WO2000020145A1

WO2000020145A1 - A method of manufacturing a fluid control valve and a fluid control valve

Info

Publication number: WO2000020145A1
Application number: PCT/DK1998/000429
Authority: WO
Inventors: Holger Tychsen
Original assignee: York International A/S
Priority date: 1998-10-07
Filing date: 1998-10-07
Publication date: 2000-04-13
Also published as: AU9432998A

Abstract

A fluid control valve comprises a valve housing, a closure element (4) and a valve spindle, the valve housing being provided with a valve seat and with an axial, cylindrical, valve guide bore (7). The closure element is provided with a valve cone (9) and with a valve stem (10), slidably received inside the valve guide bore. According to the invention the valve stem comprises exterior bearing surfaces adapted for sliding engagement with the valve guide bore, and a groove or planar facet, whereas the valve guide bore comprises a forged projection (17) for sliding engagement with the groove or planar facet in order to guide the closure element in non-rotatable engagement with the valve housing. The invention provides a method of manufacturing a fluid control valve as well as a fluid control valve.

Description

A Method of Manufacturing a Fluid Control Valve and a Fluid Control Valve

The present invention relates to a method of manufacturing a fluid control valve and to a fluid control valve. The invention more particularly relates to fluid control valves, wherein a closure element may be displaced axially between an open and a closed position and vice versa by the operation of a rotating shaft.

The invention still more particularly relates to fluid control valves for use m refrigerant loops, subject to high internal pressures, high differential, internal pressures m either direction and a wide range of temperatures.

Norwegian allowed application No. 120 771 teaches a fluid control valve comprising a valve housing, a closure element and a rotatable valve spindle, wherein the the closure element comprises a hexagonal stem portion received m sliding engagement m a hexagonal bore m the valve housing and wherein stem portion comprises a countersunk bore with an internal thread in threaded engagement with a thread of the valve spindle. The closure element is displaced by rotation of the spindle, the hexagonal parts providing sliding non-rotational guidance of the closure element. This valve is designed for use as a tap for water.

The inventor has tested a design for a fluid control valve comprising a valve housing, a closure element and a valve spindle, wherein the valve housing is provided with a hexagonal bore which slidingly receives a hexagonal stem of the closure element and wherein the closure element is displaced by the rotation of a spindle m threaded engagement witr a thread in a countersunk bore m the stem. The inventor has found that this design achieves a satisfactory performance, but only at the cost of a relatively complicated manufacturing procedure. In particular, the provision of the mating pair of hexagonal surfaces and especially the shaping of the female part requires a complicated manufacturing procedure.

International patent application PCT/DK97/00402 relates to a fluid control valve which uses a plain cylindrical bore fitted with an internal rivet fitted m the wall of the bore for guiding the valve stem. The valve stem is provided with mating exterior bearing surfaces, i.e. surfaces shaped substantially as parts of a cylindrical surface centered at the stem axis. In order to provide non-rotating, axially slidable guidance of the valve stem, the valve stem comprises a groove or a planar facet which cooperates with the rivet m the cylindrical bore.

The invention, m a first aspect, provides a method as recited m claim 1.

This method permits the manufacturing of a valve wherein non-rotational axial control of the closure element is secured by a forged projection. This avoids the need of a separate part for non-rotational control. This method is advantageous by simplifying the manufacturing operations and by eliminating all risk of parts co ing loose inside the valve. The risk of parts coming loose inside a valve is a focus of great attention due to tne potentially devastating effects of such parts being introduced into connected extensive conduits, such as refrigerant loops.

The pair of cooperating axial guide means may be implemented m various ways, such as by a stem and a sleeve or by a pair of sleeves m mutual registry, etc.

The inner component may be associated with the closure element and the outer component with the valve housing or vica versa.

According to a preferred embodiment, the second cylindrical surface is provided by selecting a sleeve, and the forging takes place by punching the sleeve from a face opposite the surface adapted for receiving the first cylindrical surface. Thus, if the sleeve, which comprises the second cylindrical surface, is placed as the exterior component, punching will take place from the outside and, conversely, in embodiments where the sleeve would be used as the interior component, punching would take place from the sleeve inside.

Acordmg to preferred embodiments, the forging may take place by use of a punch and a die, and the forging may involve punching with partial shearing of material. The die controls the deformation of material. Partial shearing of the material permits forming of the projection as appropriate.

According to a preferred embodiment, the second body is provided by selecting a piece of ductile material, such as fine grained steel or stainless steel. Use of ductile materials permits extensive cold working without forming cracks or degrading the structural properties of the workpiece .

According to a further preferred embodiment, the axial non-rotational face or groove of the first body may also be provided by forging a substantially axial planar face. The forging process achieves a surface which cooperates well with the projection forged m the second body.

The invention, in a second aspect, provides a fluid control valve as recited m claim 7. This valve obtains non-rotational axial guiding of the closure element with no separate parts required.

According to a preferred embodiment, the valve stem exterior contour has the shape of a regular polygon with rounded corners, the rounded corners providing effectively parts of a cylmdric surface centered at the stem axis and thereby providing the bearing surfaces. The exterior contour may e.g. have the shape of a square or of an equilateral triangle with rounded corners. Ample axial guiding is provided by the partially cylmdric surfaces provided by the rounded corners only. The planar faces may be manufactured by simple operations and may be adapted to provide different spacmgs or widths as appropriate .

In the valve according to the invention a spindle may be secured rotating and non-displaceable engagement with the valve housing while the closure element is axially displaceable relative to the spindle, e.g. by mating threads, or a spindle may be secured m rotating and non- displaceable engagement with the valve closure element to be displaced axia] ly together with the valve closure element by cooperating threads of the spindle and the valve housing.

According to a particular preferred embodiment, the spindle is provided with a double set of threads of different or opposite pitch, one thread engaging a respective mating thread of the closure element and the other thread engaging a respective mating thread of the valve housing. This embodiment provides a very sturdy control of the closure element displacement, capable of operating properly, also when subjected to substantial internal, differential fluid pressures m either direction.

According to a preferred embodiment the valve stem exterior contour has the shape of a regular polygon with rounded corners. In this case any of the planar sections may provide the planar facet for sliding engagement with the key. This facilitates the assembly procedure.

According to a preferred embodiment the stem has tne shape of a square or an equilateral triangle with rounded corners .

Further features and advantages of the invention will appear from the appended description of preferred embodiments given with reference to the drawings wherein

Fig. 1 shows a valve according to the invention m axial section,

Fig. 2 shows parts of the valve of Fig. 1 a section perpendicular to the axis,

Fig. 3 shows part of the body adapted for providing the valve guide bore, at the forging stage, Fig. 3a showing a section by a plane perpendicular to the guide bore axis, and Fig. 3b showing a section by a plane which includes the guide bore axis, and

Fig. 4 shows part of the valve guide bore m cooperation with part of the valve closure element, Fig. 4a showing a section by a plane perpedicular to the guide bore axis, and Fig. 4b showing a section by a plane which includes the guide bore axis. All figures are schematic and not necessarily to scale and illustrate only those parts which are essential in order to enable those skilled in the art to understand and practise the invention whereas other parts are omitted from the drawings for the sake of clarity. Throughout the drawings identical references have been used to designate identical or similar features.

Reference is first made to Fig. 1 for a description of the valve according to the invention.

The valve 1 basically comprises a valve housing 3 assembled from a valve body 21 and a valve cover or valve bonnet 22. The valve housing receives a closure element 4 which is axially displaceable within the valve housing in order to permit a valve cone 9 to sealingly engage a valve seat 6 or selectively to lift off the valve seat. In this way a fluid conduit 2 defined by the valve housing 3 may be selectively opened or blocked to fluid passage, in a way which is generally known in the art.

The closure element 4, which will be explained in more detail later, basically comprises a valve cone 9 adapted for permitting sealing engagement with the valve seat 6 and supported by a valve stem 10 which is received in a valve guide bore 7. The sliding engagement between the valve stem and the valve guide bore provides accurate guidance of the closure element 4 to be displaceable along an axis 11 of the valve guide bore in order that the valve cone 9 will engage the seat 6 properly. The axis 11 is also referred to as the valve axis.

A spindle 5 basically comprises a spindle shaft 25 fitted with a spindle hand wheel 28 by which the shaft may be rotated. The shaft 25 is received in the valve cover bore

23 which may be provided with seals or the like as known in the art. The spindle shaft extends from the hand wheel through the valve cover bore 23 and axially through and projecting slightly beyond the guide bore 7 in the position illustrated in Fig. 1. The valve seat 6, the valve guide bore 7 and the valve cover bore 23 are all generally defined by rotational surfaces centered along the valve axis 11.

The spindle shaft 25, adjacent the end proximal to the valve seat comprises a male thread 26, referred to as the proximal spindle thread.

The spindle shaft at a position spaced from and distally from the valve seat further comprises a second male thread 27 referred to as the distal spindle thread which matingly engages a thread 24 in the valve cover.

Reference is now made to Fig 2 for a description of further details of the valve. Fig. 2 illustrates a section by the line A-A in Fig. 1, showing again the closure element and the component providing the valve cover, whereas parts of the valve body and all components associated with the spindle have been removed for the purposes of clarity.

Fig. 2 illustrates a guide wall 8, which is a sleeve-like part integral with the valve cover, and which comprises the valve guide bore 7. The guide wall 8 has been formed by a method to be described further on so as to exhibit an impression 19 vis-a-vis a downward bulge 17, which projects into the valve guide bore.

Fig. 2 illustrates how the downward oriented top surface 18 of the bulge 17 slidingly engages one of the flat surfaces or facets 15 of the valve stem 10 which, in this embodiment, is shaped as a square with rounded corners. As referred to above, the closure element 4 comprises the valve cone 9 supported by the valve stem 10. As may be seen fig. 2, the stem section has the outer contour of a square with rounded corners. According to the invention, the rounded corners are shaped as parts of a cylinder sized for closely guided, sliding engagement inside the valve guide bore 7 along the axis 11.

The angular extent of the cylindrical sectors, also referred to as stem bearing surfaces 12, vis a vis the angular extent of the planar facets may be varied withm a wide range as appropriate to suit different sizes of bulges. It is also possible to use one size of bulge for a wide range of guide bore diameters by appropriate sizing of the angular extent of the facets.

Referring again to Fig. 1, the stem comprises a circular, countersunk bore with a female thread 14 adjacent the end distally from the valve cone. This thread 14 is adapted for mating engagement with the spindle proximal thread.

The proximal and the distal spindle threads as well as the respective mating threads are oppositely pitched, order that the spindle on rotation is displaced axially m the same direction as the closure element, but with half the excursion.

Reference is now made to Fig. 3 for an explanation of the forging operation involved tne manufacturing of the valve guide bore.

Fig. 3 illustrates part of the body providing the guide bore 7 m two sectional views, Fig. 3a showing a section perpendicular to the axis, and Fig. 3b showing a section by a plane including the axis. The figures essentially show a cylindrical sleeve comprising the guide wall 8 which defines on the inside the guide bore 7. This component may e.g. be manufactured by a casting and drilling operation, possibly including finishing or honing operations so as to produce a cylindrical guide bore 7 as appropriate.

Then for the purpose of the forging operation, a die 31 is introduced into the bore. The die 31 essentially takes the form of a solid, cylindrical body with an axial elongate die recess 32 the upper surface portion, as appears from Figs. 3a and 3b. The die 31 is adapted to closely fit the guide bore 7 except for the portion at the recess. A punch 30 is approached from the outside, i.e. from the top as shown m Figs. 3a and 3b. The die 31 comprises an elongate tool with a round or rectangular cross-section and a slant front face as illustrated m Fig. 3b. The die is approached vis-a-vis the recess 32.

The die is driven radially into the guide wall 8 with a pressure force sufficient to deform and partially shear the material so as to leave a permanent impression in the outside and so as to establish an inward projection mside the guide bore 7 as illustrated in Fig. 4.

Reference is now made to Fig. 4 for an explanation of the cooperation between part of the axial guide core and part of the closure element. Fig. 4 shows only cooperating portions of these components, Fig. 4ct illustrating these cooperating portions m a section by a plane perpendicular to the axis, and Fig. 4b illustrating the same portions m section by a plane wh ch includes the axis. Thus Fig. 4 shows the stem 10 in an embodiment comprising three planar facets 15 separated by cylindrical portions adapteα for registry inside the guide bore 7. Fig. 4 illustrates the impression 19 left by the punch m the guide wall outside and the corresponding inward bulge 17 with the bulge top surface 18. The bulge top surface 18 cooperates with an adjacent facet 15 so as to prevent relative rotation of the stem 10.

According to a preferred embodiment, the facets 15 are fact provided by a drop forging operation. Due to conditions of this process, the facets 15 are not precisely axial but exhibit rather a small taper, such as between V_ and 1 degree inwards towards the right m Fig. 4b. This has the consequence that the play between the bulge top surface 18 and the adjacent facet 15 varies depending on the axial displacement of the parts. This variation the radial play translates into a variation m the angular play of the stem. However, the inventor has found that this is acceptable for the intended use, and that the play will fact hardly be noticed by the user.

In a preferred embodiment, the guide bore has an inner diameter of 23 mm and the guide wall has a thickness of 2.9 mm. The punch tool cross section is 4 by 8 mm, and the punch tool is driven to create an impression of a depth of 2 mm m the material. The depth of the projection relative to the adjacent parts of the inner wall is approx. 2 mm. The material used for the component was of the type TSTE 285 according to DIN 17103, i.e. a fine gra stainless steel. The force applied to the punch was approx. 3000 kiloponds, equivalent to 30 kN.

Although various components have been explained m particular detail above, it should be remembered that this explanation has the sole purpose of exemplifying how the invention might be practised, but is no way intended to limit the scope of the invention which is defined exclusively by the appended patent claims.

Claims

PATENT CLAIMS

1. A method of manufacturing a fluid control valve, said valve comprising a valve housing, provided with a valve seat and with first axial guide means, and a closure element, provided with a valve cone and with second axial guide means, the closure element being adapted for being guided by mutual cooperation between the first and second guide means in selective axial displacement between a closed position, in which the valve cone is in sealing engagement with the valve seat and an open position, in which the valve cone is spaced from the valve seat, comprising the steps of

-selecting for one of the axial guide means a first body having a first cylindrical surface,

-providing the first body with at least one axial, non- rotational face or groove, -selecting for the other one of the axial guide means a second body having a second cylindrical surface adapted for cooperating with the first cylindrical surface, -forging the second body to provide a non-rotational projection adapted for non-rotational, guiding cooperation with the non-rotational face or groove of the first cylindrical surface.

2. The method according to claim 1, wherein the second cylindrical surface is provided by selecting a sleeve with an inner and an outer cylindrical surface, and wherein the forging takes place by punching the sleeve from that of the cylindrical surfaces, which is situated opposite the surface, which is adapted for receiving the first cylindrical surface.

3. The method according to claim 1, wherein the step of forging takes place by use of a punch and a die.

4. The method according to claim 1, wherein the forging step involves punching with partial shearing of material.

5. The method according to claim 1, wherein the step of selecting the second body comprises selecting a piece of ductile material, such as fine grained steel or stainless^' steel .

6. The method according to claim 1 wherein the step of providing the first body with at least one axial, non- rotational face or groove comprises forging a substantially axial, planar face.

7. A fluid control valve comprising a valve housing, which valve housing is provided with a valve seat and with an axial, cylindrical, valve guide bore, and a closure element, which closure element is provided with a valve cone and with an axial valve stem slidably received inside the valve guide bore for guiding the closure element in axial displacement between a position, where the valve cone is in sealing engagement with the valve seat and a position, where the valve cone is spaced from the valve seat, - said valve stem comprising exterior bearing surfaces adapted for sliding engagement with the valve guide bore, and a groove or planar facet, said valve guide bore comprising a forged non- rotational projection adapted for sliding engagement with the groove or planar facet in order to guide the closure element in non-rotatable engagement with the valve housing.

8. The valve according to claim 7, wherein the valve stem exterior contour as seen in a section perpendicular to the stem axis has the shape of a regular polygon with rounded corners, the rounded corners being substantially shaped as sections of a cylindric surface, centered at the stem axis and providing said exterior bearing surfaces .

9. The valve according to claim 7, wherein said contour has the shape of a square or of an equilateral triangle with rounded corners.

10. The valve according to claim 7, wherein the valve guide bore comprises a cylindrical sleeve, and wherein the projection is formed by forging part of the sleeve using a punch and a die.

11. The valve according to claim 7, wherein the valve guide bore comprises a bore in a body of ductile material such as fine grained steel or stainless steel.

12. The valve according to claim 7, wherein the valve stem comprises a countersunk, threaded bore, adapted for cooperation with a spindle of the valve, which spindle comprises an external, mating thread, located at a position proximal to the valve seat.

13. The valve according to claim 12, wherein the valve housing comprises an internal, axial, threaded bore, while the spindle comprises an external, mating thread, located at a position distal from the valve seat.

14. The valve according to claim 12, wherein the spindle comprises a first, external thread at its end proximal to the valve seat and a second, external thread, spaced from the first one and pitched opposite the first one, in that the valve stem comprises a countersunk bore with an internal thread adapted for mating cooperation with said first thread, and in that the valve housing comprises an axial bore with an internal thread adapted for mating cooperation with said second thread.