KR100499758B1 - Vibration damping system - Google Patents

Abstract

An apparatus and method for damping vibrations, such as sound, in a vibration generating device, such as household appliance 10, are disclosed. The restriction layer 12 and the adhesive layer 13 are provided. The adhesive layer 13 is made of a viscosity improving material 21 such as cellulose fiber and an adhesive material 22. The restraint layer 12 is attached to the surface 11 of the device by an adhesive layer 13.

Description

Vibration Damping System {VIBRATION DAMPING SYSTEM}

FIELD OF THE INVENTION The present invention relates to apparatus and methods for damping vibration (eg, acoustic), and more particularly to a constraint layer damping system with improved resistance to creep, ie slow transverse motion of the constraint layer with respect to the surface of the vibration source. will be.

Vibration damping of mechanical systems is of increasing importance in the industrial field because vibration has many undesirable effects. For example, consumers are becoming increasingly sensitive to the undesirable sounds produced by vibration systems. In addition, vibrations cause failures of electronic products, mechanical connection sites, and fixing devices, and reduce the perception of the consumer's quality in various products. For example, automakers have recognized that an important part of many consumer purchase decisions is the thumping of solids when the car door is closed. Likewise, the quality of home appliances is sometimes evaluated in part by the recognition of the robustness of the structure.

For manufacturers of home appliances such as washing machines, dryers, refrigerators, microwave ovens, ovens, stoves, dishwashers, etc., it has become important to significantly reduce vibrations in terms of flat sheet materials for home appliances, and consumers who are deciding to purchase Can evaluate the quality of the product by the low frequency sound generated when hitting the side of the home appliance. In addition, the provision of such a system is important for reducing the noise level generated by household appliances when the side vibrates. This is especially the case because of the increasing number of homes that place such household appliances in the main living room.

Acoustic damping systems generally operate by converting vibrational energy into thermal energy. For example, vibration energy can be converted into thermal energy by friction at the interface, which exhibits vibration damping characteristics. Alternatively, if an elastic material having a small elastic modulus is positioned between the surface of the vibration energy source and another surface or restraint layer, shear deformation may occur in the material.

For example, Pre Finish Metal Inc. Supplies a product called Polycoreu, which consists of a metal shell surrounding a thin viscoelastic core material. This inner core converts the mechanical energy of the vibrations into heat and then dissipates this heat. This configuration is for reducing the vibration noise generated in the vibration source.

Similarly, 3M provides a product entitled "Scotchdamp ^™ Vibration Control System" that couples the restraint layer to the vibration sound source by one of several adhesive layers. The shear rate and acoustic loss factors of these products depend on frequency and temperature as well as other factors.

In addition to the adhesive, the confinement layer may be coupled to the vibration source of the vibration sound by a magnetic material. For example, the vibration damping material disclosed in US Pat. No. 5,300,355 includes a magnetic composite type damping material consisting of bonding an adhesive elastic sheet containing magnetic powder to a restraining plate such as a metal plate. In such a system, it is reported that the damping material is adsorbed to the vibration source by magnetic force and has surface adhesion, so that the vibration damping characteristic over a wide temperature range is improved.

The fundamental problem with vibration damping systems is that the constraint layer can be separated from the surface of the vibration source. In other words, the restraining layer may fall during transport or use. In order to measure the resistance to the occurrence of such casualties, shock / shear tests have been developed, for example, to measure the position of the restraint layer by moving household appliances away from a certain distance at a certain angle and temperature. If the adhesive properties of the adhesive are insufficient, the restraint layer can be removed, potentially causing dissimilarity in the household appliance, increasing the likelihood of at least reducing its damping effect or even percepting unwanted vibrational sounds.

However, a further problem has been recognized that viscoelastic materials have limited fluidity as one of their properties. According to this property of the adhesive, the confinement layer can move transversely with respect to the surface of the vibration source during use, especially when the constraint layer is positioned perpendicular to the vibration source. The slow movement of the confinement layer relative to the surface of the vibration source is referred to herein as "creep," which, if not suppressed, can eventually lead to a catastrophic failure in the form of loosening of the confinement layer.

Disclosure of the Invention

It is an object of the present invention to increase the resistance to creep in a vibration damping system, while maintaining or increasing the acoustic damping effect of the confinement layer damping system and to maintain good resistance to fatal failures due to impact and shear forces.

The present invention achieves these and other objects by providing an apparatus and method for damping vibration or sound in a vibration generating mechanical system such as a home appliance, and the present invention provides a restraint layer, a viscosity improving material and an adhesive material. Providing an adhesive layer comprising a, and using the adhesive layer and attaching the restraint layer to the surface of the mechanical system. The adhesive layer may be a composite of an adhesive layer, such as a viscoelastic adhesive material, and a viscosity enhancing material, for example in the form of cellulose fibers. Such cellulose fibers may be wetted by an adhesive that penetrates the fiber carrier sheet to some extent.

The present invention is explained with reference to the accompanying drawings below.

1 is a device consistent with some embodiments of the vibration damping system of the present invention.

2A is a perspective view of a first embodiment of a vibration damping system of the present invention.

FIG. 2B is a cross-sectional view of the vibration damping system of FIG. 2A.

2C is a perspective view of a second embodiment of a vibration damping system of the present invention.

3A-3C are graphs illustrating creep resistance characteristics of the present invention for various criteria expressed in inches (mm) of creep (y-axis) per time (x-axis).

4 is a cross-sectional view of an adhesive layer in which a release film is disposed on a main surface of the adhesive layer of FIG. 2B.

5 is a cross-sectional view of a third embodiment of a vibration damping system of the present invention.

1 illustrates one embodiment of a vibration damping system of the present invention. In FIG. 1, a household appliance 10, such as a washing machine or laundry dryer, has a side panel or surface 11. In such embodiments, any household appliance can benefit from the present invention, including means capable of performing functions or operations (eg, washing, drying, cooking, etc.) and generating vibrations or shocks during the operation. In this embodiment, however, the household appliance 10 is a laundry dryer that includes a drum 20 that holds laundry for several cycles.

The panel 11 is formed of a plate material such as a sheet metal on which an enamel paint layer is formed. This unmodified panel 11 vibrates greatly and acts as an acoustic generating diaphragm against vibrations generated by the household appliance 10 or by an object striking the surface 11. At least one of the panels 11 of the household appliance 10 is attached with a vibration damping system 100 comprising a restraint layer 12 and an adhesive layer 13. The vibration damping system 100 is aesthetically offset in the center of the top panel by the length of the top panel (System 100 ^I ), in the center of one or both side panels (System 100 ^II ), toe plate It may be formed on one or more surfaces 11, such as those in (system 100 ^III ), those in the bottom panel (system 100 ^IV ), and the like. The position of the vibration damping system 100 depends on the shape of the component in the household appliance 10. One or more systems 100 are located where sound is generated or where they do not interfere with other components.

Constraint layer 12 is shown as having the shape of an elongated metal bar or straight plate, but if desired, may be any shape, such as circular, ovoid, square, irregular, and the like. Constraint layer 12 may include any suitable shape that helps to stiffen surface panel 11. This rigid shape of the confinement layer 12 is constrained flat with the bend 14 (see FIG. 2C) over the length of the confinement layer 12 to provide greater rigidity due to the angular surface of the confinement layer 12 cross section. It may be a simple shape including curved edges 16 (see FIG. 2A) that span the width or length of layer 12. Although the bent portion 14 is shown in a chevron shape, an arc shape, a flat plate shape, or the like may be used if desired.

The confinement layer may also include one or more anti-interference flanges designed to prevent the confinement layer 12 from falling into the interior working element of the appliance 10, otherwise the appliance may be separated if the constraint layer is separated. It interferes with the internal working elements of the product. As shown in FIGS. 1 and 2A, the system 100 ^I attached to the inner surface of the top panel 11 of the household appliance 10 includes a curved edge 16 that spans the width of its ends. Act as an anti-interference flange. This flange 16 prevents the system 100 ^I from rubbing against the drum and eventually falling off the top panel 11.

Any suitable material may be used as the restraint layer 12 as long as it has a large modulus of elasticity in at least one direction relative to the surface to be attached. In other words, the restraint layer 12 must have a relatively large bending stiffness, and therefore must be more resistant to bending than the surface 11 on which the restraint layer is formed, thereby causing a shear force in the adhesive layer 13 so that vibrations are converted into thermal energy. To be converted. For example, the constraint layer 12 may be a plate made of sheet metal, iron, aluminum, stainless steel, copper, or the like, and a plastic plate made of phenol resin, polyamide, polycarbonate, polyester, or the like. And fiber-enhanced plastic plates produced by improving plastic plates using fibers such as glass fibers and carbon fibers, or slate plates, hydrated calcium silicate plates, plaster boards, fiber mixed cement plates, ceramic plates, and the like. It may have a high modulus of elasticity, such as an inorganic rigid plate, or an organic rigid plate including asphalt, asphalt-impregnated fibers, wood, and the like.

The vibration damping system 100 may be located anywhere inside or outside the home appliance 10. When exposed to the outside, constraint layer 12 may comprise a paint layer and a non-functional shape or profile for aesthetic purposes.

As shown in FIGS. 2A and 2B, the adhesive layer 13 is positioned between a vibration source such as panel 11 and the restraint layer 12 to attach the restraint layer 12 to the panel 11 and to the panel 11. It acts to dampen vibration of). The adhesive layer 13 is made of a viscosity improving material 21 and an adhesive 22, as shown in FIG. 2B. Viscosity enhancing material 21 not only improves the viscosity of the adhesive and thereby increases creep resistance, but also reinforces the adhesive to increase the adhesive's resistance to impact and shear forces.

As the adhesive 22, a viscoelastic material which converts vibrations into thermal energy by the shear force generated in the viscoelastic material is preferable. Any suitable viscoelastic adhesive material can be used if it remains viscous after curing. For example, the adhesive can be any one or more of the following adhesives: pressure sensitive hot or cold melt adhesives, acrylic based adhesives such as acrylic viscoelastic polymers, pressure sensitive damping polymers, adhesive epoxy resins, Urea resin, melamine resin, phenol resin, vinyl acetate, cyanoacrylate, urethane, synthetic rubber, etc. Adhesives are for example acrylic adhesive A-1115 from Avery-Dennison, acrylic adhesive MACtac ^™ XD-3780 from Morgan Adhesives, Reynolds CO. Synthetic rubber based hot melt adhesive R-821, or acrylic adhesive V-514 of Venture Tape. The performance of such commonly available adhesives is shown in FIG. 3A.

FIG. 3A shows graphically a comparison of adhesion performance against inches (mm) of creep (y-axis) in a damping system using cellulose material after immersion for 60 minutes at 75 ° F (24 ° C.), where the painted metal A 150 gram weight is applied at 125 ° F. (52 ° C.) over a period of time (x axis) to the confinement layer 12 in the panel.

The viscosity enhancing material 21 of the adhesive layer 13 generally reduces the fluidity of the final adhesive layer, thereby reducing the amount of static creep and dynamic creep present in the vibration damping system. The viscosity improving material 21 may include one or more of organic fibers including cellulose and carbon fibers, and inorganic fibers including glass fibers, steel wool, synthetic fibers, and the like.

The viscosity improving material 21 exhibits a structure interposed between the vibration source such as the side panel 11 of the home appliance 10 and the restraint layer 12. This structure allows the side panel 11 and the restraint layer 12 to move relative to each other within the limits, but increases the viscosity of the adhesive layer 13 (ie, resistance to flow) to the restraint layer 12 and the restraint layer 12. Permanent displacement between the side panels 11 is reduced. In other words, the restraint layer 12 generally does not creep to the side panel 11 as much as occurs in the same damping system that does not include the viscosity enhancing material 21.

This advantage of the present invention is shown in FIG. 3B, which shows a viscosity enhancing material, ie cellulose fiber (paper-shaped product), with a nearly similar system (eg, the same surface 11 as the same MACtac ^™ XD-3780 adhesive). Constraint layer of damping system compared to a nearly similar system (see line B) containing the same confinement layer 12 and 150 grams applied to the surface at 125 ° F (52 ° C.) but no adhesive such as a viscosity enhancing material was formed. The resistance to creep at is increased (see line A.) As shown, creep is relatively negligible in the presence of a viscosity enhancing material, while in the absence of a viscosity enhancing material the creep is within a few hours. Cause poor adhesion.

In a preferred embodiment, the viscosity enhancing material 21 of the adhesive layer 13 is a cellulose material, the fibers of which are dimensioned and mated to allow the liquid adhesive to penetrate into the cellulose carrier material, the penetration of which The cellulosic material may be immersed in the adhesive, pressurized, rolled, or by any other suitable method. Such penetration can occur within microns or throughout the cellulosic material.

The adhesive layer 13 is manufactured by applying the liquid adhesive 22 to the viscosity enhancing material 21 and then curing the adhesive 22 to form a core coated with the adhesive. A number of methods can be used to apply the adhesive 22 to the viscosity enhancing material 21 or the carrier material. For example, a roll coat process (measured adhesive liquid is applied to one or both sides of the opposing rollers and a core, such as a viscosity enhancing material, passes between the opposing rollers), spray coating, brush Coatings, knife coatings, foams in the form of mechanical or chemical application of agitated adhesives or foams (the bubbles are dissipated leaving a thin coating), curtains ) Coating, slot die or injection coating (adhesive is injected into the carrier or viscosity enhancing material through the slot), or calendering.

As shown in FIG. 4, a suitable release film 15 may be formed or disposed in a known manner on the main surface (top and bottom) of the core or adhesive layer 13 coated with an adhesive.

The method of the present invention provides a constraining layer 12, provides an adhesive layer 13 comprising a viscosity enhancing material 21 and an adhesive 22, and uses the adhesive layer 13 on the surface of the home appliance. Attaching the constraint layer 12. In order to place the restraint layer 12 in the home appliance, the first release film 15 (if present) is removed to expose the adhesive coating surface of the adhesive layer 13, and a certain pressure is applied to restrain the adhesive layer 13. Disposed on layer 12, and the second release film 15 (if present) is removed to expose the opposing adhesive coating surface of adhesive layer 13, and the opposing surface of adhesive layer 13 is disposed on the side of home appliance 10 The panel 11 is placed under a certain pressure. Alternatively, the adhesive layer 13 may be initially placed on the side panel 11 and then the restraint layer 12 may be disposed on the opposite surface of the adhesive layer 13.

The actual attachment of the damping system 100 to the panel is to apply pressure to the panel 11, which is the confinement layer 12, the adhesive layer 13, or the adhesive layer 11 on one side and meshes against the hard surface on the other. It may include using a roller or hand. Various methods do not make a significant difference in the creep resistance of the adhesive layer 13. For example, 2.1 lbs (953 g) [M] on a standard roller according to the total pressure (eg, Pressure Sensitive Tape Counsel guidelines) as shown in FIG. 3C using an Avery-1115 adhesive. ], 4.5 lbs (2041g) [N], or 8.2 lbs (3719g) [O]) weighed 150 grams at 125 ° F (52 ° C) after 60 minutes of immersion at 70 ° F (21 ° C). It does not make a significant difference in inches (mm) of creep (y-axis) resistance in the usual range and conditions applied to the constraint layer 12 in the painted metal panel over the (x-axis).

As shown in the graphs of FIGS. 3A-3C, the present invention reduces the total amount of creep caused by forces perpendicular to the surface of the restraining layer 12 with respect to the side panel 11. These tests were performed on various immersion times, immersion temperatures, and test temperature conditions in painted metal panels, such as MACtac ^™ XD-3780 and Avery 1115 adhesive. In this test, the thickness of the cellulose fiber core forming the viscosity improving material 21 was 4.2 millimeters, and the coating thickness of the adhesive was 2.35 millimeters (acrylic) in either case. The total thickness of the adhesive layer 13 was 8.9 millimeters. The minimum deviation (± 10%) in these dimensions is predicted and some tolerance for this thickness is predicted and can be tolerated. These materials are 120 ° F (49) with a 3 ″ × 8 ″ (76 mm × 203 mm) galvanized constrained layer that is entirely attached to the 4 ″ × 10 ″ (102 mm × 254 mm) painted panel using an adhesive cover. Shock / shear test, which was submerged at 30 < 0 > C for 30 minutes and then dropped at 72 inches (1829 mm) height.

Viscosity enhancing material 21 may be replaced with a foam core, such as cross-linked polyethylene foam or air impregnated urea compound. For example, the adhesive is applied to both sides of a 1/32 ″ (0.79 mm) crosslinked polyethylene foam core (IM 2730 from Morgan Adhesive Company) with minimal penetration of the adhesive into the foam core, which is 4 ″ × A 3 ″ × 8 ″ (76 mm × 203 mm) galvanized restraint layer attached entirely to the 10 ″ (102 mm × 254 mm) painted panel using an adhesive cover for 30 minutes at 120 ° F (49 ° C). After immersion, the impact / shear test was passed, dropping off at a height of 24 inches (610 mm). In other words, the foam core acts as a carrier. This embodiment shows good impact / shear test results, but does not exhibit sound suitable for application in consumer electronics. In other words, if a foam core is used in place of a viscosity enhancing material, a satisfactory "knock" is not always present on the side of the crashed appliance. In addition, the foam core does not exhibit good creep resistance. However, foam cores may be more appropriate in other applications.

Alternatively, the polyester core or other plastic carrier of the Venture Tape may exhibit a good acoustical state in the acoustic attenuation of the consumer electronics, but there is a split between the carrier and the adhesive layer and resistance to creep than the viscosity enhancing material. Lower.

As shown in FIG. 5, in another embodiment of the present invention, the adhesive layer 13 ′ is made of an adhesive material and at least one damping layer 30 made of a viscosity enhancing material 31 and a viscoelastic damping material 32. Two or more sublayers comprising one or more adhesive layers 34. The viscoelastic damping material 32 may be any suitable viscoelastic material, such as polymer, asphalt, or the like, and the viscosity enhancing material and adhesive material may be any suitable material, such as the foregoing. However, in this embodiment where creep is a concern, the adhesive material is preferably relatively viscous and resistant to creep, and the adhesion function of the adhesive layer 13 is mostly performed by the adhesive layer 34, and the adhesive layer 13 '. It is preferable that the attenuation function of the?) Is mostly performed by the attenuation layer 30. It can be appreciated that the adhesive layer 13 ′ may include various arrangements of damping and adhesive layers other than the arrangement shown in FIG. 5 to meet specific design criteria for the particular use of the vibration damping system 100. .

Although the present invention has been described with respect to preferred embodiments, the present invention is not limited to these preferred embodiments. For example, the present invention is applicable to any vibration system that requires damping at any surface. For example, the present invention can be applied for vibration damping in panels of automobile doors, trunks, hoods and the like. It is also envisaged to apply the present invention to electronic devices such as computer housings or other vibration sensitive devices. The present invention causes slow movements (creeps) where relative vibration or acoustic damping is needed, in particular where the damping device may or may not be placed on a horizontal or vertical surface, or which may or may not lead to a large failure of adhesive bonding. Can be applied where any force is applied.

In view of the foregoing, various modifications and variations of the present invention will be apparent to those skilled in the art within the scope of the present invention. The invention should not be unduly limited to the exemplary embodiments disclosed herein. Instead, the boundaries and scope of the invention are set forth in the appended claims.

Claims (15)

In the vibration damping method in the vibration generating device comprising attaching the restraint layer 12 to the surface 11 of the vibration generating device by the adhesive layer 13 containing the viscosity improving material and the adhesive material, And wherein said viscosity enhancing material is in the form of organic fibers. The adhesive material 22 according to claim 1, wherein the adhesive material 22 is a pressure-sensitive hot melt adhesive, an acrylic base adhesive such as an acrylic viscoelastic polymer, a pressure-sensitive damping polymer, an adhesive epoxy resin, a urea resin, a melamine resin, a phenol resin, a vinyl acetate. And at least one of cyanoacrylate, urethane, and synthetic rubber. The vibration damping method according to claim 1 or 2, wherein the adhesive layer (13) is formed by adding the adhesive material in a liquid state to the viscosity improving material and curing the adhesive material. The vibration device according to claim 1 or 2, wherein the adhesive layer includes a release film on the main surface of the adhesive layer, and the release film is removed to attach the restraining layer to the surface of the vibration generating device. Attenuation method. The vibration as claimed in claim 1, wherein the restraint layer 12 is attached to an exposed surface of the vibration generating device, the restraint layer comprising a paint coating on at least one side of the restraint layer. Vibration damping method in the generator. The vibration damping method according to claim 1 or 2, wherein the restraint layer is attached to an inner surface of the vibration generating device. Constraining layer 12, and A vibration damping system comprising an adhesive layer (13) having a viscosity enhancing material and an adhesive material, And wherein said viscosity enhancing material is in the form of organic fibers. 8. The vibration damping system according to claim 7, wherein the viscosity improving material (21) comprises one or both of cellulose and carbon fibers. 9. The vibration damping system according to claim 8, wherein the adhesive layer comprises a viscosity improving material made of cellulose fiber in which the adhesive material has penetrated. 10. Vibration damping system according to claim 7, 8 or 9, characterized in that the adhesive layer (13) is a viscoelastic material. 10. The adhesive layer according to claim 7, 8 or 9, further comprising at least one layer comprising the viscosity improving material and at least one adhesive layer comprising the adhesive material. Vibration damping system. The method of claim 7, 8, or 9, wherein the adhesive layer moves less than 2.54 cm (1 inch) in 10 hours when a constant force of 150 grams or less is applied at 52 ° C. (125 ° F). Vibration damping system characterized in that it exhibits resistance to creep. 10. The vibration damping system according to claim 7, 8 or 9 comprising a viscous adhesive material. Means of performing work, At least one surface 11 for generating sound in response to vibration, and 10. Vibration generating device comprising a vibration damping system (100) according to claim 7, 8 or 9, wherein a restraining layer is attached to the surface (11) by an adhesive layer (13). 15. The vibration damping system of claim 13, wherein the restraint layer of the vibration damping system comprises a material having a higher bending resistance than the surface to which the restraint layer is attached.