Scroll compressor

Abstract: Object: To provide a simple and cheap fitting structure by which a sealed terminal (51) is easily fitted within a fitting hole (53) and getting out thereof can be prevented. Construction: To insert a sealed terminal (51) into a fitting hole (53) and to pressingly insert a push nut (57) having a plurality of nails (57a) into the fitting hole (53), thereby to fit a sealed terminal (51) within a fitting hole (53).

Description: BACKGROUND OF THE INVENTION: Field of the Invention: The present invention relates to a scroll type compressor suitable for air conditioners for vehicles. Description of the Prior Art: One example of a conventional scroll compressor is shown in Fig. 3. In Fig. 3, a hermetic housing, being designated by numeral 1, consists of a cup-like body 2, a cover 4 fixed thereto by bolts 3 and a cylindrical element 6 fixed thereto by bolts (not shown in the figure). A rotating shaft 7, passing through said cylindrical element 6, is supported rotatably by the hermetic housing 1 via bearings 8 and 9. A stationary scroll 10 and a swivel scroll 14 are provided within the hermetic housing 1. Said stationary scroll 10 has an end plate 11 and a spiral wrap 12 provided standingly on its inner surface, said end plate 11 being tied to the cup-like body 2 by bolts 13. Further, a discharge port 29 is dug at the central part of the end plate 11 so that opening and closing of the discharge port 29 is made by a discharge valve 30. The swivel scroll 14 has an end plate 15 and a spiral wrap 16 provided standingly on its inner surface, said spiral wrap 16 being of a substantially same shape as the spiral wrap 12 of the stationary scroll 10. The swivel scroll 14 and the stationary scroll 10 are engaged with each other eccentrically by a length of a radius of the revolution and with a deviation of angle of 180 degrees, as shown in the figure. Thus, a tip seal 17 provided buriedly on the tip surface of the spiral wrap 12 being sealingly contacted to the inner surface of the end plate 15, and a tip seal 18 provided buriedly on the tip surface of the spiral wrap 16 being sealingly contacted to the inner surface of the end plate 11, the side surfaces of spiral wraps 12 and 16 make line contacts each other at a plurality of places, thereby a plurality of compression chambers 19a and 19b, being nearly in a point symmetry each other around the centers of the spirals, is formed. Within a cylindrical boss 20 provided projectingly at the central part of the outer surface of the end plate 15, a drive bush 21 is insertedly provided and is rotatable via a revolutional bearing 23, and within a slide groove 24 dug in said drive bush 21, an eccentric drive pin 25 provided eccentrically and projectingly at the inner end of the rotating shaft 7 is inserted slidably. Said drive bush 21 is fitted with a balance weight for balancing dynamic unbalances caused by revolutional swivel motions of the swivel scroll. The outer circumferential surface of the end plate 11 and the inner circumferential surface of the cup-like body 2 being sealingly contacted each other, thereby the inner space of the hermetic housing 1 being partitioned, a high pressure chamber 31 is formed on the outer side of the end plate 11 and a low pressure chamber 28 is defined on the inner side of the end plate 11. On the other hand, a suction chamber 32 and a discharge chamber 33 being formed within the cover 4, the discharge chamber 33 is connected to the high pressure chamber 31 by a path (not shown in the figure) and the suction chamber 32 is directly connected to the low pressure chamber 28. Incidentally, numeral 36 designates a thrust bearing provided between the circumferential edge of the outer surface of the end plate 15 and the inner end surface of the cylindrical element 6, numeral 26 designates a rotation preventing mechanism consisting of an Oldham coupling for allowing revolutional swivel motions of the swivel scroll 14 but preventing a rotation thereof, and numeral 35 designates a balance weight fixed to the rotating shaft 7. Thus, upon an electromagnetic clutch 37 being turned on, a power from a running engine (not shown in the figure) is transmitted to the rotating shaft 7 via a belt 38 and the electromagnetic clutch 37. With rotation of the rotating shaft 7, the swivel scroll 14 is driven via the eccentric drive pin 25, the drive bush 21 and the boss 20, and the swivel scroll 14, being prevented from rotating by the rotation preventing mechanism 26, does revolutional swivel motions on a circular track having a radius of the revolution, i.e. a radius being the eccentricity amount between the rotating shaft and the eccentric drive pin 25. Then, the line contact parts of the side surfaces of the spiral wraps 12 and 16 move gradually to the direction of the spiral centers, and as a result, the compression chambers 19a and 19b move, with volume thereof being reduced, to the direction of the spiral centers. Accompanying therewith, a gas flown into the low pressure chamber 28 from a suction inlet (not shown in the figure) via the suction chamber 32 is taken into each of the compression chambers 19a and 19b from openings of the outer finish ends of the spiral wraps 12 and 16. While being compressed, the gas comes in the central chamber 22 and, passing through the discharge port 29 and pushingly opening the discharge valve 30, it is discharged into the high pressure chamber 31 and flown out through a discharge outlet (not shown in the figure) via the discharge chamber 33. While the swivel scroll 14 is making revolutional swivel motions, it receives a centrifugal force acting to the direction of the eccentricity and a gas force by the compressed gas existing in each of the compression chambers 19a and 19b, and by a composition of forces, the swivel scroll 14 is pushed to the direction to increase the revolutional radius and thereby the side surfaces of the spiral wrap 16 contact sealingly to the side surfaces of the spiral wrap 12 of the stationary scroll 10 and prevent leakage of the gas in the compression chambers 19a and 19b. Further, accompanying with the side surfaces of the spiral wrap 12 and the side surfaces of the spiral wrap 16 making sliding motions while keeping sealing contacts, the revolutional radius of swivel scroll 14 automatically changes, and accompanying therewith, the eccentric drive pin 25 makes sliding in a slide groove 24 along its longitudinal direction. Within the discharge chamber 33, a thermosensor 50 is provided so that said thermosensor 50 senses temperatures of the discharge gas and turns off the electromagnetic clutch to stop the compressor when the temperature of the discharge gas rises to a certain specified temperature. Said thermosensor 50 is connected to an outer wiring 52 via a sealed terminal 51 fitted to the cover 4. Said sealed terminal 51 is inserted into a fitting hole 53, being a through hole dug on the cover 4, from its inner opening so that the front surface of the sealed terminal 51 touches a shoulder part 59 formed on the inner surface of the fitting hole 53, a snap ring 54 is put in a groove 55 provided dugly on the inner circumferential surface of the fitting hole 53 so as to position on the rear surface of the sealed terminal 51, thereby the sealed terminal 51 is fitted to the cover 4. Incidentally, numeral 56 designates an O-ring for preventing the high pressure gas in the discharge chamber 33 from leaking through an interstice between the fitting hole 53 and the sealed terminal 51. In said conventional scroll compressor, a snap ring 54 is used for fitting the sealed terminal 51 within the fitting hole 53, but the groove 55 in which the snap ring 54 is put is very small (e.g. the groove 55 is 1.1 mm wide and 0.5 mm deep when the inner diameter of the fitting hole 53 is 18 mm), and for this reason a finishing work of the groove 55 to take off residual flashes must be done by a hand work, which requires a high cost of work. Further, if some flashes remain not taken off due to a hand work, there is a fear that the O-ring 56 might be harmed by the remaining flashes when the sealed terminal 51 is inserted into the fitting hole 53, and thereby the high pressure gas in the discharge chamber 33 may leak outside. SUMMARY OF THE INVENTION: It is therefore an object of the present invention to dissolve the above-mentioned shortcomings in the prior art, and one feature of the present invention is a scroll compressor in which a stationary scroll and a swivel scroll engaged with each other are provided in a hermetic housing and the swivel scroll makes revolutional swivel motions, characterized in that a sealed terminal to send outside a signal from a sensor provided within the hermetic housing is inserted into a fitting hole passing through an outer wall of the hermetic housing, a push nut having a plurality of nails at the outer circumferential part, the nails being slightly inclined and the outer diameter of the nails being slightly larger than the inner diameter of the fitting hole, is inserted pressingly into the fitting hole and thereby the sealed terminal is fitted within the fitting hole. Another feature of the present invention is that said plurality of nails are provided with equal intervals on the outer circumferential part. Further another feature of the present invention is that said push nut has a hole at the center, which is large enough for a cover tube to pass a signal wire to send outside a signal of the sealed terminal to pass through. Further another feature of the present invention is that the sealed terminal and the push nut, being pre-assembled as a unit, are inserted into the fitting hole and thereby fitted within the fitting hole. Further another feature of the present invention is that said push nut is lapped on the rear surface of said sealed terminal and pre-assembled as a unit by a spot welding, etc. Further another feature of the present invention is that said sealed terminal is divided into two parts, a front part and a rear part, and said push nut is placed between so divided sealed terminals and thereby pre-assembling as a unit is made. According to the present invention, a sealed terminal is inserted within a fitting hole, a push nut is pressingly inserted within the fitting hole, then nails on the outer circumferential part of the push nut bite upon the inner circumferential surface and thus the sealed terminal can be fitted within the fitting hole. Further, according to the present invention, a cover tube to pass a signal wire to send outside a signal of a sealed terminal can be easily placed so as to pass through a central hole, which is large enough, of a push nut. Further, according to the present invention, a sealed terminal and a push nut, if pre-assembled as a unit, can be easily fitted within a fitting hole by being inserted together into the fitting hole. BRIEF DESCRIPTION OF THE DRAWINGS: In the accompanying drawings: Fig. 1 shows a first preferred embodiment of the present invention, wherein Fig. (A) is a cross section of a main part of the present invention and Fig. (B) is a view seen from a direction of an arrow B of Fig. (A). Fig. 2 shows a push nut, wherein Fig. (A) is a front view thereof and Fig. (B) is a cross section taken on line B-B of Fig. (A). Fig. 3 is a longitudinal cross section of a scroll compressor of the prior art. Fig. 4 is a cross section of a main part showing a second preferred embodiment of the present invention. Fig. 5 is a cross section of a main part showing a third preferred embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS: A first preferred embodiment of the present invention is shown in Fig. 1. As shown in Fig. 1, a sealed terminal 51 is inserted into a fitting hole 53, passing through a cover 4, from its inner opening so that a front surface of the sealed terminal touches a shoulder part 59 of the fitting hole 53, then a push nut 57 is pressingly inserted into the fitting hole 53 so that a front surface of the push nut contacts pressingly to a rear surface of the sealed terminal 51, thus the sealed terminal 51 is fitted to a hermetic housing 1. Incidentally, numeral 60 designates a cover tube to pass a signal wire connected to a thermosensor 50, which cover tube passes sealingly through a through hole 61 dug in the sealed terminal 51. A push nut, as shown in Fig. 2, being made by a press forming of a thin plate (e.g. 0.4 mm thickness) of a heat treated spring steel, has a circular hole 57c dug at the center of an annular body 57b and a plurality (six in the figure) of nails 57a slightly inclined to the inclined backward direction and formed on the outer circumferential part of the body 57b. The outer diameter D of the nails 57a is made slightly larger (e.g. by 0.2 mm) than the inner diameter d of the fitting hole 53. Other constructions and functions being same as those of the prior art shown in Fig. 3, corresponding elements are designated by same numerals. Thus, a sealed terminal 51 is inserted in a fitting hole 53, further a push nut 57 is pressingly inserted, and thereby nails 57a bite upon the inner surface of the fitting hole 53 and the sealed terminal 51 is fitted easily and quickly within the fitting hole 53. Once the sealed terminal 51 is fitted, even if a force acts on the sealed terminal 51 in the direction opposite to the direction of insertion (acting when an outer wiring 52 is being connected), the outer diameter D of the nails 57a wants to enlarge and the tips of the nails 57a further encroach upon the inner surface of the fitting hole 53, and hence there is no chance of the sealed terminal 51 getting out of the fitting hole 53. A second preferred embodiment of the present invention is shown in Fig. 4. In this second preferred embodiment of the present invention, a push nut 57 is lapped over an outer surface of a sealed terminal 51 so that the nails 57a face to the outward direction, a body 57b of a push nut 57 is applied by a spot welding 63 at a plurality of places with intervals on the circumferential direction, thus the sealed terminal 51 and the push nut 57 are pre-assembled as a unit. And interstices between a cover tube 60 and a through hole 61 are filled with, and sealed by, a molten glass 64 and thereby the cover tube 60 is fixed in the sealed terminal 51. Thus, a pre-assembled unit of the sealed terminal 51 and the push nut 57 is inserted in a fitting hole 53 so that a front surface of the sealed terminal 51 touches a shoulder part 59, then nails 57a of the push nut 57 bite upon the inner surface of the fitting hole 53, and the sealed terminal 51 and the push nut 57 are fitted within the fitting hole 53 with one action. Other constructions and functions being same as those of the first preferred embodiment shown in Fig. 1 and Fig. 2, corresponding elements are designated by same numerals. A third preferred embodiment of the present invention is shown in Fig. 5. In this third preferred embodiment of the present invention, a sealed terminal is divided into two parts, a front part and a rear part, and between so divided two elements 51A and 51B, a body 57b of a push nut 57 is placed so that nails 57a thereof face to the outward direction. And interstices between a cover tube 60 and a through hole 61 are filled with a molten glass, thereby elements 51A and 51B and the push nut 57 are pre-assembled as a unit. Thus, a pre-assembled unit of the sealed terminal 51 and the push nut is inserted in a fitting hole 53, and these elements can be fitted within a fitting hole 53 with one action. Other constructions and functions being same as those of the first preferred embodiment shown in Fig. 1 and Fig. 2, corresponding elements are designated by same numerals. According to the present invention set out in Claim 1, a sealed terminal is inserted in a fitting hole and a push nut is pressingly inserted in the fitting hole, thereby the sealed terminal can be fitted within the fitting hole. As a result, a work to make a groove to receive a snap ring and a work to take off residual flashes, as heretofore necessitated, are not required so that the necessary man-hour can be reduced, and a damage of an O-ring due to residual flashes of the groove does no longer occur so that a gas in the hermetic housing can be prevented from leaking outside. If a sealed terminal and a push nut are pre-assembled as a unit, they can be fitted within a fitting hole only with such a single action as that the sealed terminal and the push nut are inserted together, and a further reduction of assembling work can be attained comparing with the invention set out in Claim 1. While the preferred form of the present invention has been described, variations thereto will occur to those skilled in the art within the scope of the present inventive concepts which are delineated by the following claims.

Claims: A scroll compressor in which a stationary scroll (10) and a swivel scroll (14), engaged with each other, are provided within a hermetic housing (1), and said swivel scroll (14) makes revolutional swivel motions, a sealed terminal (51) to send outside a signal from a sensor (50) provided within said hermetic housing (1) is inserted into a fitting hole (53) passing through an outer wall of said hermetic housing (1), characterized in that a push nut (57) having a plurality of nails (57a), the outer diameter of which is slightly larger than the inner diameter of said fitting hole (53), is pressingly inserted into said fitting hole (53), thereby said sealed terminal (51) is fitted within said fitting hole (53). A scroll compressor as claimed in Claim 1, characterized in that said plurality of nails (57a) are provided with equal intervals on the circumferential part. A scroll compressor as claimed in Claim 1 or Claim 2, characterized in that said push nut (57) has a hole (57c) at the center thereof, which hole is large enough for a cover tube (60) to pass a signal wire to send outside a signal of said sealed terminal (51) to pass through. A scroll compressor as claimed in any one of Claim 1 to Claim 3, characterized in that said sealed terminal (51) and said push nut (57), being pre-assembled as a unit, are inserted into said fitting hole (53) and thereby fitted within said fitting hole (53). A scroll compressor as claimed in Claim 4, characterized in that said push nut (57) is lapped over the rear surface of said sealed terminal (51) and thereby pre-assembling as a unit is made by a spot welding (63), etc. A scroll compressor as claimed in Claim 4, characterized in that said sealed terminal (51) is divided into two parts, a front part and a rear part, said push nut (57) is placed between so divided two parts of said sealed terminal (51) and thereby pre-assembling as a unit is made.

Inventors: IIO TAKAYUKI, ISHII MIKIHIKO, MIURA SHIGEKI, TANIGAKI RYUHEI, IIO, TAKAYUKI, ISHII, MIKIHIKO, MIURA, SHIGEKI, TANIGAKI, RYUHEI, Iio, Takayuki, Mitsubishi, Jukogyo K.K., Ishii, Mikihiko, Mitsubishi, Jukogyo K.K., Miura, Shigeki, Mitsubishi, Jukogyo K.K., Tanigaki, Ryuhei, Mitsubishi, Jukogyo K.K.
Applicants: MITSUBISHI HEAVY IND LTD, MITSUBISHI JUKOGYO KABUSHIKI KAISHA
Application year: 1995
Main classification: F04C29
IPC codes: F04C18, F04C29, F04C28, H01B17