Patent ID: 12191734

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described below based on embodiments shown inFIGS.1to6.

FIG.1shows a rotor (1) applied in cylindrical pole type rotatory electric machines, composed simply of a shaft (2) and a pack of plates (3), also called the rotor package, in which the coils (4) of the conductive element are inserted.FIG.1further illustrates, in cross-section, an axial support (10) of the radial retaining cover (11) of the rotor. It is understood that a person skilled in the art would have no difficulty in understanding that the rotor may include other components not described herein, so that only the elements relevant to the understanding of the present invention will be described and presented.

The rotor package (3) can be divided into three portions: a first region where the coils are inserted into slots and remain internal to the pack of plates, and two end regions, more commonly called rotor coil heads, where the ends of the coils (4) are external to the pack of plates (3). The coils (4) when grouped in the same slot are called turns.

The rotor according to the present invention further comprises at least one axial retaining device (5) positioned externally to the coil head, more specifically between the last turn of the coil head and an axial support (10) of the rotor radial retaining cover1.

The rotor shown inFIG.1has four poles. Thus, in the illustrated embodiment, the rotor comprises eight axial retaining devices (5), one on each rotor pole (1), four at one end of the rotor and four at the opposite end of the rotor.

FIG.2shows a perspective view of the radial retaining device.

The axial retaining device (5) comprises a substantially flat base (6) where at least one resilient element (7) is arranged.

As best illustrated inFIG.3, the substantially flat base (6) has at least one niche (8) for receiving the at least one resilient element (7) and at least two corresponding indentations (9a,9b) which are used as anchoring points for lashing the axial retaining device (5) with bandage tapes to the coil head.

In this context, the lashing is preferably performed against the outermost turn of coil, making a complete turn along the entire axial extension of the turn. That is, the bandage tape is arranged in such a way as to “embrace” the height of the outermost turn in that portion where it is planned. The bandage material used is normally a pre-impregnated fiberglass tape composed with polyester resin, but any insulating material applied to electric machines can be used, as long as the thermal class temperature of the electric machine is observed.

Thus, the two indentations (9a,9b) are arranged on opposite edges of the substantially flat base (6) in corresponding positions on opposite edges.

In the preferred embodiment of the present invention shown in the figures, the axial retaining device (5) comprises a substantially flat base (6) has four spaced oval niches (8) for receiving four oval resilient elements (7).

In the preferred embodiment of the present invention shown in the figures, the axial retaining device (5) comprises a substantially flat base (6) that has four spaced oval niches (8) for receiving four oval resilient elements (7), so that the lashing bandage tape is arranged in that gap. If necessary, the lashing can be performed by turns of the tape, the folded portions of the tape being overlapped in the gap.

In this sense, it should be noted that the axial retaining device (5) according to the present invention can comprise a different amount of resilient elements (7), and the resilient elements can have different formats. For example, in one embodiment of the present invention, the axial retaining device may comprise two spaced apart oblong resilient elements, the spacing between the elements forming the lashing gap. In another embodiment, the axial retaining device may comprise two rows of circular resilient elements whose spacing between the rows forms the lashing gap.

As best illustrated inFIG.3, in one embodiment of the present invention, the substantially flat base (6) is formed from an insulating composite material, such as an epoxy resin-impregnated fiberglass laminate, the rolling direction of the material being the lashing direction of the device to the coil head, that is, parallel to the faces of the base.

In the case of this lamination, the layers of the composite material are subjected to compression against the face of the coil head, which is the ideal direction of operation for composite materials such as those made of fiberglass, which generally does not have good tensile strength.

The resilient elements (7) are preferably made of silicone and vulcanized in the niches (8) of the substantially flat base (6).

Thus, as best illustrated inFIGS.3and4, in an embodiment of the present invention, each of the niches (8) has a central recess (8a) that receives a corresponding shoulder (7a) of the resilient element (7). This configuration helps the process of fixing the resilient elements.

The axial retaining device (5) according to the present invention is positioned over the most extreme portion of the coil head (4), so that the substantially flat base (6) is positioned over the last turn of the head coil (4), with the face having the resilient elements (7) facing away from the coil head.

FIG.6shows a sectional view taken from the AA section shown inFIG.5. As shown inFIG.6and as known by those skilled in the art, the rotor is closed radially by a cover (11), preferably forged in steel, which is fixed to the rotor end by a support disc (10). Cover (11) and support disc (10) are commonly referred to as the “steel cover assembly”.

Thus, after closing the rotor, the resilient elements (7) of the axial retaining device (5) are in contact with the support disc (10), so that the axial movement of the coil head causes the device to be pressed between the coil head and the support disc (10). With the pressure against the device, the compression of the resilient material of the resilient elements (7) occurs.

This compression of the resilient elements (7) results in a control of the intensity of the axial displacement, so that the axial retaining device (5) provides a controlled freedom for the displacement of the coil head during its axial expansion.

Thus, the resilient elements (7) provide sufficient compressibility to absorb the axial expansion of the coil head (4), controlling the axial displacement of the coil head.

Having described examples of preferred embodiments of the present invention, it should be understood that the scope of the present invention encompasses other possible variations of the inventive concept described, being limited only by the content of the appended claims, including the possible equivalents.