DE102019112957A1 - Annular seal for spark plug or the like - Google Patents

Abstract

A sealing unit 1 comprises annular first and second sealing elements 10, 20, each sealing element having annular first and second sealing surfaces 12, 22, 13, 23. The sealing members are disposed coaxially with their first sealing surfaces 12, 22 to define an interface 2 forming an angle θ with the central axis X of the unit, and then axially at their second sealing surfaces 13, 23, relative axial and radial Displacement Δa, Δr between the first sealing surfaces 12, 22 to effect. The radial displacement Δr produces an hoop stress Hc, Ht which causes elastic deformation in one or both of the seal members 10, 20.

Description

Field of engineering

This disclosure relates to seals, and more particularly, though not exclusively, seals for use in sealing a threaded body, such as a threaded body. As a spark plug or a glow plug, with respect to a mounting surface of an internal combustion engine.

State of the art

Annular seal rings and seals for spark plugs are generally needed to act in compression between axially opposed surfaces of the spark plug and the cylinder head. In general, such gaskets are made of metal to elastically deform to compensate for settling motion or unevenness while maintaining a pressure-tight seal over the operating temperature ranges of the engine.

Such gaskets may be damaged by plastic deformation resulting from the application of excessive heat or excessive axial forces in use.

Seals of the type mentioned above have a generally S-shaped cross-section, such as through US 9,181,918 B2 taught.

However, it may be that the curved surfaces provide only small contact areas and thus only limited heat transfer between the spark plug and the cylinder head. Better heat transfer is desirable to cool the spark plug and gasket in use, and may extend the useful life of one or both components.

Summary

Accordingly, the present disclosure, in its various aspects, provides a seal and method of forming a seal as defined in the claims.

The seal includes first and second annular seal members, each seal member having first and second annular seal surfaces. The seal is formed by assembling the seal members to form a unit defining an opening extending along an axis X extending through both of the sealing members, wherein the first sealing surfaces are disposed in opposing abutting relationship at an annular interface, and the second sealing surfaces define outer, opposing and outwardly facing surfaces of the unit. A compressive force F is then applied to the second sealing surfaces in opposite directions of the axis X used to axially compress the sealing elements.

When viewed in one plane P that the axis X A straight line that is collinear or tangent to each of the first sealing surfaces at the interface intersects the axis X at an acute angle θ which is selected to have a relative axial ( .DELTA.a ) and radial ( .delta..sub.R ) Displacement between the first sealing surfaces at the interface in response to a compressive force F causes. At least one of the sealing elements is in response to a hoop stress ( ht . hc ) by the relative radial displacement .delta..sub.R is generated, elastically extensible or compressible.

list of figures

• 1 und 2 eine Draufsicht bzw. und eine Unteransicht eines ersten Dichtungselements sind;
• 3 und 4 eine Draufsicht bzw. und eine Unteransicht eines zweiten Dichtungselements sind;
• 5 ein Schnitt A - A (1) durch das erste Dichtungselement ist;
• 6 ein Schnitt B - B (3) durch das zweite Dichtungselement ist;
• 7 eine Seitenansicht der ersten und zweiten Dichtungselemente, zusammengesetzt, ist;
• 8 ein Schnitt A - A und B - B durch die Einheit von 7, in einer gemeinsamen Ebene P, die die Achse X enthält, ist;
• 9 eine Draufsicht der Einheit von 7 ist, die die Ringspannungen veranschaulicht, die durch die ersten und zweiten Dichtungselemente durch axiale Kompression der Einheit erzeugt wird;
• 10 die Einheit von 7 in Verwendung zeigt, um eine Dichtung zwischen einer Zündkerze und dem Zylinderkopf eines Verbrennungsmotors auszubilden; und
• 11 und 12 einen Teil der Einheit von 10 vor bzw. nach der axialen Kompression der Dichtung zeigen; und
• 13 eine andere Dichtungseinheit gemäß einer zweiten Ausführungsform zeigt.

Further features and advantages will be apparent from the illustrative embodiments which now will be described, by way of example only and not limitation of the scope of the claims, and with reference to the accompanying drawings, in which:
1 to 12 show a first embodiment, wherein:

• 1 and 2 are a plan view and a bottom view of a first sealing element;
• 3 and 4 are a plan view and a bottom view of a second sealing element;
• 5 a cut A - A ( 1 ) is through the first sealing element;
• 6 a cut B - B ( 3 ) through the second sealing member;
• 7 a side view of the first and second sealing elements, is composed;
• 8th a cut A - A and B - B through the unity of 7 , in a common plane P, which is the axis X contains is;
• 9 a top view of the unit of 7 illustrating the hoop stresses generated by the first and second seal members by axial compression of the unit;
• 10 the unity of 7 shown in use to form a seal between a spark plug and the cylinder head of an internal combustion engine; and
• 11 and 12 a part of the unit of 10 before and after the axial compression of the seal; and
• 13 another sealing unit according to a second embodiment shows.

Reference numerals and characters appearing in more than one of the figures indicate the same or corresponding elements therein.

Detailed description

Referring to 1 - 6 includes a first seal or seal unit 1 a first sealing element 10 and a second sealing element 20 , Each sealing element is annular and defines a central opening 11 . 21 extending along a central axis X extends.

In this specification, the terms "axial" and "radial" are with reference to the central axis X and "annular" means in the form of a ring surrounding the central opening, irrespective of whether the ring is circular or not circular. For practical reasons, however, each sealing element 10 . 20 generally circular so that most or, as exemplified by the illustrated embodiment, the entire surface, including the first and second sealing surfaces, are surfaces of revolution and the sealing element is a body of revolution about its central axis X includes.

Each sealing element 10 . 20 defines an annular first sealing surface 12 . 22 and an annular second sealing surface 13 . 23 ,

In use are the first and second sealing elements 10 . 20 coaxially assembled to a unit 1 form an opening 11 . 21 defined along the central axis X extends through both of the sealing elements, as in 7 and 8th shown.

In the assembled state, the first sealing surfaces 12 . 22 in opposing abutting relationship at an annular interface 2 arranged through the abutting portions of the first sealing surfaces 12 22 is defined.

10 - 12 show how the seal unit 1 Can be used to make a threaded body 40 , such as a spark plug or a glow plug, via a threaded opening 41 in a combustion chamber 42 an internal combustion engine 43 install. The threaded body is arranged to pass through the central opening 11 . 21 the sealing unit 1 goes, so the second sealing surfaces 13 . 23 each on a sealing surface 44 the threaded body and an opposite sealing surface 45 abut the engine, which may form part of a cylinder head or engine block. In the illustrated example, the threaded body becomes 40 in the direction of the arrow in 12 by screwing in the opening 41 advanced to a compressive force F on the seal unit 1 apply.

Referring in particular to 8th and 12 is seen when looking at a plane P containing the axis as shown, a straight line 2 ' collinear or tangential to each of the first sealing surfaces 12 . 22 at the interface 2 the axis X at an acute angle θ cuts.

The angle θ is chosen so that it has a relative axial displacement .DELTA.a and relative radial displacement .delta..sub.R between the first sealing surfaces 12 . 22 at the interface 2 causes when the compressive force F on the second sealing surfaces 13 . 23 in opposite directions of the axis X , as shown, is applied to the sealing elements 10 . 20 axially compress. With relative displacement is the movement of the first sealing surface 12 . 22 meant in relation to each other.

The angle θ may be selected according to the coefficient of friction and other parameters defined by the selected material and other geometric parameters of the sealing elements according to design principles well known in the art to obtain the desired relationship between the applied stress and strain.

Also referring to 9 generates the relative radial displacement .delta..sub.R between the first sealing surfaces 12 . 22 a tension ring tension ht in the radially outermost, first sealing element 10 , to which by a pressure ring tension hc in the radially innermost, second sealing element 20 is reacted. At least one of the first and second sealing elements 10 . 20 is arranged (inter alia by a suitable selection of the sealing material) such that it reacts in response to the hoop stress ht or hc elastically extensible or compressible, which in turn is the relative radial displacement .delta..sub.R allowed.

The balanced elastic forces energize the sealing unit to the second sealing surfaces 13 . 23 resiliently axially outward and apart against the opposite surfaces 44 . 45 the environment of use and the first sealing surfaces 12 . 22 resilient and radially compress. The sealing unit can thus move to accommodate the movement in the environment of use while simultaneously providing a sealing force across the interface 2 and axially between the opposing surfaces 44 . 45 which also maintains the effective thermal conduction through the sealing unit between the opposing surfaces 44 . 45 over the first and second sealing elements 10 . 20 and across the interface 2 allowed.

One or both of the first and second sealing elements 10 . 20 can be arranged so that they affect the hoop tension ht or hc react by circumferential elastic deformation.

The first sealing surface 12 of the first sealing element 10 For example, it may be arranged to be radially outward with respect to the axis X to the first sealing surface 22 the second sealing element 20 is shifted when the pressure force F is applied to the sealing elements 10 . 20 axially compress. Thus, the first sealing element 10 in response to the tension ring tension ht caused by the relative radial displacement .delta..sub.R the first sealing surface 12 outwards to the first sealing surface 22 be elastically extensible.

Advantageously, the first sealing element 10 be arranged so that it has the resulting tension ring tension ht in normal use, when not held radially outward, as in the example of 12 shown where the first sealing element 10 radially outward from the axis X can move away freely. In this way, the sealing unit can be arranged in a recess, without relying on the radially inwardly facing wall of the recess limits its radial extent, so that it can be easily removed from the recess when needed. Similarly, the second sealing element 20 be arranged so that it is the pressure ring tension hc endures without the threaded body 40 in its radially inner surface touching, which is its central opening 11 Are defined.

The sealing unit can over the threaded body 40 be installed or removed or (not shown) on the threaded body in the manner of a conventional seal or a sealing ring, which are used in spark plugs and the like, be captive.

Referring again to 10 - 12 you can see that the second sealing surfaces 13 . 23 outer, opposite and outwardly facing surfaces of the unit 1 which are oriented to respond to the compressive force F, which, in use, to the second sealing surfaces 13 . 23 in opposite directions of the axis X be applied to the sealing elements 10 . 20 axially from the rest of the position of the 11 to the axially compressed use position of 12 compress.

For practical reasons and as exemplified by the illustrated embodiment, the second sealing surface 13 . 23 axial end faces or outermost ends of the unit 1 define.

One or each of the second sealing surfaces 13 . 23 may be in a flat plane normal to the axis X extend and / or, when viewed in a plane ( P ), which is the axis X contains, along a straight line normal to the axis X , The unit 1 Thus, it can be arranged between opposite, flat surfaces normal to the direction of axial compression, as in FIG 10 - 12 illustrated.

In alternative embodiments, one or both of the second sealing surfaces 13 . 23 inclined or curved with respect to the axis X be to touch the correspondingly shaped surface in its intended position of use.

Preferably, each of the second sealing surfaces extends 13 . 23 over a relatively large surface area, for effective heat transfer across the seal unit 1 between the axially opposite surfaces 44 . 45 an engine and a spark plug or other threaded body 40 or any other environment of use that keeps the seal unit in compression.

In particular, referring to 8th is, in the illustrated embodiment, when viewed in a plane P the axis X , each of the second sealing surfaces 13 . 23 normal (ie perpendicular) to the axis X with a radial width R1 respectively. R2 while the unit 1 an entire radial width R3 between their inside and outside diameters on each side of the axle X having. To provide a compact sealing unit with good heat transfer capability when the entire radial width R3 is measured in normal use in an axially compressed state of the seal unit, such as in 12 illustrates the radial width R1 . R2 each of the second sealing surfaces 13 . 23 not less than 0.4 × R3, more preferably not less than 0.5 × R3.

When viewed in one plane P that the axis X contains, one or both the first sealing surfaces 12 . 22 extend along a straight or curved line which is a common line of their respective abutting portions at the interface 2 can define, so the interface 2 along a straight or curved line in the plane P can extend.

Thus, as exemplified by the illustrated embodiment, each of the first sealing surfaces 12 . 22 in the longitudinal section plane P along a straight line that extend the acute angle θ the interface 2 to the axis X (in 5 and 6 through a parallel line X ' shown) defined.

Referring again to 8th In the illustrated embodiment, the interface extends 2 in the plane P that the axis X contains, along a straight line with a length L2 ,

The unit 1 has a maximum axial length L1 , which, as in the illustrated example, between the parallel planes of the second sealing surfaces 13 . 23 can be defined. It can be seen that the axial length L1 in the energized usage position of 12 compared to the non-energized resting position of 11 is reduced.

To have good heat transfer capability in a seal unit 1 given axial length L1 provide when the lengths L1 and L2 measured in normal use in an axially compressed state of the unit, for example as in 12 represented, the common line can be the interface 2 defines a length L2 have, wherein L2 ≥ 0.3 · L1. (In this case, if the common line is not straight, the line should be L2 measured according to their curvature.)

Each of the first and second sealing elements 10 . 20 may be made of a metal or metal alloy or any other suitable material or materials selected from, for example, suitable elasticity, thermal conductivity, and other properties known in the art according to the intended application are known.

A metal or a metal alloy may be suitable for many applications, such. B. sealing of spark plugs or other threaded bodies for installation in a combustion chamber.

When the first and second sealing members are made of a metal or a metal alloy or other suitable material, the thermal conductivity and mechanical strength can be achieved by disposing the first and second sealing members 10 . 20 be further improved in a monolithic construction - that is, when viewed in a plane P that the axis X includes defines each of the first and second sealing elements 10 . 20 a cross section bounded by a boundary having no bends.

This is in the illustrated embodiment of FIG 1 - 12 to see where both sealing elements 10 . 20 to have a monolithic construction.

To illustrate the point shows 13 a cut in a plane P that the axis X contains, by a similar unit in an alternative embodiment, a first sealing element 110 and a second sealing element 120 contains. The first sealing element 110 has a monolithic construction, which on average has a limit 101 without bends (points at which the curvature changes from convex to concave) - that is, a continuous boundary that protrudes in the absence of inward facing regions or concavities. The second sealing element 120 is not quite monolithic, with a cutoff on average 101 is defined with bends, the small concavities 102 define in their border.

Of course, good mechanical strength (especially resistance to axial compression) and thermal conductivity can still be obtained if such concavities are small in relation to the overall size of the cut.

Thus, in the example of 13 to see that, when viewed in one plane P that the axis X contains, each of the first and second sealing elements 110 . 120 defines a cross-section with a cross-sectional area, and at least 80% of the cross-sectional area of each respective cross-section in an imaginary boundary 103 may be contained, which is completely within the respective cross section and has no bends.

The border 103 the second sealing element 120 is considered a small distance inwards from the border 101 defined, which represents the outer surface of the cut. The majority of the cut is free of concavities, which is why the second sealing element 120 is essentially monolithic.

In summary, a sealing unit comprises 1 annular first and second sealing elements 10 . 20 wherein each sealing member has annular first and second sealing surfaces 12 . 22 . 13 . 23 having. The sealing elements are coaxial with their first sealing surfaces 12 . 22 abutted to an interface 2 to define an angle θ with the central axis X the unit forms, and then axially at their second sealing surfaces 13 . 23 to relative axial and radial displacement .DELTA.a . .delta..sub.R between the first sealing surfaces 12 . 22 to effect. The radial displacement .delta..sub.R generates a ring tension hc . ht which provides an elastic deformation in one or both sealing elements 10 . 20 causes.

The first and second sealing members may be configured such that illustrates the first sealing element 10 has an inner and outer diameter which is larger than the respective inner and outer diameter of the second sealing element 20 in that the second sealing element fits partially or substantially into the first sealing element, the interface 2 For example, forming a partial conical surface of revolution therebetween. The radially inner and outer surfaces of the unit (the radially outer surface 14 the first, larger sealing element 10 and the radially inner surface 24 the second, smaller sealing element 20 As shown, cylindrical surfaces of revolution about the axis may be included X so that the unit fits perfectly around a cylindrical threaded body and / or into a cylindrical recess. However, other configurations may be adopted to suit a particular usage situation.

In alternative embodiments, one of the first sealing surfaces could extend along a straight line and the other along a curved line, or both could extend with a common curvature (selected to define the desired relationship between axial displacement and radial and hoop stresses) to a curved one Define interface.

Industrial Applicability

The novel seal unit can be used as a gasket or seal in static (i.e., non-rotating) applications rather than "S" or other configuration elastically compressible gasketing units to provide effective heat transfer between axially opposed sealing surfaces, e.g. As an engine and a spark plug, a glow plug, a fuel injector, a sensor or other threaded body, which is installed in a combustion chamber via a threaded opening in the engine to provide, which extends the life of the sealing unit and the associated components.

The sealing unit can be used in situations where the sealing elements are radially indefinite, so that they can be easily removed with the threaded body, even if they are installed in a recess, without sticking to the walls to jump back.

Thermal conductivity between the sealing surfaces can be improved by selecting the relative dimensions of the sealing elements such that L2 ≥ 0.3 * L1 for good conductivity between the first and second sealing elements and / or such that R1 ≥ 0.4 * R3 and R2 ≥ 0.4 R3, preferably R1 ≥ 0.5 · R3 and R2 ≥ 0.5 · R3, for good conductivity between each of the sealing members and the respective sealing surface of the motor, the threaded body or other use environment, and further arranging each sealing member so that it has a has substantially monolithic construction, as discussed above, and most preferably by providing all of these features in combination.

A relatively monolithic construction can also provide better resistance to crushing and thus ensure that the seal assembly is less prone to damage by axial compressive forces as compared to an "S" shaped or other folded configuration known in the art.

In order to maximize resistance to axial compression, the first and second sealing elements may 10 . 20 further configured (inter alia by selecting an appropriate interface angle θ ) that the first and second sealing elements 10 . 20 can be axially compressed (ie, stay within their elastic limits) without permanent deformation, to their combined axial length L1 to a value equal to the total axial length (in plane P ) of only one of the first and second sealing elements 10 or 20 to reduce.

In this case, the axially longer sealing element or, if both sealing elements have a same axial length, each sealing element may define a solid body which, when viewed in a straight line in the axial direction between its second sealing surface 13 . 23 and an axially opposite, outwardly facing surface 15 . 25 of the respective sealing member extends continuously, so that the massive body in compression between the opposing surfaces 44 . 45 the usage environment is placed against the surfaces 13 and 15 or against the surfaces 23 and 25 acts when both sealing elements are maximally stretched elastically. The opposite surface 15 or 25 can, as shown, a smaller radial width than the respective second sealing surface 13 or 23 respectively.

In this way, the monolithic body of the axially longer or (if of equal axial length) each of the first and second sealing elements 10 . 20 act in compression between the opposing sealing surfaces of the use environment to an excessive axial compressive force F withstand, without further the tension or compression ring tension ht . hc in one item to increase, so the unit 1 can resiliently return to a functional (ie elastically axially outwardly biased) state when the excessive compressive force decreases.

Many other adjustments can be made within the scope of the claims.

In the claims, reference numerals and characters in parentheses are provided for convenience of reference only and should not be considered as limiting features.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• US 9181918 B2 [0004]

Claims (10)

A gasket (1) comprising an annular first sealing member (10) and an annular second sealing member (20), each sealing member having an annular first sealing surface (12, 22) and an annular second sealing surface (13, 23); wherein the sealing members are configured to define, when assembled to form a unit (1), an opening (11, 21) extending along an axis (X) through both of the sealing members: the first sealing surfaces (12, 22) are disposed in opposing abutting relation at an annular interface (2), wherein, when viewed in a plane (P) containing the axis, a straight line (2 ') is collinear or tangent to each the first sealing surfaces at the interface intersect the axis (X) at an acute angle θ, and the second sealing surfaces (13, 23) define outer, opposite and outwardly facing surfaces of the unit (1), wherein the angle θ is selected to cause a relative axial (Δa) and relative radial (Δr) displacement between the first sealing surfaces (12, 22) at the interface (2) when a compressive force (F) is applied to the second sealing surfaces (Fig. 13, 23) in opposite directions of the axis (X) is applied to axially compress the sealing elements (10, 20); and at least one of the sealing members (10, 20) is elastically extensible or compressible in response to a hoop stress (Ht, Hc) generated by the relative radial displacement (Δr). Seal after Claim 1 wherein the first sealing surface (12) of the first sealing element (10) is arranged to be displaced radially outward with respect to the axis (X) to the first sealing surface (22) of the second sealing element (20) when the compressive force ( F) is applied to axially compress the sealing elements; and the first seal member (10) is elastically extensible outwardly in response to a tension ring tension (Ht) generated by the relative radial displacement (Δr); and the first seal member (10) is arranged to withstand the tension ring tension (Ht) in normal use when not held radially outward. Seal after Claim 1 wherein the abutting portions of the first sealing surfaces (12, 22) at the interface (2) extend along a common line in a plane (P) containing the axis (X). Seal after Claim 3 wherein, in normal use in an axially compressed state of the unit (1), when viewed in the plane (P) containing the axis (X), the unit (1) has a maximum axial length L1 and the common line has a length L2, where L2 ≥ 0.3 * L1. Seal after Claim 1 wherein, when viewed in a plane (P) containing the axis (X), each of the first and second sealing members (10, 20) defines a cross-section bounded by a boundary (101) having no bends. Seal after Claim 1 wherein, when viewed in a plane (P) containing the axis (X), each of the first and second sealing members (10, 20) defines a cross section having a cross sectional area and at least 80% of the cross sectional area of each respective cross section in an imaginary one Boundary (103) may be included, which is completely within the respective cross section and has no bends. Seal after Claim 1 wherein, when viewed in a plane (P) containing the axis (X), at least one of the second sealing surfaces (13, 23) extends along a straight line normal to the axis (X). Seal after Claim 1 wherein each of the first and second sealing members (10, 20) is made of a metal or a metal alloy. A unit comprising a threaded body (40) for sealing installation by means of a threaded opening (41) into a combustion chamber (42) of an internal combustion engine (43) and seal (1) Claim 1 in that the sealing surfaces (13, 23) in use are arranged so that they abut respectively on a sealing surface (44) of the threaded body (40) and an opposite sealing surface (45) of the motor (43). A method of forming a seal (1) comprising: providing an annular first seal member (10) and an annular second seal member (20), each seal member having an annular first seal surface (12, 22) and an annular second seal surface (13, 23) having; Assembling the first and second sealing members to form a unit (1) defining an opening (11, 21) extending along an axis (X) through both of the sealing members (10, 20), wherein: the first sealing surfaces (11) 12, 22) are disposed in opposing abutting relation at an annular interface (2), wherein, when viewed in a plane (P) containing the axis (X), a straight line (2 ') is collinear or tangential to each of first sealing surfaces (12, 22) at the interface (2) the axis (X) intersects at an acute angle θ, and the second sealing surfaces (13, 23) define outer, opposite and outwardly facing surfaces of the unit (1); Applying a compressive force (F) to the second sealing surfaces (13, 23) in opposite directions of the axis (X) to axially compress the sealing elements (10, 20); Causing, by the compressive force (F), a relative axial (Δa) and radial (Δr) displacement between the first sealing surfaces (12, 22) at the interface (2); Generating, by the relative displacement (Δr), a hoop stress (Ht, Hc) in at least one of the sealing members (10, 20); and causing, in response to the hoop stress (Ht, Hc), elastic stretching or compression of at least one of the sealing members (10, 20).

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