Hermetic terminal structure

Abstract: A hermetic terminal assembly (2) includes a body member (3) with a bottom portion (4), and a surrounding boundary or flange portion (6) with at least one current conducting pin (9) sealed in an opening (7) in the bottom portion (4) and an over-surface stratum (12) disposed in said body member (3), in close proximity facing relation with said bottom and boundary portions (4,6), and having stratum holding means (17) therefor.

Description: BACKGROUND OF THE INVENTION The present invention relates to hermetic terminal structural assemblies and more particularly to hermetic terminal assemblies which maximize over-surface distance. In the hermetic terminal assembly art, a number of construction arrangements have been utilized to prevent conductive pins, which pins serve to conduct current to isolated drive sources such as drive motors, disposed in hermetically sealed compressor housing shells, from electrically shorting to surrounding electrically conductive areas such as the aforementioned housing shells of compressors These past arrangements have included surrounding conductive pins with insulated over-surface collars or sleeves, such as the insulating extended sleeve arrangement 23 disclosed in U.S. Patent No. 4,584,433, issued to B. Bowsky, et al. on April 22, 1986 and the sleeve arrangement 17 disclosed in U.S. Patent No. 5,471,015, issued to F. Dieter Paterek, et. al. on November 28, 1995. These two aforementioned patents were further concerned with conductive pin fusing and with pin chemistry, respectively, attention being particularly directed to the aperture 38 of flattened neck portion 37 of pin 17 in U.S. Patent No. 4,584,333 and to the relative coefficients of expansion and softening point temperatures in U.S. Patent No. 5,471,015. A still somewhat different arrangement to minimize electrical shorting is disclosed in U.S. Patent No. 4, 984,973, issued to T. Itameri-Kinter et al. on January 15, 1991, wherein an electrically insulated cap member along with an electrically insulative adhesive provides an over-surface between a conductive pin and a metallic body member with gaps being provided between the cap and metallic body member and the pin and cap member allegedly to protect the over-surface from contaminants and possible unwanted current paths. Another prior art electrical terminal assembly is disclosed in U.S. Patent No. 4,609,774, issued to David M. LeMieux, et al. on September 02, 1986, wherein epoxy coatings are provided on the inner and outer surfaces of the terminal body wall and around the current conducting pins for enhancing electrical insulation between the pins and the body wall. A hermetic terminal assembly as defined in the precharacterizing portion of the independent claim 1 is disclosed in JP patent publication 62-271975 which discloses a stratum of insulating material facing the bottom and boundary portions of the terminal body member in close fitting proximity. In accordance with the present invention, a novel and unique hermetic terminal structure is provided which utilizes in part some of the features of past terminals and at the same time recognizes and avoids a number of previous structural limitations and problems, the present invention providing a unique and unobvious over-surface and pin construction for hermetic terminal assemblies which minimizes the possibilities of electrical shorting and, at the same time, which is straightforward and economical in manufacture, assembly and maintenance, requiring a minimum of operating steps and parts in manufacture, assembly and maintenance. Various other features of the present invention will become obvious to one skilled in the art upon reading the disclosure set forth herein. BRIEF SUMMARY OF THE INVENTION More particularly the present invention, as defined in the independent claim 1, provides a unique hermetic terminal assembly comprising: a body member including a generally flat bottom portion and a boundary or flange portion extending along the periphery of the bottom portion, the bottom portion having at least one opening therein; a current conducting pin extending through the bottom portion opening; a stratum of insulating material facing the bottom and boundary or flange portions of the body member in close fit proximity therewith, the stratum of insulating material having at least one opening corresponding with the opening of said bottom portion of the body member with the current conducting pin also extending therethrough; insulating pin sealing means extending between and sealing the periphery of said current conducting pin to the periphery of the opening in the bottom portion, and stratum holding means to maintain the stratum in proximate close fit facing position with respect to the bottom and the boundary or flange portions of the body member and to fill any spaces therebetween. In addition, the present invention provides novel arrangements for holding the stratum in dose fit relation with the body member portions and provides for stratum treatment and design which enhances the sealing of spaces therebetween, including the utilization of a fluid binding insulating adhesive which sets to hold the stratum firmly in close proximity to the body member with minimum space therebetween to prevent contaminant filling. Advantageous features of the terminal assembly are defined in the dependent claims. It is to be understood that various changes can be made by one skilled in the art in one or more of the several parts of the novel structural assembly disclosed herein without departing from the scope of the claims. BRIEF DESCRIPTION OF THE DRAWINGS Referring to the drawings which disclose an advantageous embodiment of the present invention and a modification thereof: Figure 1 is a schematic, cross-sectional view of a hermetic terminal assembly incorporating one embodiment of the present invention; and Figure 2 is a slightly enlarged, partially broken away, overall side view of a novel insulated stratum, a portion of which is incorporated as part of the hermetic terminal assembly of Figure 1 DETAILED DESCRIPTION OF THE INVENTION As can be seen in the drawings, the hermetic terminal assembly 2 includes a metallic cup-shaped body member 3 which is of a preselected configuration and which is formed from cold rolled steel material - all as is generally well known in the art. Cup-shaped body member 3 includes a generally flat bottom portion 4 and a boundary portion 6, here disclosed in the form of an integral flange or sidewall extending along and outwardly from the periphery of bottom portion 4 to surround the inner face of bottom portion 4. As also is known in the art, bottom portion 4 is provided with three substantially equally spaced and equally sized openings 7 (only one of which can be seen in Figure 1). Each opening 7 is defined by an interior wall surface of annular lip 8 which is an integral part of cup-shaped body member 3 and which extends outwardly from the inner face of bottom portion 4 to be within boundary or flange 6 of body member 3. A suitable electric current conductive pin 9 extends through each opening 7 with the peripheral, circumferential surface of each pin 9 being spaced in relation to the interior wall surface of annular lip 8 and each opening 7. An insulating glass seal 11 extends between the circumferential periphery of each pin 9 and the wall of the respective opening 7 and the interior wall surface of annular lip 8 to seal the pin 9 in body member 3 so as to be in insulated relation with the body member 3. in accordance with one feature of the present invention, an extended over-surface stratum 12 of wafer-like or disk form and of suitable insulating material capable of resisting temperatures as low as forty-nine (49) degrees Celsius (one-hundred-twenty (120) degrees Fahrenheit) to as high or higher than one-hundred-twenty-one (121) degrees Celsius (two-hundred-fifty (250) degrees Fahrenheit), and as high as approximately one-hundred-forty-nine (149) degrees Celsius (three-hundred (300) degrees Fahrenheit), advantageously of a filled polyphenyl sulfide is provided to fit in close proximity with the inner face of bottom portion 4 and the inner face of flange or sidewall 6 of cup-shaped body member 3. Stratum 12 can be of varying thickness, depending upon the environmental conditions involved, so as to be appropriately sized and configured in wafer form. The thickness of the stratum can be in the approximate range of one point zero one six (1.016) mm (point zero four (.04) inches) two point five four (2.54) mm (zero point one (0.1) inches) and advantageously one point two seven (1.27) mm (point zero five (0.5) inches). The wafer-like stratum 12 can include three openings 13, each opening correspondingly aligned with one of the openings 7 in the bottom portion 4 of body member 3 (only one such opening being disclosed in Figure 1 of the drawings). In this regard, it is to be noted that each stratum opening 13 is not only positioned to be correspondingly aligned with an opening 7 in the bottom portion 4 of cup-shaped body member 3, but the stratum opening 13 is further sized to engage in close proximity fit with an outer periphery of annular lip 8. As can be seen in Figure 1 of the drawings, the bottom face of wafer-like stratum 12 adjacent the inner face of bottom portion 4 is provided with a peripherally extending ridge 14 and, as can be seen in Figure 2, the peripheral outer face of wafer-like stratum 12 can be knurled to provide ridges 16, the irregularly created surface by ridges or knurls 16 presenting concomitant spaces to retain an insulating liquid epoxy adhesive 17 of preselected flow and setting properties which when injected will fill any spaces between stratum 12 and the facing portions of cup-shaped body member 3 of Figures 1 and 2. In this regard, it is further to be noted that in the inventive embodiment of Figures 1 and 2, wherein the stratum 12 is held in close proximity facing position with respect to the inner face of bottom portion 4, the outer face of annular lips 8 adjacent the corresponding openings and the inner face of boundary or flange portion 6, that stratum 12 can be provided with three female insulating crowns 18 (Figure 2). Each crown 18 accommodate passage of a current conducting pin 9 therethrough and engages in close proximity to the outer face surfaces of annular lip 8 and a glass seal 11. It is to be noted that any spaces between the close proximity engaging parts and crowns 18 are also filled with insulating liquid epoxy adhesive 17 - this further adhesively enhancing the maintenance of the stratum 12 in the close proximity facing position and minimizing the possibilities of the lodging of undesirable contaminants and electrical shorting

Claims: A hermetic terminal assembly comprising: a metallic body member (3) including a generally flat bottom portion (4) and a boundary portion (6) extending along the periphery of said bottom portion (4), said bottom portion (4) having at least one opening (7) therein; a current conducting pin (9) extending through said opening (7); a stratum of insulating material (12) facing said bottom and said boundary portions (4, 6) of said body member (3) in close fitting proximity therewith, said stratum (12) of insulating material having at least one opening (13) corresponding with said opening (7) of said bottom portion (4) of said body member (3) with said current conducting pin (9) also extending therethrough; insulating pin sealing means (11) extending between and sealing the periphery of said current conducting pin (9) to the periphery of said opening (7) in said bottom portion (4); characterized by stratum holding means to maintain said stratum (12) in facing close fitting proximity position with respect to said bottom and said boundary portions (4, 6) of said body member (3); said stratum holding means comprising an insulating fluid binding adhesive (17) which sets between said stratum (12) and said body member portions (4, 6) filling spaces therebetween. The hermetic terminal assembly of claim 1, characterized in that said stratum (12) of insulating material is capable of resisting temperatures as low as forty-nine (49) degrees Celsius (one-hundred-twenty (120) degrees Fahrenheit) and as high as one-hundred-twenty-one (121) degrees Celsius (two-hundred-fifty (250) degrees Fahrenheit). The hermetic terminal assembly of claim 1, characterized in that said stratum (12) of insulating material has a thickness in the range of one point zero one six (1.016) mm (point zero four (0.04) inches) to two point five four (2.54) mm (zero point one (0.1) inches). The hermetic terminal assembly of claim 1, characterized in that said stratum (12) of insulating material has a thickness advantageously of one point two seven (1.27) mm (point zero five (0.05) inches). The hermetic terminal assembly of claim 1, characterized in that at least one of said close proximity facing surfaces of said stratum (12) and said body member portions (4, 6) includes retaining ridges (14, 16). The hermetic terminal assembly of claim 1, characterized in that said body member (3) is cup-shaped to include said bottom portion (4) in flat configuration with said boundary portion (6) being in the form of an outwardly extending flange to form said boundary portion (6). The hermetic terminal assembly of claim 1, characterized in that said insulating pin sealing means (11) is glass. The hermetic terminal assembly of claim 1, characterized in that said opening (7) in said body member (3) includes an annular lip (8) with said insulating pin sealing means (11) extending between the periphery of said conducting pin (9) and said annular lip (8). The hermetic terminal assembly of claim 1, characterized in that stratum (12) is a filled plastic material. The hermetic terminal assembly of claim 1, characterized in that said stratum (12) is a wafer of polyphenyl sulphide. The hermetic terminal assembly of claim 1, characterized in that said adhesive (17) is a liquid epoxy adhesive of preselected flow and setting proportions. The hermetic terminal assembly of claim 1, characterized in that said opening (7) in said bottom portion (4) includes an annular lip (8) with said insulating pin sealing means (11) extending between the periphery of said conducting pin (9) and said annular lip (8), said stratum (12) including a raised crown portion (18) to surroundingly extend thereover. The hermetic terminal assembly of claim 1, characterized in that said stratum (12) of insulating material facing said bottom portion (4) of said body member (3) has a peripheral ridge (14) to form a retaining wall. The hermetic terminal assembly of claim 1, characterized in that said stratum (12) of insulating material facing said boundary portion (6) of said body member (3) has a preselectively knurled surface forming retaining ridges (16) thereon. The hermetic terminal assembly of claim 1, characterized in that said bottom portion (4) and said stratum (12) of insulting material includes three corresponding pairs of spaced openings (7, 13), and, three spaced current conducting pins (9) passing respectively therethrough.

Inventors: HONKOMP GLENN A, QUADIR TARIQ, HONKOMP, GLENN A., QUADIR, TARIQ
Applicants: EMERSON ELECTRIC CO, EMERSON ELECTRIC CO.
Application year: 1999
Main classification: H01B17
IPC codes: H01B17, H01R9