Claims:We claim:
1. A regulator (106) and Slip-Ring End (SRE) frame (102) assembly for an electrical machine, said assembly comprising:
a cover (110) for said regulator (106),
characterized in said assembly,
said regulator (106) fastened to said SRE frame (102) by at least one first fastener (108), said first fastener (108) comprising an inner thread (107) at one end, and
said cover (110) fastened to said regulator (106) by fixing at least one second fastener (112) in said inner thread (107) of said at least one first fastener (108).
2. The regulator (106) and SRE frame (102) assembly as claimed in claim 1, wherein said cover (110) is sealed to the SRE frame (102) using a gasket (104).
3. The regulator (106) and SRE frame (102) assembly as claimed in claim 1, wherein said first fastener (108) comprises a stud.
4. The regulator (106) and SRE frame (102) assembly as claimed in claim 1, wherein said second fastener (112) comprises a screw.
5. A method for assembling a regulator (106) and a Slip-Ring End (SRE) frame (102) of an electrical machine, said method comprising the steps of:
? fitting said regulator (106) on said SRE frame (102) using at least one first fastener (108), said first fastener (108) comprising an inner thread (107); and
? fitting a cover (110) on said regulator (106) with at least one second fastener (112) into said inner thread 107.

, Description:Field of the invention:
[0001] The present disclosure relates to an assembly of a slip ring end frame with a regulator, for an electric machine and specifically for an alternator.

Background of the invention:
[0002] Loosening of regulator mounting screw is a regular problem in electrical machines such as alternator. Such screw loosening leads to alternator failure. In general, the failure occurs when the alternator is subjected to very high temperatures such as during a painting process. In the existing design, the regulator via cover with gasket sealing is fastened to Slip-Ring End (SRE) frame of the alternator for ground path. The fastening is done by screw with defined torque value to ensure the bus bar of the regulator in in firm contact with SRE frame for good ground return path of current.
[0003] A regulator structure generally comprises a regulator, a brush holder, a ground bus-bar, a gasket and a cover with screw. The gasket is used for water / dust sealing purposes. The regulator structure is fastened onto the SRE frame or cover, along with regulator cover with gasket sealing. During the painting process, the temperature goes around 150°C or more. At this high temperature, the rubber gasket gets softened, which leads to loosening of the regulator screw. Thus leading to circuit breakage of return path of bus bar from grounding to SRE frame, and the alternator fails to function.
[0004] Hence, there is a need for an assembly to mitigate the loosening of the regulator screw/fastener and thereby prevent failure of alternator.

Brief description of the accompanying drawings:
[0005] An embodiment of the disclosure is described with reference to the following accompanying drawings,
[0006] Fig. 1 illustrates an exploded view of regulator and Slip-Ring End (SRE) frame assembly, according to an embodiment of the present invention;
[0007] Fig. 2 illustrates a side cross-sectional view of the regulator and SRE frame assembly, according to an embodiment of the present invention, and
[0008] Fig. 3 illustrates a method of assembling the regulator and SRE frame, according to the present invention.
Detailed description of the embodiments:
[0009] Fig. 1 illustrates an exploded view of regulator and Slip-Ring End (SRE) frame assembly, according to an embodiment of the present invention. The regulator 106 and Slip-Ring End (SRE) frame 102 assembly for an electrical machine comprises a cover 110 for the regulator 106. The regulator 106 comprises other components comprising a brush holder, a ground bus-bar, a gasket 104 and the like. The regulator 106 along with other components is fastened to the SRE frame 102 by at least one first fastener 108. The first fastener 108 comprises an inner/internal thread 107 at one end. The cover 110 is fastened to the regulator 106 by fixing the at least one second fastener 112 in the inner thread 107 of the at least one first fastener 108. In the present invention each of the first fastener 108 and the second fastener 112 are used.
[0010] Fig. 2 illustrates a side cross-sectional view of the regulator and SRE frame assembly, according to an embodiment of the present invention. The cross-sectional view is shown for one of the assembling points. The cover 110 is fastened to the regulator 106 and is sealed to the SRE frame 102 using the gasket 104. The first fastener 108 comprises a stud. The second fastener 112 comprises a screw.
[0011] The SRE frame 102 as a sub-function accommodates the regulator 106 and has a provision for current return-path and heat dissipation. The bus bar of the regulator 106 facilitates the return ground path for current via SRE frame 102. The regulator 106 is directly fastened to SRE frame 102 by the first fastener 108 with defined torque values. Thus ensuring the bus bar of the regulator 106 to be in firm contact with the SRE frame 102 for good ground return path of current in all circumstance of temperature variation and vibration as per specification. The first fastener 108 also comprises an internal thread 107 to accommodate the at least one second fastener 112. The cover 110 with rubber gasket 104 is fastened on top of the first fastener 108. The assembly ensures the good sealing function achieved by squeezing of the seal and avoids water/dust ingress and meets the specification.
[0012] Fig. 3 illustrates a method of assembling the regulator and SRE frame, according to the present invention. The method comprises, a step 302 comprising fitting the regulator 106 on the SRE frame 102 using at least one first fastener 108. The first fastener 108 comprising inner threads 107. A next step 304 comprises fitting a cover 110 on the regulator 106 with at least one second fastener 112 into the inner thread 107 of the first fastener 108. The cover 110 is fastened to the regulator 106 and is sealed to the SRE frame 102 using the gasket 104. The first fastener 108 comprises a stud. The second fastener 112 comprises a screw.
[0013] According to an embodiment of the present invention, the regulator 106 along with the other components are directly fastened to SRE frame 102 by the first fastener 108 with defined torque. The bus bar ensures the regulator 106 is in firm contact with the SRE frame 102 for good return path of current (ground). The cover 110 with rubber gasket 104 sealing is fastened on top of the first fastener 108, thereby avoiding the cover 110 in-between the regulator 106 and the SRE frame 102 and thus preventing loosening of torque due to change in property of the rubber gasket 104 seal at high temperature. Any change in ambient temperature does not affect the regulator 106 mounting screw torque value. The present invention provides secure fastening of regulator 106 with SRE frame 102. Alternatively, an intermediate stud fastening for regulator 106 and SRE frame 102 is provided. The electrical machine comprises but not limited to the alternator.
[0014] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.