CA2142850A1

CA2142850A1 - Camshaft bearing surface linishing tool

Info

Publication number: CA2142850A1
Application number: CA 2142850
Authority: CA
Inventors: James Norman Eastwood
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-06-18
Filing date: 1994-06-20
Publication date: 1995-01-05
Also published as: GB2284167B; GB2284167A; WO1995000293A1; GB9503058D0; AU6990194A; AU683895B2

Abstract

2142850 9500293 PCTABS00035 To this end, there is provided a linishing tool for reconditioning a camshaft integral bearing surface of a cylinder head including an elongate body (1) having an outer surface (2), at least a portion of the outer surface of the body being a linishing surface (3), and at least one handle (5) provided at an end of the body, the body having at least one cylindral section (8) with a lateral cross section having a diameter corresponding to the required bearing diameter of the camshaft integral bearing surface. The metal finishing process of "linishing" involves the use of a surface covered by fine particles of hard material which acts as an abrasive for the removal of matter by scratching and grinding. This is distinguished from line borers, reamers and files which all use a cutting action to remove material.

Description

WO 9~100293 Z ~ 3 PCTIAU94100333 ... .. ~ ,.

ET BEARING SURFACE l~ ~ING TOOI, This invention relates to a linishing tool for use in the reconditioning of cylinder heads of internal combustion piston engines.
A common problem with internal combustion piston en~ines is that the cylinder head can become warped due to adverse operating conditions leading to localised hot S spots in the cylinder head andlor unba}anced forces or pressures acting on the head. A
warped cylinder head needs to be reconditioned to bring the clearances substantially back into spec;fication before it can be reused.
During recondltioning, the integral camsha~ bearing surfaces supporting the overhead carnshaft may need to be realigned. The current procedure for realigning the bearing surfaces is to use a line borer to ream~ the: "camsha~ tunnel" to the required clearance. The line borer ls essen~ially a metal cut~Lng: tool which requires the cylinder head to be accurately seeured in position relative to the line borer before the procedure can be conduc~ed. l~ealigning camsha~ integral bea3~ng surfaces is therefore $~ present a ~ime consurning procedure. ~
: 15 ~ ~ It IS an object of the invention to provide a relatively simple tool for realigning camsha~ integral: bearing ~ surfaces which will reduce the time required to conduct this procedure.
To ~his end, there is pr~ided a linishing tool for reconditioning a camsha~ integral bearing surface of a cylinder head includ~ng an elongate body ha~nng an outer sur~ace, at : least a portion of the outer s~i~face of the body being a linishing surfiace, and at least one handle provided at an;end ofthe body, the body having at least one cylindl~cal section with a lateral cross-sectlon~having a diamet corresponding to the required bearing diameter of the camsha~L integral boaring surface.
: ~ The "required bealing diameter" is the radius of cun~ature of the integral bearing ~` 25 surface ~;vhich enables the surface :to support a camsha~ without binding of that camsha~
when fitted.
The m~ firishing p~cess of "linishing" invo~ves the use of a surface covered by fine ~: particlès of hard material which acts as an abrasivé ~or the removal of mat~er by scratching ~d;grinding. I~is i~ nguished ~om line borers~ re~mers and files which ~1 use a cutting action to remuve maten~l.

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~ ~X~ S~T (Rule 2~

wO 95/0029~ 28 ~ ~ 2" PCTIAU94/00333 A substantial portion of the body outer sur~ace may comprise the linishing surface.
The linishing surface may for example be in the forrn of a spiral band circling the cylindrical section(s), and may preferably cover about 50% of the outer surface of the elongate body.
Altematively, the linishing surface may be in the fosm of a plurality of parallel flutes~extending longitudinally along the cylindrical sec~on(s). In another al~ernative, the lir~ishing surface may compr~se substantialiy the entire outer surface of the elongate body.
The elongate body may be provided by a plurality of cylindrical sections arranged in a row with the~r axes of symme~y co-axial with a common elongate axis of the body. The diameter of the lateral cross-section of each cylind~ical section may preferably decrease sequentially from one end of the body to the end thereof. The diameter of the lateral cross~section of each cylindrieal section corresponds to the required bea~ing diameter of a particular camsha~
inte~al bealing surface of the cylinder head. A range of linishing tools can therefore be produced for diffierent production cyli}~der heads, even ~n the case where the bearing di~neters of each integral bearing surface varies on a particular cylinder head.
:15 A;handle may be provided at opposing ends of the elongate body the handles may be :: : substantially cylindrical and may have a la~eral cross-section with a diarneter less than the diameter of the cylindrical section with the smallest diameter.
Preferred examples of the present invention will hereina~er be described w~th ;: ; reference to the accompanying drawings, in which:
Figure 1 is a side elevation view of one example of a linishing tool according to the ~nvention; and Figure 2 is a detailed side ~qew of another example of the linishing tool of the present inve~tion.
Refe~ing initially ~o the linis~g tool shown in Figure 1, the linishing tool includes an elongate c,rliIldrical body 1 h~ving an outer surface 2. At least a portion of the outer , ` ~e 2 is in ~e folm of a linis~ng surl~ce 3 . In ~e illus~ated example, the linishing surface 3 is in t~e fonn of a spiral circling the body 1 ~om one end to the opposing end thereof. The lin~sbmg sw~ace 3 :pref~ably covers about 50% ofthc outer surface. Other alTangements are :~ ~ also pos~ible and the linishinig surface 3 could altematively compnse a plurality of parallel ~utes e~tending longnudinally along the body I . The adv~tage of having a linishing surfa~e SUBS;~UI~ S~T ~Rule 2~i) WO gS/00293 21 L~ n PCT/AU94/00333 "3"
3 covering only a portion of the body outer surface 2 is that the smooth surfaces 4 between the linishing surfaces 3 provide a discharge path for material removed by the linishing tool.
Nevertheless, it is also envisaged that the linishing surface 3 comprise substantially the en~ire outer surface 2.
The diameter of the elongate body 2 corresponds to the required bearing diameter of ~he camsha~ in$egral bearing surfaces of the cylindrical head. Where the bearing diameters of each bearing surface valies sequenti~lly along the cylinder head, the body 1 may include a plurality of cylindrical sections 7, 8 as shown in a detail view in Figure 2 with the diameter ofthe lateral cros~section of each section corresponding to the required bearing diameter of 10 a parhcular be~ing sur~ce. The axis of symmetry of each cylindrical section 7, 8 a~e co axial with a ~ommon elongate axis of the body 1. The cylindrical sec~ion diameters can decrease in diameter sequerltially from one end of the body 2 to the other end thereof providing a series of stepped changes in diameter. A range of linishing tools can therefore be produced $o suit e~ v~g camsha~ bealing diarneters already in production cylinder heads.
Handles are provided at opposing ends of the elongate body 1 and are cylindrical in form. The lateral cross-section of each handle 5 has a diameter less than that of the lateral cross section of the cylirldrical section with the smallest diameter.
The linishing tool is used by placing the elongate body 1 of ~he tool in the "camsha~
~:: tunnel" as defined by the integral bearing surfaces, and by moving the ~ool in a direction :~: 20 parallel to its elongate axl5 and/or rota~ing the tool about the axis so th~t ~he linishing surfaces 3 abrades the bearing s~rface removing all of the "high spots" therein which would cause binding ofthe camsh~ if not removed . Although the illustrated ~xample shows handles for nanual ~use of the linishing tool, h is also envisaged that the linishing tool be motor driven.
~: ~ As the linishing tool works on all the beaIing sur~aces sLmultanes)usly, the bearing surfaces 25 are alig~ed more quickly than by $he knowll procedure. Furth~ore, because the tool is dimFnsioned to the required bearing diameter(s3, and because the linishing process provides a smooth finish, the bearing surfaces ~ more accurately finished to the required cleara~ace.
The linis~ing tNol can be macl~ed ~om a single bar of blight steel or ~om mild steel `: ; which is then ~ckel plated. The handles S would therefore be integral with the elongate 30 body 1; The linishing su&ce is applied ~o the outer surface ofthe body I by known means, the abra~ive matelial prefierably beulg silicon carbide (commonly known "carbo~ndum"3 or SUB~;$~U~E 5H~T ~Rulc 2~;) "4"

diamond dust, al~hough other materials are also envisaged. It is also envisaged that the handles be ma~ie separately from the elongate body. Aiternatively, if the linishing tool is to be used only a ~ew times, then the tool could be made of wood with an abras1ve coating applied using adhesive on the body.

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, SUBSlrlUlEl SE~(Rule 26)

Claims

"5"

1. This Camshaft Bearing Alignment Linisher will save a considerable amount of time in alignment of camshaft bearings in overhead camshaft cylinder heads. The present system used to align the camshaft tunnel is called a "Line Boring System", this system would normally take forty five minutes to align the camshaft tunnel.

2. Our system would take approximately two minutes the labour saving is enormous in comparison. The cost of our Linishing Alignment System is approximately one sixth the price of Line Boring System.

3. Our system of alignment is able to be operated by non skilled labour.
The other systems need an experienced and qualified operator, as the Line Boring Machinery is quite complicated.

4. The camshaft bearing Alignment Linishing System has been devised to provide a more economical form of aligning camshaft tunnels of overhead camshaft cylinder heads, to both make the job more accurate and save valuable labour time in the process.
A camshaft fitted to camshaft tunnel which is out of alignment will cause a seizure of the camshaft in the bearings.

5. Our alignment system will align the bearings so the camshaft will free spin and cannot seize in the bearings.

6. The Cutting and Linishing surface is coated with Diamond matrix particles which have an almost endless life compared to other machines already in service.

7. The Cutting and Linishing surface could be coated with any form of abrasive that may reduce the cost of producing the Camshaft Bearing Linishing Tool.

"6"

8. The Linishing tool is used by placing the elongated body of the tool in the Camshaft tunnel as defined by the Integral bearing surface, and by moving the tool in a direction parallel to its elongated axis and/or rotating the tool about the axis so that the Linishing surface will abrade the bearing surface removing all of the high spots therein which would cause binding of the camshaft if not removed.

9. This tool in its present form is manually hand operated for the simplicity of operation.

10. It is also envisaged that the tool be motor driven creating a similar operation, but would remove material faster and fit into a production line situation.

11. The Linishing tool can be machined from a single bar of bright steel or from mild steel which is then nickel plated. The handles would therefore be Integral with the elongated body.

12. The Linishing surface is applied to the outer surface of the body by known means, the abrasive material preferably being Diamond Matrix although other materials maybe also envisaged.

13. It is also envisaged that the handles be made separately from the elongated body.

14. Alternatively the Linishing tool can be made out of wood or plastic or such like products to produce a throw away or disposable tool which can be coated with carborundum or silicon carbide or similar abrasive surfaces.