WO1990002017A1 - Method of manufacturing valve etc. housings - Google Patents

Method of manufacturing valve etc. housings Download PDF

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Publication number
WO1990002017A1
WO1990002017A1 PCT/GB1989/000956 GB8900956W WO9002017A1 WO 1990002017 A1 WO1990002017 A1 WO 1990002017A1 GB 8900956 W GB8900956 W GB 8900956W WO 9002017 A1 WO9002017 A1 WO 9002017A1
Authority
WO
WIPO (PCT)
Prior art keywords
cylinder
cold
mould
valve block
valve
Prior art date
Application number
PCT/GB1989/000956
Other languages
French (fr)
Inventor
Kyrre Guttorm SJØTUN
Original Assignee
Kongsberg Automotive A/S
Brunner, Michael, John
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
Application filed by Kongsberg Automotive A/S, Brunner, Michael, John filed Critical Kongsberg Automotive A/S
Publication of WO1990002017A1 publication Critical patent/WO1990002017A1/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D17/00—Pressure die casting or injection die casting, i.e. casting in which the metal is forced into a mould under high pressure
    • B22D17/20—Accessories: Details
    • B22D17/22—Dies; Die plates; Die supports; Cooling equipment for dies; Accessories for loosening and ejecting castings from dies
    • B22D17/24—Accessories for locating and holding cores or inserts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
    • B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
    • B23P15/001—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass valves or valve housings

Definitions

  • the present invention relates to the manufacture of valve housings, and particularly to the manufacture of valve housings which are formed within an alloy block, for example, multiple valve openings being located in a single block in order that fluid channels connecting the multiple valves can be connected without external fittings.
  • valve spools and the like particularly those which are required to work axially, require the valve chamber to have a high degree of coaxiality and cylindricity whilst at the same time providing a surface macro-structure which has a high degree of smoothness.
  • lengthy finishing processes are required such as honing or super-finishing.
  • the manufacturing cost therefore of valve and like assemblies produced by such methods is extremely high.
  • chambers formed by casting and then boring, reeming and finishing result in a surface macro structure which has microscopic circular striations, resulting in undesirable tolerances between cylinder chamber and valve spool or piston.
  • Valve chambers in a block have been manufactured by the so-called "hot chamber” injection moulding process in which the material to be moulded is retained in a molten bath and is injected under pressure directly from the molten bath to the mould.
  • Cylindrical chambers are formed by spigots in the mould around which the material is formed, but in order to enable subsequent removal of the mould formers and spigots from the casting, it is necessary for the spigots to have a slight taper, in the order of 1* , so that chambers so formed require further finishing to achieve the desired degree of finish.
  • working the surface of the cylindrical chamber cuts through the "casting skin" formed after the casting or moulding process and thus results in a chamber which, due to the microscopic porocity, of the casting, may not be absolutely fluid tight.
  • a valve or like housing is formed by the steps of cold forging a cylinder; and inserting the cold-forged cylinder in a mould and injection moulding around the cylinder to form a valve block or housing.
  • the injection moulding process is a warm or hot chamber process as mentioned above, but it is envisaged that a cold chamber process, in which molten casting material is injected in a number of individual steps, may be used if desired.
  • a cold chamber process in which molten casting material is injected in a number of individual steps, may be used if desired.
  • the advantage of the warm or hot chamber method is that it is considerably quicker and there are fewer inpurities incorporated in the moulding or casting as a result of the multiple injection steps, since, in the warm or hot chamber method, the injection apparatus itself lies under the surface of the moulten casting material.
  • a particular advantage of the method according to the invention is the negligible distortion of the cylinder and highly accurate location that can be achieved due to the high internal surface quality of the cylinder achieved by the cold forging step.
  • a cold forged cylinder has a very high degree of cylindricity and coaxiality and can thus be located on a locating spigot which is an extremely close sliding fit within the cylinder. This is just not possible with other methods where the cylinder is formed, for example, by a process which includes drilling, reeming etc. in which the surface finish is of lesser quality, resulting in less accurate fitting within the mould and the possibility therefore of distortion during the moulding process.
  • a cold forged tube or cylinder has a surface macro-structure which extends in the axial direction to reduce friction and wear in a working valve spool or actuator sliding within the cylinder.
  • Such cold forged cylinders have a considerably harder surface than that available with conventionally drilled and finished cylinders which increases the wear resistance of the surface.
  • cold forged tubes or cups are not heated to the same degree during their initial manufacture and are therefore substantially free from internal stresses and tensions and thus relatively insensitve to temperature changes which, in other structures can lead to cracks and unsatisfactory finished products.
  • Figure 4 shows a warm or hot chamber moulding process at two separate stages, schematically in sectional form.
  • Figure 1 shows in parts a, b and c respectively, three separate stages during the cold forging of a cylinder which may be used to provide a valve cylinder for a spool valve in a valve assembly in accordance with the present invention.
  • Cold-forging techniques are, in themselves, well known and therefore the method shown in Figure 1 will not be described in detail.
  • the cylinder 1 which is formed during the cold forging part of the process has a very high degree of cylindricity and internal surface smoothness, the cylinder being formed by the extrusion of the material of the cylinder (for example stainless steel or aluminium) by impacting a mandrel 2 onto the surface of the material from which the cylinder is to be formed, the material being held in a matrix 3. As the mandrel impacts and works the material, the cylinder 5 is formed coaxial with and closely spaced around the mandrel 2.
  • the material of the cylinder for example stainless steel or aluminium
  • Figures 2 and 3 show the formation of cylinders of different cross-sections in order to illustrate the variety of different shaped cylinders that may be produced by the drop-forging process, in turn to illustrate the wide range of valve spool cylinder forms which may be employed.
  • Figure 4a shows a warm chamber injection moulding process prior to injection of molton material, in this case magnesium, into a mould, to form a valve block or housing.
  • the mould comprises mould halves 10,11 mounted on platens 12,13 as is conventional.
  • a cavity 4 formed between the mould halves contains three valve spool cylinders 15, each of which is supported on a cylindrical spigot 16 so as to be accurately and firmly held in position within the mould cavity.
  • Each of the spigots 16 lies with its axis substantially parallel to the direction of opening and closing of the mould halves in order to enable the finished moulded product to be removed from the mould cavity at the end of the moulding process.
  • Each of the cylinders 15 is formed by a cold forging process such as that of Figures 1, 2 or 3 and the supporting spigot 16 in each case is formed so as to be an extremely accurate and close fit within the related cylinder, so that when the molten magnesium is injected (as will be described later) there is reduced possibility of movement or distortion of the cylinder. It is due to the cold forging of each of the cylinders that close tolerances can be achieved. As is shown in Figures 4(a) and 4(b) (top cylinder) the lip of the cylinder can be widened so as to locate positively in the opposite mould half and thus further prevent any possibility of movement during moulding-in.
  • the mould includes a bath 17 of molten magnesium 18 which extends to the mould cavity 14 via a cylinder 20 into which an injection ram 21 is rapidly moved back and forth (in the direction of arrow 22) in order to force the magnesium into the mould cavity and around the cylinders 15.
  • This step is shown completed in Figure 4(b).
  • high pressures around 50 Bar
  • the high degree of cylindricity of the cylinders 15, in turn allowing a very close fit on the spigots 16 serves to avoid or reduce any distortion or movement of the cylinders, thus providing highly accurate valve cylinder bores in the finished product, without the time consuming, and thus expensive, prior methods.
  • An advantage of using the so called warm or hot chamber injection moulding process is that dross and magnesium oxides which are formed at the surface 19 of the bath of molten magnesium, are this kept from entering the flow of magnesium to the mould thus reducing impurities and improving the quality of the casting.
  • a cold chamber injection moulding process as described above, but this is not shown in the drawings for the sake of simplicity. Both magnesium and alluminium alloys may be injection moulded in a cold chamber process, but the warm or hot chamber process is only presently capable of being used with magnesium alloys.
  • a further advantage of the hot chamber process is the increase in production velocity, to the extent that between one and two hundred strokes per hour may be achieved in comparison with less than one hundred for a cold chamber process.

Abstract

A valve block or like housing is formed by the steps of cold forging a cylinder (15) and inserting the cold-forged cylinder in a mould (10, 11), after which molten metal is injection moulded around the cylinder to form the valve block or housing with the cylinder forming a valve cylinder.

Description

DESCRIPTION
METHOD OF MMUFACPTU_.I_.G- VALVE ETC PQgSINGS
The present invention relates to the manufacture of valve housings, and particularly to the manufacture of valve housings which are formed within an alloy block, for example, multiple valve openings being located in a single block in order that fluid channels connecting the multiple valves can be connected without external fittings.
It is known to injection mould magnesium and similar alloys around cylindrical valve chambers which have been pre-formed by separate casting, reeming or drilling processes. Valve spools and the like, particularly those which are required to work axially, require the valve chamber to have a high degree of coaxiality and cylindricity whilst at the same time providing a surface macro-structure which has a high degree of smoothness. In order to produce such chambers by conventional methods, lengthy finishing processes are required such as honing or super-finishing. The manufacturing cost therefore of valve and like assemblies produced by such methods is extremely high. Furthermore, chambers formed by casting and then boring, reeming and finishing, result in a surface macro structure which has microscopic circular striations, resulting in undesirable tolerances between cylinder chamber and valve spool or piston.
Valve chambers in a block have been manufactured by the so-called "hot chamber" injection moulding process in which the material to be moulded is retained in a molten bath and is injected under pressure directly from the molten bath to the mould. Cylindrical chambers are formed by spigots in the mould around which the material is formed, but in order to enable subsequent removal of the mould formers and spigots from the casting, it is necessary for the spigots to have a slight taper, in the order of 1* , so that chambers so formed require further finishing to achieve the desired degree of finish. Furthermore, working the surface of the cylindrical chamber cuts through the "casting skin" formed after the casting or moulding process and thus results in a chamber which, due to the microscopic porocity, of the casting, may not be absolutely fluid tight.
In order to overcome these problems and in accordance with the present invention therefore a valve or like housing is formed by the steps of cold forging a cylinder; and inserting the cold-forged cylinder in a mould and injection moulding around the cylinder to form a valve block or housing.
Preferably, the injection moulding process is a warm or hot chamber process as mentioned above, but it is envisaged that a cold chamber process, in which molten casting material is injected in a number of individual steps, may be used if desired. The advantage of the warm or hot chamber method is that it is considerably quicker and there are fewer inpurities incorporated in the moulding or casting as a result of the multiple injection steps, since, in the warm or hot chamber method, the injection apparatus itself lies under the surface of the moulten casting material.
A particular advantage of the method according to the invention, which is not achievable with other methods which involve casting around a pre-formed cylinder, is the negligible distortion of the cylinder and highly accurate location that can be achieved due to the high internal surface quality of the cylinder achieved by the cold forging step. A cold forged cylinder has a very high degree of cylindricity and coaxiality and can thus be located on a locating spigot which is an extremely close sliding fit within the cylinder. This is just not possible with other methods where the cylinder is formed, for example, by a process which includes drilling, reeming etc. in which the surface finish is of lesser quality, resulting in less accurate fitting within the mould and the possibility therefore of distortion during the moulding process. Additionally, a cold forged tube or cylinder has a surface macro-structure which extends in the axial direction to reduce friction and wear in a working valve spool or actuator sliding within the cylinder. Such cold forged cylinders have a considerably harder surface than that available with conventionally drilled and finished cylinders which increases the wear resistance of the surface. Furthermore, cold forged tubes or cups are not heated to the same degree during their initial manufacture and are therefore substantially free from internal stresses and tensions and thus relatively insensitve to temperature changes which, in other structures can lead to cracks and unsatisfactory finished products.
The speed of manufacture of blocks using the two stage process of the invention is considerably quicker than any producing comparable results that has hither to been achievable, resulting in cheaper manufacturing costs. At the same time, cold forging offers the possibility of greater repeatability, better functioning due to reduced friction in use, and higher tolerances, resulting in better quality finished products.
One example of a method according to the present invention will now be described with reference to the accompanying drawings, in which:- Figures 1, 2 and 3 show similar stages of three different cold forging processes used to produce cylindrical articles, any one of which may be appropriate for use in the process of the invention, depending upon the required structure of the valves in the valve housing; and.
Figure 4 shows a warm or hot chamber moulding process at two separate stages, schematically in sectional form. Figure 1 shows in parts a, b and c respectively, three separate stages during the cold forging of a cylinder which may be used to provide a valve cylinder for a spool valve in a valve assembly in accordance with the present invention. Cold-forging techniques are, in themselves, well known and therefore the method shown in Figure 1 will not be described in detail. However, it should be noted that the cylinder 1 which is formed during the cold forging part of the process has a very high degree of cylindricity and internal surface smoothness, the cylinder being formed by the extrusion of the material of the cylinder (for example stainless steel or aluminium) by impacting a mandrel 2 onto the surface of the material from which the cylinder is to be formed, the material being held in a matrix 3. As the mandrel impacts and works the material, the cylinder 5 is formed coaxial with and closely spaced around the mandrel 2.
Figures 2 and 3 show the formation of cylinders of different cross-sections in order to illustrate the variety of different shaped cylinders that may be produced by the drop-forging process, in turn to illustrate the wide range of valve spool cylinder forms which may be employed. Turning now to Figure 4, Figure 4a shows a warm chamber injection moulding process prior to injection of molton material, in this case magnesium, into a mould, to form a valve block or housing.
As shown, the mould comprises mould halves 10,11 mounted on platens 12,13 as is conventional. A cavity 4 formed between the mould halves contains three valve spool cylinders 15, each of which is supported on a cylindrical spigot 16 so as to be accurately and firmly held in position within the mould cavity.
Each of the spigots 16 lies with its axis substantially parallel to the direction of opening and closing of the mould halves in order to enable the finished moulded product to be removed from the mould cavity at the end of the moulding process.
Each of the cylinders 15 is formed by a cold forging process such as that of Figures 1, 2 or 3 and the supporting spigot 16 in each case is formed so as to be an extremely accurate and close fit within the related cylinder, so that when the molten magnesium is injected (as will be described later) there is reduced possibility of movement or distortion of the cylinder. It is due to the cold forging of each of the cylinders that close tolerances can be achieved. As is shown in Figures 4(a) and 4(b) (top cylinder) the lip of the cylinder can be widened so as to locate positively in the opposite mould half and thus further prevent any possibility of movement during moulding-in.
The mould includes a bath 17 of molten magnesium 18 which extends to the mould cavity 14 via a cylinder 20 into which an injection ram 21 is rapidly moved back and forth (in the direction of arrow 22) in order to force the magnesium into the mould cavity and around the cylinders 15. This step is shown completed in Figure 4(b). During injection, high pressures (around 50 Bar) are present in the mould and the high degree of cylindricity of the cylinders 15, in turn allowing a very close fit on the spigots 16, serves to avoid or reduce any distortion or movement of the cylinders, thus providing highly accurate valve cylinder bores in the finished product, without the time consuming, and thus expensive, prior methods.
An advantage of using the so called warm or hot chamber injection moulding process is that dross and magnesium oxides which are formed at the surface 19 of the bath of molten magnesium, are this kept from entering the flow of magnesium to the mould thus reducing impurities and improving the quality of the casting. However, it is possible to employ a cold chamber injection moulding process as described above, but this is not shown in the drawings for the sake of simplicity. Both magnesium and alluminium alloys may be injection moulded in a cold chamber process, but the warm or hot chamber process is only presently capable of being used with magnesium alloys. A further advantage of the hot chamber process is the increase in production velocity, to the extent that between one and two hundred strokes per hour may be achieved in comparison with less than one hundred for a cold chamber process.
An additional advantage is found to lie in the fact that in the axial direction of the macrostructure the cold forging process also provides a so-called "closed" profile as opposed to an "open" process which is achieved in machining processes such as turning or drilling, so that valve spools fitted in the valve cylinders can be more effectively sealed therein.

Claims

1. A method of forming a valve block or like housing comprising the steps of:
(a) cold forging a cylinder;
(b) inserting the cold-forged cylinder into a mould; and
(c) injection moulding metal around the cylinder to form a valve block or housing.
2. A method according to claim 1, wherein the injection moulding step is a warm or hot chamber process.
3. A method according to claim 1, wherein the injection moulding step is a a cold chamber process, in which molten casting material is injected in a number of individual steps.
4. A method according to any of claims 1 to 3, wherein a plurality of cylinders are cold forged and inserted into a mould to form a plurality of valve chambers or like in a valve block.
5. A method according to any of claims 1 to 4, wherein the or each cylinder is supported in the mould on a spigot which is an accurate and close fit within the cylinder.
6. A valve block or like housing formed by the steps of cold forging a cylinder, inserting the cold-forged cylinder in a mould, and injection moulding around the cylinder to form a valve block or housing.
7. A valve block or like housing formed by the nethod of any of claims 1 to 5.
8. A valve block or like housing according to claim 6 or claim 7, wherein the cylinder is stainless steel or aluminium and the surrounding metal is a magnesium alloy.
PCT/GB1989/000956 1988-08-31 1989-08-17 Method of manufacturing valve etc. housings WO1990002017A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB888820550A GB8820550D0 (en) 1988-08-31 1988-08-31 Method of manufacturing valve etc housing
GB8820550.5 1988-08-31

Publications (1)

Publication Number Publication Date
WO1990002017A1 true WO1990002017A1 (en) 1990-03-08

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PCT/GB1989/000956 WO1990002017A1 (en) 1988-08-31 1989-08-17 Method of manufacturing valve etc. housings

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AU (1) AU4192689A (en)
GB (1) GB8820550D0 (en)
WO (1) WO1990002017A1 (en)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5197529A (en) * 1989-10-02 1993-03-30 Bill Caugherty Method and apparatus for die casting metal
US7348046B2 (en) 2004-06-16 2008-03-25 Ems-Chemie Ag Polymer mixture of aliphatic polyamides and partially aromatic polyamides, moulded articles thereof and use thereof
EP2123694A1 (en) 2002-12-17 2009-11-25 Ems-Chemie Ag Copolyamides
US8022170B2 (en) 2002-12-17 2011-09-20 Ems-Chemie Ag Copolyamides
CN102366877A (en) * 2011-09-08 2012-03-07 昆山恒源机械制造有限公司 Processing method of valve block
US8268956B2 (en) 2006-12-08 2012-09-18 Ems-Chemie Ag Transparent mold made of a polyamide molding material
US8383244B2 (en) 2011-06-17 2013-02-26 Ems-Patent Ag Semiaromatic molding compounds and uses thereof
US8404323B2 (en) 2010-03-12 2013-03-26 Ems-Patent Ag Impact-resistant modified polyamide moulding compound and container formed therefrom
US8586662B2 (en) 2007-11-16 2013-11-19 Ems-Patent Ag Filled polyamide molding materials
US8604120B2 (en) 2010-07-30 2013-12-10 Ems-Patent Ag Polyamide moulding compound for producing moulded articles with a soft-touch surface and also corresponding moulded articles
US9109115B2 (en) 2013-03-15 2015-08-18 Ems-Patent Ag Polyamide moulding compound and moulded articles produced herefrom
US9133322B2 (en) 2012-10-02 2015-09-15 Ems-Patent Ag Polyamide moulding compounds and use thereof in the production of moulded articles
US9453106B2 (en) 2012-05-23 2016-09-27 Ems-Patent Ag Scratch-resistant, transparent and tough copolyamide moulding compounds, moulded articles produced therefrom and uses thereof
US9963591B2 (en) 2012-12-18 2018-05-08 Ems-Patent Ag Polyamide molding material and moldings manufactured from same
EP3587000A1 (en) 2018-06-27 2020-01-01 Fundacíon Tecnalia Research & Innovation Method for manufacturing a reinforced bi-metallic casting composite and apparatus for manufacturing a reinforced bi metallic casting composite

Citations (4)

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Publication number Priority date Publication date Assignee Title
US3276082A (en) * 1961-09-22 1966-10-04 Reynolds Metals Co Methods and apparatus for making cylinder block constructions or the like
US4122596A (en) * 1977-10-05 1978-10-31 Ford Motor Company Magnesium die-cast brake master cylinder
JPS5997752A (en) * 1982-11-25 1984-06-05 Honda Motor Co Ltd Production of cylinder made of aluminum alloy
US4516594A (en) * 1984-04-03 1985-05-14 Diesel Equipment Limited Multi-part valve with a valve seat skeleton and cast valve body

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3276082A (en) * 1961-09-22 1966-10-04 Reynolds Metals Co Methods and apparatus for making cylinder block constructions or the like
US4122596A (en) * 1977-10-05 1978-10-31 Ford Motor Company Magnesium die-cast brake master cylinder
JPS5997752A (en) * 1982-11-25 1984-06-05 Honda Motor Co Ltd Production of cylinder made of aluminum alloy
US4516594A (en) * 1984-04-03 1985-05-14 Diesel Equipment Limited Multi-part valve with a valve seat skeleton and cast valve body

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN, Vol. 8, No. 210 (M-328) (1647), 26 September 1984; & JP-A-59097752 (Honda Giken Kogyo K.K.) 5 June 1984 *

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5197529A (en) * 1989-10-02 1993-03-30 Bill Caugherty Method and apparatus for die casting metal
EP2123694A1 (en) 2002-12-17 2009-11-25 Ems-Chemie Ag Copolyamides
US8022170B2 (en) 2002-12-17 2011-09-20 Ems-Chemie Ag Copolyamides
US7348046B2 (en) 2004-06-16 2008-03-25 Ems-Chemie Ag Polymer mixture of aliphatic polyamides and partially aromatic polyamides, moulded articles thereof and use thereof
US8268956B2 (en) 2006-12-08 2012-09-18 Ems-Chemie Ag Transparent mold made of a polyamide molding material
US8586662B2 (en) 2007-11-16 2013-11-19 Ems-Patent Ag Filled polyamide molding materials
US8404323B2 (en) 2010-03-12 2013-03-26 Ems-Patent Ag Impact-resistant modified polyamide moulding compound and container formed therefrom
US8604120B2 (en) 2010-07-30 2013-12-10 Ems-Patent Ag Polyamide moulding compound for producing moulded articles with a soft-touch surface and also corresponding moulded articles
US8383244B2 (en) 2011-06-17 2013-02-26 Ems-Patent Ag Semiaromatic molding compounds and uses thereof
CN102366877A (en) * 2011-09-08 2012-03-07 昆山恒源机械制造有限公司 Processing method of valve block
US9453106B2 (en) 2012-05-23 2016-09-27 Ems-Patent Ag Scratch-resistant, transparent and tough copolyamide moulding compounds, moulded articles produced therefrom and uses thereof
US9133322B2 (en) 2012-10-02 2015-09-15 Ems-Patent Ag Polyamide moulding compounds and use thereof in the production of moulded articles
US9963591B2 (en) 2012-12-18 2018-05-08 Ems-Patent Ag Polyamide molding material and moldings manufactured from same
US9109115B2 (en) 2013-03-15 2015-08-18 Ems-Patent Ag Polyamide moulding compound and moulded articles produced herefrom
EP3587000A1 (en) 2018-06-27 2020-01-01 Fundacíon Tecnalia Research & Innovation Method for manufacturing a reinforced bi-metallic casting composite and apparatus for manufacturing a reinforced bi metallic casting composite

Also Published As

Publication number Publication date
AU4192689A (en) 1990-03-23
GB8820550D0 (en) 1988-09-28

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