JP2786929B2 - Electromagnetic shielding gasket - Google Patents

Description

The present invention relates generally to filters, which require shielding or grounding to prevent interference or damage by electromagnetic radiation.
It relates to a shielding gasket for interconnecting electronic / electromagnetic components such as attenuators, connectors, circuit boards and other electronic or non-electronic devices. More specifically, the invention as a whole is independent of the loading force acting on the gasket,
The present invention relates to a conductive gasket that allows components to be interconnected without transmitting or leaking electromagnetic energy therethrough.

(Prior art and its problems) In a modern electronic device, separate components or units of the electronic device are connected to each other by a cable or the like, and such components themselves are used interchangeably or interchangeably. It is well known to be manufactured in a modular form, consisting of separate subsystems that can be used. Recognize that in many cases, if not most, all modular units and subsystems should be isolated from electromagnetic radiation emitted from other subsystems or external sources within the system. It is important to. Insufficient coupling of components results in reduced efficiency due to energy loss and impedes the effective operation of other related electronic components.

Undesirable loss of electromagnetic energy and problems associated with interference have been known for some time. This problem is particularly important in the case of components which have to change the operating characteristics of the device or make the device movable or have to be repeatedly interconnected and disconnected for maintenance. In such a situation, the mechanical and electrical coupling means of the component may be a conductive elastomer or a combination of elastomeric materials in any number of forms, such as a critical electromagnetic transmission line or gasket surrounding the device. Often use.

Common types of gaskets currently used in such fields are conductive elastomers of high conductivity elastomeric materials, silver plated aluminum composites or similar materials, in order to provide effective shielding. It is. Other types of gaskets currently in use include metallic materials or combinations of mesh strips in round or rectangular shapes, braided wires in round or rectangular shapes, expanded metals, round and round strips, etc. It is formed. These various materials are made of metallic materials or filled with elastomeric materials and have a high degree of elasticity.

Many, if not all, of the gaskets of the above-described form provide an electromagnetic shielding effect to some extent,
Each has the disadvantage of being permanently deformed when loaded. That is, these materials "set" when a load is applied, and then, when such load changes, form a void or separation, thereby permitting electromagnetic energy to be transmitted therethrough. The above disadvantages described in general terms can be illustrated by the specific example of a microwave connector of the screw type, which connector is connected to the component by mechanical screws or the like. It has a deformable elastomeric gasket. Either repetitive or intermittent use, the elastomeric member is "set" and therefore does not provide a reliable electromagnetic shielding effect when connectors are repeatedly connected and disconnected.

This problem is more pronounced when the gasket is subjected to thermal cycling. The repetitive heating and cooling of the gasket results in significant relaxation,
Even when the gasket is unloaded due to repetitive bonding and separation, the components normally connected
A hole is formed through which the electromagnetic energy passes.

Although a shield gasket has been described that includes an elastomeric component, other metallic materials such as braided wires, woven gaskets, circular strips or expanded metal that set under load are typically very rigid,
It cannot fit small diameters or irregularities well, thus allowing electromagnetic energy to leak through it. The irregularities described above include mating components having surface deformations or surface finishes that are not tightly coupled to each other, and such components utilize gaskets to provide electromagnetic shielding to certain electromagnetic energy frequencies. Provide the required degree of continuity.

In particular, with respect to the frequency of electromagnetic energy, the commercial microwave band is in the range of about 100 MHz to about 1 GHz, while the military microwave band is in the range of 1 GHz to 300 GHz. Electromagnetic energy as used herein is a general term that includes the entire spectrum of electromagnetic energy frequencies, and specifically, as used below, electromagnetic interference (EMI) and radio frequency interference (RFI) are both It relates to interference due to the desired electromagnetic or radio frequency energy entering a designated part of the device and can be used interchangeably. In general, the ability to shield components from the emission and penetration of electromagnetic energy is often referred to as the shielding effect.

The most important factor of electromagnetic shielding is the frequency of its electromagnetic energy or its wavelength. It is known that all electromagnetic waves consist of two essential elements, a magnetic field and an electric field. The two fields are perpendicular to each other and the direction of wave propagation is perpendicular to the plane containing the two elements.
The relative magnitude between the magnetic field (H) and the electric field (E) depends on how far the wave is from its source and the nature of the source itself. The ratio of the magnetic field E pair field H is called the wave impedance Z _W.

Thus, it can be seen that the shielding effect for a particular gasket depends on whether the electromagnetic energy is generated in the device concerned or from a device remote from the gasket.

If the source has a large amount of current compared to its potential, such as generated by a loop, transformer or power line, it is called an electromagnetic current source with a small value of E to H, or a low impedance source. On the other hand, if the source operates at high pressure and only a small amount of current flows, the source impedance is high and the wave is commonly called an electric field.

It is important to recognize that when very far from the source, the ratio of E to H is equal for both waves, regardless of their direction. In this case, the wave is called a plane wave and the wave impedance is equal to 377 ohms, which is the natural impedance of free space.

It is known that the intrinsic impedance of a metal approaches zero as the conductivity approaches infinity. Because of the large difference between the intrinsic impedance of the metal and the intrinsic impedance of free space, waves generated from sources remote from the metal receptor reflect most of its energy and are transmitted very little. This is, of course, not the case for magnetic fields where the more unreflected energy is absorbed, which makes it increasingly difficult to shield against magnetic fields, i.e. fields with low impedance. is there. Since the magnetic field has a conductivity that is less than infinite, a portion of the magnetic field is transmitted across the boundary determined by the thick can of the metal shield.

A much more important factor of the shielding effect is the presence of holes or gaps in the shield. Due to the presence of a gap or hole in the shield, a magnetic field is radiated through the shield unless continuity is maintained across the gap. Thus, the function of the EMI gasket is to maintain current continuity within the shield.

Of course, the importance of the air gap depends on the frequency of the impinging electromagnetic energy. For example, electromagnetic energy having a frequency of 1 GHz has a wavelength of about 11.6 inches, while electromagnetic energy of 100 GHz has a wavelength of about 0.12 inches. In general, the hole size should be less than the wavelength of electromagnetic energy divided by 20 for effective shielding in commercial applications, and for avionics applications, the hole size should be less than the electromagnetic energy wavelength. It is necessary that the wavelength be equal to or less than 1/50 of the wavelength.

Other factors that directly affect the size of the air gap, and hence the shielding effectiveness, are the surface finish of the mating part to be sealed, the environmental change of the shielding material with little or no change in conductivity due to corrosion cell action, etc. It has to be capable of withstanding. The ability of the gasket to maintain a stable dimension for a constant load between mating parts throughout its life will prevent changes in the gasket's conductivity and open its voids (this is acceptable in terms of shielding effectiveness). Is not important).

The gaskets of the present invention distort under load to provide a substantially constant force between the mating points and / or between the surfaces to ensure high conductivity and thus within useful temperature and cycling standards. An effective electromagnetic shield is achieved by utilizing a tilted coil spring having closely spaced coils that provides a high degree of shielding. Further, the gasket of the present invention provides sufficient flexibility to accommodate changes due to torque effects, eccentricities, irregularities and other variables and provides the required load and open low area. Maintain the effective shielding effect from very low frequency to extremely high frequency.

According to the present invention, an electromagnetic shielding gasket includes a coil spring that obstructs propagation of an electromagnetic wave therethrough, wherein the coil spring is provided within a distortion range of each coil of the coil spring. And, independent of the compression of the coil spring, it has a plurality of individual coils which can obstruct the propagation of electromagnetic waves therethrough. The individual coils are interconnected and arranged at an angle to the center line of the coil spring. Since the propagation of electromagnetic waves is impeded independently of the compression of the coil spring, the gasket allows the engagement of irregularities and is independent of the change in the spacing between the engagement surfaces due to temperature effects. More specifically, according to the present invention, the electromagnetic sealing gasket takes the form of a continuous coil spring when the individual coils are joined together. further,
An inner coil spring can be disposed within the coil spring so that electromagnetic waves can propagate therethrough. The inner coil spring has a plurality of individual inner coils for preventing the propagation of electromagnetic waves therethrough within the range of distortion of the individual inner coils and independently of the compression of the inner coil spring. The individual inner coils are interconnected and disposed at an angle with respect to the centerline of the inclined coil spring;
It is further possible to tilt in the opposite direction to the coil or in the same direction as the coil.

More specifically, the electromagnetic shielding gasket according to the present invention comprises a girder-type axially elastic coil spring that obstructs the propagation of electromagnetic waves therethrough, the coil spring being inclined along its center line. And the rear edge portion of each coil is positioned relative to a normal normal to the centerline and has a rearward angle that defines the force-distortion characteristics of the coil spring. A front angle for positioning the leading edge portion of each coil with respect to the normal can be provided, and the front angle can be greater than the rear angle. The coils are interconnected to form a girder type axially elastic coil spring, the rear edge of which is located along the outer diameter of the girder type axially elastic coil spring, while The leading edge portion can be located along the inner diameter of an axially resilient coil spring of the garter type.

In another embodiment, an electromagnetic shielding gasket according to the present invention comprises a radially resilient canted coil spring that obstructs the propagation of electromagnetic waves therethrough, wherein the plurality of individual canted springs are inclined along its centerline. A coil, a rearward angle for positioning a trailing edge portion of each coil with respect to a normal perpendicular to the center line, and a forward angle for positioning a leading edge portion of each coil with respect to the normal line. . Means are provided for orienting the plurality of coils at a bending angle that determines the load-distortion characteristics of the radially resilient canted coil spring, the bending angle being greater than 0 ° and less than 90 °.

EXAMPLES The advantages and features of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings.

Referring first to FIG. 1, there is shown an example of a load-distortion curve 10 for purposes of illustrating the characteristics of an elastic coil spring comprising a gradient coil suitable for an electromagnetic shielding gasket according to the present invention.

As shown in FIG. 1, when a load is applied to the spring, the spring deflects substantially linearly, as shown by line portion 12, after which the point after the initial post-distortion load begins to remain relatively constant. The minimum load point 14 shown is reached. In the case of the axially elastic garter type spring described below, the load is applied in the axial direction, whereas in the case of the radially elastic garter type spring described below, the load is applied in the radial direction.

Between the point of minimum load 14 and the point of maximum load 16, the load distortion curve is constant or shows a slight rise as shown in FIG. The area between the point of minimum load 14 and the point of maximum load 16 is known as the effective distortion range 18. The spring is typically loaded such that it can operate within this range, as shown at point 20, for typical springs utilized with shields, gaskets, etc. for both sealing and electromagnetic shielding purposes. . If the spring is loaded beyond point 16 of maximum load, it will respond with a sharp distortion and reach a butt point 22 where overloading results in permanent deformation of the spring.

FIG. 1 also shows a total distortion range 24 defined as the distortion between the unloaded point and the maximum load point 16 of the spring.

2A and 2B show the center line as a whole.
A circular welding spring showing a plurality of coils 32 wound clockwise (see arrow 34) inclined counterclockwise along 36
30 is shown.

As shown more clearly in FIG. 2b, each coil has a trailing edge portion 40 and a leading edge portion 42, and the trailing edge portion 40 positions the trailing edge portion 40 of each coil 32 relative to the normal 50. And, as will be described in more detail below, has a rearward angle 48 which provides a means of defining the effective elastic range of the spring 30.

In addition, forward angle 54 provides a means of positioning leading edge portion 42 of coil 32 with respect to the normal.

The spring 30 has a trailing edge portion 40 along the outer diameter 58 of the spring 30 (second
(See FIG. A) and the leading edge portion 42 is formed by interconnecting the coils 32 in a manner that forms a garter-type axially resilient coil spring along the inner diameter 60 of the spring 30.

As shown most clearly in FIG. 2b, the spring 30 according to the present invention comprises a leading edge portion 42 disposed at a forward angle 54 that is always greater than a trailing angle 48 defining a trailing edge portion 40. .
That is, when the coil is wound in a circular shape about the centerline 32, each winding portion has a trailing edge portion and a leading edge portion, and when following the trailing edge portion 40 of the coil 32, the leading edge along the centerline 32 The forward movement of the part is greater than the forward movement along centerline 32.

FIGS. 3a and 3b show the same physical dimensions and the same linear dimensions as the spring 30 shown in FIGS. 2a and 2b, and in the counterclockwise direction (see arrow 70). A wound, circular weld spring 68 according to the present invention is shown. In this case, the spring
68 are the rear angles respectively as shown in FIG. 3b
A plurality of coils 72 have a trailing edge portion 74 and a leading edge portion 76 defined by 80 and a forward angle 82.

Like the spring 30, the coil 72 of the spring 68 has an outer diameter of the trailing edge.
The leading edge portions are interconnected in a manner forming a girder-type axially resilient coil spring descending along 86 and descending along the inner diameter 84 of the spring 68.

Curve A in FIG. 4 shows the performance of the spring 30 or 68,
Spring B shows the performance of a prior art spring with the same physical properties, but with a different trailing edge along the outside of the spring. These two springs have approximately the same force-distortion characteristics within their effective distortion range, but the point of maximum load is about 40% different.

According to the invention, the front angle 54 is greater than the rear angle,
Moreover, it has been found that the rearward angle can be varied in the range of 1 ° to 35 ° as long as it is larger than 20 ° and smaller than 55 °.
Changes in the rearward angle of the spring have a significant effect on the elastic properties of the spring, independent of the forward angle. This is illustrated in FIG. 5, which is a force-distortion curve for springs C and D having the spring parameters listed in Table 1. The spring parameters listed here are only for indicating the result of the positioning of the rear angle and the trailing edge of the spring. The actual spring parameters will depend on the desired spring size, load and application.

The springs C and D are the same springs having the same wire diameter, spring inner diameter, coil height and substantially the same front angle, but different rear angles, and thus the coil spacing. As is evident from FIG. 5, the effective distortion of spring D is about 50%, while the effective distortion of spring C is 45%. This is independent of the forward angle. Therefore, the springs can be distorted by utilizing only springs having the same wire diameter, inner diameter and coil height of smaller dimensions than previously possible, and changing only the forward angle of the spring. It is possible to design different elastic properties, such as the required force.

As described above, increased force-distortion properties can be used with sealants or gasket materials to achieve a beneficial effect. In this case, the spring cavity is a predetermined value, and the spring inner diameter and the coil height are determined by this value.

If the coil spacing is kept constant, the rear angle can be varied with the front angle to specially design the spring to achieve special elastic properties. For example, for the springs E, F and G listed in the table, the smaller the rearward angle, the greater the force required to deflect the spring, as shown in FIG. This allows the spring to be formed with a smaller wire diameter and a smaller coil spacing. Conversely, when the coil interval is constant, the effective distortion range increases as the rear angle increases.

This property is important and allows the coil spring according to the invention, as described below, with itself or with a conductive elastomer, to be effective as an electromagnetic shielding gasket.

Referring now to FIGS. 7a and 7b, a circular weld clockwise spring 100 according to the present invention is shown generally showing a plurality of coils 102 tilted clockwise along a centerline 104 thereof. Is shown. As shown more clearly in FIG. 7b, each coil 102 has a trailing edge portion 108 and a leading edge portion 11
The trailing edge portion 108 orientates the trailing edge portion 108 of each coil 102 relative to the normal 114 and provides a means for determining the effective elastic range of the spring 100 as described in more detail below. It has an angle 112.

Further, forward angle 116 provides a means for defining the direction of leading edge portion 110 of coil 102 with respect to normal 114.

The spring 100 has a trailing edge portion 108 along the inner diameter 120 (FIG. 7a).
And a leading edge portion 110 is formed by interconnecting the coils 102 in a manner that forms a garter-type axially resilient coil spring along the outer diameter 122 of the spring 100.

As clearly shown in FIG. 7b, a spring according to the invention
100 has a leading edge portion 110 disposed at a forward angle 116 that is always greater than a trailing angle 112 that defines a trailing edge portion 108. That is, when the coil is wound in a circular shape about the centerline 104, each wound portion has a leading edge portion 110 and a trailing edge portion 108, and follows the centerline 104 when following the trailing edge portion 108 of the coil 102. The forward movement of the leading edge portion is greater than the forward movement along the centerline 104.

The coil spring 100 whose inner rear angle is inclined has substantially the same load as the coil spring 30 whose outer rear angle is inclined.
Although having distortion characteristics, the specific load-distortion characteristics of each spring are different. For example, a coil spring with a slanted inner rear angle
The coil spring 30 having the same wire diameter and dimensions as 100 and having the outer rear angle inclined has a maximum load point located higher than the coil spring with the inner rear angle inclined (first).
See figure).

Referring now to FIG. 8, a gutter-type axial spring 212 having a plurality of coils 214 within an annular seal 216
Illustrated is an electromagnetic shielding gasket 210 according to the present invention, and as will be described in more detail below, this annular seal 216 extends a garter type axially elastic coil spring 212 in a preselected direction. It provides a means to support the impossibility and control its elastic properties.

FIG. 9 shows a typical load-distortion curve A of the springs 30 and 100 described above for comparison. Also shown is the load-distortion curve B of a spring according to the invention having a certain bending angle for the purpose of showing its properties.

This load-distortion curve B shows the characteristics of the spring 212 according to the present invention, showing the load-distortion portion 236 of the wire diameter up to the maximum load point 238. After the point of maximum load 238, the load decreases with distortion of portion 240. As a result, a saddle-shaped distortion range is formed between the maximum load point 238 and the abutment point 242.

This type of load-distortion characteristic is particularly advantageous for electromagnetic spring seals which are locked in a groove and are tensioned by a spring. In this case, the spring provides a relatively constant load over a predetermined effective distortion range 244, but at point 2
If it changes beyond the effective range limit at 46,248, the load will increase sharply. Thereby, the spring seal is self-centered in the groove or the like.

FIG. 10 schematically shows a cross section of a tilted coil spring according to the present invention, wherein the bending angle θ of the spring 212, the measured coil width CW, the measured coil height CH, and the measured spring height H is shown. The bending angle θ can be clockwise (solid line) or counterclockwise (dashed line).

As shown in FIG. 11a, the axially flat spring 212 may be bent 30 ° counterclockwise, for example, as shown in FIG. 11b,
Or, for example, as shown in FIGS. 11d and 11e, they can be turned 30 ° and 60 ° clockwise, respectively. Although the illustrated spring is shown in a circular shape, other shapes, such as elliptical or rectangular, may be used depending on the shape of the mating component between which the spring 212 and / or seal 216 is positioned. It is.

As illustrated in the accompanying drawings, the bending angle θ is determined by the position of the spring and by measuring the angle θ from the horizontal to the intersection with the centerline of each cone or inverted cone.
It is defined as the angle formed by the generally circular spring forming such a conical or inverted cone. By changing the bending angle θ, different loads can be obtained, and the degree of the load depends on the bending angle θ. That is, as will be demonstrated below, the greater the bending angle θ, the greater the generated force. The force generated under load is such that the spring is conical as shown in FIG.
11 It should be understood that this is independent of the inverted conical shape as shown in FIG. That is, the springs in FIGS. 11b and 11d function in the same state.

Curves A, B, C and D in FIG. 12 show the force-distortion characteristics of a series of springs with a bending angle θ from 0 ° to 90 °, and the specifications of these springs are listed in Table 3. Each spring A, B, C, D
Is the same at all points except the bending angle θ.

Curve A in FIG. 12 has a bend angle of 0 ° and the spring 30 or
Shown is a spring 212 that is a typical example of 100. Curve B has a bending angle of 15
゜ shows a spring 212 and shows an increase 268 in the characteristic limits characteristic of a spring formed in accordance with the present invention. This gradual increase results in maximum load characteristics more clearly illustrated by curves C, D and E, corresponding to springs C, D and E in Table 3.

As shown in FIG. 12, as the bending angle θ increases, the load increases by about 90 ° at the maximum point. Importantly, each
After the maximum load indicated by 270, 272, 274 is achieved, the force drops rapidly to approximately the force indicated by springs A, B. Thus, these springs have substantially the same effective ranges 276, 278 and 280 as spring A, which is not bent. However, as is evident from FIG. 12, these effective regions border on steep load-distortion characteristics. The spring according to the invention has advantages in a number of applications as described above. As mentioned above, the illustrated spring has a generally circular shape, but can easily be fitted into another application having an irregular shape.
That is, the spring can be easily fitted into a shape other than a circle.

As shown in Table 3, the maximum load is significantly larger than the reference load. In fact, when the bending angle is 90 °, 1725% of the reference load
Reach Therefore, a larger load can be provided by employing this bending angle. Therefore,
As mentioned above, smaller wires can be used, which allows more coils to be used per inch, thus reducing the stress on the seal when loaded and reducing the gasket 210 It is possible to increase the shielding effect.

Also, as described above, the spring according to the present invention, which exhibits the force-distortion curves shown by curves C, D and E in FIG.
It can be used in self-locking and self-centering applications, which were previously impossible with a spring exhibiting the force-distortion curve shown by curve A in the figure.

Referring now to FIG. 13, there is illustrated an electromagnetic shield gasket 310 having a radially elastic coil spring 312 in accordance with the present invention, wherein a radially elastic spring 312 is provided with a plurality of annular seals 316 within an annular seal 316. Shown with a coil 314, the annular seal 316 includes a garter-type radially resilient coil spring 31 as will be described in more detail below.
2 is provided so as not to be stretchable in a preselected direction and provides a means for controlling its elastic properties.

The load-distortion curve of spring 312 is illustrated in FIG.

The load-distortion characteristics were measured as shown in FIG.
It can be measured at 0. Radially elastic springs 3
The holder 32 holds the 32 in the housing 334, thereby restraining the spring 332 in the cavity 338. Apply a load to the outer diameter of the spring 332 using the peripheral spacer
The force required to pass 342 through the inner diameter of spring 332 is measured.

The radially elastic spring 312 may be bent counterclockwise by 30 ° as shown in FIGS. 11b and 11c, for example, as shown in FIG. As shown in FIG. 11e, they can be turned clockwise by 30 ° and 60 °, respectively. Although the illustrated springs are shown in a circular shape, they may be other shapes than a circle, such as elliptical or rectangular, depending on the shape of the mating component between which the spring 312 and / or the seal 316 are positioned. It is possible.

As shown in the drawing, the bending angle θ is determined by the angle θ from the horizontal direction to the point of intersection with the center line of each cone or inverted cone, depending on the position of the spring, and the angle of the cone or inverted cone is determined. It is defined as the angle formed by the generally circular spring that forms. By changing the bending angle θ, different loads can be obtained, and the degree of the load depends on the bending angle θ. That is, as will be demonstrated below, the greater the bending angle θ, the greater the generated force. The force generated under load depends on whether the spring has a conical shape as shown in FIG. 11b or an inverted conical shape as shown in FIG. 11d. Note that it is irrelevant. That is, the eleventh
The springs in FIGS. B and 11d function in the same way.

The spring 312 has a trailing edge portion defined by a rearward angle and a leading edge portion defined by a forward angle, as described below.

When a radial load is applied to the spring 312, the load is greater when the bending angle is 90 ° than when the bending angle is 0 °, and the load gradually increases from 0 ° to 90 °. Further, a spring 312 having a trailing angle, or a trailing edge portion along the inner diameter of the spring, has both the same bending angle compared to a spring having a trailing angle, or a trailing edge portion along the outer diameter of the spring. In that case, a significantly greater force is generated.

This increases the possibility of special designs. That is, while exhibiting the same or greater force in response to distortion,
A wider range of wire diameters and coil intervals can be designed. This has significant advantages when the spring is used with a seal as described above for electromagnetic shielding purposes.

Following the above description of various canted coil springs suitable for use as an electromagnetic shielding gasket, reference is made to FIG. 15 which shows a typical application where the gasket shielding spring 400 is used in a coaxial connector 410. Generally, the connector 410 is attached to the bulkhead 414 via a screw,
400 is compressed between the connector housing 416 and the bulkhead 414. The connector has pins 420 for transmitting electromagnetic energy. The temporary connection between the connector 410 and the coaxial cable 424 is made through a conventional screw connector 426 utilizing the screw 448 of the connector 410.

16 and 17 are enlarged views of the housing 416 having the groove 430 for supporting the spring 400. FIG. As shown in FIG. 16, the groove 430 has a depth d that is less than the height of the spring 400, which allows the spring 400 to be compressed between the housing 416 and the partition 414 (FIG. 17). The dimensions and shape of the spring 400 are set according to the basic principles described above, so that the spring 400 has a substantially constant load versus distortion curve. Thus, despite the varying degree of compression of the spring due to irregularities in the surface of the groove 430 and the partition 414, the spring 400
0 provides a constant axial force between the housing and the bulkhead 414. Importantly, such forces are maintained despite the thermal cycling of the connector that can deform or permanently deform prior art elastomeric seals (not shown) used in similar configurations. Is Rukoto.

As a result, the spring 400, which can be formed of any suitable conductive material, maintains continuity within the groove 430 and within the bulkhead 414 surrounding the conductor 420, thereby allowing electromagnetic waves to pass therethrough. Can be prevented from propagating through.

Referring to FIG. 18, another application of a gasket 450 formed according to the present invention in accordance with the basic principles described above is illustrated. In this case, the spring 450 is formed in any other shape such as a substantially circular shape or a rectangular shape, and is supported by a shelf 452 attached to the frame 454. Shelf this spring 450
The method of support on 452 is such that the spring 450 is electromagnetically shielded and can support a slide card 456 that is mounted on the frame 454 and needs to be locked in place.

As mentioned above, the open area of the electromagnetic shield can provide a source of leakage. With this in mind, the coils and springs according to the present invention are selected such that when distorted, the open area between the coils is within its acceptable range for a particular application. The distance depends, of course, on the wavelength of the electromagnetic energy to be shielded. In consideration of this, FIG. 19 illustrates a change in the open area between the coils due to a change in the distortion of the shield gasket spring 460. Spring with back angle B of 17 ° and wire diameter of 0.0035 inch
Typical dimensions for 460 are shown. Spring height
A spring with 0.025 inches and a spring width of 0.029 inches is used. In FIG. 19, when the distortion D is 0, the open area is 0.0035 inches, when the distortion is 24%, the open area is 0.0062 inches, and when the distortion is 37-1 / 2%, the open area is 0.0089 inches. Is shown.

It is understood that the rearward angle of the spring affects the spring open area. This is illustrated in FIGS. 20a and 20b, where a spring having a height of 0.162 inches and a wire diameter of 0.022 inches has an open area A ₁ of 0.000062 at a rearward angle of 16.5 °.
3inch ² and open area A ₂ is 0.00 when the rear angle is 30 °
0893 inch ² .

In situations where additional electromagnetic shielding is desired, an electromagnetic shielding gasket 500 as shown in FIGS.
Is an outer coil spring 5 in which an inner coil spring 504 is disposed.
02, both coil springs 502, 504 are formed as axially elastic or radially elastic springs as described above, and their coils are tilted in the same or opposite directions along centerline 506. (See FIGS. 22a and 22b). FIGS. 22a and 22b show the outer spring under load.
A gasket 500 is shown that compresses 502 to a position where it contacts the inner spring 504.

Another embodiment of the present invention is illustrated in FIGS. 23a, 23b and 24a, 24b, where the electromagnetic shield 510 may impart additional conductivity to the gasket 510. One or more coil springs 512, 514 filled with conductive elastomer. The gasket 520 illustrated in FIGS. 24a and 24b includes a coil spring 522 having a central rod or tube 524 therein as described above. This rod or tube 524 is conductive to the electromagnetic shield and can be solid with sufficient strength to act as a stop for the spring 522 and prevent permanent damage. For the purpose of showing how the invention can be advantageously applied,
Although described above with respect to certain electromagnetic shielding gaskets according to the present invention, the present invention is not limited thereto. Accordingly, all modifications, adaptations, or equivalent constructions devised by those skilled in the art should be considered to be within the scope of the present invention as set forth in the appended claims.

[Brief description of the drawings]

FIG. 1 is a diagram of a theoretical load versus distortion curve showing various parameters of an elastic coil spring according to the present invention. FIGS. 2a and 2b depict a trailing edge portion along the outer diameter of the spring. 3a and 3b, respectively, a circular welded clockwise wound spring according to the present invention having a rearward angle defining and a forward angle defining a leading edge portion along the inner diameter of the spring; 3b has the same physical dimensions as the spring shown in FIGS. 2a and 2b, and defines a rearward angle defining a trailing edge portion along the outer diameter of the spring and a forward angle along the inner diameter of the spring. FIG. 4 is a plan view and side view, respectively, of a circular counterclockwise wound spring having a forward angle defining an edge portion; FIG. 4 is a view of the load versus distortion curve of the spring shown in FIGS. 2 and 3; FIG. 5 shows various types having a trailing edge portion along the outer diameter corresponding to the spring dimensions listed in Table 1. FIG. 6 is a diagram of the load versus distortion curve of a counterclockwise wound spring loaded in the axial direction, FIG. 6 is a diagram of the load versus distortion curve of an axial spring having different rearward angles, FIGS. 7a and 7b. Is a plan view and a side view, respectively, of a circular welded clockwise spring according to the invention having a forward angle outside the spring and a rearward angle inside the spring; FIG. 8 is an annular axially elastic according to the invention; FIG. 3 is a perspective view of an electromagnetic shielding gasket with various coils, showing a plurality of coils interconnected in a manner to form a girder type axially elastic coil spring, wherein the spring has a preselected bending angle direction; In the annular seal, the elastic characteristics of the coil spring, which is elastic in the axial direction, are controlled, and the spring is supported in the annular seal so that it cannot be extended. And thereby FIG. 9 shows a plurality of springs that concentrate a preselected force on the sealed portion of the valve, FIG. 9 shows the load versus distortion curve of a spring formed in accordance with the present invention, and FIG. 10 calculates the bending angle θ. 11a, 11b, 11c, 11d and 11e show a coil spring tilted axially with a bending angle θ for the purpose of showing how to do it.
Is a diagram showing axial springs having various bending angles, FIG. 12 is a diagram of a plurality of force-distortion curves corresponding to an annular axially elastic coil spring having different bending angle directions, FIG. FIG. 4 is a perspective view of an electromagnetic shielding gasket having a radially loaded coiled spring seal according to the present invention, wherein a plurality of interconnected interconnects are formed in a manner to form an axially resilient coil spring generally of the garter type. Wherein the spring is disposed within the annular seal in the direction of the pre-selected bending angle to control the elastic properties of the elastic coil spring in the annular axial direction and extend the spring within the annular seal. To allow the independent action of the internal spring,
FIG. 14 shows a plurality of springs that concentrate a preselected force on the sealing portion of the seal, FIG. 14 shows a test device for measuring load versus distortion characteristics, and FIG. FIG. 16 is an enlarged sectional view of the gasket shown in FIG. 13 in a no-load condition, and FIG. 17 is an enlarged sectional view of the gasket shown in FIG. 13 under a loaded condition. Figure, Figure 18 shows the card installed in the frame,
FIG. 19 is a cross-sectional view of an application example of another electromagnetic shielding gasket, FIG. 19 is a diagram showing the effect of spring distortion on the open area of the inclined coil spring, FIG. 20a and FIG. FIGS. 21a and 21b are views of an electromagnetic shielding gasket having two tilted coil springs in a no-load situation, showing that the angle is dependent on the angle; FIGS. 22a and 22b are FIGS. 23a and 23b are views of an electromagnetic shielding gasket having two coil springs with two inclined coil springs filled with an elastomer, and FIGS. Figures 24a and 24b are views of an electromagnetic shielding gasket having a coil spring and a center rod or tube. 10: distortion curve, 12: line portion 14: point, 16: point 18: distortion range, 20: point 22: butting point, 24: distortion range 30: spring, 32: coil 36: center line, 40: trailing edge Part 42: Leading edge, 46: Point 48: Backward angle, 50: Normal 54: Forward angle, 60: Inside diameter 68: Spring, 72: Coil 74: Trailing edge, 76: Leading edge 80: Rearward angle, 82: forward angle 84: inner diameter, 86: outer diameter 100: spring, 102: coil 104: center line, 108: trailing edge 110: leading edge, 112: rear angle 114: normal, 116: forward angle 122: Outer diameter, 210: Gasket 212: Spring, 214: Coil 216: Annular seal, 236: Distorted part 238: Point, 240: Distorted part 242: Butt point, 276, 278, 280: Effective range 310: Gasket, 312: Spring 314: Coil , 316: Seal 330: Test device, 332: Spring 334: Housing, 336: Holder 338: Cavity, 340: Spacer 400: Spring, 410: Connector 414: Partition, 416: Housing 420: Pin, 424: Cable 426: Connector, 428: Screw 430: Groove, 450: Spring 452: Shelf, 454: Frame 4 56: Slide card, 460: Spring 500: Gasket, 502,504: Coil spring 510: Shield gasket, 512,514: Spring 520: Gasket, 522: Spring 524: Pipe

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 52-144601 (JP, U) JP-A 55-101098 (JP, U) JP-A 46-10565 (JP, Y1) (58) Field (Int.Cl. ⁶ , DB name) H05K 9/00

Claims (21)

(57) [Claims] 1. A coil spring type electromagnetic shielding gasket (500, 510) for hindering the propagation of electromagnetic waves therethrough, within a distortion range of an outer coil (502, 512) and independently of the compression of the outer coil. The gasket (500, 510) comprises a plurality of outer coils (502, 512) such that the outer coils can obstruct the propagation of electromagnetic waves therethrough, the outer coils being interconnected and arranged at an angle to the center line of the gasket (500, 510). And a rear portion in which each coil of the outer coils (502, 512) is disposed at a rear angle of the outer coil with respect to the center line, and a front portion disposed at a front angle of the outer coil with respect to the center line. And wherein a forward angle of the outer coil is greater than a rearward angle of the outer coil, and further disposed within the outer coil (502, 512), wherein a gasket (500, 510) is provided for the inner coil. Within the distortion range,
And independent of the compression of the inner coil spring, a plurality of inner coils (504,
514), wherein the inner coils (504, 514) are interconnected and disposed at an angle to the centerline of the gasket (500, 510), each coil of the inner coil (504, 514) being inboard with respect to the centerline. A rear portion disposed at a rear angle of the coil, and a front portion disposed at a front angle of the inner coil with respect to the center line, wherein a front angle of the inner coil is rearward of the inner coil. An electromagnetic shielding gasket characterized by having a larger angle. 2. An electromagnetic shield gasket (500) according to claim 1, wherein said inner coil (504) and outer coil (502) are inclined in the same direction with respect to a center line. gasket. 3. An electromagnetic shield gasket according to claim 1, wherein said inner coil and said outer coil are inclined in opposite directions with respect to a center line. gasket. 4. The electromagnetic shielding gasket (500, 510) according to claim 1, wherein both ends of the outer coil (502, 512) are connected to each other, and both ends of the inner coil (504, 514) are connected to each other. An electromagnetic shielding gasket, forming a continuous coil spring having a continuous inner coil disposed within an outer coil. 5. An electromagnetic shielding gasket according to claim 4, wherein the void areas in the inner and outer coils are filled with a conductive elastomer (316). 6. An axially resilient coil spring type electromagnetic shielding gasket (30) of the garter type, wherein said coil spring type gasket (30) is within the distortion range of the individual coil (32). And independent of the compression of the coil (32), comprises a plurality of individual coils (32) so as to be able to obstruct the propagation of electromagnetic waves therethrough, said individual coils (32) being arranged along their center line. A rearward angle (48) for positioning the trailing edge portion (40) of each coil relative to a normal normal to the inclined and centerline and determining the force-distortion characteristics of the coil (32); A front angle for positioning the leading edge portion (42) of each coil, the front angle being greater than the rear angle, along the outer diameter of the axially elastic coil spring (30) of the garter type; Rear edge (40) and girder type axially elastic coil I by the method capable of forming an elastic coil spring type gasket (30) in the axial direction of the gutter the type front has an edge portion (42) along the inner diameter (30), said coil (3
(2) An electromagnetic shielding gasket, characterized by being mutually connected. 7. The electromagnetic shielding gasket (30) of claim 6, wherein the rearward angle (48) is greater than about 1 °, less than about 40 °, and the forward angle (54) is greater than about 1 °. An electromagnetic shielding gasket characterized by being smaller than 55 mm. 8. An electromagnetic shielding gasket (30) according to claim 6, wherein the rearward angle (48) is an axially resilient electromagnetic shielding spring gasket (30) of the garter type in the axial direction of the spring gasket. Defining an effective distortion to exert a substantially constant force in the axial direction in response to the distortion of the spring gasket (30), wherein the effective distortion is in the range of about 5% to about 50% of the distortion of the spring gasket (30). An electromagnetic shielding gasket, characterized in that: 9. An electromagnetic shielding gasket (68) of the garter type axially resilient coil spring type, wherein the coil spring type gasket (68) is provided within the distortion range of the individual coil (72). And a plurality of individual coils (72), which can obstruct the propagation of electromagnetic waves therethrough, independent of the compression of said coils (72), said individual coils (72) being inclined along their center line. A rearward angle (80) for positioning the trailing edge portion (74) of each coil (72) with respect to a normal perpendicular to the center line and determining the effective elastic area of the coil (72); A front angle (82) larger than the rear angle, which is a front angle at which the front edge portion (76) of each coil (72) is positioned, and an axially elastic coil spring type of a garter type. Trailing edge (74) along the inner diameter of gasket (68) and girder type Forming a garter type axially elastic coil spring type gasket (68) having a leading edge portion (76) along the outer diameter of the axially elastic coil spring type gasket (68) An electromagnetic shielding gasket, wherein the coils (72) are connected to each other. 10. The electromagnetic shielding gasket according to claim 9, wherein the front angle (82) is smaller than 35 °. 11. The electromagnetic shielding gasket according to claim 10, wherein a plurality of coils are inclined clockwise. 12. The electromagnetic shielding gasket according to claim 10, wherein the rearward angle (80) is larger than 1 ° and smaller than 35 °. 13. The electromagnetic shielding gasket (68) according to claim 12, wherein the rearward angle (80) is substantially constant in the axial direction in response to axial distortion of the spring gasket. An electromagnetic shielding gasket defining an effective distortion that exerts the force of claim 1, wherein said effective distortion is in the range of about 5% to about 50% of the distortion of the spring gasket. 14. The electromagnetic shielding gasket according to claim 10, wherein the rearward angle (80) is less than about 11 °. 15. An electromagnetic shielding gasket (310) comprising an annular axially resilient coil spring which obstructs the propagation of electromagnetic waves therethrough, said gasket (310) being capable of distorting individual coils (314). A plurality of individual coils (314) within a range and independently of the compression of the gasket (310) so as to be able to obstruct the propagation of electromagnetic waves therethrough;
The individual coils (314) are inclined along their center lines and position the trailing edge portion (74) of each coil (314) relative to a normal normal to the center line and The rear angle (80) determines the rear angle (80) for determining the force-distortion characteristic and the front angle (82) for positioning the leading edge portion (76) of each coil (314) with respect to the normal.
Said coil (314) being interconnected in such a way as to form a gasket of a garter-type axially elastic coil spring, and further comprising a garter-type axially elastic. A non-stretchable coil spring type gasket (310) in a preselected direction,
An electromagnetic shielding gasket comprising an annular seal (316) for controlling its elastic properties. 16. The electromagnetic shield gasket (310) of claim 15, wherein said annular seal (316) supports and orients the coil (314) at a bending angle greater than 0 ° and less than 90 °. An electromagnetic shielding gasket comprising a cavity. 17. The electromagnetic shielding gasket (310) of claim 16, wherein the bending angle is selected to provide saddle-like load-distortion characteristics. 18. The electromagnetic shielding gasket according to claim 17, wherein the bending angle is greater than about 15 °. 19. An electromagnetic shield gasket seal according to claim 17, wherein the bend angle is greater than about 60 °. 20. The electromagnetic shielding gasket seal (310) according to claim 17, wherein the rear edge portion is disposed along the outer diameter of an axially elastic coil spring of a garter type, and the front edge portion is provided with a garter seal. An electromagnetic shielding gasket, which is disposed along the inner diameter of a coil spring that is elastic in the axial direction of the model. 21. The electromagnetic shielding gasket (310) according to claim 17, wherein a front edge portion is disposed along an inner diameter of a garter type axially elastic coil spring, and a rear edge portion is a garter type. An electromagnetic shielding gasket, which is disposed along an outer diameter of a coil spring that is elastic in an axial direction.