WO2014079983A1

WO2014079983A1 - Electric motorized vibrator

Info

Publication number: WO2014079983A1
Application number: PCT/EP2013/074508
Authority: WO
Inventors: Carlo SILINGARDI
Original assignee: ITALVIBRAS - GIORGIO SILINGARDI - SpA
Current assignee: ITALVIBRAS - GIORGIO SILINGARDI - SpA
Priority date: 2012-11-26
Filing date: 2013-11-22
Publication date: 2014-05-30
Anticipated expiration: 2015-05-26
Also published as: EP2922642B1; ITMO20120288A1; EP2922642A1

Abstract

An electric motorized vibrator (1), comprising a casing (2) provided with a first through hole (3) for the insertion of a first shaft (5) that is arranged with the corresponding mutually opposite ends protruding from the casing and associated with respective first sets of eccentric masses and first electric motor means (7) interposed between the first hole (3) and the first shaft (5) for the rotary actuation of the first shaft about its own longitudinal axis (A1); the casing (2) comprising at least one second through hole (4) for the insertion of at least one second shaft (6) that is arranged with the corresponding mutually opposite ends protruding from the casing and associated with respective second sets of eccentric masses, second motor means (8) of the electric type being further provided and interposed between the second hole (4) and the second shaft (6) for the rotary actuation of the second shaft about its own longitudinal axis (A2).

Description

ELECTRIC MOTORIZED VIBRATOR

The present invention relates to an electric motorized vibrator.

Electric motorized vibrators are known, which are generally used for the generation and transmission of controlled vibrations to vibrating machines, such as sieves and other apparatuses for transporting various types of products.

Such electric motorized vibrators are essentially constituted by a casing that supports, rotatably about its own longitudinal axis, a shaft that has mutually opposite ends protruding from the casing and coupled to corresponding sets of eccentric masses, and which is rotationally actuated about its own longitudinal axis by an electric motor. Such electric motor is composed of an annular rotor element, which is keyed on the central portion of the shaft accommodated inside the casing, and an annular stator element, which is arranged outside the latter and is also accommodated inside the casing, which are mutually electromagnetically coupled.

The aforementioned casing consists of a single piece, generally obtained by casting iron, alloys of aluminum or of steel, which comprises a through hole for the insertion of the shaft, along which an annular seat is defined in which the stator element is fitted by interference following a thermal deformation applied to the casing.

Such casing furthermore has a space for a terminal board for accommodating elements for electrical connection of the stator to a source of electricity.

The motorized vibrator is completed by a pair of protection elements which are applied to the casing to cover the ends of the shaft and the corresponding sets of eccentric masses.

For some particular applications, two electric motorized vibrators of the type described above are installed on the vibrating machine, arranged side by side in parallel and conveniently synchronized in operation.

In this manner, for example, by making the two motorized vibrators rotate in opposite directions it is possible to obtain unidirectional vibrations at right angles to the plane defined by two longitudinal axes Al and A2 of the shafts of the two motorized vibrators if the eccentric masses are equal, or in a variable direction with a resulting elliptical centrifugal force vector if the eccentric masses are different.

For such installations, usually the motorized vibrators are fixed on a rigid support structure, such as a beam, a tube or the like, which is interposed between a pair of side walls on the frame of the vibrating machine and connected to those walls.

The efficacious operation of these applications is linked to the correct synchronization of the two motorized vibrators. Such synchronization depends not only on the characteristics of the motorized vibrators themselves, but also on the mechanical rigidity of the vibrating machine in its entirety, as well as on the rigidity of the supporting structure of the motorized vibrators and of the mechanical connection of said structure to the vibrating machine.

Therefore, in order to achieve the synchronization of the two motorized vibrators it is essential to ensure the highest possible rigidity of the supporting structure and of the vibrating machine, which must conveniently be built and strengthened in order to support the weight of the supporting structure as well.

Furthermore, at startup time, before synchronization, which normally occurs in a few seconds or fractions of a second, the motorized vibrators arranged side by side, precisely because they are not yet synchronized, produce "anomalous" stresses, both rotary and torsional, which are transmitted to the supporting structure. If the supporting structure is not sufficiently rigid, these stresses can damage the vibrating machine or hinder the synchronization of the vibrators. In both cases, anomalous stresses occur on the machine which, if they persist, can lead to the fatigue failure of the vibrating machine or of parts of it. Keeping the center distance between the two vibrators contained can simplify the operation of the machine, by minimizing the structural reinforcements needed for giving the machine the required rigidity.

Therefore, in order not to penalize the dimensioning of the vibrating machine it is necessary to keep such center distance as contained as possible.

It follows from this that these applications of conventional electric motorized vibrators are not devoid of drawbacks among which is the fact that they require a design of the supporting structure and of the entire vibrating machine which is fit for purpose and which makes it possible to ensure sufficient characteristics of mechanical rigidity, with consequent increase in weight and in costs.

Such aspect also influences the choice of motorized vibrators, which must be larger as the overall weight of the vibrating machine increases, greatly adding to the overall cost.

Furthermore, the minimum center distance between the two motorized vibrators cannot be less than values determined by the encumbrances of the casings of the individual motorized vibrators, or less than a sufficient safety distance between the two, which is necessary in order to prevent accidental impacts and to permit access for maintenance operations.

It must also be considered that the operation of the vibrating machine is affected by the distance between the rotation axes of the two motorized vibrators and the center of gravity of the machine itself, with the behavior improving at the cost of a reduction in such distance.

The aim of the present invention is to eliminate the above-mentioned drawbacks of the background art by providing an electric motorized vibrator that makes it possible to reduce, or even eliminate, the transmission of needless stresses to the vibrating machine, and hence the risk of failure to synchronize the two motorized vibrators, thus simplifying the design thereof and reducing the weight and implementation costs thereof. Within this aim, an object of the present invention is to provide an electric motorized vibrator in which the center distance between the rotating shafts is minimized.

Another object of the present invention is to provide an electric motorized vibrator that enables an installation that is such that a reduction of the distance between the rotation axes of the motorized vibrators and the center of gravity of the vibrating machine is achieved.

Another object of the present invention is to provide an electric motorized vibrator that is easy to install on vibrating machines.

Last but not least, another object of the present invention is to provide an electric motorized vibrator that has simple structure, that is easy and practical to implement, safe to use and effective in operation, and relatively low-cost.

This aim and these objects are all achieved by the present electric motorized vibrator, comprising a casing provided with a first through hole for the insertion of a first shaft that is arranged with the corresponding mutually opposite ends protruding from said casing and associated with respective first sets of eccentric masses and first electric motor means interposed between said first hole and said first shaft for the rotary actuation of said first shaft about its own longitudinal axis, characterized in that said casing comprises at least one second through hole for the insertion of at least one second shaft that is arranged with the corresponding mutually opposite ends protruding from said casing and associated with respective second sets of eccentric masses, second motor means of the electric type being further provided and interposed between said second hole and said second shaft for the rotary actuation of said second shaft about its own longitudinal axis.

Further characteristics and advantages of the present invention will become more apparent from the detailed description of a preferred, but not exclusive, embodiment of an electric motorized vibrator, which is illustrated for the purposes of non-limiting example in the accompanying drawings wherein:

Figure 1 is a partially exploded axonometric schematic view of an electric motorized vibrator according to the invention;

Figure 2 is an exploded perspective schematic view of the motorized vibrator of Figure 1 ;

Figure 3 is a schematic and partially sectional plan view from above of the electric motorized vibrator according to the invention;

Figure 4 is a schematic perspective view of the casing of the electric motorized vibrator according to the invention;

Figure 5 is a cross-sectional schematic perspective view of the casing in Figure 4, cut away along a plane perpendicular to the rotation axes of the shafts that support the eccentric masses;

Figure 6 is a schematic perspective view showing the motorized vibrator according to the invention fitted on the frame of a vibrating machine.

With particular reference to the figures, the reference numeral 1 generally designates an electric motorized vibrator.

The motorized vibrator 1 comprises a casing 2 which has a first through hole 3 and at least one second through hole 4 in which the following are inserted, respectively: a first shaft 5 and at least one corresponding second shaft 6 which are arranged with the mutually opposite ends protruding from the casing 2 and associated with respective sets of eccentric masses, not shown since they are conventional.

The motorized vibrator 1 is furthermore provided with first and second electric motor means, respectively 7 and 8, which are interposed between the first hole 3 and the first shaft 5 and between the second hole 4 and the second shaft 6 for the rotary actuation of the shafts themselves about the corresponding longitudinal axes A 1 and A2.

It should be noted that the first and the second motor means, respectively, 7 and 8, are independent of each other both structurally and functionally.

Preferably, the first shaft 5 and the second shaft 6 are arranged with the corresponding longitudinal axes Al and A2 substantially mutually parallel and, thus, also the corresponding first hole 3 and second hole 4 extend in parallel along the casing 2. According to this embodiment, the motorized vibrator 1 is particularly adapted for applications requiring the generation of unidirectional vibrations or of vibrations with an elliptical centrifugal force vector.

However, the possibility is not ruled out of having different possible configurations of the motorized vibrator according to the invention in which the first and second shafts can have different orientations, i.e. in which there are two or more second holes in which respective second shafts are inserted which support eccentric masses and corresponding second electric motor means.

The motorized vibrator 1 furthermore has bearings which are accommodated in the casing 2 and which support the shafts 5 and 6 in rotation, but these are not shown since they are conventional.

More precisely, the casing 2 is a single piece, for example obtained by casting iron or metallic alloys, and is constituted, essentially, by a jacket 9 with a cross-section similar to an ellipse and flanged at the opposite ends, the internal cavity of which is divided by a longitudinal partition 10 for separating the first and second holes, respectively 3 and 4.

In this manner the center distance between the first and the second shaft, respectively 5 and 6, can be reduced with respect to conventional applications of two motorized vibrators arranged side by side in parallel.

Furthermore, the fact that the two shafts 5 and 6 rotate while being supported by a single casing 2 brings with it a substantial cancellation of the needless stresses generated by the individual shafts, which are thus not transmitted to the vibrating machine to which the motorized vibrator 1 is applied.

Each of the motor means 7 and 8 comprises a corresponding annular stator element 11 and 12 that is accommodated within the first or second hole 3 or 4 and a respective rotor element 12 and 14 that is keyed on the first or second shaft 5 or 6, which are mutually electromagnetically coupled.

According to a conventional method, each stator element 11 or 12 is inserted into the corresponding hole 3 or 4 and is locked in it by interference as a consequence of the deformation of the casing 2 which is achieved by heating thereof.

Each stator element 11 or 12 is positioned in a central region of the corresponding hole 3 or 4 defined between the jacket 9 and the partition 10 which has a reduced cross-section.

Each rotor element 13 or 14 is directly keyed on the corresponding shaft 5 or 6 at the midpoint according to a method known to the person skilled in the art.

The axial coupling of the shafts 5 and 6 to the casing 2 is ensured by adapted mechanical connection means by obstruction, which are not shown in detail.

The casing 2 has a single space 15 for a terminal board, which is defined on the jacket 9 in one of the regions of connection with the partition 10, for accommodating elements for the electrical connection of the stator elements 11 and 12 to an electric power source, and is closed by a cover, not shown.

The rear wall of the space 15 is provided with a pair of openings 16 which are connected to the inside of the holes 3 and 4 through passages 17 defined in the partition 10.

Provided in the side wall that delimits the space 15 are through holes 18 for the passage of electric connecting cables.

Alternatively, the casing 2 can have separate terminal board spaces which are connected to each hole 3 and 4, for accommodating the electrical connection elements of the corresponding stator element 11 or 12. In this case the partition 10 can be continuous, i.e. without the aforementioned openings 17, and the two holes 3 and 4 can be unconnected.

The motorized vibrator 1 has, lastly, a pair of protective structural elements 19 which are associated with the casing 2 on opposite sides so as to cover the protruding ends of the shafts 5 and 6 and the corresponding sets of eccentric masses and the connection to the supporting frame T of a vibrating machine, which is not shown in detail.

Figure 6 shows a possible installation configuration of the motorized vibrator 1 provided with protective structural elements 19 which are associated with the frame T.

Advantageously, each protective structural element 19 is constituted by a respective tubular body that has mutually opposite flanged ends for connection to the casing 2 and to the frame T.

More precisely, each protective structural element 19 has respective flanges 20 and 21 at its mutually opposite ends, for joining with the casing 2, which is also flanged, by way of first threaded connection elements 22, and with a pair of mutually opposite walls of the frame T by way of second threaded connection elements 23.

In this manner the motorized vibrator 1 can be directly connected to the supporting frame of the vibrating machine without requiring supplementary supporting elements (beams, tubes, etc.) which complicate its design, by increasing the overall weight and implementation costs thereof.

The absence of such supplementary supporting elements, substituted by the protective structural elements 19, makes it possible to bring the rotation axes Al and A2 closer to the center of gravity of the vibrating machine.

Furthermore, this system of mounting the motorized vibrator 1 on the vibrating machine enables a direct, and hence more efficient, transmission of the vibrations.

The operation of the present invention is very similar to that of conventional motorized vibrators, but with the performance and the possibilities for application optimized.

In practice it has been found that the invention as described achieves the intended aim and objects and, in particular, attention is drawn to the fact that the motorized vibrator according to the invention makes it possible to contain, or even cancel out, the transmission of unwanted stresses to the vibrating machine, thus simplifying its design and reducing the weight and overall cost thereof.

Moreover, the motorized vibrator according to the invention makes it possible to minimize the center distance between the rotating shafts, thus optimizing the synchronization step and, thus, simplifying the construction of the vibrating machine to which it is applied.

Last but not least, the motorized vibrator according to the invention is easy to install on the vibrating machine with which it is intended to be used and makes it possible to achieve a reduction of the distance between the rotation axes of the motorized vibrator and the center of gravity of the machine itself, further improving the efficiency of the application.

The invention, thus conceived, is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

Moreover, all the details may be substituted by other, technically equivalent elements.

In practice the materials employed, as well as the contingent dimensions and shapes, may be any according to requirements without for this reason departing from the scope of protection claimed herein.

The disclosures in Italian Patent Application No. MO2012A000288 from which this application claims priority are incorporated herein by reference. Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly, such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs.

Claims

1. An electric motorized vibrator (1), comprising a casing (2) provided with a first through hole (3) for the insertion of a first shaft (5) that is arranged with the corresponding mutually opposite ends protruding from said casing and associated with respective first sets of eccentric masses and first electric motor means (7) interposed between said first hole (3) and said first shaft (5) for the rotary actuation of said first shaft about its own longitudinal axis (Al), characterized in that said casing (2) comprises at least one second through hole (4) for the insertion of at least one second shaft (6) that is arranged with the corresponding mutually opposite ends protruding from said casing and associated with respective second sets of eccentric masses, second motor means (8) of the electric type being further provided and interposed between said second hole (4) and said second shaft (6) for the rotary actuation of said second shaft about its own longitudinal axis (A2).

2. The motorized vibrator (1) according to claim 1, characterized in that said first and second shafts (5, 6) are arranged so that their respective longitudinal axes (Al, A2) are substantially mutually parallel.

3. The motorized vibrator (1) according to claim 1 or 2, characterized in that said casing (2) comprises a longitudinal partition (10) for separating said first hole (3) and said at least one second hole (4).

4. The motorized vibrator (1) according to one or more of the preceding claims, characterized in that each one of said first and second motor means (7, 8) comprises a respective stator element (11, 12) that is accommodated within the first or second hole (3, 4) and a respective rotor element (13, 14) that is keyed on a central portion of said first or said second shaft (5, 6), which are mutually electromagnetically coupled.

5. The motorized vibrator (1) according to claim 4, characterized in that said casing (2) comprises at least one compartment (15) for accommodating elements for the electrical connection of the stator elements (11, 12) of said first and second motor means (7, 8) to an electric power source.

6. The motorized vibrator (1) according to one or more of the preceding claims, characterized in that it comprises a pair of protective structural elements (19) which are associated with said casing (2) on opposite sides in order to cover the protruding ends of said first and second shafts (5, 6) and of the corresponding first and second sets of eccentric masses and in order to directly connect said motorized vibrator to the supporting frame (T) of a vibrating machine.

7. The motorized vibrator (1) according to claim 6, characterized in that each one of said protective structural elements (19) is constituted by a tubular body that has mutually opposite flanged ends (20, 21) for connection to said casing (2) and to said frame (T).

8. The motorized vibrator (1) according to claim 6 or 7, characterized in that the end (21) of each one of said protective structural elements (19) faces the direction opposite to said casing (2) directly associable with said frame (T).