Scroll type fluid apparatus

COMPLETE SPECIFICATION (ORIGINAL)

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Sanaen Corcoration 20 Kotobuki-cho, Isesaki-shi Gunma 372

JAPAN © a Name and Address ⁰ . 1· or Applicant:

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Spruson & Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia for the invention entitled:

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Scroll Type Fluid Apparatus ;·,*·.The following statement is a full description of this invention, including the • ’ best method of performing it known to me/us © a « © a β » o«

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• ABSTRACT OF THE DISCLOSURE

This invention discloses a scroll type supercharger in which dual orbiting scrolls synchronously orbit. The supercharger includes a first ‘ orbiting scroll having a first end plate from which a first spiral element * extends and a second orbiting scroll having a second end plate from which a * ' second spiral element extends. A first concave shell comprises a first fixed scroll having third end plate from which a third spiral element extends. A second concave shell comprises a second fixed scroll having fourth end plate from which a fourth spiral element extends. The first and second concave shells are firmly joined to define a chamber in which first, second, third and fourth spiral elements exist. The first orbiting scroll and first fixed scroll are maintained angularly and radially offset from each other so that the first and third spiral elements interfit to form at least one pair of fluid pockets. The second orbiting scroll and second fixed scroll are also maintained angularly and radially offset from each other so that the second and fourth spiral elements Interfit to form at » I r f ;

c- .· least one pair of fluid pockets. The first and second orbiting scrolls are firmly joined to be generated synchronous orbital motion by driving ' mechanism operatively connected to both orbiting scrolls. A rotation ,_4I preventing device prevents rotational motion of both orbiting scrolls during orbital motion of both orbiting scrolls. Both orbiting scrolls cooperatively define a hollow portion therebetween. The hollow portion is filled with discharged compressive air which is generated by orbital motion of orbiting scrolls to set off axial force pushing first and second end ; plates, thereby bending of first and second end plates is prevented.

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SCROLL TYPE FLUID APPARATUS BACKGROUND OF THE INVENTION Field of the Invention

This invention relates to a scroll type fluid apparatus, and more particularly, to a scroll type supercharger used for an automotive engine.

Description of the Prior Art

A scroll type fluid apparatus can be applied to a compressor or a supercharger. When a high compression ratio is required rather than a high discharge flow rate, the scroll type fluid apparatus is applied to the compressor as disclosed in U.S. Patent No. 4,477,238. The other hand, when the high discharge flow rate is required rather than the high compression ratio, the scroll type fluid apparatus is applied to the supercharger as disclosed in Japanese Patent Application Publication No. 58-62,301.

However, above-mentioned scroll type supercharger can not be sufficiently obtained the high discharge flow rate in comparison with other type of supercharger, such as, a roots displacement compressor as disclosed in Japanese Utility Model Application Publication No. 62-183,092, on condition that an outer dimension of each fluid apparatus is generally same.

To eliminate this defect, DE 3,141,525—A (West Germanic Patent Application Publication) discloses a scroll type supercharger including an orbiting scroll having a plate member from which first and second spiral elements oppositely project. A third spiral element interfitting with the first spiral element to define at least one pair of fluid pockets projects from an inner surface of one end of a housing. A fourth spiral element interfitting with the second spiral element to define at least one pair of fluid pockets projects from an inner surface of another end of the housing. A driving mechanism including a crank shaft is operatively connected to the orbiting scroll and to effect orbital motion of the orbiting scroll. Rotational motion of the orbiting scroll is prevented by a rotation preventing device during orbital motion of the orbiting scroll.

A pair of balance weights are attached to both axial ends of a crank pin of the crank shaft.

In above-mentioned scroll type supercharger, pressure in the fluid pockets is gradually increased with decreasing volume of the fluid pockets during orbital motion of the orbiting scroll. Therefore, the plate member receives force of which direction is in parallel with an axis of the crank shaft (reciting axial force hereinafter) in virtue of pressure in the fluid pockets. But, above-mentioned axial force is generated in virtue of pressure in the fluid pockets which are defined by first and third spiral

-•2BJG/214P elements and, second and fourth spiral elements respectively. Therefore, axial forces received by the plate member are set off each other thereby the plate member can avoid being bent by axial forces. This manner makes • above-mentioned scroll type supercharger have an advantage.

However, in above-mentioned scroll type supercharger, both first and ‘ second spiral elements are formed on the single plate member. Therefore, it is difficult to manufacture the orbiting scroll with satisfying accuracy of relative location of the first spiral element to the second spiral element. Accordingly, this causes poor productivity and high manufacturing cost.

SUMMARY OF THE INVENTION

It is a primary object of this invention to provide a scroll type supercharger having a easily manufacturing orbiting scroll with setting off axial forces received by a plate member of the orbiting scroll.

A scroll type supercharger includes an orbiting scroll having a plate member from which a first spiral element and a second spiral element oppositely extend. A first concave shell includes afirst fixed scroll • « » &lt;

««»* having an first end plate from which a third spiral element extends. A second concave shell includes a fixed scroll having an second end plate

Γ, ^from which a fourth spiral element extends. The first and second concave •«c shells cooperatively define a chamber in which the first, second, third and ’*” fourth spiral elements exist. The orbiting scroll and the first fixed o t r ⁰ scroll are maintained to angular and radially offset each other so that the first and third spiral elements interfit to form at least one pair of fluid pockets. The orbiting scroll and the second fixed scroll also maintained

.... to angularly and radially offset each other so that the second fourth t « ” ' spiral elements interfit to form at least one pair of fluid pockets. A driving mechanism is operatively connected to the orbiting scroll to effect . ., orbital motion of the orbiting scroll. A rotation preventing device ··♦'«· *“* prevents rotational motion of the orbiting scroll during orbital motion of the orbiting scroll. The driving mechanism includes a crank shaft having a .» ,« balance weight. The plate member of the orbiting scroll is divided into a

0 t .o \ first plate member having the first spiral element and a second plate *· '·* member having the second spiral element to define a hollow portion in which the balance weight is disposed. The hollow portion is linked to the central fluid pockets.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a vertical longitudinal sectional view of a scroll type supercharger in accordance with one embodiment of the present invention.

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Figure 2 is a perspective view of the scroll type supercharger shown in Figure 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to Figure 1, scroll type supercharger 10 in accordance with one embodiment of the present invention is shown. Supercharger 10 includes - ' orbiting scroll 20 having first and second plate members 21, 22. First and second spiral elements 211, 221 oppositely extend from each first and second plate members 21, 22 respectively. Each first and second bosses

212, 222 are respectively formed at an end surface of each first ana second plate members 21, 22 opposite each first and second spiral elements 211,

221 to face each other. First and second annular projections 213, 223 of which height is longer than height of bosses 212, 222 respectively project from the end surface of each first and second plate members 21, 22 to contact each other at both projecting ends thereof and surround first and second bosses 212, 222. An inner portion of the projecting end of first projection 213 and an outer portion of the projecting end of second projection 223 are cut-out respectively to dispose 0-ring 30 used for t t f c .t ' sealing a mating surface between the projecting ends of first and second ,,projections 21 3, 223, A plurality of bolts 31 are screwed into first and ;·, second projections 213 and 223 from an end surface of first plate member 21 •

.- opposite first projection 213 to firmly secure first plate member 21 to *’*' second plate member 22. In result, hollow portion 32 is defined by first • t · • and second plate members 21, 22 and, first and second annular projections

213, 223.

Front casing 40 (to the left in Figure 1) includes first end plate ,,,, portion 411 from which third spiral element 412 extends. In result, first • I ?

‘ end plate 411 and third spiral element 412 substantially form fixed scroll

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41. yhe first plate member portion of orbiting scroll 20 and first fixed , ., scroll 41 are maintained angularly and radially offset from each other so • β t ”” that first and third spiral elements 211, 412 interfit to form at least one pair of fluid pockets 23. Third boss 413 is formed at an outer surface of ., first end plate 411, that is, opposite third spiral element 412.

» β » • ‘ Rear casing 50 (to the right in Figure 1) includes second end plate β * * ’ *· *,ί 511 f_rom which fourth spiral element 512 extends. In result, second end plate 511 and fourth spiral element 512 substantially form second fixed scroll 51. The second plate member portion of orbiting scroll 20 and second fixed scroll 51 are maintained angularly and radially offset from each other so that second and fourth spiral elements 221 and 512 interfit to form at least one pair of fluid pockets 24. Fourth boss 513 is formed

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9 0 4 at an outer surface, that is, opposite fourth spiral element 512. Adapter 514 having annular flange portion 514a which outwardly extends from an outer peripheral surface of adapter 514 is provided with a plurality of outlet ports 5l4b. Adapter 514 is fitted into an innner peripheral wall of fourth boss 513 to contact flange portion 5l4a to fourth boss 513. A plurality of bolts 515 is screwed into flange portion 5l4a and fourth boss

513 to firmly secure adapter 514 to rear casing 50.

Each first, second, third and fourth spiral element 211, 221, 412 and 512 is provided with seal element 33 at its axial end surface. Front and rear casings 40, 50 are firmly joined by a plurality of bolts 42a and nuts 42b through gasket 43 to define operational chamber 25.

Driving mechanism 600 includes drive shaft 60. Holes 414, 516 are centrally formed at first and second end plates 411 and 511 respectively to be penetrated through drive shaft 60. Deive shaft 60 is rotatably supported by third boss 413 and adapter 514 through bearings 44 and 52 forcibly inserted in an inner peripheral wall of third boss 413 and adapter

514 respectively. Bearing 52 is firmly secured to adapter 514 by snap ring 521 and nut 522. Pulley 61 is mounted onto an front end (to the left in Figure 1) of drive shaft 60 after toothed wheel 62. Toothed wheel 62 is firmly secured onto drive shaft 60 by nut 63 and key mechanism 64. Pulley 61 is also firmly secured onto drive shaft 60 by nut 65 and key mechanism 66. Spacer 67 is disposed between nut 63 and pulley 61. Shaft seal mechanism 68 is disposed at a rear of bearing 44.

Crank pin 69 is penetrated through drive shaft 60 and is firmly secured to a central portio of drive shaft 60 by nut 691. An axis of crank pin 69 is radially offset from an axis of drive shaft 60 with a predetermined distance. Cavity 692 is longitudinally bored through crank pin 69 to link central fluid pockets 23a, 24a. crank pin 69 is rotatably supported by bosses 212, 222 through bearings 45, 46 forcibly inserted in an inner peripheral wall of bosses 212, 222. Accordingly, first and second plate members 21, 22 orbit synchronously in virtue of driving mechanism 600.

Balance weight 693 is disposed at crank pin 69 opposite the axis of crank pin 69 with respect to the axis of drive shaft 60 and is fixedly secured thereto by key mechanism 694. Port 695 is formed at crank pin 69 to link cavity 692 to hollow portion 32.

Rotation preventing mechanism 70 includes crank shaft 71 having pin member 72 extending from a rear end of crank shaft 71. Crank shaft 71 penetrates through cylindrical portion 73 formed at a top of front casing in order to be in parallel with drive shaft 60. A pair of bearings 47,

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are disposed at an inner peripheral wall of both ends of cylindrical portion 73 to rotatably support crank shaft 71. An axis of pin member 72 is radially offset from an axis of crank shaft 71 with a predetermined

- distance which is similar to the distance between the axis of crank pin 69 ’ and the axis of drive shaft 60. Between bearings 47 and 48, balance weight

- ' 74 is disposed at crank shaft 71 opposite the axis of pin member 72 with respect to the axis of crank shaft 71 and is fixedly secured to crank shaft 71 by key mechanism 75.

Tooth wheel 711 is mounted onto an front end (to the left in Figure 1) of crank shaft 71 and is firmly secured crank shaft 71 by nut 712 and key mechanism 713. Toothed wheel 711 is similar to toothed wheel 62, that is, each toothed wheels 62 and 711 has same diameter and number of teeth. Toothed wheels 711 and 62 are engaged through timing belt 80 to rotate synchronously.

One end opened box 75 provided with bearing 49 and shaft seal 81 therewithin is disposed between first and second plate members 21 and 22. The open end of box 75 faces first plate member 21 and is provided with * * * C ;

r.rl annular flange 751 radially extending therefrom. Pin member 72 penetrates through first plate member 21 and inserts into an inside of box 75. Box 75 rotatably supports pin member 72 through bearing 49. shaft seal 81 is • r _tc mounted onto pin member 72 in front (to the left in Figure 1) of bearing *‘‘‘_f 49. Annular flange 751 is fixedly secured to first plate member 21 by • * * plurality of bolts 82. A closed end of box 75 is fixedly secured to second plate member 22 by plurality of bolts 83.

Accordingly, rotational motion of first and second plate members 21, ,,_lt 22 is prevented by rotation preventing mechanism 70 during orbital motion • t « “ ¹ of first and second plate members 21, 22, thereby only their synchronous ft 4 « ’♦’“^l orbital motion is permitted.

, ,, Semicircular holes 91, 92 are respectively formed at front and rear ©ft i casing 40, 50 to form inlet port 90 as shown in Figure 2.

Operation of the scroll type supercharger comprising above-mentioned ,, ,, structure is as follows.

©04 • * Driving force is transferred to pulley 61 from an outer power source, ©» 4 % °»ί such as, an engine of vehicle (not shown) through belt (not shown), thereby drive shaft 60 rotates. This rotation converted to orbital motion of orbiting scroll 20 through crank pin 69; rotational motion is prevented by rotation preventing mechanism 70. Air introduced into operational chamber 25 through inlet port 90 is taken into the outer fluid pockets 23b, 24b between first plate member 21 portion of orbiting scroll 20 and first fixed

-6BJG/214P scroll 41, and second plate member 22 portion of orbiting scroll 20 and second fixed scroll 51, then moves inwardly towards the center of spiral elements 211, 412 and 221, 512 due to the orbital motion of orbiting scroll

20. As the air moves towards central pockets 23a, 24a, it undergoes a resultant volume reduction and compression, for example, 0.1 - 0.8 kg/cm G. This compressive air is discharged to an outlet pipe (not shown) linking supercharger 10 to the engine of the vehicle (not shown) through outlet ports 514b. Particularly, compressive air in fluid pocket 23a is discharged to the outlet pipe after flowing through cavity 692 and joining compressive air in fluid pocket 24a. A part of compressive air flows into hollow portion 32 through cavity 692 and port 695 so that hollow portion 32 is filled with compressive air. In result, first and second plate members

21, 22 can avoid being bent by axial force generated in virtue of pressure in the fluid pockets.

Furthermore, a radial dimension of the casing of supercharger can be reduced due to disposing balance weight 693 within hollow portion 32.

This invention has been described in detail in connection with the preferred embodiment. This embodiment, however, is merely for example only and the invention is not restricted thereto. It will be understood by those skilled in the art that other variations and modifications can be easily made within the scope of this invention as define by the appended claims.

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