Patent Publication Number: US-6659736-B2

Title: Mounting arrangement for a hermetic compressor

Description:
This is a continuation of Application No. PCT/BR00/00011, filed Feb. 3, 2000. 
    
    
     FIELD OF THE INVENTION 
     The present invention refers to a mounting arrangement for the fixation and lower suspension of a hermetic compressor, usually employed in small refrigerating appliances, such as those existing in refrigerators, freezers, etc. 
     BACKGROUND OF THE INVENTION 
     There are well known in the prior art the hermetic compressors comprising a shell, which is formed of a steel plate at least in its lower half portion and in whose bottom are affixed external basic plates, for seating and affixing the shell onto a supporting structure. Also in the bottom of the shell are internally attached metallic pins for mounting the lower suspension of a motor-cylinder block assembly provided inside the shell. 
     In these known compressors, the mounting arrangement of the basic plates and metallic pins to the shell involves the use of welding (of the projection type) as a fixation means between said parts. In this constructive solution, the basic plates are externally welded to the bottom of the shell and then the shell receives internally, also by welding, the metallic pins into which will be posteriorly inserted the suspension means, such as the known suspension pins. 
     While this mounting arrangement of the prior art leads to a safe mutual fixation of the different parts, it has the inconveniences of a higher cost in the process of joining the component parts, the adjustment of a higher number of parameters of the involved machines in the welding process, less guarantee for maintaining the dimensional standards between the welded parts, a higher number of components to be aggregated to the compressor and a higher number of steps in the manufacturing process. 
     DISCLOSURE OF THE INVENTION 
     It is a general objective of the present invention to provide a mounting arrangement for the components considered herein in a hermetic compressor, allowing to simplify the productive process, reducing the number of components and the cost, and offering more guarantee for maintaining the dimensional standards of the product to be obtained. 
     The objective above is attained by providing a mounting arrangement for a hermetic compressor of the type comprising a shell formed of a metallic plate at least in its lower portion and affixing, externally, basic plates for seating and affixing the hermetic compressor on a supporting structure and, internally, pins for mounting the suspension. 
     According to the invention, the shell incorporates, inferiorly and in a single piece, for each basic plate, at least one tubular projection with the upper end opened to the inside of the shell and with the lower end closed, fitted and tightly retained inside a drawn recess of a respective basic plate, each tubular projection and each respective drawn recess being mechanically and jointly deformed, so that the lower end of the tubular projection presents an external contour substantially larger than the external contour of the remaining of the axial extension of said tubular projection, the internal contour of the drawn recess being defined by the external contour of the respective tubular projection along the extension thereof. 
     The mounting arrangement defined above allows to achieve, by means of a single fitting and mechanical shaping operation, the fixation of each basic plate to the shell, with the simultaneous formation of a usually cylindrical housing internally to each tubular projection and which is opened to the inside of the shell, and in whose inside may be fitted a respective pin of the lower suspension system of the motor-cylinder block assembly of the compressor. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention will be described below, with reference to the attached drawings, in which: 
     FIG. 1 is a vertical sectional view of the lower portion, or half-lower portion of a shell having a mounting arrangement of basic plates and internal metallic pins according to the prior art; 
     FIG. 2 is a similar view to that of the previous figure, but illustrating the mounting arrangement according to the invention; 
     FIG. 3 shows the detail Y enlarged from FIG. 2, illustrating the fixation arrangement between a basic plate and the shell; and 
     FIG. 4 is a similar view to that of the previous figure, but illustrating a suspension means construction. 
    
    
     BEST MODE OF CARRYING OUT THE INVENTION 
     As illustrated in the figures, the present mounting arrangement is used to affix, under a shell  10  of a hermetic compressor, a number of basic plates  20 , through which the compressor is seated and affixed to a fixation structure. 
     Shell  10  is only illustrated from its lower portion, which is formed of a steel plate adequately dimensioned and shaped so as to lodge therewithin, through non-illustrated suspension means, a motor-cylinder block assembly, which is not illustrated either. In FIGS. 1 and 2 is illustrated a lower portion of the shell  10  carrying, in a lateral window, a connector C provided with terminals internally and externally provided in relation to the shell and affixed to a body made of an electrically non-conductive material. 
     According to the prior art mounting arrangement, as illustrated in FIG. 1, the shell  10  incorporates lower drawn portions  11 , whose end wall defines, externally, a surface portion, which is usually orthogonal to the axis X of the shell  10  and against which is welded a respective basic plate  20  provided with at least one throughbore  21  for inserting fastening pins (not illustrated). 
     Also according to the prior art as illustrated in FIG. 1, the end wall of each lower drawn portion  11  defines, internally, a surface portion, which is usually parallel to the external surface portion and against which is welded the base of a respective metallic pin  30 , which is upwardly projected, in order to receive the suspension means of the motor-cylinder block assembly to be mounted inside the shell  10 . These suspension means usually comprise helical springs, which are inferiorly fitted into the metallic pins  30  and superiorly coupled to the cylinder block of the compressor. 
     The mounting arrangement of the present invention is illustrated in FIGS. 2,  3  and  4 . According to the invention, the shell  10  incorporates, inferiorly and in a single piece, more specifically from the end wall of its lower drawn portions  11 , according to the illustrated embodiment, a tubular projection  12  with the upper end  12   a  opened to the inside of the shell  10  and with the lower end  12   b  closed. 
     As illustrated, the tubular projections  12  are usually obtained by drawing and have their lower end  12   b  fitted and tightly retained inside a drawn recess  22  of a respective basic plate  20 , it being understood, however, that each basic plate may be coupled to one or more tubular projections. 
     Each pair of tubular projections  12  and respective drawn recess  22  are mechanically deformed, so that the lower end  12   b  of the tubular projection  12  presents an external contour substantially larger than the external contour of the remaining of the axial extension of said tubular projection  12 , whereby said lower end  12   b  takes the form of an enlarged head of usually circular contour. 
     The drawn recess  22  of the basic plate  20  is deformed together with the respective tubular projection  12  fitted therein, so that its internal contour be defined by the external contour of the respective tubular projection  12  along the extension of the latter. Thus, the drawn recess  22  of the basic plate  20  tightly embraces the lower end  12   b  of the respective tubular projection  12 , providing a solid and safe fixation of the basic plate  20  to the shell  10 , with no need of welding. 
     Considering that the basic plates  20  and the shell  10  may be led to a mutual initial fitting of the drawn recesses  22  in the tubular projection  12 , which are previously produced at the time in which the basic plates  20  and the shell  10  are stamped, the final fixation operation is achieved by the simple joint mechanical deformation of the fitted parts. 
     As illustrated in FIGS. 2 and 3, the mechanical deformation of the mutually fitted parts is made in order to maintain the internal transversal section of the tubular projections  12  with a circular or preferably constant polygonal form along the axial extension of said tubular projections  12 , allowing that inside the latter be directly fitted the suspension means of the motor-cylinder block assembly (FIG. 4) to be mounted inside the shell  10 . 
     As it may be observed, besides minimizing the welding operations and the previous relative positioning of the parts before the welding, the present arrangement allows to eliminate the usual metallic pins  30  of the prior art.