EP0740054A2 - Herstellungsverfahren eines Zylinderkopfes - Google Patents

Herstellungsverfahren eines Zylinderkopfes Download PDF

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Publication number
EP0740054A2
EP0740054A2 EP96106651A EP96106651A EP0740054A2 EP 0740054 A2 EP0740054 A2 EP 0740054A2 EP 96106651 A EP96106651 A EP 96106651A EP 96106651 A EP96106651 A EP 96106651A EP 0740054 A2 EP0740054 A2 EP 0740054A2
Authority
EP
European Patent Office
Prior art keywords
valve seat
cylinder head
valve
head unit
blanks
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP96106651A
Other languages
English (en)
French (fr)
Other versions
EP0740054B1 (de
EP0740054A3 (de
Inventor
Shuhei Adachi
Junkichi Amano
Hiroyuki Sakai
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Yamaha Motor Co Ltd
Original Assignee
Yamaha Motor Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP7102004A external-priority patent/JPH08296417A/ja
Priority claimed from JP7101998A external-priority patent/JPH08296416A/ja
Priority claimed from JP7102016A external-priority patent/JPH08296418A/ja
Priority claimed from JP7109727A external-priority patent/JPH08303296A/ja
Application filed by Yamaha Motor Co Ltd filed Critical Yamaha Motor Co Ltd
Publication of EP0740054A2 publication Critical patent/EP0740054A2/de
Publication of EP0740054A3 publication Critical patent/EP0740054A3/xx
Application granted granted Critical
Publication of EP0740054B1 publication Critical patent/EP0740054B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F1/26—Cylinder heads having cooling means
    • F02F1/36—Cylinder heads having cooling means for liquid cooling
    • F02F1/38—Cylinder heads having cooling means for liquid cooling the cylinder heads being of overhead valve type
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01L—CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES
    • F01L3/00—Lift-valve, i.e. cut-off apparatus with closure members having at least a component of their opening and closing motion perpendicular to the closing faces; Parts or accessories thereof
    • F01L3/22—Valve-seats not provided for in preceding subgroups of this group; Fixing of valve-seats
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F2001/241—Cylinder heads specially adapted to pent roof shape of the combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F1/00—Cylinders; Cylinder heads 
    • F02F1/24—Cylinder heads
    • F02F2001/244—Arrangement of valve stems in cylinder heads
    • F02F2001/245—Arrangement of valve stems in cylinder heads the valve stems being orientated at an angle with the cylinder axis

Definitions

  • This invention relates to a method for producing a cylinder head unit of an internal combustion engine, comprising the steps of casting a cylinder head having valve openings, providing said valve openings with valve seats by fastening valve seat blanks and applying a finishing treatment to said valve openings and said valve seats.
  • the cylinder head units for engines were formed by casting aluminum alloy materials, and valve seats were attached to the valve face surfaces for the intake valves and exhaust valves. Since these valve seats would be exposed to high heat as they made repeated contact with the air intake and exhaust valves, they were formed from a sintered ferrous metal that has excellent resistance to wear and high temperatures. As is shown in Figure 18, they were pressed into a retaining hole formed in the openings on the combustion chamber side of the cylinder head for the air intake ports and exhaust ports to unitize them with the cylinder head unit.
  • Figure 18 is an enlarged sectional view of a conventional valve seat that was press-fitted into the cylinder head.
  • 1 is the cylinder head unit
  • 2 is the press-fitted type of valve seat
  • 3 is the retaining hole for the valve seat.
  • the retaining hole 3 for the valve seat was formed by machining around the port opening area of the cylinder head.
  • valve seats 2 were installed by first making the retaining holes 3 as described above in the cylinder head unit 1, and then by heating the cylinder head unit 1 in a furnace to cause the diameter of the retaining holes 3 to increase, and then pressing-in the valve seats. To wit, the valves seats would be attached to the cylinder head unit by shrink fitting.
  • valve guide retaining holes are cut at the same time as the retaining holes 3 using a machining process.
  • the problem with using press fitting for the valve seats is that it is not possible to simplify the production process or to shorten the production time.
  • the reasons are first, the retaining holes 3 for the press fitting must be positioned with high accuracy to position the valve seats, and the machining processing takes too much time.
  • Second is the fact that a heating furnace has to be employed in a beating process for affixing the valve seats 2 to the cylinder head unit.
  • this objective is solved for a method for producing a cylinder head unit as indicated above in that during casting of the cylinder head manufacturing reference surfaces are formed thereon and that the position for said valve seat blanks on said valve openings is determined on the basis of indexing on said manufacturing reference surfaces, and then metallurgically bonding said valve seat blanks to said valve openings.
  • said manufacturing reference surfaces define three directions comprising a first end surface on the side of said cylinder head facing a cylinder body, a second surface parallel to said first surface and a third surface being perpendicular to both the first and second surfaces.
  • valve seat blanks In order to exactly position said valve seat blanks at the valve openings it is advantageous when said position for said valve seat blanks is dependent from the axial direction of valve guide holes or from knock pin holes both holes drilled after casting.
  • a preferred bonding process for said valve seat blanks with said cylinder head unit comprises the steps of placing a valve seat base material onto a surface of said openings of said cylinder head unit and pushing an electrode against the end face of said valve seat base material opposite to said cylinder head unit with a pushing direction matched with an axis of said intake or exhaust valve, whereby said electrode being adapted to apply electricity to said cylinder head unit through said valve seat base material.
  • the pressing force and/or said electricity are applied according to a predetermined pattern.
  • valve seat blank is pressed around the port openings and electrical resistance is used to heat the zone where the two are in pressure contact; this causes the temperature to rise at the surfaces where the two are in pressure contact, causing the atoms to become mutually dispersed.
  • a layer of co-crystalline alloy is formed between the metal material of the valve seat and the component metal materials of the cylinder head unit.
  • any machining of the cylinder head is superfluous, and in addition, a heating furnace to heat up the cylinder head for the purpose of attaching the valve seats also is superfluous.
  • valve seat blank in attaching the valve seat blank to the cylinder head, when contrasted to the press fitting of the valve seat, there is no need for the boring of special guide holes for the valve seats prior to their attachment.
  • heating process for the cylinder head that utilizes a heating furnace, and the washing process needed to remove foreign matter therefrom prior to heating have been eliminated.
  • valve seat blank in attaching the valve seat blank to the cylinder head unit, special guide holes for the valve seats need not be drilled prior to their attachment.
  • heating process for the cylinder head that utilizes a heating furnace, and the washing process needed to remove foreign matter therefrom prior to beating have been eliminated.
  • the indexing for the attachment openings and the boring of the foregoing holes for component parts is performed on the basis of common manufacturing reference surfaces, which means that the positioning relationships between the two remain unaffected by casting tolerances.
  • Other preferred embodiments of the present invention are laid down in further dependent claims.
  • Figure 1 is a sectional view of the valve seat area of a cylinder head employing valve seats attached using the manufacturing method of this invention
  • Figure 2 is a sectional view showing the valve seat blank positioned over the port opening, in this figure only a part of the cylinder head and valve seat are shown in the enlargement.
  • Figure 3 shows a front view of a press device which is used in implementing this invention's cylinder head manufacturing method
  • Figure 4 is the same shown in a side view
  • Figure 5 is a sectional view showing the electrode in contact with the valve seat material.
  • Figure 6 is a graph which shows the pressure pattern, the electrical current values and the degree of embedding.
  • Figure 7 is a sectional view showing the formation of the alloy layer from the stock metal of the cylinder head and the metal film covering the valve seat blank;
  • Figure 8 is a sectional view showing the onset of the plastic flow of the metal from the cylinder head stock;
  • Figure 9 is a sectional view showing the embedding of the valve seat blank into the cylinder head;
  • Figure 10 is a sectional view showing the finishing of the valve seat,
  • Figure 11 is a top view showing a shield utilization example;
  • Figure 12 is a block diagram that explains the process steps for manufacturing a cylinder head according to the first embodiment.
  • 11 represents the cylinder head unit of a four-cycle engine; this cylinder head unit 11 was formed by casting an aluminum alloy material. Formed in it is a downward-opening dome-shaped concave zone 12 that forms a combustion chamber and an air intake port 13 that opens at one end of this concave zone 12, and an exhaust port 14. Also formed when casting this cylinder head unit 11 are manufacturing reference surfaces that define three directions, they are composed of the cylinder body end surface, a parallel surface, and another that is perpendicular to the two.
  • These manufacturing reference surfaces can be formed, for example, on the concave zone 12 that forms the foregoing combustion chambers and on the inner wall of the cam chain chamber (not shown).
  • the manufacturing reference surface formed on the foregoing concave area can be formed by partially notching upward into the cylinder head in the area of the concave zone 12, near the spark plug hole (not shown).
  • the manufacturing reference surface on the inner wall surface of the chain chamber, etc. one may form it by partially notching the inner wall of the chain chamber, just as was done for the foregoing concave zone 12.
  • the air intake valve 17 and exhaust valve 18 are attached in the upper wall areas of the foregoing air intake port 13 and exhaust port 14 by valve guides 15, 16, and valve seats 19 are attached around the openings to both ports 13, 14.
  • the foregoing valve guides 15, 16 have been press fitted into valve guide retainer holes 11a formed by machining the cylinder head unit 11.
  • the retainer holes 11a for the valve guides are formed in a manner such that their axial lines C coincide with the axial lines of the openings 13a and 14a of the air intake port 13 and the exhaust port 14, respectively.
  • the machining of the valve guide retainer holes with respect to the foregoing openings 13a, 14a is performed by indexing on the manufacturing reference surfaces that were formed during the casting of the cylinder head unit 11.
  • valve seat 19 shown in Figure 1 is a ring-shaped piece of valve seat blank that was attached to the cylinder head 11 by the method of this invention, and subsequently machined to its finished dimensions.
  • the foregoing valve seat blank bears the reference number 20.
  • the valve seat blank 20 is composed of a ring-shaped sintered ferrous alloy 21 , for example, with a copper film 22 covering its surface.
  • valve seat blank 20 is positioned over the openings 13a, 14a for the air intake port 13 and exhaust port 14, the latter being of a shape such that a part of their outer circumferential surfaces lies adjacent to the inside of these openings 13a, 14.
  • the bottom surface of the cylinder head unit 11 (the surface containing the concave areas 12 forming the combustion chambers) is facing upward.
  • the outside circumferential surface of the valve seats 20 assumes an increasingly smaller outside diameter as it gets closer to the side facing the cylinder head unit, thereby forming a sloping surface.
  • the bottom surface 20b of the valve seat blank 20 is sloped increasingly toward the cylinder head unit as its axis is approached. This means that the outside circumferential surface 20a and the bottom surface 20b join to form a convex curved surface. In Figure 2, this convex surface has been labeled 20c.
  • a ridge area 23 which partially narrows the inside diameter of the intake and exhaust ports 13, 14.
  • This ridge area 23 is formed during the post-casting machining of the cylinder head unit 1.
  • This ridge area 23 comprises the attachment opening used in this invention.
  • valve seat blank 20 By placing this valve seat blank 20 over the foregoing openings 13a, 14a as shown in Figure 2, the convex curved surface 20c on the seats comes into contact with the ridge area 23 on the cylinder head unit 11.
  • the inside circumferential surface of the valve seat blank 20 is composed of sloped surface 20d which slopes in a manner such that the inside diameter of the valve seat blank 20 diminishes the closer to the cylinder head unit 11, and an axially extending surface 20e which extends from the sloped surface 20d parallel to the axial direction.
  • the press device 24 shown in Figures 3 and 4 is used to join the above-structured valve seat blanks 20 to the cylinder head unit 11 at the aforementioned openings 13a, 14a.
  • a lower platen 26 is affixed to the lower area of the frame 25 of the press apparatus 24 and, positioned above this lower platen, is a movable upper platen 27 which can be freely moved up and down.
  • the foregoing lower platen 26 and the upper platen 27 are respectively attached through electrically conducting materials 26a, 27a to an electric power supply (not shown) which supplies them with electricity.
  • the conducting materials 27a connected to the upper platen 27 are structured to deform with the rise/fall operation of the upper platen 27, or to rise and fall with it. Also, in this embodiment, the upper platen 27 forms the anode while the lower platen is the cathode.
  • a laser displacement meter comprising a reflector 29 which reflects laser light to measure the displacement of the upper platen 27.
  • the lower electrode 31 is affixed atop the foregoing lower platen 26, and then the cylinder head unit 11 is rested atop this lower electrode 31. At this time, the concave areas 12 that form the combustion chambers in the cylinder head 11 are facing upward and the axial line of the port opening to which the valve seat blank 20 will be attached aligned with the axial line of the rod 28a of the foregoing cylinder apparatus 28.
  • a guide rod 32 is inserted into the retaining hole for valve guide 15, 16 for the port to which the valve seat blank 20 is to be attached, from the side that has the concave areas 12 that form the combustion chambers.
  • This guide rod 32 is composed of a round metal rod 32a which is covered by a layer of insulating material 32b such as alumina. The positioning is determined and retained by a stopper 32c that fits into the valve guide retaining hole 11a.
  • the method used to form the foregoing layer of insulating material 32b was flame spraying of alumina or other ceramic material onto a round rod 32a and then polishing to finish.
  • valve seat blank 20 is placed over the port opening and then the upper electrode 33 is rested atop the valve seat blank 20.
  • This upper electrode 33 has a guide hole 33a into which fits the foregoing guide rod 32. Its lower end has a tapered surface 33b that closely fits the foregoing sloped surface 20d ( Figure 2) of the valve seat material, and an axially extending surface 33c which fits tightly around the axially extending surface 20e of the valve seat blank 20 to keep it in position
  • a magnet 33d affixed to the lower end of the upper electrode 33 which can magnetically hold and release the valve seat blank 20.
  • the upper electrode 33 is aligned coaxially with the port opening for the cylinder head 11; the above mentioned tapered surface 33b and circumferential surface 33c are in close contact with the valve seat blank 20, thereby positioning it for a coaxial fitting to the port opening.
  • the top electrode 33 After resting the upper electrode 33 on the valve seat blank 20, the top electrode 33 is rotated and a check is made to assure that the valve seat blank 20 is correctly fitted therein.
  • the cylinder apparatus 28 drives the upper platen 27 downward so that the foregoing upper electrode is in tight contact. At this time the lower surface of the upper platen 27 is parallel to the top surface of the upper electrode 33.
  • the foregoing cylinder apparatus 28 drives the upper platen 27 downward to hold the foregoing valve seat blank 20 using the upper electrode 33 at a constant pressure against the cylinder head unit 11.
  • the direction of this pressure being applied to the valve seat blank 20 coincides with the axial direction of the port openings 13a, 14a. Because of this, the pressure on the valve seat blank 20 is in line with the axial direction of the port openings 13a, 14a.
  • the pressing force is varied as shown by the solid line showing the pressing force pattern in Figure 6. To wit, there is a first pressing force P1, a constant and relatively low level of force that is applied initially, and following that, a relatively higher constant second pressing force P2 is applied for the duration of the operation.
  • the composition in the area of the interface is a co-crystalline alloy consisting of copper from the copper film 22 and aluminum alloy from the cylinder head unit 11.
  • Figure 7 shows a model of the interface area at this time.
  • the area marked by A is that where there has been a mutual dispersion of atoms and the formation of the foregoing co-crystalline alloy.
  • This plastic flow exhibits approximate vertical symmetry as shown in Figure 7, centered around the area of initial contact, so that, as shown in Figure 8, in conjunction with the liquefied co-crystalline alloy mentioned above, the plastic flow is pushed to the outside the contact zone.
  • the area wherein the co-crystalline alloy has been pushed out is labeled B.
  • a part of the copper film 22 on this valve seat blank 20 has been converted into co-crystalline alloy and expelled from the contact zone, a part of the ring-shaped unit 21 is in contact with the aluminum alloy, and in this area, there is also a dispersion of atoms between them.
  • the area in which this dispersion takes place is shown by C in Figure 8.
  • valve seat blank 20 begins to become embedded into the cylinder head unit 11.
  • the application of pressure is increased from the time that this valve seat blank 20 starts to embed until time T3 shown in Figure 6 is reached; this is the second pressing force P2 that was described above.
  • the plastic flow of the aluminum alloy increases, and the amount of co-crystalline alloy that is expelled also increases.
  • the co-crystalline alloy composed of copper and aluminum alloy in the un-reacted areas of the contact zone lies the co-crystalline alloy composed of copper and aluminum alloy, and as described above, this phenomenon repeats to further liquefy and eliminate the co-crystalline alloy.
  • the sintered ferrous alloy composing the ring 21 has its atoms mutually disperse with the aluminum alloy at their increasingly broadening interface.
  • the amount of embedding of the valve seat blank 20 may be determined by computing the difference between the position from where the upper platen 27 began its descent to its final position. Should this value not lie within a pre-determined tolerance D (see Figure 6), then the attachment would be regarded as defective.
  • the above described tolerance D was from about 0.5 to 2 mm in this example. While the tolerance depends upon the material used for the cylinder head unit 11, normally, it should range between about 1 mm and 1.5 mm.
  • the heat retention test would involve heating the cylinder head 11, as shown in Figure 9, in a furnace with exposure to the atmosphere to 300° C for from 24 to 200 hours, cooling, and then performing the foregoing separation test.
  • the heat shock experiment could be performed on the cylinder head 11, as shown in Figure 9, by 10 repetitions of heating it in a furnace to 300° C with exposure to the atmosphere, removing it from the furnace, and immediately cooling to 0° C by immersing in ice water, and then checking the valve seat blank 20 for separation or for any cracks before subjecting it to the foregoing separation test.
  • the final finishing of the valve seats shown in Figure 9 may be performed by machining away the unneeded areas, for example, to the shape shown in Figure 10. This final finishing removes the unneeded areas and the copper film from the ring 21, but it leaves the valve seats 19 attached to the cylinder head unit 11 by the atom dispersion zone C that is shown in Figure 10.
  • the metallurgical bond formed between the aluminum alloy of cylinder head 11 formed in the above described manner and sintered ferrous alloy of the valve seat 19 is essentially different from a mechanical bond and non-continuous bond that lacks its atom dispersion. Further, this method also differs metallurgically from the welding method wherein electrical resistance heating is applied at the interface of two materials to cause their localized melting, and then the current is cut to allow the liquid phases to cool and harden.
  • the metallurgical bond that was obtained with the cylinder head in this embodiment did not leave a residual molten reaction layer, but derives from the formation of a continues structure by mutual dispersion of atoms at the interface between both materials.
  • valve seat blank 20 In attaching the valve seat blank 20 to the cylinder head unit 11 as described above, in cases where the effects of the magnetic field generated by the application of current cause the co-crystallized alloy to be expelled in a specific direction from the junction area, it is preferable to position a shield 34 adjacent to the upper electrode 33 as is shown in Figure 11.
  • Figure 11 is a top view showing the case where a shield is employed. That figure shows the upper electrode positioned against the valve seat blank 20 and the cylinder head unit 11. Detailed descriptions of the other parts will be omitted since they are the same as or similar to the ones described in Figures 1 through 10.
  • the shield 34 used in this embodiment is formed from a vertically split cylinder made of ferrous ferromagnetic material, and the crown area of the outside circumferential surface points toward the frame 25 of the press apparatus 23.
  • the direction for the frame 25 position is shown by the arrow in that figure.
  • Figure 12 shows the manufacturing procedure used to join the valve seat blanks 20 to the cylinder head 11 using the above described method.
  • step 101 the manufacturing reference surfaces are formed during the casting of the cylinder head unit 11.
  • step 102 the convex shaped areas 23 are formed as the junction opening around the port openings 13a, 14a.
  • step 103 the retaining holes 11a for the valve guides are formed.
  • step 104 the valve seat blank 20 is positioned.
  • the cylinder head unit 11 after having undergone the machining process, is affixed in the foregoing press apparatus 24, then, as described above, the guide rod 32 and the upper electrode 33 are used to position the valve seat blanks 20 over the port openings 13a, 14a.
  • a washing process prior to this positioning operating in order to remove any cuttings that were generated during the machining. This cleaning process can be implemented by water washing, or by compressed air cleaning of the cylinder head unit.
  • step 106 the valve seat blank 20 is pressed against the cylinder head unit 11 by the press apparatus 24, and current is based between the valve seat blank 20 and the cylinder head unit 11. This process joins the valve seat blank 20 to the cylinder head unit 11.
  • the valve guides 15, 16 are press fitted into the valve guide retaining holes 11a in the cylinder head unit.
  • the valve guides 15, 16 are inserted cold, but in the case of using a shrink fit method as in the prior art, a heating process 108 can be applied prior to the press fitting process 107 for the valve guides. In such a heating process 108, the cylinder head unit 11 would be heated in a furnace, and the unheated valve guides 15, 16 would be inserted and then held in place by the shrinkage from cooling.
  • step 109 involves the rough machining of the valve seat blanks; these, along with the valve guides 15, 16, are subsequently finished off into valve seats 19 in the next step 110.
  • the subsequent processes involve seating the intake and exhaust valves 17, 18 into the valve seats 19 and inspecting for sealing, and machining the camshaft bearing areas.
  • This machining of the bearing can be performed after the finishing of the valve seats 19 and valve guides 15, 16, or, it can be performed either before or after the foregoing step 103 where the retainer holes for the valve guides are machined, or step 107 where the valve guides are inserted.
  • valve guides 15, 16 would be pressed in (step 107) and then after that, the valve seat blanks 20 would be positioned (step 104), and the valve seat blanks 20 would be pressed, and current passed through them (step 106). It is also possible to insert a washing process 105, or a heating process 108 involving either cylinder head unit 11 heating, or cooling of the valve guides 15, 16 prior to the press fitting of the valve guides 15, 16.
  • valve guide retaining holes 11a can be used for the positioning of the valve seat blanks 20 over the openings for attachments, so that, compared with the method that uses press fitting for the valve seats, it is not necessary to drill any special guide holes for the valve seats prior to attaching them.
  • This method also renders unnecessary any use of a furnace to heat the cylinder head unit for the purpose of attaching the valve seats, as it does any need to remove machining cuttings prior to loading the cylinder head 11 into the heating furnace.
  • the positioning of the valve seat blanks 20 on the port openings 13a, 14a was performed using the retaining holes for the valve guides, but it is also possible to use as a positioning guide the holes used for the assembly of the cylinder head.
  • the nock pin holes (not shown) which hold nock pins (not shown) that facilitate the positioning of the cylinder head unit 11 on the cylinder body (not shown).
  • Figure 13 shows the production steps involved when these nock pin holes are used for indexing the position and pressing of the valve seat blanks 20.
  • Figure 13 is a block diagram showing the procedure for cylinder head manufacturing for the case when the nock pin holes are utilized for the positioning of the valve seat blanks after the machining process. In the figure, explanation will be omitted for those reference numbers that are the same or similar to those used in Figure 1 through 12.
  • the nock pin hole machining is performed in step 120. Then, in steps 104 and 106 the valve seat blanks 20 are positioned, and the valve seat blanks 20 are pressed and current is applied. At this time, the nock pin holes are utilized to determine the position of the valve seat blanks 20 around the opening and the direction of pressure application.
  • step 103 After attaching the valve seat blanks to the cylinder head 11 in this manner, in step 103, the machining is done to make the valve guide retainer holes 11a. The positioning is also performed for this machining process based on indexing relative to the nock pin holes. This process is followed by the valve guide press fitting process in step 107, the valve seat blank rough finishing operation in step 109, and by the valve seat blank final finishing process in step 110.
  • valve guide retention hole machining process in step 103 ⁇ the valve guide press fitting process in step 107 ⁇ the valve seat blank positioning process in step 104 ⁇ the valve seat blank pressing and current application in step 106 ⁇ the valve seat rough finishing process in step 109 ⁇ and the valve seat final finishing in step 110 would be used to complete the process.
  • Example 1 The same types of effects as in Example 1 are realizable when this structure is employed.
  • Figure 14 is a block diagram that will be used to explain the manufacturing processed for cylinder heads according to this third embodiment. In the figure, detailed explanation will be omitted for those reference numbers that are the same as or similar to the ones used in Figures 1 through 13.
  • step 201 in Figure 14 for this method for manufacturing cylinder heads manufacturing reference surfaces are cast into the cylinder head unit 11, and the openings for the attachment of the valve seat blanks 20 are formed.
  • step 202 the positioning of the valve seat blanks over the attachment openings is based upon indexing relative to the manufacturing reference surfaces.
  • step 203 the pressing and the current passage is performed on the valve seat blanks 20.
  • the direction of the pressing of the valve seat blanks is set to be in the axial direction of the intake and exhaust valves 17, 18, on the basis of indexing on the manufacturing reference surfaces.
  • step 103 the retaining holes for the valve guides are bored ⁇ in step 107 the valve guides are press fitted ⁇ in step 109 the valve seat blanks are rough finished ⁇ and in step 110 the valve seat blanks receive their final finish processing to complete the process.
  • the junction openings where the valve seat blanks 20 are attached are formed during casting, and the manufacturing reference surfaces that were also formed during casting are used for positioning the valve seat blanks 20 over the foregoing junction openings. Therefore, compared to the conventional press fitting of valve seats, there is no machining needed on the cylinder head prior to the attachment of the valve seats. In addition, there is no need to heat up the cylinder head in a furnace for the purpose of attaching the valve seats, and moreover, because the foregoing two processes are not needed, neither is the washing process.
  • FIG 15 is a block diagram that will be used to explain the method of manufacturing cylinder heads Detailed explanation will be omitted for those reference numbers that refer to the same or similar parts used in the foregoing Figures 1 through 14.
  • step 201 in Figure 15 the method of cylinder head manufacturing forms manufacturing reference surfaces during the casting of the cylinder head unit, at which time the junction openings for the joining the valve seat blanks 20 are also formed.
  • the valve guide retainer holes 11a are bored (step 103). After that, it is the same procedure as shown in Figure 12 for Example 1. As it was with that example, it would also be possible to reverse the valve seat blank joining process and the valve guide press fitting process.
  • the junction openings where the valve seat blanks 20 will be attached are formed by casting, and the valve guide retainer holes 11a are used for positioning the valve seat blanks 20 over the foregoing junction openings. Therefore, compared to the case wherein the valve seats are press fitted, the method does not require the boring of a special valve seat hole prior to attaching the valve seat. In addition, it is possible to eliminate the heating process in the furnace for the cylinder heads, as well as the washing process that was required before loading the cylinder heads into that heating furnace.
  • Example 4 the valve guide retainer holes 11a were used as an index in the positioning of the valve seat blanks 20, but it would be possible as well to use the holes in the cylinder head which facilitate its assembly for the same purpose.
  • the nock pin holes (not shown) which hold nock pins (not shown) that facilitate the positioning of the cylinder head unit 11 on the cylinder body (not shown).
  • Figure 16 shows the production steps involved when these nock pin holes are used for indexing the position and pressing of the valve seat blanks 20.
  • Figure 16 is a block diagram showing the cylinder head manufacturing process when the nock pin holes are used for positioning the valve seat blanks 20 at the junction openings that were formed during casting. Detailed explanation will be omitted for those reference numbers that refer to the same or similar parts used in the foregoing Figures 1 through 15.
  • step 201 of Figure 16 When the nocking holes are used to determine the positioning, as is shown in step 201 of Figure 16, when casting the cylinder head unit, the manufacturing reference surfaces and the junction openings where the valve seat blanks 20 will be attached are formed during the casting process. After casting, first the nock pin holes are bored (step 120). After that, the steps proceed in the same way as shown for Example 2 in Figure 13. As before, it would also be possible to reverse the valve seat blank attachment process and the valve guide press fitting process.
  • both the valve seat blanks 20 and the cylinder head port openings 13a, 14a has convex areas (convex curved surface 20c and ridge area 23) formed upon them.
  • the examples featured these convex zones as being pressed against each other, but it is not absolutely necessary to form convex areas on both parts; they may be on one or the other parts.
  • This example is shown in Figure 17, (a) through (c). Irrespective of whether the junction openings where the valve seat blanks 20 are attached were formed during casting or by a machining process, it is possible to modify the shapes involved as described below.
  • Figure 17 is a sectional view showing other embodiments where the shapes at the pressure area have been changed.
  • examples are shown where there is a convex area formed on the valve seat blank; in (c) the example is for a projection formed only on the cylinder head.
  • explanation will be omitted for reference numbers that indicate the same or similar parts in the preceding Figures 1-10.
  • valve seat blank 30 has approximately the same shape as used in the previous examples, but there is a flat sloped surface formed around the port openings 13a, 14a upon which the valve seat blank 20 makes contact.
  • the outer circumferential surface of the valve seat blank 20 is structured to fit into the port openings 13a, 14a. Also, the inside circumferential surface of the valve seat blank 20 differs from that described in the foregoing embodiments, it has an axially extending surface 20e that extends through the entire thickness of the valve seat blank 20.
  • valve seat blank has a flat sloping surface that comes into contact with the ridge 23 on the cylinder head unit 11.
  • the material used to make the cylinder head was AC4C stock
  • the valve seat blanks 20 were composed of sintered ferrous alloy in ring shapes 21 that were immersed in molten copper to create a film of copper covering them, but such could have been formed by electroplating, and the materials used and the method of forming the covering film are not limited to those described in the embodiments.
  • the material used to comprise the cylinder head unit 11 could be any of the materials conventionally used for engine cylinder heads such as AC4B stock, AC2B stock, etc. Any type of sintered ferrous alloy can be used to make the ring shaped members 21, and there is no great difference whether they are coated by immersion in molten copper or electroplated.
  • the metal used to coat the ring shaped members 21 can be any that will form co-crystalline metal with the stock of the cylinder head unit 11. In selecting these materials and the film forming method, the most cost effective method should be chosen from the perspective of producing cylinder heads as an industrial product.
  • valve seat blank 2 was embedded in the foregoing examples was detected in the final stage of the process, but the displacement could be continuously measured while pressing, and then whether or not it was within the permissible tolerance could be checked periodically. By so doing, it is possible to eliminate defects and save the time that would be wasted in producing them.
  • the method of manufacturing cylinder heads according to the first invention involves forming during the casting process manufacturing reference surfaces which define three intersecting directions, and additionally, junction openings around the port openings where the valve seat blanks will be installed, and then after casting, by using the foregoing manufacturing reference surfaces to index the position of the valve seat blanks, which are composed of sintered ferrous rings coated with a metal film, and set them in place, and to again use the manufacturing reference surfaces as an index to apply pressure to the valve seat blanks in a direction that coincides with the axial direction of the intake/exhaust valves, and then, by heating the contact zone between the cylinder head and the valve seats using electrical resistance, causing the temperature to increase at the contact interface where the two are being pressed together, and causing the atoms to mutually disperse at that interface.
  • a co-crystalline alloy layer will be formed from the metal that coats the valve seat blanks and the cylinder head stock metal.
  • this co-crystalline alloy converts to a liquid phase at a low temperature
  • the foregoing resistance heating converts it into a liquid phase
  • the valve seat blank being pressed and heated, causes a plastic flow to cause this metal, along with the stock metal from the cylinder head, to be expelled from the junction.
  • valve seat blanks in joining the valve seat blanks to the cylinder head unit, no machining of the cylinder head is required prior to the attaching operation; this compared to the conventional method where valve seats are pressed in which does required initial machining of the cylinder head.
  • the use of a heating furnace for the purpose of heating the cylinder head for seat insertion is not needed, nor is a wash process needed prior to those steps.
  • manufacturing reference surfaces that define three intersecting directions are formed and the openings around the ports where the valve seat blanks make contact are shaped, then after casting, the manufacturing reference surfaces are used to determine the machining position for making the various holes needed in the cylinder head structure, and then, these holes are used for indexing the position of the valve seat blanks composed of sintered ferrous alloy rings covered by a metal film and then are further used to align the pressing direction upon the valve seat blanks to match the axial direction of the valve axes for the intake and exhaust valves; next, electrical resistance heating is used to heat the contact zone between the cylinder head unit and the valve seat blank, so that the temperature at the contact interface between the two increases and the atoms mutually disperse.
  • the metal material comprising the coating film on the valve seat blanks forms a co-crystalline layer with the metal stock from the cylinder head.
  • this co-crystalline alloy converts to a liquid phase at a low temperature
  • the foregoing resistance heating converts it to a liquid phase
  • the valve seat blank being pressed and heated, causes a plastic flow to cause this metal, along with the stock metal from the cylinder head, to be expelled from the junction.
  • the valve seat blanks in attaching the valve seat blanks to the cylinder head unit, there is no requirement to first make a special valve guide hole, as there is in the press-fitting method, before attaching the valve seat blanks. Also not needed are a heating process using a furnace to heat the cylinder head units for the purpose of fitting the valve seats, or a washing process to prepare the cylinder head units for the heating furnace.
  • the conventional method that employed the heating process did not allow cylinder head processing during the interval over which they were cooling down, so the elimination of this heating process can cause a dramatic simplification of the production process and a shortening of the production time.
  • the conventional heating furnaces would accommodate a plurality of cylinder heads and heat them all at once, the device required a great deal of space, and eliminating it allows more effective utilization of factory space. Further, the elimination of the beating furnace enables the shortening of the conveyor line for the cylinder heads, thereby shortening the conveyance time between machining devices.
  • one hole can serve multiple purposes, thereby bringing about a cost advantage.
  • the method of manufacturing cylinder heads according to the third invention involves forming, during the casting of the cylinder head, working references surfaces that define three directions and intersect, and then, after casting, determining the positions for machining the port opening and the various component holes in the cylinder head on the basis of these manufacturing reference surfaces, and then shaping the area of the port openings that makes contact with the valve seat blanks and boring the foregoing component holes, and next utilizing the foregoing holes to determine the position for the placement of the valve seat blanks, which are composed of sintered ferrous alloy rings covered with a metal film, and then, using the holes again as a reference for the application of pressure in the axial direction of the intake and exhaust valves, followed by the heating of the contact zone between the cylinder head unit and the valve seat blank using electrical resistance heating which causes the atoms at the interface between the two to mutually disperse at the compressed junction.
  • the metal from the coating film on the valve seat blanks forms a co-crystalline alloy layer with the stock metal from the cylinder head.
  • this co-crystalline alloy converts to a liquid phase at a low temperature
  • the foregoing resistance heating converts it to a liquid phase
  • the valve seat blank which is being pressed and heated, causes a plastic flow to cause this metal, along with the stock metal from the cylinder head, to be expelled from the junction.
  • this third invention when attaching the valve seat blanks to the cylinder head, it is not necessary to have a special process beforehand to bore guide holes for the valve seats prior to their attachment. In addition, it is possible to eliminate the heating furnace and the heating process that was used conventionally to attach the valve seats, and eliminate the washing process that was needed prior to loading the cylinder head units into the furnace.
  • valve seat blanks were attached to the cylinder head and the foregoing component holes, and accordingly, the positional relationship between the two remains unaffected by casting tolerances. Since this makes it possible to use the component holes as a reference in accurately positioning the attachment openings, it is possible to attach valve seat blanks with a high degree of precision.
EP96106651A 1995-04-26 1996-04-26 Herstellungsverfahren eines Zylinderkopfes Expired - Lifetime EP0740054B1 (de)

Applications Claiming Priority (12)

Application Number Priority Date Filing Date Title
JP102004/95 1995-04-26
JP10200495 1995-04-26
JP7102004A JPH08296417A (ja) 1995-04-26 1995-04-26 エンジン用シリンダヘッド
JP10199895 1995-04-26
JP7101998A JPH08296416A (ja) 1995-04-26 1995-04-26 バルブシートの接合方法
JP10201695 1995-04-26
JP101998/95 1995-04-26
JP7102016A JPH08296418A (ja) 1995-04-26 1995-04-26 バルブシートおよびバルブシートの剥離試験方法
JP102016/95 1995-04-26
JP7109727A JPH08303296A (ja) 1995-05-08 1995-05-08 シリンダヘッドの製造方法
JP109727/95 1995-05-08
JP10972795 1995-05-08

Publications (3)

Publication Number Publication Date
EP0740054A2 true EP0740054A2 (de) 1996-10-30
EP0740054A3 EP0740054A3 (de) 1996-11-27
EP0740054B1 EP0740054B1 (de) 2003-03-12

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EP96106651A Expired - Lifetime EP0740054B1 (de) 1995-04-26 1996-04-26 Herstellungsverfahren eines Zylinderkopfes

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EP (1) EP0740054B1 (de)
DE (1) DE69626561T2 (de)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998028523A1 (en) * 1996-12-21 1998-07-02 Unova U.K. Limited Method of fitting a valve seating ring and an apparatus therefor
EP2481519A1 (de) * 2011-02-01 2012-08-01 ELWEMA Automotive GmbH Verfahren und Anlage zur Verarbeitung eines bearbeiteten Automobilteils, insbesondere zur Verarbeitung eines Zylinderkopfs
CN111271185A (zh) * 2018-12-04 2020-06-12 通用汽车环球科技运作有限责任公司 具有混合阀座插件的气缸盖组件

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018218241A1 (de) * 2018-10-24 2020-04-30 Mahle International Gmbh Verfahren zur Montage eines Ventilsitzrings an einem Zylinderklopf einer Brennkraftmaschine

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US3728940A (en) * 1971-02-01 1973-04-24 Tobin Arp Mfg Co Apparatus for cutting valve seats in engine castings
US3935679A (en) * 1974-07-22 1976-02-03 Grede Foundries, Inc. Grinding fixture
JPS6176742A (ja) * 1984-09-25 1986-04-19 Toyota Motor Corp バルブシ−トリングレス軽合金シリンダヘツド
JPS63131853A (ja) * 1986-11-20 1988-06-03 Mitsubishi Motors Corp シリンダヘッドの加工方法
US4896638A (en) * 1988-12-07 1990-01-30 Ford Motor Company Fabricating internal combustion engine cylinder heads with close tolerance internal surfaces
DE4036614A1 (de) * 1989-11-16 1991-05-23 Mitsubishi Metal Corp Ventilsitz aus einer gesinterten fe-basis-legierung mit hoher verschleissfestigkeit
JPH05332106A (ja) * 1992-05-29 1993-12-14 Nissan Motor Co Ltd 内燃機関のバルブシート
FR2694788A1 (fr) * 1992-08-12 1994-02-18 Renault Conduit d'admission pour culasse de moteur à combustion interne et procédé de réalistion.
JPH084581A (ja) * 1994-06-15 1996-01-09 Mitsubishi Heavy Ind Ltd 鋳造部品

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US3728940A (en) * 1971-02-01 1973-04-24 Tobin Arp Mfg Co Apparatus for cutting valve seats in engine castings
US3935679A (en) * 1974-07-22 1976-02-03 Grede Foundries, Inc. Grinding fixture
JPS6176742A (ja) * 1984-09-25 1986-04-19 Toyota Motor Corp バルブシ−トリングレス軽合金シリンダヘツド
JPS63131853A (ja) * 1986-11-20 1988-06-03 Mitsubishi Motors Corp シリンダヘッドの加工方法
US4896638A (en) * 1988-12-07 1990-01-30 Ford Motor Company Fabricating internal combustion engine cylinder heads with close tolerance internal surfaces
DE4036614A1 (de) * 1989-11-16 1991-05-23 Mitsubishi Metal Corp Ventilsitz aus einer gesinterten fe-basis-legierung mit hoher verschleissfestigkeit
JPH05332106A (ja) * 1992-05-29 1993-12-14 Nissan Motor Co Ltd 内燃機関のバルブシート
FR2694788A1 (fr) * 1992-08-12 1994-02-18 Renault Conduit d'admission pour culasse de moteur à combustion interne et procédé de réalistion.
JPH084581A (ja) * 1994-06-15 1996-01-09 Mitsubishi Heavy Ind Ltd 鋳造部品

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1998028523A1 (en) * 1996-12-21 1998-07-02 Unova U.K. Limited Method of fitting a valve seating ring and an apparatus therefor
US6259054B1 (en) 1996-12-21 2001-07-10 Unova U.K. Limited Method of fitting a valve seating ring and an apparatus therefor
EP2481519A1 (de) * 2011-02-01 2012-08-01 ELWEMA Automotive GmbH Verfahren und Anlage zur Verarbeitung eines bearbeiteten Automobilteils, insbesondere zur Verarbeitung eines Zylinderkopfs
CN111271185A (zh) * 2018-12-04 2020-06-12 通用汽车环球科技运作有限责任公司 具有混合阀座插件的气缸盖组件

Also Published As

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DE69626561D1 (de) 2003-04-17
EP0740054B1 (de) 2003-03-12
DE69626561T2 (de) 2003-09-25
EP0740054A3 (de) 1996-11-27

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