IMPROVEMENT IN THE STATORS FOR REFRIGERATION COMPRESSOR MOTORS

Abstract: Electric compressor for refrigerators comprising a stator stack, a plurality of slots, a respective plurality of electric windings inserted in said slots, a respective plurality of insulating layers provided between said slots and said electric windings, and a plurality of electric leads terminating said electric windings. An insulating block (1) is provided on the stator, to which the electric leads from said windings are brought directly, said block being provided with a plurality of recesses (4) adapted to accommodate respective connections of said leads from said windings with corresponding external power-supply leads (3). The block is provided with an appendix (6) capable of being inserted in the space between a pair of contiguous electric windings and arranged in contact with a surface of said stator stack: it comprises channels (9) oriented towards the respective recesses accommodating said connections and opening into the same recesses, said channels being open outwardly and adapted to lock in place said external power-supply leads (3).

Description: IMPROVEMENT IN THE STATORS FOR REFRIGERATION COMPRESSOR MOTORS DESCRIPTION The present invention refers to a particular form of arrangement provided to accomodate, attach and connect to each other the electric leads coming from the stator of an electnc motor and the respective electric wires that connect said leads with the external power-supply and control cπcuitry. Although reference to a statoi used in the electric motors of compressors foi refrigerating apparatuses is made in the following description foi reasons of illustrative convenience, it will anyway be appreciated that the present invention shall be understood to extend to also covei statoi s used in different applications, provided that they fall within the scope of the present invention as defined in the appended claims Electric compi essors for refrigeration appaiatuses are known in the art which use motoi s that in most cases are of the asynchronous single-phase type with the auxiliary winding in the cncuit only during the stalling period Motois of this type have thiee output leads (le. common, mam winding, secondary winding); said output leads are usually connected to said external wires by crimping oi welding each one of such leads to the respective wire, wherein the so obtained connection is then protected by the application of heat-shπnkmg tubes. The connection with the extenor of the sealed box occurs by means of a particular block which is attached to said sealed box and to which the external wires are connected. Such a manufacturing technique, however, has a number of practical drawbacks, the first one of which is given by the fact that the process of crimping, protecting with a heat-shrinking tube, and accomodation of the connechon in a niche to be found within the windings has to be carried out in a fully manual mannei , so that it is associated with high costs and a lowei quality owing to the electnc leads being so easily bioken Furthei moie, theie is practically no possibility foi automated mtei mediate testing to be earned out to check the so made electnc contacts foi continuity and this means a furthei falling off of the manufactui ing quality and a coi responding lnciease m rejects at the testing stations at the end of the production lines A connection block is known fiom the Italian utility model application no PN94U000040 to the same Applicant, which is adapted to be fiimly inserted in the spaces existing between two oi moie pans of electnc windings and adhenrig against one of the statoi sui faces Accoi ing to the cited utility model, said block is provided with a numbei of appendixes to moi e effectively fix said block to the windings, said block being furthei piovided with a pluiabty of notches, each one of them accomodates the tei mmal of a lead coming from the electric windings, a respective teimmal of an external power-supply wne and a I elated contact adapted to establish an electiical connection between the just cited iβspective teiminals It has howevei been found expei lmentally that in leal-life laige-scale industi ial pioduction piocesses such a solution, albeit effective and advantageous, still has a maigin foi fuithei improvement, in paiticulai in connection with the saving effects that can be obtained in the use of matenal, considenng that, in the cited solution, the external electric wires must be appropnately inserted in the block and it can be readily appreciated that such an operation has obviously a cost in terms of both material usage, due to the necessary extension of said wires, and additional working requirements, since the connection between a lead and the correspondmg extension wire must be made manually and the connection itself must then force-fitted to sit in the mass of the winding m order to ensure an adequate resistance to accidental pulls and jerks that may be imparted to the lead or wire. The solution is also known from the patent specification GB 2002969 to Danfoss which is based on the use of a terminal employed to serve as a connection means between the stator windings and the corresponding external leads Such a component part, howevei , is not capable of being assembled with automated methods; furthermore, its fastening proves quite uncertain and unreliable as far as both positioning and stability aie concerned, since the part is substantially retained only by said windings. It would therefore be desnable, and it is actually a mam puipose of the present invention, to provide a statoi foi lefπgeiation compiessoi motors which is capable of being manufactured in a highly automated, standardized marmei , enables the afoie described steps of manual piocessmg to be eliminated while ensuring a high inherent quality of the manufacturing techniques used, and is further capable of being manufactured and assembled in a cost-effective, convenient manner with the use of materials and techniques that are readily available in the art. Such an aim is reached in a compiessoi accoi ding to the description which is given below by way of non-limiting example with reference to the accompanying drawings, in which - Figures 1 and 2 are views from the top and the bottom, respectively, of a detail of the present invention, - Figure 3 is a vertical front view of the same detail shown in the Figures above, as seen from the outside; - Figure 4 is a vertical side cross-sectional view of the same detail as above; - Figure 5 is a vertical front view of the same detail shown in the Figures above, as seen from the opposite side with respect to Figure 3; - Figure 6 is a side view of the same component part; - Figure 7 is a vertical cross-sectional view of a stator according to the present invention, wherein the component part shown in the preceding Figures is sectioned as shown in Figure 4; - Figure 8 is a view from the outside and in the center line of a stator according to the present invention; - Figuie 9 is a view from the outside and on a plane which is orthogonal to the center line and situated at an appi oximately median height of the statoi stack according to the present invention The invention consists substantially of a small insulating block 1 to which both the electnc wires (not shown) coming from the windings 2 and the external power-supply wires 3 aie bi ought foi connection In ordei to fulfil the desned requn ements of simplicity and low cost, the statoi connections aie made in such a manner that the same leads coming from the respective windings aie not spliced with wne extensions, but extend themselves so as to leach said connectioon block 1 dnectly. In oidei to ensure the connection with the external wn es 3, the latter aie joined to the l espective winding leads by means of simple electric connection means, eg. by means of such a simple technique as crimping, which may also be of an unpiotected type for the leasons that will be explained furthei on In order to confer stability to the whole set of such connections in general, m said connection block 1 there is provided a plurality of distinct recesses 4 which are open on a side and separated from each other by appropriate partition baffles 5, and into which said joints between the winding leads and the external wires are fitted by force. It is therefore apparent that the presence of said partition baffles 5 can make it unnecessary for the above mentioned wire joints to be electrically insulated, since said wire jomts, after they have been inserted by force in their respective recesses, are automatically insulated by said baffles. In order to determine the position of the connection block, and make it stable, the same block is provided with an appendix 6 adapted to be fitted by force into the groove forming between a pair of contiguous windings plugging into the slots of the stator stack 7. In particular, if said appendix 7 is provided with an appropriately shaped and sized plane side 8, it can be inserted in said groove with its plane side adhering against the surface of the stator stack, so that the pressure sti esses applied by the contiguous windings on said appendix are capable of holding said block firmly in a stable position In an advantageous mannei , so as to favour a firm positioning of said electnc joints between winding leads and external powei -supply wires, there are piovided, on the edge of said recesses, respective channels 9 that are oriented so as to lead and open into the respective recesses. In the passages provided foi the respective external wπes to be inserted by piessuie fitting, said channels 9 are pi ovided with restrictions 1 1 , pi eferably in the shape of one-way restrictions as shown in Figure 3, so that the external wne, once it has been inserted thereinto, is no longer able to come out thereof if it happens to be sti essed by pulling forces, tensions or jerks applied to it up to a certain value A further improvement which is effective in ensuring greater stability to the positioning of said connection block, consists in providing the same block with two side tabs 1 1 , 12 that aie so shaped as to be able to substantially lay on the quasi-cylindncal surface of the windings, as this is shown m particular m Figures 1 , 2, 8 and 9 It will of course be appreciated that in a preferred manner said tabs are symmetrical with respect to a vertical plane passing through the center of the block, and are further positioned on the side of the block which is opposite to the side to which said appendix 6 is attached, so that the combined effect of forces and resistances exerted by the contiguous windings on both said appendix and said tabs is such as to cause the block to be held in a stable position In an advantageous mannei , so as to definitively consolidate the position of the block, the lattei is tied together with the windings by the threads 13 that are genei ally used to consolidate them Finally, in oidei to pi event said tying thieads fiom being able to slip off the external surface of the tabs, the latter are so made as to be piovided with leliefs 14 extending parallelly to the dnection of the thieads that surmount the same tabs, as this is shown in Figures 1 , 2 and 3 The presence of such leliefs along with the fact that said tying thieads a e in ti action ensures the definitive stabilization of the connection block in the desued position, as well as the immovability thei eof It will be appieciated that what has been descnbed and lllusti ated above with leference to the accompanying drawings has been given meiely by way of non-limiting example of the invention and that a number of valiants and modifications theieto may be intioduced without departing fiom the scope of the piesent invention

Claims: CLAIMS 1 Electric compressor, in particular for household-type refrigeration appbances comprising a statoi stack, a pluiabty of slots, a lespective plurabty of electnc windings (2) inserted in said slots, a respective plurabty of insulating layers ai ranged between said slots and said electnc windings a pluiabty of electnc leads terminating said electric windings, characterized in that - thei e is provided a small insulating block ( 1 ) which is firmly attached to said statoi and to which the electric leads coming from said windings ai nve directly, said smab block is piovided with a pluiality of recesses (4) adapted to accomodate lespective joints between the leads coming fiom said windings and coi l espond g external powei -supply wnes (3) said small block is furthei piovided with a single appendix (6) that is capable of being firmly mtioduced in the space available between a pan of contiguous electi IC windings and is a ranged in contact with a sui face of said statoi stack 2 Compiessoi accoi mg to claim 1 characterized in that theie are piovided channels (9) which aie partially open to the outside and aie adapted to letain said external powei -supply wnes, said channels being onented towatds the lespective lecesses (4) accomodatmg said joints so as to lead and open thereinto 3. Compressor according to any of the preceding claims, characterized in that said appendix is provided with a plane side (8) facing the body of the stator, against which it adheres at least partially. 4. Compressor according to any of the preceding claims, characterized in that said small block is provided with two side tabs (11 , 12) which are curved in the shape of an arch towards said windings and are adapted to lay upon a part of the outer surface thereof, said tabs being arranged at the opposite sides of the central body of said small block. 5. Compressor according to claim 4 , characterized in that said two side tabs are provided with outwards oriented rebefs (14) that aie adapted to engage the tying threads ( 13) wound around the coils of the windings 6. Compressor according to claim 2 or 3 , characterized in that said side tabs aie separated from the surface of said statoi stack, are substantially symmetrical and arranged on the side of said smab block which is opposite to the side on which said appendix (6) is in contact with said statoi stack

Inventors: LANG RUDOLPH, LANG, RUDOLPH
Applicants: LANG RUDOLPH, ZANUSSI ELETTROMECC, LANG, RUDOLPH, ZANUSSI ELETTROMECCANICA S.P.A.
Application year: 1997
Main classification: H02K3
IPC codes: H02K3