reproduces as a negative the shape of said printed circuit board on a board <NUM> and also of its components, in particular said housing <NUM> comprises a plurality of further housings for at least one part of the electronic or electric components protruding from said printed circuit board <NUM>, of which said printed circuit board <NUM> is preferably provided, and in particular for each electronic or electric component of said printed circuit board <NUM> and preferably also of said electric noise suppression device <NUM>, which is preferably mounted or integrated on said printed circuit board <NUM>.

According to the invention said at least one filler element <NUM> permits to minimize the free volume inside said brushed electric motor <NUM>, in particular below a minimum volume necessary for triggering an explosion or a combustion in presence of flammable fluids or with a risk of explosion, and also at the same time it allows the integration of said printed circuit board <NUM> and other electric and/or electronic components inside said brushed electric motor <NUM>, and in particular said at least one filler element <NUM> also integrates the function of a protective casing for the same within said printed circuit board <NUM> and of other electric and/or electronic components inside said brushed electric motor <NUM>.

Preferably said at least one filler element <NUM> has a plurality of filler elements <NUM> made with a polymeric material for attenuate the noise emission of said brushed electric motor <NUM>.

According to the invention said at least one filler element <NUM> comprises a first filler element 20A and a second filler element 20B.

According to the invention said first filler element 20A comprises a first housing for said first face of said printed circuit board <NUM>, and also said second filler element 20B comprises a second housing for a second face of said printed circuit board <NUM>, for completely enclosing said electric circuit and at least one part of the components of said printed circuit board <NUM>.

Preferably said at least one filler element <NUM> comprises a third filler element 20C which comprises a substantially central through hole <NUM> within which said second outer end <NUM> of said rotor <NUM> is inserted.

In particular said third filler element 20C comprises an annular gasket <NUM> for prevent the entry of water or fluids into a portion of said brushed electric motor <NUM> in which said printed circuit board <NUM> is housed, preferably said annular gasket <NUM> is made integral or realized in a single piece with said third filler element 20C and in particular the same is made integral or realized in a single piece with said through hole <NUM> of the same.

In particular within said first filler element 20A and said third filler element 20C are positioned in opposite longitudinal portions with respect to said rotor <NUM>, and also said first filler element 20A and said third filler element 20C comprise respective longitudinal peripheral portions for their mutual connection and for avoid a contact with said rotor <NUM> and maintain a correct mutual position and also advantageously for better absorb vibrations during operation of said brushed electric motor <NUM>.

Preferably said respective longitudinal peripheral portions are provided with coupling means for mutually constrain said first filler element 20A and said third filler element 20C.

Besides preferably said first filler element 20A and said third filler element 20C and in particular also said respective peripheral longitudinal portions comprise a plurality of grooves for a corresponding plurality of tie rods which allow to close said brushed electric motor <NUM> and of which said brushed electric motor <NUM> is preferably provided.

Preferably said outer case <NUM> has a cylindrical shape, and also preferably said brushed electric motor <NUM> comprises a first closure element <NUM> and a second closure element <NUM> for close said outer case <NUM> and in particular for close two corresponding open axial ends of said outer case <NUM>; in particular said first closure element <NUM> and said second closure element <NUM> comprise corresponding annular gaskets which are positioned on a cylindrical outer surface of the same for have an high degree of protection from moisture and an high waterproofing degree so avoiding the entry of fluids, moisture and gas inside said brushed electric motor <NUM>.

Advantageously, this allows to further reduce the presence of moisture internally to said brushed electric motor <NUM> further reducing the "tracking" phenomenon, hence the deposition of conductive dusts on said printed circuit board <NUM>.

Preferably said second closure element <NUM> comprises a plurality of through holes for the insertion of said plurality of tie rods on which corresponding annular gaskets are inserted, for prevent the passage of water or other fluids or gases inside said brushed electric motor <NUM>, and also in particular said plurality of tie rods is screwed in corresponding blind holes made starting from an inner face of said first closure element <NUM> for hermetically close said brushed electric motor <NUM> so preventing the passage of fluids and in particular of water inside said brushed electric motor <NUM>.

Furthermore preferably said third filler element 20C comprises a groove which coupling with said first closure element <NUM> of said outer case <NUM> defines an inner chamber substantially waterproof and watertight, for further prevent the passage of water or fluids into a portion of said brushed electric motor <NUM> in which said printed circuit board <NUM> is housed.

Preferably said brushed electric motor <NUM> comprises said plurality of tie rods provided with corresponding gaskets.

In particular said brushed electric motor <NUM> comprises two permanent magnets and a rotor <NUM> comprising a plurality of windings or coils not shown in the figures, said two permanent magnets and said rotor <NUM> being inserted within said outer case <NUM>; in particular said rotor <NUM> is positioned between said two permanent magnets which are opposite to each other with respect to a symmetry and rotary axis of said rotor <NUM> internally to a cavity <NUM> with which said outer case <NUM> is provided, and also said rotor <NUM> includes two cylindrical ends, a first inner end <NUM> and a second outer end <NUM> which is inserted in a through hole formed in particular inside a first closure element <NUM> of said outer case <NUM> and which protrudes externally to the same for define a shaft of said brushed electric motor <NUM> for transmitting a rotary movement.

Also in particular said brushed electric motor <NUM> comprises preferably a ball bearing which supports said first inner end <NUM> of said rotor <NUM>, for allow the free rotation of said rotor <NUM>.

Preferably said polymeric based material is a polyamide based material, preferably nylon and in particular nylon <NUM>.

Preferably said brushed electric motor <NUM> is an electric motor for the handling of fluids, in particular of liquids, and also preferably said brushed electric motor <NUM> is used for pumping a coolant fluid or a combustion fluid, in particular chosen between a coolant fluid for refrigerators or heat pumps, a liquid or gaseous hydrocarbon, which are affected by the problem of a ignition of combustion or burst in presence of electrical discharges or sparks.

Preferably said brushed electric motor <NUM> comprises an electric power cable having in particular also an electric cable for the grounding of the metal parts and in particular connected to said preferably metallic outer case <NUM>.

According to another aspect of the present invention, it is provided a pump <NUM> for fluids, preferably of the membrane type, or of the rotary type with palettes or similar for the handling of liquids, in particular for coolant fluids or fuels, which comprises a brushed electric motor <NUM> having one or more of the previously described features and/or according one of the previously described variant of realization.

In particular said pump <NUM> for fluids is integrated with said brushed electric motor <NUM> for reduce the number of components and for limit the overall dimensions.

Preferably said pump <NUM> comprises a pumping head which is integrated with said brushed electric motor <NUM>, which is in particular integrated to an end of the same, and preferably which is connected to said first closure element <NUM> of said brushed electric motor <NUM>.

This advantageously allows to avoid the burst of said fluid which is pumped by said brushed electric motor <NUM>, while maintaining high electrical performance of the same.

Furthermore this allows to maintain a reduced weight and to minimize noise emissions, in the case where said pump <NUM> is used for a water purifier with reverse osmosis.

Preferably said first closure element <NUM> of said brushed electric motor <NUM> defines with said pumping head a second air chamber which allows to further reduce the passage of said fluid internally to said brushed electric motor <NUM>.

According to a further aspect of the present invention, it is provided a use of said pump <NUM> for fluids with one or more of the following applications: reverse osmosis plants, carbonator-refrigerator device, water dispensers, coffee machines, vending machines.

It must be understood that the present invention is also referred to each of the previous devices or plants, each of which comprises at least one pump <NUM> of the type previously described which comprises at least a brushed electric motor <NUM> with one or more of the previously described features and/or according to one of the previously described variants.

Claim 1:
Brushed electric motor (<NUM>) comprising an outer case (<NUM>), two brushes and a rotor (<NUM>) having a first axial end (<NUM>) and a second axial end (<NUM>) which is inserted within said outer case (<NUM>), said brushed electric motor (<NUM>) being in particular usable in environments with risk of fire or explosion or in presence of potentially explosive or flammable fluids and comprising at least one filler element (<NUM>) made with a polymer based material, said at least one filler element being positioned internally to said outer case (<NUM>) of said brushed electric motor (<NUM>), for minimizing the free volume within said brushed electric motor (<NUM>) and for allowing at the same time to maintain high power and high performance characteristics of said brushed electric motor (<NUM>), so minimizing the possibility of trigger of a burst or fire and characterized in that said brushed electric motor (<NUM>) further comprises a printed circuit board (<NUM>) which is inserted internally to said outer case (<NUM>), and wherein said at least one filler element (<NUM>) comprises a housing (<NUM>) for said printed circuit board (<NUM>) for preventing short circuits due to dusts produced by said two brushes and wherein said at least one filler element (<NUM>) comprises a first filler element (20A) and a second filler element (20B), wherein said first filler element (20A) comprises a first housing for a first face of said printed circuit board (<NUM>), and said second filler element (20B) comprises a second housing for a second face of said printed circuit board (<NUM>), for completely enclosing said electric circuit and at least a part of the components of said printed circuit board (<NUM>).