This application relates to and claims the benefit and priority to Spanish Patent Application No. P201331710, filed Nov. 22, 2013.
The disclosure relates to shock-absorbers capable of joining a first component subjected to vibrations to a second component. The disclosure also relates to the method for manufacturing the shock-absorbers.
Shock-absorbers capable of joining a first component subjected to vibrations, such as a vehicle exhaust pipe, for example, to a second component, such as a vehicle frame, for example, are known. These shock-absorbers are usually made of rubber and must be rigid enough to withstand the static loads to which it is subjected, such as the weight of the first component, for example, which usually hangs from the shock-absorber. However, the greater the rigidity of the shock-absorber the lower the vibration damping power, i.e., the more rigid the shock-absorber is, the more vibrations it will transmit. To solve this problem, shock-absorbers comprising a complex shape to reduce some areas and thus reduce the total rigidity of the shock-absorber are known.
Likewise, rubber shock-absorbers internally comprising a metal insert are also known, for example, a steel or an aluminum insert, with greater density than the rubber insert, such that it provides an increase in the total rigidity of the shock-absorber.
In this manner, JP2010210015 A discloses a shock-absorber for hanging an exhaust pipe (first component) which is subjected to vibrations for joining it to a vehicle frame (second component). The shock-absorber comprises a base body comprising a first area designed for being joined to the first component and a second area designed for being joined to the second component. The base body is made of rubber and internally comprises an embedded metal insert. When the shock-absorber is subjected to static and dynamic loads, the base body made of rubber is deformed, tending to become longer. The metal insert comprises a series of curvatures which tend to be aligned when the base body is deformed, which allows the insert to deform. When the deformation of the metal insert reaches a limit, it changes into a rigid body preventing the plastic deformation of the base body.
According to some implementations a shock-absorber suitable for joining a first component subjected to vibrations, such as a vehicle exhaust pipe, to a second component, such as a vehicle frame is provided. The shock-absorber comprises a first area which is designed for being joined to the first component and a second area designed for being joined to the second component. The shock-absorber also comprises a first elastic material covering a large part of the volume of the shock-absorber and a second elastic material of a lower density located at least in the first area. The second material at least partially contacts the first component.
Vibration transmission from the first component, such as a vehicle exhaust pipe, to the second component, such as a vehicle frame, is significantly reduced by the shock absorber in a simple, economical and effective manner, it not being necessary to provide the shock-absorber with complex shapes for reducing the total rigidity. At the same time, an excessive increase in the density or total volume of the shock-absorber is prevented, which would be counterproductive for minimizing vibration transmission.
Additionally, assembling operations in assembly lines are also made easier because at least the first component is inserted in a non-rigid area, which makes the operation of inserting the first component into the first area easier.
These and other advantages and features of the will become evident in view of the drawings and the detailed description of the invention.
According to the implementations disclosed herein, a shock-absorber 1 is provided that is suitable for joining a first component 2 subjected to vibrations to a second, preferably static, component 3. The shock-absorber 1 includes a first area 5 which is designed for being joined to the first component 2 and a second area 6 designed for being joined to the second component 3. The shock-absorber 1 also includes a first elastic material 4a covering a large part/majority of the volume of the shock-absorber 1 and a second also elastic material 4b but of a lower density located at least in the first area 5. The second material 4b at least partially contacts the first component 2.
The first material 4a comprises a density and geometry that provides the shock-absorber 1 with sufficient rigidity so that it can withstand the static loads to which it is subjected without exceeding its elastic limit. This material, as seen in the drawings, covers a majority of the volume of the shock-absorber 1. For damping the vibrations that can be transmitted by the first component 2, which is subjected to vibrations, the shock-absorber is provided with a second material 4b capable of absorbing the vibrations. Therefore, the shock-absorber 1 comprises a second elastic material 4b, the density of which is less than the density of the first material 4a, arranged such that the second material 4b contacts the first component 2.
The shock-absorber 1 is therefore rigid enough to withstand the static loads to which it is subjected, and flexible enough (where required) to stop vibration transmission from the first component 2 to the second component 3.
In this sense,
With respect to some of the implementations disclosed herein, the density of the second material 4b is preferably less than or equal to 1 g/cm3, and the sum of densities of the first material 4a and the second material 4b is preferably less than or equal to 2 g/cm3. In this manner, the shock-absorber 1, on one hand, is robust enough so that it can withstand the static loads to which it is subjected without exceeding its elastic limit, and on the other hand, is flexible enough so as to minimize or prevent vibration transmission from the first component 2, which is subjected to vibrations and joined to the first area 5, to the second component 3 which is attached to the second area 6. However, to even further optimize vibration absorption, non-rigid areas (made up of the second material 4b) locally distributed in the shock-absorber 1 are added. Therefore, it is not necessary for the shock-absorber 1 to comprise complex shapes which aid in reducing the total rigidity thereof, nor does the density or the total volume of the shock-absorber 1 increase excessively, which would be counterproductive for minimizing vibration transmission. The greater the rigidity of the shock-absorber the lower the vibration damping power, i.e., the greater the density the more rigid the shock-absorber will be, and the more rigid the shock-absorber 1 is, the more vibrations it will transmit..
Examples of the first material 4a can be EPDM (ethylene-propylene-diene monomer), natural rubber, thermoplastic or the like and examples of the second material 4b can be silicone sponge, EPDM sponge, polyurethane sponge or the like. According to some implementations the first material 4a of the shock-absorber 1 is preferably EPDM and the second material 4b is preferably silicone sponge that is over-molded onto the first material 4a in a liquid form.
The main material of the shock-absorber 1 is the first material 4a covering most/majority of the volume of the shock-absorber 1 and comprising such a density that it provides sufficient rigidity so that the shock-absorber 1 can withstand the static loads to which it is subjected without exceeding its elastic limit. A second material 4b of less density also forms a part of the shock-absorber and is coupled to the first material 4a. The objective of using the second material 4b is not to reinforce the first material 4a but rather to provide flexible areas capable of absorbing the vibrations that may be transmitted by the first component 2 which is subjected to vibrations. To achieve this effect effectively, the second material 4b is arranged in the first area 5 such that the second material 4b at least partially contacts the first component 2, as seen in the examples of
Optionally, the second area 6 of the shock-absorber 1 can also comprise the second material 4b, as seen in
In the implementation of
It is also possible to include in any of the implementations a third area, or a strip, formed by the second material 4b which is arranged in an intermediate area between the first area 5 and the second area 6, for example.
Usually, the first component 2 which is subjected to vibrations tends to comprise a protuberance in the form of a shaft, or coupling means, for being able to be coupled or attached to the shock-absorber. The first area 5 of the shock-absorber 1 according to any of the implementations may thus comprises a hole, which may have a circular section, enabling attachment with the first component 2. At least part of the second material 4b is arranged inside the hole, the second material 4b comprising a central hole which allows inserting the protuberance or coupling means of the first component 2. The first component 2 therefore directly contacts the second material 4b along at least a portion or the entire contact area between the first component 2 and the shock-absorber 1. In the example of
The second area 6 of the implementation of
The first area 5 and the second area 6 of the shock-absorber 1 of
Likewise, the first area 5 and the second area 6 of the shock-absorber 1 of
In the examples of
According to any of the implementations disclosed herein, the second material 4b may be over-molded on the first material 4a in a manner as described below, a single part with two different elastic materials being obtained. According to some implementations a chemical binding is made between the first material 4a and the second material 4b. Other types of attachments are also possible.
According to one implementation, in a first step the first material 4a is obtained by molding or extruding a first elastic material, or by a similar method. The product obtained in this first step is used as an insert in a subsequent molding step where the insert is introduced in the cavity of a mold to then pour or inject the second material 4b onto the first material 4a.
As mentioned above, the second material 4b may be silicone sponge, which comprises a base component that is in liquid form and is mixed with a reagent in a mixing step. In the molding step, the mixture obtained is poured or injected into the cavity of the mold, where the insert formed by the first material 4a has been previously placed, such that the mixture expands and fills the gap existing between the insert and the cavity of the mold in a curing step. Since the base component is in a liquid state, it makes pouring the mixture into the mold easier, not requiring specific specializes equipment for pouring or injecting the mixture into the mold. This operation can even be performed manually. When the curing step ends, the shock-absorber 1 is removed from the mold in a removal step.
The second material 4b may adopt the desired color and texture and to that an additive, e.g. a dye, is added to the mixture in the mixing step before being poured or injected into the cavity of the mold. Both the first material 4a and the second material 4b can thus be of the same color giving the impression that the shock-absorber 1 is made only of a single material, or can be of different colors such that the shock-absorber 1 can acquire a distinctive look.
According to any of the implementations, the first area 5 and/or the second area 6 can comprise at least one protuberance to make the adhesion of the second material 4b on the first material 4a easier, there being provided not only a chemical binding but also a mechanical attachment.
Accordingly, a shock-absorber 1 may be manufactured in a fast and economical manner.
Number | Date | Country | Kind |
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P201331710 | Nov 2013 | ES | national |