NZ216319A

NZ216319A - Lubricating system for a turbocharger

Info

Publication number: NZ216319A
Application number: NZ216319A
Authority: NZ
Inventors: J A Mceachern; J W Brogdon
Original assignee: Teledyne Ind
Priority date: 1985-05-30
Filing date: 1986-05-27
Publication date: 1988-02-29
Also published as: SE8602121L; BR8602391A; GB8612165D0; GB2175957A; DE3617403A1; IT1190576B; AU5786386A; SE8602121D0; IT8667438A0; JPS627935A; FR2582727A1

Description

2 16319 "6 0~ c XcMitt.jiO ....f.01,0^/9^: fouDZ4]0.6. * ' 2 9 FEB 1988.,..

Publication DjV? " " P.O. Journal. No: .l.wG"**' PATENTS FORM NO: 5 PATENTS ACT 1953 COMPLETE SPECIFICATION "LUBRICATION SYSTEM FOR A TURBOCHARGER" WE, TELEDYNE INDUSTRIES, INC of 1901 Avenue of the Stars, Los Angeles, California 90067, U.S.A. a company organised and existing under the laws of California, U.S.A., hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- 1 16319 Background of the Invention I. Field of the Invention The present invention relates generally to turbochargers and, more particularly, to a turbocharger with an improved lubrication systen.

II. Description of the Prior Art There have been a number of previously known devices which hydrostatically damp a shaft rotatably mounted to a housing. Examples of such devices are shown in U.S. Patent no: 3,881,841 to Straniti, May 6, 1975 and U.S. patent no: 3,158,413 to Shelley, November 24, 1964.

In these previously known devices, a thin layer of lubricant, commonly known as a squeeze film damper, is entrapped between an outer race of the bearing assembly and the housing in which the shaft is rotatably mounted.

This squeeze film damper hydrostatically damps shaft vibration by hydrostatic action.

There have, however, been a number of previously known disadvantages with such hydrostatically damped bearing assemblies. One such disadvantage is that, after a period of time, the lubricant which forms the squeeze film damper deteriorates. Unless new lubricant is supplied to the squeeze film damper, the dampening action of the squeeze film damper will be degraded. The same is also true when the lubricant leaks from the squeeze film damper.

The present invention provides a turbocharger construction which overcomes all of the above mentioned disadvantages of the previously known devices.

In brief, the turbocharger of the present invention com 216319 prises a main housing having a throughbore, a tubular bearing carrier having an outer periphery and an inner periphery, said bearing carrier positioned within said housing throughbore, said bearing carrier dimensioned so that said bearing carrier is positioned radially inwardly from said housing, thus forming at least one annular chamber therebetween, a shaft extending through said bearing carrier said shaft having a turbine at one end and a compressor at its other end, at least one bearing assembly for rotatably connecting said shaft to the inner periphery of said bearing carrier, a source of pressurised lubricant, means for connecting said source to one end of said annular chamber, and fluid passage means formed through said bearing carrier for connecting the other end of said annular annular chamber to said bearing assembly, wherein said/chamber is dimensioned so that lubricant in said annular chamber hydrostatically damps said bearing assembly.

Thus, in operation, lubricant flows first through the annular chamber and, upon exit from the annular chamber, lubricates the bearing assemblies. Furthermore, the oil within the annular chamber forms a squeeze film damper , for hydrostatically dampening the bearing assemblies and thus minimizing vibration between the housing and the shaft.

A better understanding of the present invention will be had upon reference to the following detailed description when read in conjunction with the accompanying drawing , wherein like reference characters refer to li^ parts throughout the several views, and in which: I Brief Description of the Drawing 1 1 '"'A /c.- 3 2 1 63 Fig. 1 is a diagrammatic view illustrating a preferred embodiment of the present invention; Fig. 2 is a fragmentary longitudinal sectional view illustrating the preferred embodiment of the present invention; and Fig. 3 is a cross sectional view taken substantially alon,<* line 3-3 in Fig. 2.

Detailed Description of a Preferred Embodiment of the Present Invention Uith reference first to Fig. 1, a preferred embodiment of the turbocharger 10 of the present invention is there- shown and connrises a main housing 12 having a shaft 14 rotatably mounted to it in a fashion which will subsequently be described in greater detail. A compressor 16 is secured to one end of the shaft 14 while a turbine 18 is secured to the other end of the shaft 14.

Upon rotation of the compressor 16, the compressor 16 inducts air at its inlet 20 (illustrated diagrammatically) and supplies compressed «-iir at its outlet 22 to the intake 24 of an internal combustion engine 26. The internal combustion engine 26 has its exhaust 28 secured to the inlet 30 of the turbine 18 and the exhaust 32 from the turbine 18 open to the atmosphere. In the conventional fashion, the exhaust from the engine 26 rotatably drives the turbine 18 which in turn rotatably drives the compressor 16 through the shaft 14.

With reference now particularly to Fijf. 2, the housing 12 includes a throuphbore 34 which is coaxial with the shaft 14 A tubular bearing housing 36 having an outwardly extending 216319 flange 38 at one end is press fit into the throughbore 34 until the flanged end 38 of the bearing housing 36 abuts against the housing 12. Preferably the housing 12 is constructed of aluminum for lightweight construction while the bearing housing 56 is constructed of steel for durability. A tubular bearing carrier 40 having. an outwardly extending flanr.e 42 at one end is then positioned coaxially within the bearing housing 36 so that the flanf.es 38 and 42 flatly abut against each other. A retaining ring assembly 44 secures the bearing housing 36 and bearing carrier 40 arainst axial movement with respect to each other.

A pair of axiallv spaced bearing assenblies 48 and 50 rotatably mount the turbocharger shaft 14 to the bearing carrier 40. Each bearing assenbly 48 and 50 preferably conprises a ball bearing assembly having its inner race secured for rotation with the shaft 14 and its outer race secured against radial movement to the inner periphery 52 of the bearing carrier 40. In addition the bearing assemblies 48 and 50 are mounted between the shaft 14 and bearing carrier 40 adjacent each end of the bearing carrier 49.

I.'ith reference now to Fig.s 2 and 3, the bearing carrier , 40 is dimensioned so t^at each of its ends is spaced radially invardly fron the inner surface of the bearing housing 36 thus forming annular chambers 54 therebetween. Referring particuarly to Fig. 2, a resilient seal 56 is sandwiched in between the tube 36 and bearing carrier 40 'adjacent the outer end of each annular chamber 54 while, 7 similarly, a resilient seal 58 is sandwiched between the ttibe 36 and bearing carrier 40 adjacent the inner end of ^ach annular chamber 54. The resilient seals 56 & 58 preferably comprise resilient O-rings. In addition, the radial width of ^ JiUtii." each annular chambcr 54 is very small, typically only a few thousandths of an inch.

Still referring to Fig. 2, a first annular spray nozzle 60 is contained within the interior of the bearing carrier 40 and has one axial end 62 which abuts against the outer race of the bearing assembly 48. Similarly, a second annular spray nozzle 64 is contained within the interior of the bearing carrier 40 and has its outer axial end 66 in abutment with the outer race of the other ball bearing assembly 48. The inner axial end 70 of the spray nozzle 64 abuts against a radially inwardly extending portion 72 on the bearing carrier 40.

A compression spring 74 is sandwiched in a state of compression between the inner axial end 76 of the spray nozzle 60 ar.d the radially inwardly extending portion 72 of the bearing carrier 40. This compression spring 74 thus balances the load evenly between the outer races of the - •bearing assemblies 48 and 50 to mininize vibration caused by unevenly loaded bearings.

^ 'Referring now to Fig. 1, a pressurized lubricant source 80 (illustrated only diagrammatically) is connected to a fluid coupling 82 formed in the housing 12. This coupling 82, in turn, is connected to two passage ways 84 and 86 formed through the housing 12.

Referring again to Fig. 2, the fluid passageway 84 is connected to a radially extending port 88 formed through the bearing housing 36 adjacent the outer end of one annular chamber 54. Similarly, the other fluid passageway 86 is connected to a radial port 90 formed 216319 f through the bearing housing 36 adjacent the outer end of the other annular chamber 54.

Still referring to 7ig. 2, a passageway 91 is formed through registerinrr bores in the bearing housing 36 and bearing carricr 40. One end of the passageway 91 is open closely adjacent the innernost end of one annular chamber 54 while the other end of the passapeway 91 is opened to ari inner side 92 of the bcarinc assembly 50. Furthemore, the passageway 90 is obliquely forr.ed with respect to the shaft axis so that it extends from the annular chamber 54 and towards the bearing assembly 50. Similarly, an oblique passageway 94 is formed through the bearing housing 36 and bearing carrier 40 so that one end of the passageway 94 is open to the other annular chamber 54 adjacent its innernost end while the other end of the passageway 94 is o^en to an inner side 96 of the other bearing assembly 48.

A pair of slinijers 100 are secured at axially spaced positions to the shaft 12 so that one slinger 100 is positioned closely adjacent an outer end of each bearing /, assembly 48 and 50. Each slinger 100 includes a radially .. -y-J' or 4i«fc o t ' t cs~r extending nortion 102, oreferably with imnellers, which Jro /«7 registers with and is closely adjacent its associated bearing assemblies 48 or 50. Each slinger 100, furthermore, is opened to a lubricant collection chamber 104 (Fig. 1) formed in the housing 12.

In operation, lubricant from the source SO is supplied under pressure to the fluid coupling 82 in the housing 12 VZEA: ... so that the lubricant flows from the source 80, through 1 1 MAY 19 37 PA • - JT OFHCE - 7 216319 the passageways 84 and 36 and to the outer ends of the annular chambers 54. The lubricant then flows axially inwardly through the annular chambers 54, through the obliquely extending passageways 91 and 94 and to the bearing assembly 48 and 50, respectively, in order to lubricate the bearing assemblies.

After passing through the bearing assemblies 48 and 50, the lubricant is exnelled radially outwardly by the slingers 100 into the lubricant collection chamber 104 in the housing 12. The lubricant is then evacuated from the chamber 104 through a oort 106 (Fig. 1) and recycled by the lubrication system in the conventional fashion.

Since the annular chambers 54 are very small in radial width, they form a saueeze film damper for hydrostatically mounting the bearing carrier 40, and thus the bearing assemblies 48 and 50, to the housing 12.

The primary advantage of this invention is the oil flow through the squeeze film dampers or annular chambers 54 is also used to lubricate the bearing assemblies 48 and 50. This provision of the invention thus ensures that a constant and fresh supply of oil is supplied to the squeeze filn dariper thereby obviating many of the previously known disadvantages of the prior art devices. Furthermore, by connecting the annular chambers 54 in series with the lubrication flow to the main bearings 48 and 50, a much simpler, inexpensive and vet totally effective construction is thereby obtained. ng described the invention, however, many modifications eto will become apparent to those skilled in the art rhich it pertains without deviation from the spirit of NEW 7r"1 * tf&v 1 1 MAY 19ffrhe — to ' PATENT C. .; w.«- 2 16319 the invention as defined by the scope of the appended claims. ©

Claims

216319 WHAT K*E CLAIM IS

1. A turbocharger comprising: a main housing having a throughbore, a tubular bearing carrier having an outer nerioherv and an inner periphery, said bearing carrier positioned within said housing throughbore, said bearing carrier dimensioned so that said bearing carrier is y positioned radially inwardly fron said housing, thus forming at least one annular chamber therebetween, a shaft extending through said bearing carrier said shaft having a turbine at one end and a compressor at its other end, at least one bearing assembly for connecting said shaft to the inner periphery of said bearing carrier, a source of pressurized lubricant, means for connecting snid source to one end of said annular chamber, and fluid passage means formed through said bearing carrier for connecting the other end of said annular chamber to said bearing assembly, wherein said annular chamber is dimensioned so that lubricant in said annular chamber hydrostatically damps said bearing assembly.

2. The turbocharger as defined in Claim 1 and comprising , a fluid seal between each end of said bearing carrier and said housing.

3. The turbocharger as defined in claim 2 wherein each fluid seal comprises a resilient O-ring. h.

The turbocharger as defined in claim 1 wherein said at least one bearing assembly comprises two sets of bearing -— races, said sets of bearing races being axially spaced 1 AY 1987 ' f - OFFICE 1° 216319 from each other, and comprising fluid seals extending between said bearing carrier and said housing which separate said at least one annular chanber into two axially spaced annular chambers, said fluid connecting means extending bet'.^een said source and one end of each annular chamber, said fluid passage means extending between the other end of one annular chamber and one set of bearing races and between the other end of the other annular chamber and the other set of bearing races.

5. The turbocharger as defined in claim 1 wherein said fluid passage means is open to one end of said bearing assembly and comprising a disk-shaped slinger secured to said shaft so that said slinger extends outwardly from said shaft adjacent the other side of said bearing assembly.

6. The turbocharger as defined in claim 5 wherein said housing includes a lubrication collection chamber open to said slinger. •)

7. The turbocharger as defined in claim 1 wherein said bearing assembly comprises a ball bearing assembly.

8. The turbocharger as defined in claim 1 and comprising a bearing housing mounted through said housing throughbore, said bearing carrier being coaxially mounted with said bearing housing, and wherein said housing is con- - 11 - 216319 structed of aluminum and said bearing housing is constructed of steel.

9. A turbocharger substantially as hereinbefore described with reference to and as shown in the accompanying drawings. TELEDYNE INDUSTRIES, IKC by their authorised agents P.L. BERRY & ASSOCIATES per: K (A /W/isdtZ^ - 12 -