Method of manufacturing a frequency tuned vibration damper assembly

Abstract

The present application relates to a method for manufacturing a frequency-tuned vibration damper assembly. A damper unit (40) for use in a shock-absorbing assembly (6) for a steering wheel (2) is disclosed. An elastic damper element (70) is molded onto an inner sleeve (52) and has a plurality of elastic ribs (77) forming a radially outer engagement surface (75) and a plurality of elastic support columns, the elastic support columns being spaced apart from each other in the circumferential direction and being flexible in all directions transverse to the axis. Methods for manufacturing the damper unit and the damper assembly are also disclosed.

Description

[0001] This application is a divisional application of the application with application date of December 14, 2018, application number 201880080374.5, and invention name “Damper unit, damper assembly, method for manufacturing damper unit and damper assembly”. Technical Field

[0002] The present disclosure generally relates to the field of frequency-tuned vibration dampers for motor vehicles. A damper unit for use in a steering wheel vibration damping assembly is disclosed. Also disclosed are a frequency-tuned vibration damper assembly including one or more such damper units, and methods of manufacturing the damper unit and the frequency-tuned vibration damper assembly. Background Art

[0003] The function of a frequency-tuned vibration damper, also known as a tuned mass damper, dynamic damper, or shock absorber, is based on a damped spring-mass system that counteracts and reduces vibrations in a structure or surface to which the damper is attached using one or more elastic damper elements that are used to transfer vibrations from the vibrating structure to at least one mass, which causes the vibrations to be out of phase in order to damp the vibrations. Examples of frequency-tuned vibration dampers are disclosed in WO 01 / 92752 A1, WO 2013 / 167524 A1, and WO 2008 / 127157 A1.

[0004] In the automotive industry, some steering wheels are equipped with frequency-tuned vibration dampers to reduce steering wheel vibrations caused by vibrations transmitted to the steering wheel from the road and engine. In these damper configurations, the weight of the airbag module can be used as part of the weight of the mass in the spring-mass system. Furthermore, steering wheels are often equipped with a horn activation mechanism, which the driver uses to activate the vehicle's horn. Mechanical horn activation mechanisms typically include one or more metal coil springs, known as horn springs, which return the horn activation mechanism to its normal state after activation. Electronic horn activation mechanisms without horn springs are also available.

[0005] EP 2 085 290 discloses an example of a prior art shock-absorbing damper structure for a steering wheel, comprising an elastic damper element disposed on a slider slidably mounted on a bolt shaft. Vibrations in the steering wheel are transmitted to the airbag assembly via the elastic damper element for damping purposes. During horn activation, the slider can slide along the bolt shaft. A conventional coil spring is placed on the bolt shaft and is compressed when the horn is activated to return the slider to its normal position when horn activation ceases. A disadvantage of this prior art is that assembly of the entire structure is complex and time-consuming, increasing manufacturing time and cost.

[0006] US Pat. No. 8,985,623 B2 discloses an alternative damper structure for a steering wheel. The overall operation is similar to that disclosed in the aforementioned EP 2,085,290, but the resilient element is enclosed in a rigid, multi-part protector structure. The protector is slidably mounted on a shaft and biased by a horn spring toward a deactivated position for the horn activation mechanism. This prior art solution suffers from essentially the same drawbacks and, in fact, requires additional cost and time to manufacture the protector.

[0007] Other disadvantages of the prior art include difficulty in frequency tuning, limited frequency range, difficulty in maintaining frequency tuning, and difficulty in obtaining the desired spring characteristics when the horn is activated. Summary of the Invention

[0008] In view of the above, the object of the present invention is to address one or more of the above-mentioned shortcomings of the prior art, and to this end, provide: (i) a damper unit for use in a shock absorbing damper assembly of a steering wheel, (ii) a vibration damper assembly for damping vibrations in a steering wheel, (iii) a method of manufacturing a damper unit, and (iv) a method of manufacturing a frequency tuned vibration damper assembly.

[0009] According to a first aspect, there is provided a damper unit for use in a frequency tuned vibration damper assembly for a steering wheel, the damper unit having an insertion end and an opposite rear end and being configured to be inserted with its insertion end through a mounting opening provided in a vehicle horn plate of the assembly,

[0010] The damper unit comprises:

[0011] - a sleeve having a central hole extending along the axis, and

[0012] - an elastic damper element which is molded radially outside the sleeve so that the sleeve and the damper element together form a unitary structure,

[0013] in:

[0014] The elastic damper element has an elastic insertion portion and an elastic support portion, the elastic insertion portion being configured to be inserted into the mounting opening of the vehicle horn plate, and the elastic support portion being configured to define a final mounting position of the damper unit;

[0015] the resilient insert portion having a plurality of resilient ribs extending at least partially along the axis and spaced apart from one another in a circumferential direction relative to the axis, the ribs together forming a radially outer engagement surface configured to directly engage an inner surface of the mounting opening;

[0016] The radially outer engagement surface has a first radial dimension, and the resilient support portion has a second radial dimension greater than the first radial dimension;

[0017] at least some of the resilient ribs have radially outwardly extending snap-lock protrusions configured to be inserted through the mounting opening to snap-lock the damper unit in its final mounted position; and

[0018] The elastic support portion has a plurality of elastic support columns, which are spaced apart from each other in the circumferential direction and extend at least partially in the direction of the axis, and each elastic support column has a distal surface facing the insertion end of the damper unit, and the elastic support column is flexible in all directions transverse to the axis, wherein the distal surface of the support column is configured to contact the rear side of the vehicle horn plate in the final installation position during assembly of the damper unit into the mounting opening of the vehicle horn plate.

[0019] During damping operation, the elastic material of the damper element is compressed in the direction of vibration. One advantage achieved by the ribbed construction is that, during damping operation, the elastic material can expand outward in the spaces between the ribs. Consequently, the damper element's spring constant exhibits a more linear characteristic compared to "compact" prior art ribless damper elements, which lack spaces into which the compressed elastomer can expand. Consequently, the use of a damper unit according to the present invention makes it possible to configure a dynamic spring-mass system that remains better tuned to the target frequency, resulting in more efficient and reliable damping operation.

[0020] Another advantage of the ribbed construction is increased frequency tuning flexibility during design and manufacturing. The damping frequency of the damper assembly can be tuned by varying the number of ribs, their circumferential, radial, and / or axial dimensions, and / or the spacing between ribs. Thus, ribs that are thicker or thinner in the circumferential direction, longer or shorter in the axial direction, longer or shorter in the radial direction, and so on can be used.

[0021] Furthermore, the frequency interval within which the damper element can be tuned can also be expanded and / or shifted by using a rib-like structure, compared to prior art elastic damper elements. By varying the rib design in different directions, it is also easier to design damper units with different damping frequencies in different directions.

[0022] At least some (preferably all) of the resilient ribs have radially outwardly extending snap-locking projections. The snap-locking projections are configured to be inserted into and through the mounting opening to snap-lock the damper unit in its final installed position. During the insertion process, the snap-locking projections may be temporarily compressed and / or moved radially inward as they pass through the mounting opening. Once the damper unit has been inserted into its final installed position, the resilient snap-locking projections automatically move radially outward and / or expand to engage the distal side of the horn plate or a sleeve secured to the mounting opening.

[0023] The support portion of the resilient damper element has a larger radial dimension than the engagement surface of the insertion portion. The dimensions of the support portion can be selected to be sufficiently large to prevent the support portion from passing through the mounting opening during assembly. Thus, the support portion of the resilient damper element can act as an insertion stop during assembly, defining the final installation position of the damper element relative to the horn plate. In the final assembly, the resilient support portion will typically directly contact the rear side of the horn plate or the rear side of a sleeve arranged in the mounting opening. In the final assembly, the support portion and the snap-locking projection will therefore be arranged on opposite sides of the horn plate and, together, hold the damper unit in a fixed position relative to the horn plate.

[0024] The support portion of the elastic damper element has a plurality of elastic support columns whose ends face the insertion end or distal end of the damper unit. The support columns are spaced apart from each other in the circumferential direction and are preferably distributed 360 degrees around the axis. The support columns extend at least partially in the direction of the axis. In a preferred embodiment, the support columns extend parallel to the axis. The elastic support columns are flexible in all directions transverse to the axis, including radial directions, circumferential directions, and combinations thereof. During assembly, in the final installed position, the distal surfaces of the support columns facing the insertion end of the damper unit will contact the rear side of the horn plate. This contact between the support columns and the horn plate will be maintained during all operation of the assembly, including during vibration damping and during horn activation. Due to friction between the support columns and the rear side of the horn plate, the support columns will move laterally in response to vibration damping operation. A particular advantage of this design with a separate and laterally flexible support strut on the rear side of the horn panel is that the vibration damping effect (which generally occurs only on the opposite side of the horn panel) will be generally less affected by the interface or contact between the horn panel and the elastic damper element on the rear side. For example, if the steering wheel is at 3 o'clock If the steering wheel vibrates horizontally back and forth in the 9 o'clock direction, the support struts at or near the 3 o'clock and 9 o'clock positions can bend horizontally in the radial direction relative to the center of the steering wheel so as not to substantially affect the vibration damping function. The support struts at the 12 o'clock and 6 o'clock positions can also bend horizontally, but in the circumferential direction so as not to substantially affect the vibration damping function. The other support struts will bend partially in the radial direction and partially in the circumferential direction.

[0025] In some embodiments, in particular in embodiments in which the damper unit is used in a vibration damper assembly for a steering wheel having a mechanical horn activation mechanism that relies on axial movement of a horn plate, the plurality of support columns form a first group of first support columns, each first support column having a distal end axially facing the insertion end of the damper unit, and the elastic support portion further has one or more second elastic support columns, each second support column having a distal end axially facing the insertion end of the damper unit and extending at least partially in the direction of the axis, wherein the distal end of the first support column is axially closer to the insertion end of the damper unit than the distal end of the second support column. In a preferred embodiment, there are a plurality of such second support columns. In some embodiments, the first support column and the second support column may have different heights.

[0026] One advantage achieved by this design is that two desirable but seemingly incompatible properties can be achieved with the same damper unit: one related to vibration damping and the other to horn actuation. With respect to vibration damping, as described above, a flexible interface between the elastic material and the rear side of the horn plate is preferred to minimize the impact on vibration damping operation. With respect to horn actuation, on the other hand, a rigid interface is preferred to initiate horn spring compression as quickly as possible when the driver depresses the horn pad. Because the horn plate is supported on its rear side by an elastic, and therefore compressible, material, there is a risk that the horn spring will not be compressed until later during horn actuation. During horn actuation, the elastic material will first be axially compressed before force can be transferred to the horn spring. When the horn pad is pressed, the horn spring is not compressed during the initial movement of the horn plate, which would result in an undesirably varying spring constant. This "dilemma" can be addressed by a design with a first support post and a second support post, thereby creating a "dynamic" support interface that changes its properties during horn plate movement.

[0027] Before the horn is activated, the first support post contacts the rear side of the horn plate, but the second support post is axially spaced from the rear side of the horn plate by an axial gap. For example, the size Δ of this axial gap can be one millimeter or a few millimeters. Other dimensions are possible. When the driver just activates the horn by pressing the horn activation pad, the horn plate will move and the first support post will be compressed. Preferably, the first support post has a relatively limited total cross-sectional size or stiffness so that this compression occurs. The total "spring constant" of the entire set of first support posts is preferably chosen to be less than the spring constant of the horn spring. Thus, the compression of the horn spring has not yet started. When the first support post is axially compressed by an amount Δ such that its distal surface is flush with the distal surface of the second set of support posts, the rear side of the horn spring will contact the first support post and the current second support post. Now, the gap Δ has been eliminated. Thus, the advantage of choosing a small size for the first set of support posts is to ensure both a flexible junction and a rapid axial compression during the initial stage of horn activation. When the axial gap Δ between the second support post and the horn plate has been eliminated, the total axial stiffness or total spring constant of the combination of all the first and second support posts is preferably chosen to be large enough so that the horn spring is compressed when the driver presses the horn activation pad.

[0028] In a preferred embodiment, if the total axial spring constants of the first set of support posts and the second set of support posts are k1 and k2 respectively, and the spring constant of the horn spring is k3, then the support posts should preferably be designed such that k1 + k2 > k3 in order to ensure that when the gap Δ is eliminated and when the resultant force from the support posts becomes greater than the pre-compression horn spring force given by k3, the horn spring is compressed.

[0029] In a preferred embodiment, k1 < k2 or k1 << k2 in order to keep the junction as flexible as possible when the horn is not activated. However, other relationships between k1 and k2 are also possible. The stiffness or compressibility of the support posts can vary in different ways. For example, the second support post can have a larger cross-section transverse to the damper axis than the first support post.

[0030] In some embodiments, the one or more second support posts form a second set of multiple second support posts that are circumferentially spaced from each other and are circumferentially staggered and spaced from the first support posts. In other embodiments, there can be only a single second support post, for example in the form of a continuous ring extending circumferentially around the axis of the damper unit

[0031] In some embodiments, the horn spring is pre-compressed before the horn is activated.

[0032] In some embodiments, the sleeve of the damper unit is a slider configured to slide along a guide shaft received in the slider's central bore in the direction of the axis when the horn is activated by the steering wheel. In such embodiments, the elastic vibration damper element may be molded onto a first portion of the slider, wherein the damper unit may further include an elastic horn spring element having a horn spring portion and an attachment portion integrally molded therewith. The attachment portion of the horn spring element may be molded onto a second portion of the slider. The horn spring portion may be configured to apply a force to the slider in the direction of the axis both before and when the horn is activated by the steering wheel.

[0033] The embodiment comprising an elastic horn spring integrally formed with the damper unit has at least the following advantages:

[0034] The number of components required for manufacturing, management, and assembly is reduced. During assembly, the damper unit is already equipped with a molded horn spring element. Therefore, there's no need to handle a separate horn spring during assembly, as it's already in place as an integral part of the damper unit. The mechanical horn spring mechanism is automatically achieved when the slider is mounted on the guide shaft.

[0035] The horn plate can be quickly and easily connected to the base structure via one or more damper units, wherein each damper unit automatically provides both the vibration damping function and the horn spring function as a direct result of mounting the unit, without the need to handle or assemble separate damping elements or separate horn springs.

[0036] By integrally molding the damper element and the horn spring element onto the slider in a single molding step, a multifunctional integrated damper unit can be manufactured. The integrated damper unit (comprising the slider, the elastic damper element, and the horn spring element) provides the slider function, the vibration damping function, and the horn spring function, respectively.

[0037] By moulding the elastic horn spring element on the slider, it is possible to both manufacture the horn spring and to bond it to the slider in one moulding operation.

[0038] - By molding the horn spring element on the slide, the quality of the final product can be improved because there is no need to align and install the horn spring separately.

[0039] The damper unit may also be used with a separate horn spring, such as a conventional metal coil spring. In other embodiments, where the damper unit is used in a damper assembly for a steering wheel with electronic horn activation rather than mechanical horn activation, the damper unit may be used without any horn spring, merely connecting the horn plate to the base structure via the elastic element to achieve a dynamic vibration damping effect.

[0040] According to a second aspect, there is provided a frequency tuned damper assembly for damping vibrations in a steering wheel, the assembly comprising:

[0041] a base structure fixed to the steering wheel and having vibrations to be damped;

[0042] car whistle board;

[0043] one or more damper units according to the first aspect, each damper unit being arranged in an associated mounting opening in the horn plate, with its radially outer engagement surface in direct contact with the horn plate for transmitting the vibrations, and with a distal end surface of the support post in contact with a rear side of the horn plate;

[0044] one or more guide shafts, each guide shaft being fixed to the base structure and received in a central bore of a sleeve of an associated damper unit; and

[0045] a mass supported by the base structure via a damper element of the damper unit for allowing movement of the mass transverse to the axis;

[0046] Wherein the damper element and the mass are configured to operate as a frequency tuned spring-mass system, forming a frequency tuned dynamic damper for damping said vibrations.

[0047] In some embodiments of a damper assembly with mechanical horn activation, the distal portion of the resilient damper assembly of each damper unit can protrude axially beyond the mounting opening in the horn plate. When the horn is activated, as the driver presses the horn pad of the steering wheel, the horn plate moves against the spring force of one or more horn springs. When the driver subsequently releases the horn pad, the horn plate is moved back to its normal position by the horn springs. This design offers the advantage that the resilient distal portion of the damper element (which protrudes axially beyond the mounting opening in the horn plate) can act as a resilient stop during the return movement of the horn plate. When the horn is activated, the distal portion of the damper element can move away from the bolt head. When the horn pad is released, the horn spring pushes the horn plate back to its normal position. During the return movement, the resilient distal portion of the damper element engages the bolt head, thereby defining a "soft" damping stop position for the return movement. Thus, the elastic damper element of a damper unit in a damper assembly for a steering wheel may have multiple functions including, but not limited to, transmitting radially directed vibrations in frequency tuned damping operation and damping axially directed horn mechanism return motion.

[0048] As is known in the art, the weight of the airbag assembly in the steering wheel can preferably be used as part of the mass for the dynamic damping function of the dynamic spring-mass system, so that a separate weight can be used for this purpose. The weight of the horn plate and other components supported by the horn plate will also affect the total weight of the seismic mass.

[0049] In a preferred embodiment, since the damper unit is inserted into and mounted in the vehicle horn plate, the portion of the elastic damper element involved in the vibration damping operation is pre-compressed.

[0050] Upon insertion and installation of the damper unit, the outer engagement surface of the damper unit directly engages the inner engagement surface of the mounting opening of the horn plate for transmitting vibrations. The inner engagement surface can be formed by the horn plate itself (e.g., made of metal), or by a sleeve fixedly connected to or molded to and extending axially from the horn plate to provide an axially extending engagement interface. Such a sleeve can be, for example, a sleeve molded onto the horn plate from a relatively rigid plastic material.

[0051] According to the present invention, a vibration damper assembly includes at least one, but preferably a plurality of, damper units. Optionally, the damper units can be configured to damp vibrations in different directions. This can be achieved by using one or more damper units for one vibration direction and one or more other damper units for a second vibration direction. Each damper unit can also be designed to damp different vibrations in different directions.

[0052] According to a third aspect, there is provided a method of manufacturing a damper unit, the method comprising:

[0053] An elastic vibration damper element is molded on a radially outer first portion of the sleeve, the elastic vibration damper element having an elastic insertion portion and an elastic support portion, the elastic insertion portion being configured to be inserted into the mounting opening of the horn plate, and the elastic support portion being configured to define a final insertion position of the damper unit; wherein:

[0054] the elastic insert portion has a plurality of elastic ribs extending at least partially along the axis and being spaced apart from one another in a circumferential direction relative to said axis, said ribs together forming a radially outer engagement surface configured to directly engage with an inner surface of the mounting opening;

[0055] - the radially outer engagement surface has a first radial dimension, and the resilient support portion has a second radial dimension greater than the first radial dimension; and

[0056] - the elastic support portion has a plurality of elastic support columns, which are spaced apart from each other in the circumferential direction and extend at least partially in the direction of the axis, and each elastic support column has a distal surface facing the insertion end of the damper unit, and the elastic support columns are flexible in all directions transverse to the axis, wherein the distal surfaces of the support columns are configured to contact the rear side of the vehicle horn plate in a final installation position during assembly of the damper unit into the mounting opening of the vehicle horn plate.

[0057] Also disclosed is a method for manufacturing a frequency tuned vibration damper assembly for damping vibrations in a steering wheel, the method comprising:

[0058] One or more damper units are used, each damper unit comprising a sleeve having a central hole extending along an axis, and an elastic vibration damper element molded on the radially outer side of the sleeve so that the sleeve and the vibration damper element together form a unitary structure, the elastic vibration damper element having:

[0059] a resilient insert portion having, at an insertion end, one or more radially outwardly extending snap-lock projections and a radially outer engagement surface axially spaced from the snap-lock projections, the radially outer engagement surface having a first radial dimension, and

[0060] - a resilient support portion having a second radial dimension greater than said first radial dimension; and

[0061] Each damper unit is inserted into the associated mounting opening in the vehicle horn plate along the axis of the damper unit in an insertion direction, wherein the damper unit is inserted into the mounting opening until a final insertion position is reached, wherein:

[0062] - the radially outer engagement surface of the elastic insert portion is in direct contact with the inner surface of the mounting opening,

[0063] - a snap-locking projection has been inserted through the mounting opening to effect a snap-locking of the damper unit relative to the horn plate, and

[0064] -The elastic support portion has come into axial contact with the rear side of the horn plate.

[0065] Specific features of the method of manufacturing a frequency-tuned damper assembly of the present invention include: during assembly, the elastic damper element and the slider / sleeve are inserted together into the mounting opening of the vehicle horn plate from only one side of the vehicle horn plate, and the elastic damper element is inserted in the insertion direction to such an extent that the elastic engagement surface engages with the internal engagement surface of the mounting opening, and the distal end portion of the elastic damper element including the snap-locking protrusion protrudes axially beyond the internal engagement surface of the mounting opening.

[0066] A first advantage of the method for manufacturing a frequency-tuned damper assembly is that assembly of the components can be completed in a shorter time because the elastic damper element and the slider are inserted together into the mounting opening of the horn plate from only one side of the horn plate during assembly. The elastic damper element and the slider form a unitary structure and are assembled from said one side of the horn plate.

[0067] A second advantage of this method for manufacturing a frequency-tuned damper assembly is that the damper unit can be easily snap-locked to the mounting plate. The damper unit is inserted to a point where one or more radially outwardly extending snap-locking projections of the resilient damper element protrude above the distal axial edge of the mounting opening. Thus, the inserted resilient damper element can be held in its correct position relative to the horn plate by the snap-locking projections. Because the one or more snap-locking projections are integrally formed with the resilient element and are therefore made of an elastic material, they can be temporarily radially compressed and / or bent during the insertion step to facilitate passage through the mounting opening. Consequently, there is no need to assemble a separate locking element from the opposite side of the horn plate, reducing assembly time and manufacturing costs.

[0068] The method of manufacturing a damper assembly may include using any of the embodiments of the damper unit described above. Thus, the damper unit may include ribs, support struts, and an integrated resilient horn spring. However, other designs are possible, such as designs without ribs and instead having a continuous radially outer engagement surface.

[0069] the term

[0070] In the present disclosure, when the elastic element is stated to be "molded" onto the sleeve or slider, it should be interpreted as meaning that the relevant element is firstly a molded detail produced by molding. Secondly, the expression "molded" should be interpreted as meaning that the relevant element is produced / molded directly onto the sleeve or slider, in contrast to prior art solutions in which the relevant element is made as a separate part, for example in the form of a conventional helical metal spring that is made separately and installed as a separate part in the assembly. In a preferred embodiment, the elastic material comprises silicone rubber.

[0071] In this disclosure, the term "slider" may refer to an element arranged to slide along a guide shaft during horn activation. This is the case when a mechanical horn activation mechanism is used. However, the term "slider" may also refer to a sleeve arranged to be mounted on a guide shaft but not to slide along the guide shaft. This is the case when an electronic horn activation mechanism is used, in which the horn plate is not configured to move axially relative to the guide shaft during horn activation.

[0072] In the present disclosure, the expression "in contact with the rear side of the whistle plate" shall be interpreted as covering direct contact with the whistle plate and direct contact with the sleeve fixed to the whistle plate around the mounting opening of the damper unit.

[0073] In the present disclosure, the term "bonding" or "bonded" should be interpreted as a connection or attachment between the relevant element and the sleeve or slide that prevents the element from falling off the sleeve or slide or being easily removed from the sleeve or slide. Therefore, the term "bonding" is to be interpreted as a connection or attachment that ensures that the relevant element (which is a component of the damper unit from the perspective of the assembly) is held in the intended position on the slide by the bonding part. In embodiments where the element can be easily removed from the slide or can easily fall off the slide, such as a cylindrical damper element with a central hole in which a guide shaft is accommodated without any mechanical bonding or adhesion acting in the axial direction, the element is not considered to be "bonded" to the slide, although radial movement relative to the slide can be restricted.

[0074] In the present disclosure, “mechanically bonded” or “mechanically bonded” should be interpreted as an alternative to “chemically bonded.” Mechanical bonding should be interpreted as a non-chemical attachment of the relevant element to the slide, ensuring that the relevant element is mechanically retained in its intended position on the slide.

[0075] In this disclosure, expressions such as "chemically bonded," "chemically bonded," "adhesively bonded," or "adhesive" are to be construed as alternatives to mechanical bonding. Chemical bonding is considered to be intermolecular bonding. In some embodiments, mechanical and chemical bonding may be used in combination. Preferred chemical bonding may be adhesive bonding rather than gluing. Chemical bonding may be provided during the molding process. In some embodiments, chemical bonding may be achieved by using overmolding techniques to provide adhesive bonding between similar or related polymers.

[0076] In the present disclosure, the term "snap lock" or the like should be interpreted as a locking mechanism that results in a locking function as the damper unit is inserted into its final installation opening. In particular, the term should be interpreted as also covering embodiments in which there is not necessarily a noticeable "snap" during insertion, but rather a gradual expansion / movement of the snap lock protrusion. BRIEF DESCRIPTION OF THE DRAWINGS

[0077] The inventive concept, some non-limiting preferred embodiments of the inventive concept and further advantages will now be described with reference to the accompanying drawings, in which:

[0078] FIG. 1A shows a steering wheel of a vehicle.

[0079] FIG1B shows the main parts of the shock absorbing assembly.

[0080] Figure 2 This is an exploded view of the shock absorber assembly;

[0081] Figure 3 and Figure 4 is a cross-sectional view of the assembly of FIG. 1B ;

[0082] Figure 5 is a side view of the assembly of FIG. 1B .

[0083] Figure 6 and Figure 7 Shown on a larger scale is the installation Figure 2 The damper unit in the assembly.

[0084] 8A to 8D show a slider of a first embodiment of a damper unit.

[0085] Figures 9A to 9E A first embodiment of a damper unit is shown.

[0086] Figure 10A and Figure 10B The integral elastic body of a damper unit according to a first embodiment is shown.

[0087] Figure 11A and Figure 11B A second embodiment of a damper unit is shown.

[0088] Figure 12A and Figure 12B A third embodiment of a damper unit is shown.

[0089] Figure 13A 13D to 13D show a slider of a fourth embodiment of the damper unit.

[0090] 14A to 14C The integral elastic body of a damper unit according to a fourth embodiment is shown.

[0091] Figures 15A to 15C A damper unit according to a fourth embodiment is shown.

[0092] 16A to 16F An assembling method using the damper unit according to the fourth embodiment is shown.

[0093] 17A to 17C A vehicle horn activation of an assembly including a damper unit according to a fourth embodiment is shown.

[0094] 18A to 18C The integral elastic body of a damper unit according to a fifth embodiment is shown.

[0095] 19A to 19C A damper unit according to a fifth embodiment is shown.

[0096] 20A to 20F An assembling method using the damper unit according to the fifth embodiment is shown.

[0097] Figure 21 An alternative assembly method using a damper unit according to a fifth embodiment is shown.

[0098] Figure 22 is a cross-sectional view of the fifth embodiment.

[0099] Figures 23A to 23C A vehicle horn activation of an assembly including a damper unit according to a fifth embodiment is shown.

[0100] Figure 24A to Figure 24C A damper unit according to a further inventive concept is shown. DETAILED DESCRIPTION

[0101] The present inventive concept generally relates to the field of frequency-tuned vibration dampers, also known as dynamic dampers. Such dampers can be used to damp vibrations in a vibrating surface or structure, such as a vibrating component such as a steering wheel of a motor vehicle. A dynamic vibration damper includes a mass that acts as a vibrating body and at least one elastic vibrator element. The mass and the at least one elastic damper element together provide a damped spring-mass system and can optionally be connected to the vibrating structure via an intermediate component.

[0102] The mass of the mass and the stiffness and damping of the elastic damping element are selected to provide a damping effect on the vibrating structure, which is expected to vibrate at one or more predetermined target frequencies. When the vibrating structure vibrates at the target frequency, the mass oscillates / resonates at the same frequency as the structure, but out of phase, so that the vibration of the structure is substantially damped. The mass can vibrate at an amplitude that is substantially greater than the vibration amplitude of the vibrating structure. The present invention relates to a damper unit for use in such a dynamic damper assembly disposed in a vehicle steering wheel to damp steering wheel vibrations.

[0103] First embodiment

[0104] FIG1A shows a steering wheel 2 in a motor vehicle 4. Vibrations from the road and the engine may be transmitted to the steering wheel 2. These steering wheel vibrations may be perpendicular to the steering column, as indicated by the up-down and left-right arrows. The steering wheel 2 is provided with a vibration damping assembly 6, schematically represented by a dashed box within the steering wheel 2, and is configured to dynamically damp at least some of the steering wheel vibrations.

[0105] As is known in the art, steering wheel 2 is also equipped with a horn activation mechanism for activating the vehicle 4's horn (not shown). To this end, a horn activation pad 8 is positioned in the center of steering wheel 2 for the driver to press when activating the horn. When the driver releases horn activation pad 8, the horn activation mechanism returns to its deactivated or initial state via one or more horn springs. In the illustrated embodiment, the horn activation mechanism is mechanical. Electronic horn activation mechanisms also exist that do not include horn springs.

[0106] Furthermore, the airbag assembly can be positioned within the steering wheel 2, below the horn activation pad 8. FIG. 1B schematically illustrates a portion 10 of the gas generator of the airbag assembly. In this embodiment, the weight of the airbag assembly is utilized as at least a portion of the total weight of the mass used in the shock-absorbing spring-mass system. Consequently, the use of separate deadweights for this purpose can be avoided or significantly reduced.

[0107] The damping assembly 6 in the steering wheel 2 is arranged on and supported by a base structure or armature 12 fixed to the steering wheel 2. Therefore, vibrations in the steering wheel 2 are also present in the base structure 12, such as Figure 7The vibration V perpendicular to the steering column is shown in FIG. The damping assembly 6 includes a horn plate 14, to which is mounted an airbag assembly comprising an inflator and an airbag. In a preferred embodiment, the horn plate 14 is constructed of metal and optionally provided with a plastic cover made of a relatively rigid plastic material molded thereon, comprising a top cover 16 and a bottom cover 18. The horn plate 14 is provided with three openings, each configured to receive a portion of a damper unit 40, as described below. In the illustrated embodiment, a cylindrical sleeve 20 is disposed around each opening in the horn plate 14 and extends above the plane of the horn plate 14. The sleeve 20 may be integrally molded with the plastic covers 16 and 18, thereby rigidly connecting the horn plate 14. In other embodiments, the sleeve 20 may be omitted.

[0108] like Figure 2 As shown, the base structure 12 may include three supports 13 that project toward the horn plate 14 and each of which is provided with a threaded bolt hole. A separate bracket 22 is supported on the supports 13. The bracket 22 has a through opening or mounting opening 24 aligned with each of the supports 13. Adjacent to each mounting opening 24, the bracket 22 has a horn spring support surface 26 facing the horn plate 14 and, on the opposite side, a bracket support surface 28 facing the base support 12. In the assembled state ( Figure 7 ), the bracket 22 is supported by the support member 13 at the bracket support surface 28.

[0109] The bracket 22 is a multifunctional bracket for supporting various components and may in particular comprise part of the horn switch mechanism of the steering wheel 2, here in the form of four contact studs 30 which project towards the horn plate 14 and align with corresponding contact pads 15 projecting from the underside of the horn plate 14. Figure 5 As shown, the contact post 30 and the contact pad 15 are generally positioned at a distance D from each other. When the horn is activated, the horn plate 14 is pressed toward the bracket 22 until the contact pad 15 and the contact post 30 electrically engage to activate the horn and the horn plate 14 stops moving. As an illustrative example, the distance D can be on the order of several millimeters.

[0110] The horn plate 14, to which the airbag assembly is fixed, is movably supported on the base structure 12 by three damper units 40. It will be noted that although the unit is referred to as a "damper unit" in this disclosure, the damper unit 40 provides a vibration damping function and a separate horn spring function, as described below. Each damper unit 40 is configured to allow the mass represented by at least the horn plate 14 and the airbag assembly to move (i) perpendicular to the axis A of the damper unit 40 for the purpose of damping vibrations, and (ii) along the main axis A for the purpose of horn activation. Referring now to Figures 8A to 8D, 9A to 9D as well as Figure 10A and Figure 10B A first embodiment of the damper unit 40 is described.

[0111] The damper unit 40 includes a slider 50, a damper element 70, and a horn spring element 90. In a preferred embodiment, the slider 50, the damper element 70, and the spring element 90 can be combined together to form a unit 40 such that the three components form a unitary structure that is ready to be connected to the base structure 12 and the horn plate 14. The components 50, 70, and 90 can be mechanically and / or chemically combined in a sense that they cannot be easily separated from each other.

[0112] Figures 8A to 8D illustrate a first embodiment of a slider 50. The slider 50 can be made of a relatively rigid material, such as a suitable synthetic resin. In a mechanical horn activation mechanism, the slider is arranged to slide on a guide shaft when the horn is activated, as described below. The slider 50 includes a tubular element 52 and a radially extending flange 56. The tubular element 52 defines a through-hole 54 for receiving the guide shaft. The flange 56 divides the tubular element 52 into a first tubular portion 58 located on one side of the flange 56 and a second tubular portion 60 located on an axially opposite side of the flange 56. In the illustrated embodiment, the first tubular portion 58 is longer than the second tubular portion 60. The flange 56 has one or more locking openings, in this case in the form of a plurality of axially oriented through-holes 62, for mechanically coupling the damper element 40 and the horn spring element 90 to the slider 50. The flange 56 also serves to absorb spring forces from the horn spring element 90 and to transmit axial forces between the slider 50 and the damper element 70.

[0113] Now refer to Figures 9A to 9E , shows the complete damper unit 40 of the first embodiment. An elastic damper element 70 is arranged on the first sliding portion 58. The elastic damper element 70 is made of an elastic material, such as silicone rubber, and is suitable for use as an elastic spring element in a dynamic damper. The damper element 70 is configured to operate as a spring-mass system together with the mass represented by at least the airbag module and the horn plate 14, forming a frequency-tuned dynamic vibration damper for damping vibrations V in the base structure 12 and the steering wheel 2.

[0114] In the embodiment shown, the damper element 70 has a generally cylindrical shape with a distal end 71 facing away from the flange 56, a proximal end 72 facing the flange 56, and an outer engagement surface 75. As an illustrative but non-limiting example, the axial length of the damper element may be approximately 7 mm. Figure 7In the final damping assembly shown, the outer engagement surface 75 of each damper element 70 engages the inner engagement surface 21 of the associated sleeve 20 on the horn plate 14 to transmit vibrations to the horn plate 14. In the illustrated embodiment, the axial length of the damper element 70 substantially corresponds to the axial length of the first sliding portion 58, but extends axially a short distance beyond the distal end of the first sliding portion 58. The proximal end 72 of the damper element 70 contacts the flange 56. The distal end 71 of the damper element 70 has an increased outer diameter to form a radially outwardly extending annular snap-lock projection 73. The proximal end 72 of the damper element 70 has a larger diameter and is arranged to extend below the horn plate 14 in the assembly 6. The proximal end 72 may have an upwardly directed support ring 74 defined by an annular groove 76, for reasons explained below.

[0115] In the first embodiment shown, the damper element 70 is divided into a plurality of axially extending ribs 77 ( Figure 9D ), the ribs 77 are distributed circumferentially around the axis A of the damper unit 40 and define spaces 78 between the ribs 77. The radially outer surfaces of the ribs 77 together form the outer engagement surface 75 of the damper element 70. The operation and advantages obtained by the ribs 77 and the spaces 78 will be explained below. In other embodiments, the damper element 40 can have the form of a circumferentially complete cylinder defining a continuous outer engagement surface.

[0116] The horn spring element 90 of the damper unit 40 is arranged on the second portion of the slider 50, in this embodiment, on the second tubular portion 60 on the axially opposite side of the flange 56, and also on a portion of the flange 56. The horn spring element 90 is made of elastic material and includes a horn spring portion 94 and an attachment portion 92 ( Figure 9C ), which are integrally molded from elastic material. During the molding of the horn spring element 90, at least its attachment portion 92 is molded onto the slider 50 so that the horn spring element 90 is correctly positioned on the slider 50 during manufacturing.

[0117] like Figure 9C As best shown in FIG, the attachment portion 92 of the horn spring element 90 has an L-shaped cross-section with one leg in contact with the shorter tubular portion 60 of the slider 50 and one leg in contact with the flange 56. In other embodiments, the shorter tubular portion 60 is omitted and the attachment portion 92 may engage only the flange 56.

[0118] The elastic material used for the horn spring element 90 can be any elastic material suitable for providing the desired horn spring function according to the desired spring constant. In a preferred embodiment, the material comprises silicone rubber. The same elastic material can be used to mold both the damper element 40 and the horn spring element 90, particularly if these elements are integrally molded. In the first illustrated embodiment, the horn spring portion 94 is bellows-shaped to provide a spring action in the direction of axis A. Other embodiments may have different spring designs that rely partially or solely on compression, rather than bending as with bellows-shaped designs. The spring constant can be varied by changing one or more parameters of the horn spring portion 94, such as the material, axial length, diameter, wall thickness, and bellows design (angle, etc.). "Break" designs with open and / or separate spring legs may also be used, providing further tuning options for the spring characteristics.

[0119] In the final damping assembly 6, the molded horn spring portion 94 is configured to function as a horn spring in the direction of axis A, exerting a spring force on the horn plate 14 via the slider 50 and the damper element 40. When horn activation ceases, a spring force is present to return the horn plate 14. Due to the pre-compression of the horn spring portion 94, the spring force also acts as a biasing spring force in the non-activated state. This advantageously allows the spring force generated by the horn spring to be readily available when the driver operates the horn.

[0120] In the illustrated first embodiment, the horn spring element 90 is molded directly onto the slider 50, eliminating the need to separately manufacture a metal coil spring and the need to attach and / or align such a separate metal coil spring relative to the slider during assembly. Currently, overmolding is considered the preferred molding method, but other techniques are also contemplated, such as 2K injection molding, in which both the slider 50 and the spring component are manufactured using a single 2K injection molding machine. While not currently preferred, the damper element 70 and the horn spring element 90 may be molded using different molding techniques. In a preferred embodiment, the horn spring element 90 is not only molded onto the slider 50 but also bonded to it. This bonding may be mechanical (including friction bonding) and / or chemical.

[0121] In the first illustrated embodiment, the horn spring element 90 is mechanically coupled to the slider 50 so as to retain the horn spring element 90 in the illustrated position on the slider 50. This is achieved by a plurality of resilient locking elements 100 which are molded integrally with the horn spring element 90 and which lockingly engage with the locking openings 62 in the flange 56. In the illustrated embodiment, the damper element 40 is also mechanically coupled to the slider 50 so as to retain the damper element 40 in the illustrated position on the slider 50. This is also achieved by the locking elements 100. In a preferred embodiment, the same locking elements 100 are used to couple the horn spring element 90 and the damper element 40 so that the resilient horn spring element 90, the resilient damper element 40 and the locking elements 100 are molded together as a unitary body which is mechanically coupled to the slider 50 via the through-holes 62. For purposes of explanation only, the embodiment shown in FIG. Figure 10A and Figure 10B , the entire elastic body 70, 90, 100 is shown without the slider 50. In this embodiment, there can also be a frictional engagement between the elastic element 70, 90 and the tubular portion of the slider 50.

[0122] In some embodiments, one or both of the damper element 40 and the horn spring element 90 can be chemically bonded to the slider 50 via bonding. Both mechanical bonding and chemical bonding, as disclosed in the accompanying drawings, can also be used for one or both of the damper element 40 and the horn spring element 90. Chemical bonding can be achieved during the molding process. Friction bonding can also be achieved solely or partially. Friction bonding can also be achieved through post-molding shrinkage of the elastic material.

[0123] Now refer to Figures 2 to 7 A method for assembling a shock absorbing assembly 6 using a plurality of damper units 40 according to a first embodiment is described. The order or sequence of the steps described herein may vary. As a first step, the bracket 22 may be placed on the support 13 of the base structure 12. As a second step, each damper unit 40, including the slider 50 and the rib-shaped damper element 70 forming an integral structure, may be placed on the support 13 of the base structure 12. Figure 2 The horn plate 14 is inserted from below into the associated mounting opening 24 .

[0124] It should be noted that the slider 50 and the elastic damper element 70 of each damper unit 40 are inserted together as a unit and only from one side of the horn plate 14. During the insertion of the damper element 70, the radially outer engagement surface 75 of the damper element 70 engages with the inner engagement surface 21 of the corresponding sleeve 20, so that the vibration V of the steering wheel can be transmitted from the damper element 70 to the horn plate 14. Preferably, the radial dimension is selected so that the damper element 70 is slightly radially compressed between the slider 50 and the inner engagement surface 21 of the sleeve 20.

[0125] During the insertion of the damper element 70, the support ring 74 formed integrally with the damper element 70 will engage the bottom side of the horn plate 14, as shown in FIG. Figure 7 As shown, the final insertion position is defined. During insertion of the damper element 70, the upper snap-locking projection 73 of the damper element 70 will be temporarily compressed to facilitate passage through the sleeve 20. In the final position, the snap-locking projection 73 will extend above the upper edge of the sleeve 20. Thus, the support ring 74 and the snap-locking projection 73 together ensure that the damper element 70 is correctly axially positioned / locked relative to the horn plate 14. A separate locking element is not required, and axial locking is automatically achieved during unilateral insertion of the damper unit. It will also be noted that in this first embodiment, the axially distal portion of the elastic damper element 70 extends axially beyond the distal edge of the sleeve 20.

[0126] When the damper element 70 has been correctly positioned in the horn plate 14, a bolt 120 can be inserted into the hole 54 of each slider 50. Each bolt 120 has a bolt head 126, a cylindrical guide shaft 122 and a threaded end 124. The tubular portion 52 of the slider 50 can slide along the guide shaft 122. Figure 7 As shown, bolts 120 are secured in bolt holes of support member 13 of base structure 12. During final tightening of each bolt 120, pre-compression of the corresponding horn spring portion 94 is achieved. As a non-limiting example, the horn spring portion may be pre-compressed by 10 mm to 7 mm during assembly and then further compressed by one or several millimeters upon activation of the horn. In the final assembly, the distal end 95 of each horn spring portion 94 engages the associated horn spring support surface 26 of bracket 22. In the final assembled state, the bolt head 126 axially engages the upper end 71 of the elastic damper element 70, with the snap-lock projection 73 protruding between the sleeve 20 and the bolt head 126.

[0127] It will be appreciated that the disclosed method of manufacturing a damper unit 40 and assembling a shock-absorbing assembly using the damper unit 40 of the present invention can provide significant advantages in terms of manufacturing cost and time, as well as in terms of quality. Compared to the prior art, which required manufacturing, handling, and assembling multiple separate parts, the inventive concept makes it possible to use only one integral damper unit 40 and a simple bolt 120 at each damper unit 40 to establish both the damper function and the horn spring function, as compared to the prior art, which required handling and assembling multiple different parts, typically from different sides of the horn plate 14.

[0128] The operation of the horn activation mechanism of assembly 6 is as follows: when the horn mechanism is not activated by the driver, each pre-compressed or biased horn spring portion 94 presses against the flange 56 of the slider 50, pushing the slider 50 upward in a direction away from the base structure 12. The axial spring force is transmitted through the flange 56 to the damper element 70 and through the support ring 74 to the horn plate 14. It will be noted here that the bolt 120 has multiple functions:

[0129] - The bolt 120 provides a guide shaft 122 for the axial movement of the slider 50 during the activation of the horn;

[0130] - the bolt head 126 defines an upper axial stop for the axial movement of the damper unit 40 , and

[0131] The bolt head 126 helps to lock the damper unit 40 in place relative to the horn plate 14 by pushing against the top of the damper element 70 .

[0132] In the illustrated embodiment, the distal end 71 of the damper element 70 extends a short distance beyond the upper edge of the sleeve 20 , whereby the upper stop position of the damper unit 40 is defined by a soft engagement between the end 71 of the damper element 70 and the bolt head 120 .

[0133] When the horn is activated, when the driver presses the horn pad 8 on the steering wheel 2, the horn plate 14 is pressed against the base structure 12. This force is transmitted to the slider 50 through the damper element 40, and the slider 50 moves along the guide shaft 122, further compressing the horn spring portion 94 in the axial direction until Figure 5 The distance D in the bolt head 124 decreases to zero and the horn switch 15, 30 is closed. When the pressure on the horn pad 8 is released, the horn spring portion 94 will return the horn plate 14 to its normal position, whereby the soft engagement between the resilient end 71 and the bolt head 124 provides a "soft" stop.

[0134] The function of the vibration damping component 6 is as follows: Steering wheel vibrations V( Figure 7) is transmitted to the elastic damper element 70 via the bolt 120 and the slider 50. The elastic damper element 70 transmits the steering wheel vibration V to the horn plate 14 via the sleeve 20, causing the mass (represented by the weight of the horn plate, the airbag assembly, and any other details supported by the horn plate 14) to vibrate out of phase, so that the vibration V in the steering wheel 2 is dynamically damped. During the damping of vibrations, the radial compression of the elastic material of the damper element 70 will vary. Due to the ribbed design of the damper element 70, the elastic material can expand into the spaces 78 between the ribs 77 during vibration. This design provides a beneficial, more linear relationship between damper compression and the spring constant of the damper element 70. In a solid cylindrical elastic material without ribs, there is no such "escape" of material, resulting in a more nonlinear spring constant, making the dynamic damping function less effective because matching the target frequency will be more difficult. Another advantage gained by the ribbed structure is increased flexibility in frequency tuning during design and manufacturing. The damping frequency of the assembly can be adjusted by varying one or more parameters, such as the number of ribs 77, the circumferential, radial, and / or axial dimensions of the ribs 77, and the spaces 78 between the ribs 77. Thus, thicker or thinner ribs can be used, longer or shorter ribs in the axial direction, longer or shorter ribs in the radial direction, etc. Furthermore, the frequency interval within which the damper element 70 is tunable can be shifted and / or expanded by using a rib-like configuration compared to prior art damper elements.

[0135] During vibration damping operation, the horn plate 14 will therefore be caused to move in a direction perpendicular to the axis A, in particular relative to the lower or proximal portion 72 of the damper element 70 which axially supports the horn plate 14. Since the radially moving horn plate 14 is in direct contact with the surface of the lower portion 72 at its rear side, this radial movement of the horn plate 14 may be caused on the bottom side and the bottom side of the horn plate 14. Figure 7 The interface between the damper element 70 at 74 would create undesirable frictional movements and silicone wear. Furthermore, such direct axial contact between the lower portion 72 of the damper element 70 and the rear side of the horn plate 14 could negatively affect the damping function (tuning). This is why the annular groove 76 is provided. Thus, the support ring 74 will be freer to move in the Figure 7 The left-right movement of the whistle plate 14 during damping results in less frictional movement between the whistle plate 14 and the damper element 70, and also results in "de-coupling" of the damped vibration from the contact between the damper element portion 70 and the rear side of the whistle plate 14.

[0136] Second embodiment

[0137] Figure 11A and Figure 11BA second embodiment of a damper unit 240 is shown. The same reference numerals are used as in the first embodiment described above, but in the 200 series. Although the solution described in the previous paragraph with the ring 74 and the annular groove 76 may be advantageous, it should be noted that the increased movability is only obtained in the vibration direction. For example, if the vibration V is in Figure 7 The middle finger points left-right, then Figure 7 The portions of the support ring 74 shown on the left and right sides will be free to move with the horn plate 12 due to the grooves 76. However, in Figure 7 At different circumferential positions on the support ring 74 towards and away from the reader, the groove 76 will not allow such side-to-side movement.

[0138] To solve this problem, the bottom of the damper element 270 according to the second embodiment may be designed as follows: Figure 11A and Figure 11B As shown in FIG. The support ring 74 of the first embodiment is circumferentially divided into a plurality of individual support posts 274, with spaces 279 circumferentially between the support posts 274. Compared to the ring design 74, the individual support posts 274 are more flexible in all radial directions. This design allows the support posts 274, which engage the rear side of the horn plate 14, to move with the horn plate 14 during vibration damping, both radially and circumferentially relative to the axis A, without substantially affecting the vibration damping operation. This design allows the support posts 274 to better follow the movement of the horn plate 14. To achieve uniform movability in all directions, the support posts 274 may preferably have a circular cross-section, i.e., have substantially the same dimensions in all directions perpendicular to the axis A.

[0139] Third embodiment

[0140] Figure 12A and Figure 12B A third embodiment of a spring unit 340 is shown for use in situations where different damping properties are required in different directions. The same reference numerals as above are used, but in the 300 series. The support columns 374 and spaces 376 are arranged as in the second embodiment. In the third embodiment, the elastic damper element 370 of the spring unit 340 has a non-circular configuration, such as an oval or elliptical configuration. Figure 12B As shown, the non-circular damper element 370 is received in a corresponding non-circular opening 321 in the horn plate 14. With this non-circular design, the assembly can be Figure 12B The vertical and horizontal directions have different tuning frequencies.

[0141] Fourth embodiment

[0142] Figures 15A to 15CA fourth embodiment of a damper unit 440 is shown. The same reference numerals as above are used, but in the 400 series. The slider 450 of the damper unit 440 is Figure 13A 13D. The elastic damper element 470 of the damper unit 440 is 14A to 14C All statements regarding the manufacturing, optional combinations, functions, materials, etc. of the above embodiments also apply to this fourth embodiment 440 in all relevant parts. The base structure 12, the bracket 22 and the horn plate 14 have been schematically shown in the figure, showing the final damper assembly.

[0143] As in the second embodiment, the damper element 470 of the damper unit 440 according to the fourth embodiment is divided into a plurality of axially extending ribs 477, which are distributed circumferentially around the axis A of the damper unit 440 and define spaces 478 between the ribs 477. The operation and advantages of the ribs described above also apply to this fourth embodiment in all relevant respects. However, the fourth embodiment of the damper unit 440 provides some additional features.

[0144] In the fourth embodiment, each rib 477 has a proximal rib portion 477a forming the vibration damping portion of the rib 477, and a distal rib portion 477b ( 14A to 14C ). The proximal rib portion 477a has a radially outer surface 475 extending parallel to the axis A. The radially outer surfaces 475 of the ribs 477 together form the outer engagement surface of the damper element 470. In the final assembly, as described above, the proximal rib portion 477a will remain slightly compressed in the radial direction. The distal rib portion 477b has a radially outwardly extending snap-locking protrusion 473 for snap-locking purposes, similar to the snap-locking protrusion 73 in the first embodiment. The snap-locking protrusion 473 has a proximal inclined locking surface 473a and a distal inclined insertion surface 473b. In addition, in the fourth embodiment shown, there may be a gap 473c in the radial direction between the distal rib portion 477b and the tubular portion 452 of the slider 450. In other embodiments, this radial gap 473c may be omitted.

[0145] The horn spring element 490 of the damper unit 440 is arranged on the lower tubular portion 460 of the slider 450 on the opposite side of the slider flange 456. The above statements regarding the structure, manufacture, alternatives and operation of the horn spring element 90 in the first embodiment apply in all relevant respects to the horn spring element 490 in the fourth embodiment. In the illustrated embodiment, the horn spring element 490 is molded integrally with the resilient damper element 470 on the slider 450, as in the first embodiment, with the resilient locking element 100 extending through the opening 462 in the slider flange 456. In this embodiment, a portion 101 of the resilient material also extends radially beyond the outer edge of the slider flange 456. In alternative embodiments, the damper element 470 and the horn spring element 490 may be held together as a single piece by the locking element 100 alone or by the portion 101 alone. For purposes of explanation only, Figure 14A and Figure 14C 4 shows the integral elastic body 470, 490, 100 without the slider 450. In this embodiment, there can also be a frictional engagement between the elastic element 470, 490 and the tubular portion of the slider 450.

[0146] In the fourth embodiment, 14A to 14C and Figures 15A to 15C As shown, the elastic damper element 470 is provided with a first set of independent support struts 474a and a second set of independent support struts 474b. The support struts 474a in the first set are slightly closer to the distal insertion end of the damper unit in the axial direction by a certain amount Δ compared to the support struts 474b in the second set. As a non-limiting example, the value of Δ can be approximately one millimeter or several millimeters. In the illustrated embodiment, the two sets of support struts 474a and 474b are staggered circumferentially. The support struts 474a and 474b are spaced circumferentially from each other and radially from the slider to ensure flexibility in all directions transverse to the axis A. In the preferred embodiment shown, the support struts 474b in the second set are larger than the support struts 474a in the first set because they have a larger cross-section perpendicular to the axis A. Hereinafter, these different struts will be referred to as smaller support struts 474a and larger support struts 474b. In the illustrated embodiment, the smaller support struts 474a have a circular cross-section, while the larger support struts 474b have an elongated cross-section. The design and shape of the support posts 474a and 474b may differ from this example. The smaller support posts 474a have essentially the same function as the support posts 274 of the second embodiment, namely, they ensure that the contact or interface between the support posts and the rear side of the horn plate 14 is flexible in the radial plane so as not to interfere with vibration damping. The function of the larger posts 474b will be explained below.

[0147] 16A to 16EA method for assembling a vibration damper assembly 6 ( FIG. 1 ) including three damper units 440 according to a fourth embodiment is shown. Figure 16F ) method. Figure 16A The damper unit 440 is shown inserted from below into one of the three openings in the horn plate 14. As in the previous embodiment, the slider 450 and elastic damper element 470 of each damper unit 440 are inserted together and only from one side of the horn plate 14. In the illustrated embodiment, each opening of the horn plate 14 is provided with a sleeve 20. The sleeve is preferably made of a relatively rigid material, such as a rigid plastic material molded into the horn plate. One function of the sleeve 20 is to provide an axially extending engagement surface for the damper element 470. Another function of the sleeve 20 is to protect the elastic damper element 470 from damage during assembly and operation.

[0148] like Figure 16B As shown, the inner radial dimensions of the sleeve are selected so that the distal angled insertion surfaces 473b of the ribs 477 guide the damper unit 440 into the opening and also help push or force the resilient damper element 470 through the opening.

[0149] Figure 16C It shows how the snap lock projections 473 of the ribs 477 will be urged radially inwards when the damper unit 440 moves through the opening of the sleeve 20. This radial movement is possible due to the inward radial bending of the distal ribs 477b and / or due to the radial compression of the snap lock projections 473.

[0150] Figure 16D The final installation position of the damper unit 440 relative to the horn plate 14 is shown. The final position is defined by the inserted position, in which the smaller support column 474a engages with the underside of the sleeve 20. This engagement may also be directly with the rear side of the horn plate 14. When the damper unit 440 has been fully inserted into its final position, the snap-locking projection 473 of the rib 477 will be as shown. Figure 16D 473a. The proximal inclined locking surface 473a of each rib 477 will now engage in locking engagement with the upper side of the snap-locking projection of the sleeve 20 to lock the damper unit 440 in place. The damper unit 440 is now held axially in its final position by the resilient damper element 470, i.e., on the one hand by the smaller support post 474a and on the other hand by the snap-locking projection 473. The larger support post 474b is not used at this stage.

[0151] As described above with respect to the first embodiment, during insertion of the damper element 470, the radially outer engagement surface 475 of the proximal rib portion 477a engages with the inner engagement surface 21 of the corresponding sleeve 20, so that the steering wheel vibration V can be transmitted from the damper element 470 to the horn plate 14. In order to achieve an appropriate vibration damping effect, preferably, the radial dimension is selected so that as a result of insertion, the damper element 470 is slightly radially pre-compressed between the slider 450 and the inner engagement surface 21 of the sleeve 20.

[0152] When the damper element 470 has been correctly positioned in the horn plate 14, the bolt 120 can be inserted into the hole 454 of each slider 450, as shown in FIG. Figure 16E Each bolt 120 has a bolt head 126, a cylindrical guide shaft 122, and a threaded end 124. The tubular portion 452 of the slider 450 can slide along the guide shaft 122. The bolt 120 is fixed in a bolt hole of the support member 13 of the base structure 12.

[0153] During the final tightening of each bolt 120 ( Figure 16F ), resulting in pre-compression of the corresponding horn spring portion 494. As a non-limiting example, the horn spring portion 494 can be pre-compressed by 10 mm to 7 mm during assembly and then further compressed by one or several millimeters when the horn is activated. In the final assembly 6, the distal end of each horn spring portion 494 engages the associated horn spring support surface 26 of the bracket 22.

[0154] like Figure 16F As shown in the enlarged view in FIG, during the final tightening of each bolt 120, the bolt head 126 can engage and axially compress the rib 477 until the distal end of the rib 477 is flush with the distal end of the slider 450. Figure 16F As shown by the arrows in FIG, this final compression will cause the snap locking protrusions 473 or ribs 477 to lock more tightly to the sleeve 20, thereby more firmly fixing the damper unit 440 in the axial direction relative to the horn plate 14. In other embodiments, this final compression may be omitted.

[0155] Now refer to 17A to 17C Describes the operation of the larger / more rigid support column 474b. Before the driver activates the horn ( Figure 17A ), the rear side of each sleeve 20 is in contact only with the smaller support column 474a, and there is an axial gap Δ between the rear side of the sleeve 20 and the larger support column 474b.

[0156] Figure 17BThe figure shows the initial stage of horn activation, at which the driver has just activated the horn by pressing the horn activation pad 8. The horn plate 14 has now moved axially a distance Δ. The small support column 474a is axially compressed due to its relatively small cross-sectional dimensions. Therefore, the compression of the horn spring 494 has not yet begun. When the small support column 474a has been axially compressed to the extent that it has the same axial height as the large support column 474b, the rear side of the sleeve 20 will contact both the small support column 474a and the large support column 474b, as shown in FIG. Figure 17B The distance Δ is now eliminated. Therefore, the advantage of selecting a small size for the first set of support posts 474a is that it ensures both a flexible interface and axial compression when the horn is activated.

[0157] Figure 17C 4. The subsequent stage of horn activation is shown. When the distance Δ toward the larger support post 474b has been eliminated, the total axial stiffness of the combination of all support posts 474a and 474b will now be sufficient to compress the horn spring portion 494 when the driver presses the horn activation pad 8. For illustration purposes only, Figure 17C The motion of the horn plate 14 and the compression of the horn spring have been shown in a very exaggerated scale. In reality, this motion may only involve about one or several millimeters.

[0158] A particular advantage achieved by including support posts 474a and 474b at different distances from the horn plate (achieved in this design by having different heights) and, optionally, different axial stiffnesses is that two advantageous properties can be simultaneously achieved: one related to vibration damping and one related to horn activation. With respect to vibration damping, a radially flexible interface between the elastic material and the rear side of the sleeve 20 or horn plate 14 is preferred. With respect to horn activation, an axially rigid interface at the same location is preferred in order to initiate horn spring compression as quickly as possible when the driver depresses the pad 8. This "difficulty" is addressed by providing different support posts 474a and 474b, creating a "dynamic" support interface.

[0159] On the one hand, when the horn is not activated, the rear side of the horn plate 14 is supported only by the relatively flexible, smaller support post 474a. This has the advantage that the interface between the elastic material and the rear side of the horn plate 14 does not interfere with the vibration damping function. When the horn is not activated, the larger support post 474b is inactive. On the other hand, when the horn is activated, it is preferable to achieve a fully developed horn spring force as quickly as possible. Due to the presence of the larger, relatively rigid support post 474b and the relatively low axial stiffness of the smaller support post 474a, the distance Δ can be eliminated very quickly when horn activation is initiated by axial compression of the smaller support post 474a, allowing the desired axially rigid interface to be established despite the flexible interface during normal vibration damping.

[0160] Fifth embodiment

[0161] 19A to 19C A fifth embodiment of a damper unit 540 is shown. The same reference numerals as above are used, but in the 500 series. The slider of the damper unit 540 has the same Figure 13A The same design as the sliding member 450 in the fourth embodiment shown in FIG13D is shown. The damper element 570 of the damper unit 540 is 18A to 18C All statements regarding manufacturing, optional combinations, functions, assembly, materials, ribs, support columns, alternatives, etc. in the previous embodiments also apply to this fifth embodiment 540 in all relevant parts.

[0162] The fifth embodiment or damper unit 540 differs from the fourth embodiment of the damper unit 440 in that the damper unit 550 of the fifth embodiment does not have an integrally formed horn spring element made of molded elastomeric material. Instead, a separate horn spring 594 is used. The horn spring 594 may be a coil spring as shown and may typically be made of metal. In the illustrated embodiment, the slider 550 is provided with an annular groove 556a at its lower or rear end for receiving the distal end of the horn spring 594, as shown. Figure 20B shown.

[0163] Figures 20A to 20E A method for assembling a vibration damper assembly 6 ( FIG. 5 ) including three damper units 540 according to a fifth embodiment is shown. Figure 20F ) method of the first embodiment. Figure 20A The damper unit 540 is shown inserted from below into one of the three mounting openings of the horn plate 14. As in the previous embodiment, the slider 550 and elastic damper element 570 of each damper unit 540 are inserted together, and only from one side of the horn plate 14. In the illustrated embodiment, each mounting opening of the horn plate 14 is provided with a sleeve 20. The sleeve 20 is preferably made of a relatively rigid material, such as a rigid plastic material molded into the horn plate. One function of the sleeve 20 is to provide an axially extending engagement surface for the damper element 570. Another function of the sleeve 20 is to protect the elastic damper element 570 from damage during assembly and operation. In this embodiment, each individual horn spring 594 is already connected to its associated damper unit 540 before the damper unit 540 is inserted into the horn plate 14. In some embodiments, the radial dimensions of the horn spring 594 and the annular groove 556a can be selected so that the end of the horn spring 594 remains secured in the groove 556a during assembly. The advantages described above in connection with single-sided mounting also apply to this embodiment.

[0164] Figure 21A second embodiment of a method for assembling a vibration damper assembly 6 including three damper units 540 according to the fifth embodiment is shown. In this embodiment, each damper unit 540 is mounted to the horn plate 14 as described above, but no separate horn spring 594 is attached to the damper unit 540. The horn spring 594 is placed separately from the damper unit 540 on the bracket surface 26 of the bracket 22. Thereafter, as Figure 21 As shown, the horn plate 14 with the damper unit 540 mounted thereon is placed on the horn spring 594. Finally, the bolt 120 is inserted and tightened as described in the other embodiments above.

[0165] Alternatives

[0166] The embodiments described above and shown in the figures can be modified in many ways.

[0167] In the illustrated embodiment, the horn activation mechanism is mechanical. Horn activation is achieved by sliding a slider along the bolt axis, moving the horn plate 14 toward the bracket 22. During horn activation, the horn spring is compressed. When the driver releases the horn activation pad 8, the horn spring (elastic or metallic) returns the horn plate 14 to its default position. In other embodiments, the horn activation mechanism may be electronic. In such an embodiment, the horn plate 14 does not need to move toward the base structure 12. Instead, the horn is activated by other means, including electronic contact. However, vibration damping is still required, and the horn plate can be connected to the base structure 12 via a damper unit as described above, but without any horn spring. In such an embodiment, the slider would not actually act as a slide designed to slide on the bolt axis during horn activation. Instead, the slider portion is a mounting sleeve into which the bolt is inserted to mount the damper unit. Since there is no sliding, no horn spring is required. In such an embodiment, the radial slider flange can also be omitted.

[0168] In the illustrated embodiment, the guide shaft is part of a bolt that screws into the vibrating base structure. The guide shaft can be implemented in different ways, such as by being integrally formed with the vibrating structure and optionally having a free threaded end for securing the assembly with a nut. Furthermore, in some embodiments, the bolt can be oriented in the opposite direction, screwing into the horn plate instead.

[0169] In an alternative embodiment, the horn plate sleeve 20 is omitted and the damper element is connected to the horn plate 14 in a different manner, optionally in direct contact with the horn plate 14 .

[0170] In other embodiments, the second tubular portion of the slider may extend further into the horn spring portion, but preferably not all the way, to allow the slider to move when the horn is activated. In some embodiments, the second tubular portion is omitted, and the horn spring element is attached to the slider in some other manner, such as simply to a flange.

[0171] In some embodiments, the outer engagement surface of the damper element may extend circumferentially approximately 360 degrees around the axis of the damper unit so that vibrations can be transmitted in substantially all radial directions. Such embodiments are also contemplated to include ribbed designs in which the outer engagement surface is discontinuous in the circumferential direction.

[0172] In other embodiments, the damper element's external engagement surface may exist in certain directions only if the damper unit is configured to transmit vibrations only in certain specific directions. This can be achieved in various ways, such as by arranging an internal protrusion in the mounting opening of the horn plate to define a circumferentially restricted internal engagement surface, such as an internal protrusion on a sleeve. This can also be achieved by designing an elastic damper element with engagement surfaces only in certain directions. In such an embodiment, in which an individual damper unit is configured to transmit vibrations only in a specific direction, the entire assembly can include multiple damper units arranged to address vibrations in different directions. As an example, one or more damper units may be configured to damp vibrations in the vertical direction, and one or more other damper units may be configured to damp vibrations in the horizontal direction.

[0173] In alternative embodiments, the slide and the corresponding channels or holes of the elastic element may have non-circular cross-sections, for example if different damping properties are required in different directions and the damper unit therefore has to be oriented in a specific way on the guide shaft.

[0174] Other inventive concepts

[0175] According to another inventive concept, there is provided a damper unit as described in any of the above embodiments, but without any sleeve or slider. Figure 24C These figures are identical to the figures except that the slider and the bottom portion of the elastic element have been removed. 18A to 18CThe damper unit can be manufactured and assembled as a single, integral elastic damper element comprising one or more structures and functions as described above. Thus, the elastic damper element can have an integral horn spring, or no horn spring at all. A locking process can also be employed, optionally utilizing compression of the bolt head as described above. During installation of the damper unit, the bolt can be introduced through a central passage or hole in the elastic damper unit and optionally into direct contact with the radially inner surface of the elastic damper unit.

[0176] According to another inventive concept, a damper unit for a frequency-tuned vibration damper assembly of a steering wheel may be provided, the damper unit having an insertion end and an opposite rear end and configured to be inserted with its insertion end through a mounting opening provided in a vehicle horn plate of the damper assembly.

[0177] The damper unit comprises an elastic damper element which is molded on the radially outer side of the sleeve so that the sleeve and the damper element together form a unitary structure,

[0178] in:

[0179] The elastic damper element has an elastic insertion portion and an elastic support portion, the elastic insertion portion being configured to be inserted into the mounting opening of the vehicle horn plate, and the elastic support portion being configured to define a final mounting position of the damper unit;

[0180] the resilient insert portion having a plurality of resilient ribs extending at least partially along the axis and spaced apart from one another in a circumferential direction relative to the axis, the ribs together forming a radially outer engagement surface configured to directly engage an inner surface of the mounting opening;

[0181] The radially outer engagement surface has a first radial dimension, and the resilient support portion has a second radial dimension greater than the first radial dimension;

[0182] at least some of the resilient ribs have radially outwardly extending snap-lock protrusions configured to be inserted through the mounting opening to snap-lock the damper unit in its final mounted position; and

[0183] The elastic support portion has a plurality of elastic support columns, which are spaced apart from each other in the circumferential direction and extend at least partially in the direction of the axis, and each elastic support column has a distal surface facing the insertion end of the damper unit, and the elastic support columns are flexible in all directions transverse to the axis, wherein the distal surface of the support column is configured to contact the rear side of the vehicle horn plate in the final installation position during assembly of the damper unit into the mounting opening of the vehicle horn plate.

[0184] According to this additional inventive concept, there may also be provided a method for manufacturing a frequency tuned vibration damper assembly for damping vibrations in a steering wheel, the method comprising:

[0185] One or more damper units are used, each damper unit comprising an elastic vibration damper element having:

[0186] a resilient insert portion having, at an insertion end, one or more radially outwardly extending snap-lock projections and a radially outer engagement surface axially spaced from the snap-lock projections, the radially outer engagement surface having a first radial dimension, and

[0187] - a resilient support portion having a second radial dimension greater than said first radial dimension; and

[0188] inserting each damper unit into an associated mounting opening in the horn plate along the axis of the damper unit in an insertion direction,

[0189] The damper unit is inserted into the mounting opening until it reaches a final insertion position, wherein:

[0190] - the radially outer engagement surface of the elastic insert portion is in direct contact with the inner surface of the mounting opening,

[0191] - the snap-locking projection has been inserted through the mounting opening to form a snap-locking of the damper unit relative to the horn plate, and

[0192] -The elastic support portion has come into axial contact with the rear side of the horn plate.

[0193] The structures, designs, methods and alternatives described above for the first to fourth embodiments may in all relevant parts be used for this further inventive concept.

[0194] This application also covers the following aspects:

[0195] 1) A damper unit for use in a frequency-tuned vibration damper assembly of a steering wheel, the damper unit having an insertion end and an opposite rear end, and configured to be inserted with its insertion end through a mounting opening provided in a horn plate of the damper assembly,

[0196] The damper unit comprises:

[0197] - a sleeve having a central hole extending along the axis, and

[0198] an elastic damper element which is molded onto the radially outer side of the sleeve so that the sleeve and the damper element together form a unitary structure,

[0199] in:

[0200] The elastic damper element has an elastic insertion portion and an elastic support portion, wherein the elastic insertion portion is configured to be inserted into the mounting opening of the vehicle horn plate, and the elastic support portion is configured to define a final mounting position of the damper unit;

[0201] the resilient insert portion having a plurality of resilient ribs extending at least partially along the axis and spaced apart from one another in a circumferential direction relative to the axis, the ribs together forming a radially outer engagement surface configured to directly engage an inner surface of the mounting opening;

[0202] The radially outer engagement surface has a first radial dimension, and the resilient support portion has a second radial dimension greater than the first radial dimension;

[0203] At least some of the resilient ribs have snap-locking protrusions extending radially outward, the snap-locking protrusions being configured to be inserted through the mounting opening to snap-lock the damper unit in a final mounted position of the damper unit; and

[0204] The elastic support portion has a plurality of elastic support columns, which are spaced apart from each other in the circumferential direction and extend at least partially in the direction of the axis. The elastic support columns are flexible in all directions transverse to the axis.

[0205] 2) The damper unit according to 1), wherein the plurality of support columns are positioned at radial positions radially outside the ribs.

[0206] 3) A damper unit according to any one of the preceding claims, wherein:

[0207] The plurality of support columns form a first group of first support columns, each first support column having a distal end axially facing the insertion end of the damper unit;

[0208] The elastic support portion further has one or more second elastic support columns, each second support column having a distal end axially facing the insertion end of the damper unit, and the distal end of each second support column at least partially extending in the direction of the axis, and

[0209] The distal end of the first support column is axially closer to the insertion end of the damper unit than the distal end of the second support column.

[0210] 4) The damper unit according to 3), wherein the one or more second support columns form a second group of multiple second support columns, the second group of multiple second support columns are spaced apart from each other in the circumferential direction, and are staggered and spaced apart from the first support columns in the circumferential direction.

[0211] 5) The damper unit according to 3) or 4), wherein the first support columns together have a first total axial stiffness, and wherein the one or more second support columns together have a second total axial stiffness, the second total axial stiffness being greater than the first total axial stiffness.

[0212] 6) The damper unit according to 4) or 5), wherein:

[0213] - the axially distal ends of the first support struts together form a first total surface area axially facing the insertion end of the damper unit, and

[0214] The axially distal ends of the second support struts together form a second total surface area axially facing the insertion end of the damper unit, the second total surface area being greater than the first total surface area.

[0215] 7) A damper unit according to any one of the foregoing, wherein the sleeve of the damper unit is a sliding member, and the sliding member is configured to slide in the direction of the axis along a guide shaft accommodated in the center hole of the sliding member when the horn is activated on the steering wheel.

[0216] 8) The damper unit according to 7), wherein:

[0217] The elastic vibration damper element is molded onto the first portion of the slider;

[0218] The damper unit further includes an elastic horn spring element having a horn spring portion and an attachment portion molded integrally with each other;

[0219] The attachment portion of the horn spring element is molded onto the second portion of the slider; and

[0220] The horn spring portion is configured to apply a force to the slider in the direction of the axis before and when the horn is activated on the steering wheel.

[0221] 9) The damper unit according to 8), wherein the elastic vibration damper element and the elastic horn spring element are molded integrally with each other.

[0222] 10) The damper unit according to 8) or 9), wherein the attachment portion of the horn spring element is mechanically coupled to the slider.

[0223] 11) A damper unit according to 10), wherein the attachment portion of the horn spring element is mechanically coupled to the sliding member by one or more molded locking elements, the one or more molded locking elements being molded integrally with the damper element and the horn spring element, and the one or more molded locking elements being mechanically locked into engagement with associated one or more locking openings in the sliding member.

[0224] 12) The damper unit according to 11), wherein the sliding member comprises:

[0225] a tubular element extending along the axis and having the bore; and

[0226] a flange extending radially outwardly from the tubular element and having the locking opening in the form of a through-hole;

[0227] Wherein the damper element and the horn spring element are positioned on opposite axial sides of the flange.

[0228] 13) The damper unit according to any one of 8) to 12), wherein the horn spring portion at least partially extends axially beyond the slider.

[0229] 14) The damper unit according to any one of 8) to 13), wherein the horn spring portion is at least partially bellows-shaped.

[0230] 15) The damper unit according to any one of 8) to 14), wherein at least one of the attachment portions of the elastic damper element and the elastic horn spring element is chemically bonded to the sliding part, for example by adhesive bonding.

[0231] 16) A frequency tuned damper assembly for damping vibrations in a steering wheel, comprising:

[0232] a base structure secured to the steering wheel and having vibrations to be damped;

[0233] car whistle board;

[0234] one or more damper units according to 1), each damper unit being arranged in an associated mounting opening in the horn plate with its radially outer engagement surface in direct contact with the horn plate for transmitting the vibrations;

[0235] one or more guide shafts, each guide shaft being fixed to the base structure and received in the central bore of the sleeve of an associated damper unit; and

[0236] a mass supported by the base structure via the damper element of the damper unit for allowing movement of the mass transverse to the axis;

[0237] Wherein the damper element and the mass are configured to operate as a frequency tuned spring-mass system, forming a frequency tuned dynamic damper for damping the vibrations.

[0238] 17) The assembly according to 16), wherein the weight of the mass block includes at least the weight of the horn plate and the weight of the airbag assembly supported by the horn plate.

[0239] 18) An assembly according to any one of 16) to 18), wherein each guide shaft is part of a threaded bolt; and wherein the bolt head of each bolt is configured to serve as a stop for limiting axial movement of the associated sliding member.

[0240] 19) An assembly according to any one of 16) to 19), wherein the distal end of the elastic rib of each damper unit is compressed by the bolt head of the associated bolt to further lock the damper unit to the vehicle horn plate.

[0241] 20) An assembly according to any one of 16) to 19), wherein the sleeve of each damper unit is a sliding member, which is configured to slide in the direction of the axis along an associated guide shaft accommodated in the center hole of the sliding member when the horn is activated on the steering wheel, and wherein the assembly also includes a horn spring for each damper unit, which is configured to apply a force to the sliding member in the direction of the axis before and when the horn is activated on the steering wheel.

[0242] 21) The assembly according to 20), wherein the horn spring is an elastic horn spring element molded on the slider.

[0243] 22) The assembly according to 20), wherein the horn spring is a separate metal horn spring arranged between the damper unit and the base structure.

[0244] 23) The assembly according to 20), wherein the one or more damper units are damper units according to 3), wherein:

[0245] - the distal end of the first support column is configured to axially contact the rear side of the horn plate before the horn is activated;

[0246] - the distal end of the second support column is separated from the rear side of the horn plate by an axial gap before the horn is activated;

[0247] The distal end of the first support column is configured to be axially compressed by an amount corresponding to the size of the axial gap during the initial stage of horn activation, so that the axial gap is eliminated and the second support column also contacts the rear side of the horn plate.

[0248] 24) A method of manufacturing the damper unit according to any one of 1) to 15), comprising:

[0249] An elastic vibration damper element is molded on a radially outer first portion of the sleeve, the elastic vibration damper element having an elastic insertion portion and an elastic support portion, the elastic insertion portion being configured to be inserted into the mounting opening of the horn plate, and the elastic support portion being configured to define a final insertion position of the damper unit; wherein:

[0250] the elastic insert portion has a plurality of elastic ribs extending at least partially along the axis and being spaced apart from one another in a circumferential direction relative to the axis, the ribs together forming a radially outer engagement surface configured to directly engage an inner surface of the mounting opening;

[0251] - the radially outer engagement surface has a first radial dimension, and the resilient support portion has a second radial dimension greater than the first radial dimension; and

[0252] The elastic support portion has a plurality of elastic support columns, which are spaced apart from each other in the circumferential direction and extend at least partially in the direction of the axis, and are flexible in all directions transverse to the axis.

[0253] 25) The manufacturing method according to 24) further includes molding an elastic horn spring element, wherein the elastic horn spring element includes a horn spring portion and an attachment portion molded into one piece with each other, wherein the attachment portion is molded on the second portion of the sleeve.

[0254] 26) The manufacturing method according to 25), wherein the elastic damper element and the elastic horn spring element are molded integrally with each other.

[0255] 27) The manufacturing method according to 26),

[0256] wherein the sleeve comprises a tubular element extending along the axis, and a flange extending radially outwardly from the tubular element, and the flange has one or more locking openings in the form of through-holes; and

[0257] wherein molding the resilient damper element and the resilient horn spring element comprises molding the damper element and the horn spring element on axially opposite sides of the flange, and the damper element and the horn spring element are integral with each other and have one or more locking elements extending through the locking opening to mechanically couple the damper element and the horn spring element to the slider.

[0258] 28) The manufacturing method according to any one of 24) to 27), further comprising frequency tuning the damper by selecting one or more parameters, the parameters comprising:

[0259] - the number of ribs,

[0260] - the circumferential, radial and / or axial dimensions of the rib, and

[0261] - the circumferential, radial and / or axial dimensions of the spaces between the ribs.

[0262] 29) A method for manufacturing a frequency tuned vibration damper assembly for damping vibrations in a steering wheel, the method comprising:

[0263] One or more damper units are used, each damper unit comprising a sleeve having a central hole extending along an axis, and an elastic vibration damper element molded on the radially outer side of the sleeve so that the sleeve and the vibration damper element together form a unitary structure, the elastic vibration damper element having:

[0264] a resilient insert portion having at an insertion end one or more radially outwardly extending snap-lock projections and a radially outer engagement surface axially spaced from said snap-lock projections, said radially outer engagement surface having a first radial dimension, and

[0265] - a resilient support portion having a second radial dimension greater than said first radial dimension; and

[0266] Each damper unit is inserted into an associated mounting opening in the vehicle horn plate along an axis of the damper unit in an insertion direction, wherein the damper unit is inserted into the mounting opening until a final insertion position is reached, wherein:

[0267] - the radially outer engagement surface of the elastic insert portion is in direct contact with the inner surface of the mounting opening,

[0268] - the snap-locking projection has been inserted through the mounting opening to form a snap-locking of the damper unit relative to the horn plate, and

[0269] The elastic supporting portion has come into axial contact with the rear side of the bicycle horn plate.

[0270] 30) The method according to 29) further includes inserting the bolt shaft of the bolt through the center hole of the sleeve in a direction opposite to the insertion direction, and connecting the distal end of the bolt to a structure fixed to the steering wheel and subjected to vibration.

[0271] 31) The method according to 29), further comprising compressing at least a portion of the elastic insertion portion by the bolt head.

Claims

1. A method for manufacturing a frequency-tuned vibration damper assembly for damping vibrations in a steering wheel, the method comprising inserting a damper unit into a mounting opening of a vehicle horn plate along an axis of the damper unit in an insertion direction, the damper unit comprising an elastic damper element molded onto a radially outer side of a sleeve such that the sleeve and the elastic damper element together form a unitary structure, wherein the damper unit is inserted into the mounting opening in the insertion direction until a final insertion position of the damper unit is reached, in which final insertion position: A plurality of radially outwardly extending snap-locking projections of the elastic damper element formed at the insertion end of the damper unit have been inserted through the mounting opening in the insertion direction to form a snap-locking of the damper unit relative to the horn plate at the front side of the horn plate, a radially outer resilient engagement surface of the resilient damper element, axially spaced from the snap-lock protrusion, having been inserted into the mounting opening and radially engaged with a radially inner surface of the mounting opening of the horn plate, and The elastic support portion of the elastic damper element has axially contacted the rear side of the horn plate to define the final insertion position, in, The method further comprises: inserting the guide shaft through the hole of the sleeve in a direction opposite to the insertion direction; and The distal end of the guide shaft is connected to a base structure which is fixed to the steering wheel and is subjected to vibrations to be damped, wherein the sleeve of the damper unit forms a slider which is configured to slide along the guide shaft.

2. The method according to claim 1, wherein The radially outer resilient engagement surface has a first radial dimension, and The elastic support portion of the elastic damper element has a second radial dimension that is larger than the first radial dimension.

3. The method according to claim 1, wherein The guide axis is the bolt axis of the bolt, and The bolt head of the bolt is configured to serve as a stopper for limiting the axial sliding movement of the sliding member along the bolt axis.

4. The method according to claim 3, further comprising: Connecting the bolt causes at least a portion of the elastic damper element to be compressed by the bolt head.

5. The method of claim 1 , further comprising connecting a mass to a base structure, the base structure being fixed to the steering wheel and being subjected to vibrations to be damped, for allowing movement of the mass transverse to the axis, wherein the elastic damper element and the mass are configured to operate together as a frequency-tuned spring-mass system, the frequency-tuned spring-mass system forming a frequency-tuned dynamic damper for damping frequencies.

6. The method according to claim 5, wherein: Connecting the mass to the base structure via the elastic damper element includes mounting an airbag assembly on the horn plate, and The weight of the mass block at least includes the weight of the vehicle horn plate and the weight of the airbag assembly.

7. The method according to claim 1, wherein The elastic insert portion of the elastic damper element includes a plurality of elastic ribs, which extend at least partially along the axis and are circumferentially spaced apart from each other relative to the axis, and the plurality of elastic ribs together form the radially outer elastic engagement surface configured to engage with the radially inner surface of the mounting opening.

8. A method of manufacturing a frequency-tuned vibration damper assembly for damping vibrations in a steering wheel, the method comprising inserting a damper unit into a mounting opening of a vehicle horn plate along an axis of the damper unit in an insertion direction, the damper unit comprising an elastic damper element molded onto a radially outer side of a sleeve such that the sleeve and the elastic damper element together form a unitary structure, wherein the damper unit is inserted into the mounting opening in the insertion direction until a final insertion position of the damper unit is reached, in which final insertion position: A plurality of radially outwardly extending snap-locking projections of the elastic damper element formed at the insertion end of the damper unit have been inserted through the mounting opening in the insertion direction to form a snap-locking of the damper unit relative to the horn plate at the front side of the horn plate, a radially outer resilient engagement surface of the resilient damper element, axially spaced from the snap-lock protrusion, having been inserted into the mounting opening and radially engaged with a radially inner surface of the mounting opening of the horn plate, and The elastic support portion of the elastic damper element has axially contacted the rear side of the horn plate to define the final insertion position, in, The resilient damper element is molded onto the radially outer side of the sleeve such that a portion of the resilient damper element extends through a locking opening of a flange extending radially outward from the sleeve.

9. A method of manufacturing a frequency-tuned vibration damper assembly for damping vibrations in a steering wheel, the method comprising inserting a damper unit into a mounting opening of a vehicle horn plate along an axis of the damper unit in an insertion direction, the damper unit comprising an elastic damper element molded onto a radially outer side of a sleeve such that the sleeve and the elastic damper element together form a unitary structure, wherein the damper unit is inserted into the mounting opening in the insertion direction until a final insertion position of the damper unit is reached, in which final insertion position: A plurality of radially outwardly extending snap-locking projections of the elastic damper element formed at the insertion end of the damper unit have been inserted through the mounting opening in the insertion direction to form a snap-locking of the damper unit relative to the horn plate at the front side of the horn plate, a radially outer resilient engagement surface of the resilient damper element, axially spaced from the snap-lock protrusion, having been inserted into the mounting opening and radially engaged with a radially inner surface of the mounting opening of the horn plate, and The elastic support portion of the elastic damper element has axially contacted the rear side of the horn plate to define the final insertion position, in, The resilient damper element is molded onto a first portion of the sleeve, and a resilient attachment portion of a resilient horn spring element is molded onto a second portion of the sleeve, the resilient horn spring element being configured to apply a force to the sleeve in the direction of the axis before and when the horn is activated on the steering wheel.

10. The method according to claim 9, wherein: The sleeve comprises: a tubular element extending along the axis and defining a bore; and a flange extending radially outwardly from the tubular element, and Therein, the elastic damper element and the elastic horn spring element are positioned on opposite axial sides of the flange.

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