US3404445A

US3404445A - Method of forming a sound attenuating and gas passage tube construction

Info

Publication number: US3404445A
Application number: US552059A
Authority: US
Inventors: Glenn R Crouse
Original assignee: OLDBERG Manufacturing CO
Current assignee: APX GROUP Inc; OLDBERG Manufacturing CO
Priority date: 1964-09-14
Filing date: 1966-05-23
Publication date: 1968-10-08
Anticipated expiration: 1985-10-08

Description

G. R.CROUSE METHOD OF FORMING A SOUND ATTENUATING Oct. '8, 1968 AND GAS PASSAGE TUBE CONSTRUCTION Original Filed Sept. 14, 1964 2 Sheets-Sheet 1 INVENTOR. 6L E/VA/ /2 64 0055 JWQW.

4 T TOAA/EK G. R. CROUSE METHOD OF FORMING A SOUND ATTENUATING Oct. 8, 1968 AND GAS PASSAGE TUBE CONSTRUCTION Original Filed Sept. 14, 1964 v 2 Sheets-Sheet 2 Eigi INVENTOR. 6L E/V/V A? 65 0035 A T TOANE United Stat s. a e 073 .7 3,404,445 7 METHOD OF FORMING A SOUND AT- TENUATING AND GAS PASSAGE TUBE CONSTRUCTION Glenn R. Crouse, Nuncia, Mich., assignor to Oldberg Manufacturing Company, Grand Haven, Mich., a corporation of Michigan I Original application Sept. 14, 1964, Ser. No. 396,247, now Patent No. 3,276,540, dated Oct. 4, 1966. Divided and this application May 23, 1966, Ser. No. 552,059

9 Claims. (Cl. 29-157) This is a division of my copending application Ser. No. 396,247 filed Sept. 14, 1964, now Patent No. 3,276,- 540.

This invention relates to the attenuation of sound waves in gas streams and particularly to apparatus for attenuating sound waves in exhaust gas streams from internal combustion engines and to a method of producing the apparatus.

It has been conventional practice in connection with automotive vehicles powered by internal combustion engines to convey the, exhaust gases through a sound attenuating muffler or silencer of substantial size to attenuate sound waves in the exhaust gas streams. A recent trend in automotive design is to lower the vehicles and such design necessitates additional struts and stress resisting frame members and such frame members render difiicult the installation and use of conventional muffler constructions.

Recent developments have been made in the use of an exhaust conduit construction embodying a plurality of connected sound attenuating units wherein the outer shells or members of the attenuating units are connected together in end-to-end relation to form a combined exhaust pipe and sound attenuating means.

It is found that in the use of constructions of this character considerable so-called shell noise is developed by reason of the comparatively thin single outer shells of the sound attenuating constructions connected to provide the exhaust gas conduit. Constructions of such character are desirable in that they provide'for a substantially unobstructed gas passage means with a plurality of sound attenuating constructions disposed in close relation or spaced in end-to-end relation, and by reason of the length of the assembly of attenuating units, objectionable sound waves in the gas stream are attenuated but the single layer outer shells are readily responsive to sound vibrations causing shell noise.

An object of the invention resides in a method of forming a sound attenuating unit or construction having a central gas passage means, a plurality of sound attenuating chambers adjacent and surrounding the gas passage means and an outer, wall or layer embracing the sound attenuating meansjwherein an inter-mediate shell of the sound'attenuating, means is distorted by lengthwise pressure during processing 'into close or snug engagement with the gas passage means and the outer shell or layer whereby the components are held in assembled relation by the distorted regions or portions of the intermediate shell providing annular spaces between the intermediate and outer shells to reduce shell noise.

Another object of the invention resides in a method of fabricating a dual shell casing of a sound attenuating construction wherein one of the shells is contracted in a lengthwise direction to effect a transverse distortion of lengthwise spaced regions thereof into snug engagement with the other shell to secure the shells in assembled relation and provide a plurality of closed annular chambers between the shells.

Further objects and advantages are within the scope of this invention such as relate to the arrangement, opera- 7 3,404,445 Patented. Oct. 8, 1968 tion and "function of the related elements of the structure, to various details of construction and to combinations of 'parts, elements per se, and to economies of'm'anufacture and numerous other features as will be apparent from a consideration of the specification and drawing of a form of the invention, which may be preferred, in which:

FIGURE 1 is a phantom or a schematic view of the frame or chassis construction of an automotive vehicle and internal combustion engine illustrating a form of tuned exhaust pipe assembly or sound attenuating system of the invention;

FIGURE 2 is an elevation-a1 view of the sound attenuating or tuned exhaust pipe illustrating one arrangement of sound attenuating units in the exhaust system for use with an internal combustion engine;

FIGURE 3 is a longitudinal sectional view illustrating one of the sound attenuating units of the exhaust system;

FIGURE 4 is a transverse sectional view taken substantially on the line 4-4 of FIGURE 3;

FIGURE 5 is a longitudinal sectional view illustrating a step in the method of forming one of the sound attenuating units;

FIGURE 6 is a sectional view similar to FIGURE 5 illustrating a further step in the method of forming the sound attenuating unit; I

FIGURE 7 is a longitudinal sectional view showing a plurality of attenuating units in connected relation forming a combined gas passage and sound attenuating construction;

FIGURE 8 is an elevational view of the construction shown in FIGURE 7, and

FIGURE 9 is a transverse sectional view illustrating the method of joining adjacent attenuating units.

The longitudinally aligned assembly of sound attenuating units and coupling tubes in end-to-end relation, provides a combined exhaust pipe and sound attenuating construction or tuned exhaust pipe having particular utility as an exhaust system for internal combustion engines in automotive vehicle constructions, the arrangement providing an effective instrumentality for attenuation of sound waves of varying lengths entrained in the exhaust gas stream and for reducing shell noise, the tubular assembly being configurated to avoid interference with other structural components of the vehicle. I

Referring to the drawings in detail and initially to FIG- URE 1, there is illustrated in phantom or schematic form, a vehicle frame or chassis 10 embodying longitudinally extending side frame members 12 and transversely disposed struts or reinforcing members 14. The frontal region of the frame 10 supports an internal combustion engine 16 of conventional V-type construction having two banks 17 of cylinders equipped with exhaust manifolds 18, an exhaust pipe or gas conveying tube 20 is fashioned with branches 21 and 22 connected with the respective manifolds 18 of the engine.

In the arrangement shown in FIGURE 1, the exhaust gas streams from both banks of cylinders 17 are converged into a single tubular means which is connected with the tuned exhaust pipe system of the invention, the latter being preferably of a character for conveying the exhaust gases for discharge at the rear of the vehicle. While FIGURE 1 is illustrative of an arrangement employing a single tubular exhaust conveying system for the exhaust from both banks of cylinders, it is to be understood that a separate exhaust conveying and sound attenuating means or system may be employed for the exhaust stream from each bank of cylinders. I

The exhaust conveying and sound attenuating arrangement of the invention comprises a plurality of gas-conveying and sound attenuating units, each contained within an outer shell or enclosure and the outer shells or enclosures welded or otherwise coupled together in end-to-end c'oupled together by a tubular coupling 32,

units

26a and 26b directly joined together, and the units 26b and 26c coupled by a tubular component 34 of a configuration to provide clearance or jounce space for an axle of the vehicle. The units 26 through 26c are of substantially the same construction although they may be fashioned of varying lengths and may be spaced lengthwise other than the arrangement illustrated in FIGURES 1 and 2 in order to attenuate a particular range of sound waves depending upon the degree or efiiciency of sound attenuation desired.

One of the attenuating units 26 is illustrated in FIG- URES 3 and 4, and steps in the method of assembling the components of the attenuating units are illustrated in FIGURES 5 and 6. With particular reference to FIGURE 3 each attenuating unit or construction is inclusive of a central tubular member 40 which provides a gas passage means or tube, the wall of the tube 40 being provided with a comparatively large number of small openings 42. Surrounding the gas passage tube 40 and spaced therefrom is a second tubular member or shell 46 which is preferably of circular cross section and concentric with the tube 40 as shown in FIGURE 4.

The shell 46 is distorted or configurated at lengthwise spaced regions during forming operations providing transverse partitions 48 which engage the peripheral surface of the gas passage tube 40 to secure the tube 40 and shell 46 in assembled relation. In the attenuating unit of the invention, an outer shell or tube 50 is telescoped over the adjacent shell 46 and is secured in fixed relation with the shell 46 by raised ridges 52 formed of the metal of the shell 46 during distortion of the spaced regions of the shell to form the partitions 48.

Each of the attenuating units, as shown in FIGURE 3, comprises an outer tubular layer or shell 50 and an adjacent inner shell 46, the shell 46 being of slightly lesser diameter than the shell 50 providing annular spaces or chambers 54 of a length equal to the'distance between adjacent ridges 52, the annular chambers 54 providing closed air spaces functioning :as cushioning means for reducing shell noise or noises caused by vibration of the shell 46 set up by sound waves of the moving exhaust gases.

The friction set up in the method of assembly between the distorted portions forming the partitions 48 and the gas passage tube 40 and between the outwardly distorted ridges 52 and the outer tube or shell 50 securely retains or holds these components of each attenuating unit in proper relation without extraneous fastening means. The annular spaces 53 between the gas passage tube 40 and the shell 46 and defined lengthwise by the partitions 48 provide sound attenuating chambers acoustically coupled with the interior of the gas passage tube 40 by the openings 42.

FIGURES 5 and 6 illustrate steps in the method of assembling the gas passage tube 40, the shell or tubular member 46 and the outer shell or closure 50. The shell 46 is initially of cylindrical tubular configuration, and in a preforrning operation at spaced regions along the tube, the metal is spun or distorted inwardly to form the peripheral recesses or grooves 55. The inner diameter of each of the inwardly extending ridges provided by a recess 55 is slightly greater than the diameter of the outer surface of the gas passage tube 40, the latter being telescoped interiorlyof the shell 46 in the position shown in FIG- URE 5, and the outer tube or shell 50 telescoped over the shell 46.

' Disposed at one end of this assembly is a base block or bolster 60 fashioned with a first circular groove 62 to accommodate the end of the gas passage tube 40, a circular ledge 64 against which abuts the end of the shell 46,

and a second circular groove 66 which receives anend of the outer shell or tube 50. Disposed at the opposite end of the assembly is a movable ram 70 of a conventional press (not shown) fashioned with a circular groove 72 which receives the opposite end of the shell 46 during closing or operative movement of the pres'sjram.

As will be apparent from FIGURE'S, the shell 46, priorto the distortion operation to form the partitions 48 shown in FIGURES 3 and 6, extends a substantial distance beyond the adjacent ends of the gas passage tube 40 and the tube or outer shell 50. l p

The press ram 70 is fashioned with a circular recess accommodating an annularmember 74 of rubber or other nonmetallic material which is aligned with the gas passage tube 40. The ram 70 is provided with a ledge forming a seat for a second annular member 76 of rubber or other nonmetallic material aligned with the outer shell or closure 50.

With the

components

40, 46 and 50 predisposed in the relative" positions shown in FIGURE 5, the ram 70 is moved toward the components to the position shown in FIGURE 6. During movement of the ram to this position, the ram exerts lengthwise crushing or compressive forces against the shell 46, lengthwise thereof, which forces distort the regions of the shall defining the grooves 55 to bend or distort the metal to form the double layer partitions 48. By reason of the crushing stresses exerted on the tub 46, outwardly extending circular beads or ridges 52 are formed which frictionally and snugly engage the outer shell or closure 50 in the manner shown in FIG- URES 6 and 9.

Thus a complete attenuating unit with the outer shell is formed by the method step shown in FIGURE 6. The

annular members

76 and 74 carried by the ram 70 provide resilient cushions to prevent damage to or distortion of the gas passage tube and the outer shell or tube 50 during the step of distorting portions of the shell 46 in assembling the components.

As particularly shown in FIGURE 3, the left-hand end of the outer shell or tube 50 extends beyond the adjacent ends of the shell 46 and gas passage tube 40 while at the other and of the assembly, the shell 46 and the gas passage tube 40 extend beyond the adjacent end of the outer shell 50. FIGURE 9 illustrates the relative positions of adjacent attenuating units with the outer shells 50 aligned and welded together to form a continuous tubular construction.

In assembly, the ends of outer shells 50 are abutted and welded as at 80 throughout the circumference of the butting regions of the walls to form a continuous impervious tube. It will be noted from FIGURE 9 that the ends of adjacent gas passage tubes 40 and adjacent ends of the inner shells 46 are respectively aligned but are slightly spaced as at 94 to facilitate the welding 80 without interference between adjacent ends of the

members

40 and 46. j

FIGURES 7 and 8 illustrate a modified assembly of several sound attenuating units with the outer shells joined to provide a single exhaust pipe or gas passage tube. As shown in FIGURES 7 and 8, two attenuating

units

26a and 26b of substantially identical construction, are dis posed in abutting relation and the outer shells 50 welded together at the weld line 80. The forward end of the unit 2611 may be welded as at 81 to a coupling tube such as the tube 32 shown in FIGURE 1. e Y

A third unit 260 of the arrangement shown in FIG- URES 7 and 8 is spaced from the other units by a length of tubing 84 of the same diameter as the outer shells 50, the ends of the tube 84 being welded to the adjacent ends of the attenuating units as at 86 and 88. The third attenuating unit may be Welded to a tailpipe member 90 as at the weld line 92. The outer shells 50 of the attenuating units with the connecting tube 84 provide a continuous imperforate exhaust gas passage tube which may be of a shape similar to that shown in FIGURE 1 for conveying exhaust gases from the engine exhaust manifold for discharge into the air through the tailpipe 90. 7 It is to be understood that the intermediate or coupling tube 84 may be bent to a desired shape such as the tube 34 shown in FIGURE 2 to provide clearance space for a component ofthe vehicle frame construction.

The assemblage of sound attenuating units having their outer shells'welded together or joined by coupling tubes in the manner described provides a comparatively long imperforate tubular means or pipe for conveying exhaust gases and enclosing the attenuating units for attenuating sound waves over abroad range of valve lengths to attain improved sound attenuation and reduce shell noise.

Through this arrangement sound waves of short length and high pitch are readily attenuated as well as longer waves of low pitch by reason of the substantial distance traversed by the exhaust gases in moving through successive sound attenuating units.

It is to be understood that the relative lengthwise arrangement of the sound attenuating units may be varied by interposing a tubular coupling member, such as

members

32, 34 or 84 between each pair of sound attenuating units, and such tubular members or couplings may be of varying lengths to secure desired attenuation of sound waves.

It is apparent that, within the scope of the invention, modifications and different arrangements may be made other than as herein disclosed, and the present disclosure is illustrative merely, the invention comprehending all variations thereof.

' Iclaim:

1. The method of forming a multiple tube assembly including the steps of distorting metal of the wall of a first tube inwardly at lengthwise spaced regions, telescoping the first tube between second and third tubes of diameters whereby the first tube is spaced from the second and third tubes, and impressing pressure lengthwise on the first tube to force'the metal at the lengthwise spaced regions into engagement with the second tube and the third tube for securing the tubes in assembled relation with annular regions between the first and second tubes and between the first and third tubes, the distorted metal providing partitions subdividing the annular spaces into lengthwise arranged individual chambers.

2. The method of forming a multiple tube assembly including the steps of distorting metal of the wall of a first tube at lengthwise spaced regions to form circular grooves therein, telescoping the first tube having the circular grooves between second and third tubes of diameters whereby the first tube is concentric with and spaced from the second and third tubes, and impressing pressure lengthwise on the first tube to concomitantly force one region of the metal defining the grooves inwardly into engagement with the second tube and another region of the metal outwardly into engagement with the third tube for securing the tubes in assembled relation with annular regions between the first and second tubes and between the first and third tubes and whereby the distorted metal forms partitions subdividing the annular regions into lengthwise arranged individual chambers.

3. The method of forming a telescoped tube assembly including the steps of distorting metal of the wall of a first tube to form longitudinally spaced inwardly extending circular grooves, disposing a second tube of lesser diameter having a perforated wall region within the first tube with the tubes in concentric relation, telescoping an imperforate walled third tube over the first tube and in concentric relation with and spaced laterally from the first tube to provideannular regions between the first and second tube and between the first and third tubes, and impressing pressure lengthwise on the first tube to concomitantly force a portion of the metal adjacent the grooves inwardly into engagement with the perforated tube and another portion of the metal outwardly into engagement with the third tube for securing the tubes in assembled relation and thereby. forming lengthwise arranged annular chambers between the first tube and the second and third tubes.

4. The method of forming telescoped tube constructions and connecting the tube constructions including the steps of distorting metal of the wall of a first tube to form longitudinally spaced, inwardly extended circular grooves, disposing a second tube of lesser diameter having a perforated wall region within the first tube with the tubes in concentric relation, telescoping a third tube having imperforate walls over the first tube and in concentric relation with and spaced from the first tube to providing an annular region between the first and second tubes, impressing pressure lengthwise on the perforated tube to concomitantly force a portion of the metal adjacent the grooves inwardly into engagement with the perforated tube and another portion of the metal outwardly into engagement with the third tube for securing the tubes in assembled relation and forming lengthwise arranged annular spaces between the first tube and the second and third tubes and the annular spaces subdivided into chambers by the distorted metal of the first tube, said first and second tubes being of lesser length than the third tube, disposing two of the telescoped tube constructions with the third tubes of each in end-to-end relation and connecting the third tubes to form a continuous imperforate pipe.

5. The method of forming a gas conveying duct enclosing tubular sound attenuating constructions including the steps of distorting metal of the wall of a first tube to form longitudinally spaced inwardly extending circular grooves, disposing a second tube of lesser diameter having a perforated wall region within the first tube with the tubes in concentric relation forming an annular region between the first and second tube, telescoping a third tube having imperforate walls over the first tube and in concentric relation with and spaced from the first tube to provide an annular region between the first and third tube, impressing pressure lengthwise on the perforated tube to concomitantly force the metal adjacent the grooves into engagement with the second and third tubes for securing the tubes in assembled relation and subdividing the annular spaces between the first tube and the second and third tubes by the distorted metal of the first tube into lengthwise arranged individual chambers, said first and second tube constituting a sound attenuating construction, disposing two of the sound attenuating constructions with the third tubes in abutting end-to-end relation, and welding the abutting regions to form a continuous imperforate gas conveying duct.

6. The method of forming and joining telescoped tube assemblies including the steps of distorting metal of the wall of a first tube to form longitudinally spaced inwardly extending circular grooves, disposing a second tube of lesser diameter having a perforated wall region within the first tube with the tubes in concentric spaced relation, telescoping a third tube having imperforate walls over the first tube and in concentric relation with and spaced from the first tube, impressing pressure lengthwise on the first tube to concomitantly force the metal adjacent the grooves into engagement with the first tube and with the third tube for securing the tubes in assembled relation and forming lengthwise arranged annular spaces between the first tube and the second and third tubes and separated by the distorted metal of the first tube into individual chambers, said first and second tubes in assembly being of lesser length than the third tube, disposing two of the telescoped tube assemblies with the third tubes of each in abutting end-to-end relation, and welding the abutting regions to form a continuous imperforate wall with the adjacent end regions of the first and second tubes of the telescoped tube assemblies in spaced relation.

7. A method of forming a sound attenuating and gas passage tube construction for use with the exhaust gas stream of an internal combustion engine of an automotive vehicle including the'steps of pre-assembling an inner perforated-gas passage tube within and spaced transverse- 1y from an intermediate tube of larger diameter, said intermediate tube having annular grooves formed therein atspaced regions, telescoping an outer tube, of a diameter larger than the intermediate tube and having an imperforate'wall over the intermediate tube in concentric relation Withwthfi intermediate tube, exerting pressure lengthwise on the intermediate tubeto distort lengthwise spaced regions'of the intermediate tube laterally into engagement with the inner gas passage tube and into engagement with the outer tube to secure the tubes in spaced relation. r

8. A method of forming a sound attenuating and gas passage tube construction for use with the exhaust gas stream of an internal combustion engine of an automotive vehicleincluding the steps of forming a telescope tubular assembly by pre-assembling an inner perforated gas passage tube within and spaced transversely from an intermediate tube of larger diameter, said intermediate tube having annular grooves formed therein at spaced regions, telescoping an outer tube of a diameter larger than the intermediate tube and having an imperforate wall over the intermediate tube in concentric relation with the intermediate tube, exerting pressure lengthwise of the intermediate tube to distort lengthwise spaced re gions of the intermediate tube laterally into engagement with the inner gas passage tube and into engagement with the outer tube to secure the tubes in spaced relation, abutting the adjacent ends of outer tubes of two of said telescoped assemblies, and welding the abutting regions of the outer tubes together circumferentially to form a gas tight seal.

9. A method of forming a sound attenuating and gas passage tube construction for use with the exhaust gas stream of an internal combustion engine of an automotive vehicle including the steps of forming a telescoped tube unit by pre-assembling aninner perforated gas passage tube within and spaced transversely from an intermediate tube of larger diameter, said intermediate tube having annular grooves formed therein at spaced regions, telescoping an outer tube of a diameter larger than the intermediate tube and having an imperforate wall over the intermediate tube in concentric but in spaced transverse relation with the intermediate tube, exerting pressure lengthwise of the intermediate tube to distort lengthwise spaced regions of the intermediate tube laterally into engagement with the inner gas passage tube and into engagement with the outer tube to secure the tubes in spaced relation, abutting the adjacent ends of outer tubes of two of said telescoped tube units, welding the abutting regions of the outer tubes together circumferentially to form a gas tight seal, disposing .an end of a plain tube in engagew ment with an end of one of said telescoped tube units, and welding the engaging regions of the outer tube of the adjacent telescoped tube unit to the end of the plain tube to form a sealed joint.

References Cited UNITED STATES PATENTS 1,878,424 9/1932 Oldberg 181-48 2,047,442 7/1936 Starkweather et al. 181-48 2,148,948 2/1939 Kingsley 18148 2,683,928 7/1954 Carson 29523 3,204,164 8/1965 Burke et a1.

3,219,142 11/1965 Deremer.

3,242,558 3/1966 Selig 29-520 X CHARLIE T. MOON, Primary Examiner.

Claims

1. THE METHOD OF FORMING A MULTIPLE TUBE ASSEMBLY INCLUDING THE STEPS OF DISTORTING METAL OF THE WALL OF A FIRST TUBE INWARDLY AT LENGTHWISE SPACED REGIONS, TELESCOPING THE FIRST TUBE BETWEEN SECOND AND THIRD TUBES OF DIAMETERS WHEREBY THE FIRST TUBE IS SPACED FROM THE SECOND AND THIRD TUBES, AND IMPRESSING PRESSURE LENGTHWISE ON THE FIRST TUBE TO FORCE THE METAL AT THE LENGTHWISE SPACED REGIONS INTO ENGAGEMENT WITH THE SECOND TUBE AND THE THIRD