JP6294156B2 - Vibration isolator - Google Patents

Description

  The present invention relates to a vibration isolator that absorbs vibration transmitted to a resin molded product, and can be applied to, for example, mobile communication ground equipment for automobiles and connected vehicles, in-vehicle electronic control units, general industrial machines, and the like. is there.

  In recent years, there have been an increasing number of cases where various electronic control devices and sensors equipped with electronic circuit boards are installed in harsh vibration environments. For example, in an electronic control device for an automobile, vibration generated from an engine and vibration generated by traveling of the vehicle are transmitted to the device. If excessive vibration is transmitted to the electronic circuit board, it may lead to failure of mounted electronic components or cracks in the solder joints. Therefore, when these devices are bolted to a vibration environment, the bolts are fastened through a vibration absorbing member such as a rubber washer as described in JP-A-2002-331935 (Patent Document 1). A method for reducing the vibration level transmitted to the target device is simple and common.

  However, when such a structure is adopted, the bolt fastening force acts on the rubber washer. Since the rubber material is a viscoelastic material, the bolt fastening force gradually decreases due to the stress relaxation action. Therefore, in order to prevent the bolts from loosening, it is necessary to periodically retighten or replace the rubber material. Therefore, there is a demand for a structure in which the bolt fastening force does not act on the vibration absorbing member.

  As such a structure, there is a structure described in Japanese Patent Laid-Open No. 7-280034 (Patent Document 2) shown in FIG. If the housing 3 of the electronic control device that is the object of vibration isolation is a resin molded product, an elastic member 6 is bonded around the metal cylindrical insert member 4 for fastening the bolt, and it is installed in the mold during resin molding. Then, by performing molding, the vibration absorbing portion can be easily attached. If this structure is adopted, the bolt fastening force does not act on the vibration absorber, so the bolt fastening reliability is greatly improved.

  On the other hand, the elastic member 6 is bonded to the entire outer peripheral surface of the cylindrical insert member. Therefore, shear deformation occurs between the side surface of the outer peripheral surface and the housing 3. Therefore, as the insert length increases, the rigidity of the shear deformation part increases, so that the rigidity of the entire vibration absorbing part increases.

  In general, in a vibration-proof structure, it is possible to reduce the transmission rate to vibration components in a lower frequency region by reducing the rigidity of the vibration absorbing portion as much as possible. The larger the structure, the lower the vibration component in the lower frequency region must be reduced. However, the longer the insert length, the lower the vibration absorption effect in the low frequency region. Therefore, a vibration isolator having lower rigidity while having reliability and manufacturability of bolt fastening has been awaited.

JP 2002-331935 A JP 7-280034 A

  The problem to be solved is to realize an anti-vibration device having the reliability of bolt fastening, manufacturability, and a high anti-vibration effect in a low frequency region.

  In order to solve the above problems, for example, the configuration described in the claims is adopted. The present application includes a plurality of means for solving the above-mentioned problems. For example, a cylindrical insert member having a bolt fastening through hole integrally formed in a resin molded product, the resin molded product, A ring-shaped elastic member is provided in a part of the space sandwiched between the insert members, and has a contact portion where the resin molded product and the insert member are in contact with each other. The contact portion includes the resin molded product and the insert member. A sliding surface that can be displaced mutually, and the insert member has a thick portion with an outer diameter of at least a portion larger than that of the other portion, and is a surface perpendicular to the axial direction of the insert member of the elastic member. One of these has a surface which contacts the said thick part, The vibration isolator characterized by the above-mentioned.

  The vibration isolator of the present invention reduces the rigidity of the vibration absorbing portion, and can achieve a high vibration isolating effect in a lower frequency region when compared with vibration isolating rubber of the same material and the same thickness.

It is a perspective view of the example of a position of the electronic controller which mounts the vibration isolator of this invention. It is A-A 'sectional drawing in FIG. It is sectional drawing explaining one of the Examples of the vibration isolator of this invention. It is a perspective view explaining the elastic member attachment state to the insert member of this invention. It is sectional drawing explaining one of the Examples of the vibration isolator of this invention. It is sectional drawing explaining one of the Examples of the vibration isolator of this invention. It is sectional drawing explaining the conventional vibration isolator.

  Each example will be described below with reference to the drawings.

  FIG. 1 is a perspective view of an electronic control device 1 including a vibration isolator 2 according to the present invention, and FIG. 2 is a cross-sectional view taken along line A-A ′ in FIG. This electronic control device 1 is assumed to be fixed to a vibration generating portion by bolt fastening. An insert member 4 is fixed to a fiber reinforced resin (FRP) casing 3 by integral molding. The insert member 4 also has a through hole for bolt fastening, and it is desirable to employ a metal material from the viewpoint of bolt fastening reliability. A flange portion 5 is provided on an end surface of the insert member, and a ring-shaped elastic member 6 is attached so as to be sandwiched between the flange portion 5 and the housing 3. In addition, at least the boundary surface 7 parallel to the bolt axis direction between the insert member 4, the casing 3, and the elastic member 6 is a sliding surface that can be displaced mutually. In this way, the boundary surface 7 does not adhere the resin molded product and the insert member 4 but has a structure that slides and moves, so that the shear rigidity between the insert member 4 and the housing 3 is compared with the conventional structure. Can be made smaller. FIG. 3 (a) is a cross-sectional view when the vibration isolator 2 of the present invention is bolted to the vibration generating portion, and FIG. 3 (b) is a cross-sectional view when the vibration generating portion side is displaced in the bolt axis direction. . The insert member 4 and the housing 3 are relatively displaced, and the elastic member 6 attached to the lower side is compressed and deformed to absorb vibration. If the same material is used, a thicker elastic member can be used to reduce the rigidity and increase the anti-vibration effect in the low frequency range. However, the housing 3 is engaged with the insert member 4. Since the thickness of the part is reduced, the dimensions should be determined in full consideration of the vibration environment in which the device is placed and the strength of the material used for the housing 3.

  In order to realize the structure as described above, it is more desirable to attach the elastic member 6 to the cylindrical insert member 4 in advance as shown in FIG. . As described above, the boundary surface parallel to the bolt axis should be a sliding surface. Therefore, after the elastic member 6 is fixed to the insert member 4, it is more desirable to perform a process for suppressing adhesion of a resin material such as application of a release material in advance on the surface exposed to the outside. On the other hand, the elastic member 6 should be fixed at a predetermined position of the insert member as shown in FIG. 4 during the molding process, but even if the interface between the flange portion and the elastic member is bonded, there is no vibration. Since the performance is not affected, an adhesive treatment such as applying an adhesive may be applied to this portion. The insert member 4 shown in FIG. 4 has a cylindrical shape, but the effect of the present invention can be obtained even if the cross section of the cylinder is not a circle but is, for example, an ellipse. The cross section may be a polygonal shape, but considering the attractive force with the elastic member, a shape close to a circle is preferable because a gap is less likely to be created. Note that the boundary surface parallel to the bolt axis may be composed of a plurality of planes or a curved surface based on the shape of the insert member 4. Further, the insert member 4 is provided with at least a part of a thick part larger than the other outer diameter, and the elastic member 6 is disposed so as to contact the surface of the thick part in a direction perpendicular to the bolt shaft. The member 6 can absorb vibration in a direction parallel to the bolt axis.

  As a resin molding method, it can be widely applied to injection molding of a thermoplastic resin and compression molding of a thermosetting fiber reinforced resin using an SMC (sheet molding compound) material. However, the relationship between the molding temperature and the heat resistance temperature of the rubber material used as the elastic member 6 should be sufficiently considered. For example, the structure of the present invention can be realized by a combination of EPDM (ethylene propylene rubber) frequently used as a vibration-proof rubber and the aforementioned SMC molding.

  Further, by adopting the present invention, the elastic member is shielded from the external environment. Many of the rubber materials used for the elastic member undergo a characteristic change by an oxidation reaction. In the structure of the present invention, since the amount of oxygen supplied to the elastic member portion is remarkably reduced, it can be expected that the vibration isolation effect is maintained for a longer period.

  In Example 1, except for the flange portion 5 of the insert member 4, a simple cylindrical shape was used. As shown in FIG. 3 (b), in the present invention, the elastic member 6 is compressed and deformed to obtain a vibration isolation effect. On the other hand, most anti-vibration rubber materials are incompressible materials. For this reason, when a compressive load is applied from the upper and lower surfaces, if the displacement of the side surfaces is restricted, the compression rigidity increases. Therefore, as shown in FIG. 5, in this embodiment, a recess 10 serving as a recess is provided in the portion of the insert member 4 that contacts the elastic member 6 as a clearance for the compression deformation of the elastic member 6. During the molding process described above, the recess 10 is sealed by the elastic member 6, so that there is no concern that the casing material will flow in. By making the elastic member easy to deform in this way, the rigidity can be further reduced. However, since the insert member 4 is provided with a partial notch shape, it is desirable that the shape and size be determined in consideration of the load acting on the insert member 4 and the like.

  In the first embodiment, the elastic member 6 is spatially fixed by providing the flange portion 5 at the end of the insert member 4 to obtain a vibration isolation effect. However, as shown in FIG. 6, a structure in which the flange portion 11 is provided in the intermediate portion of the insert member may be employed. By attaching the elastic members 6 to the upper and lower surfaces of the flange portion 11, the same vibration isolation effect as in Example 1 can be obtained, and when attaching the ring-shaped elastic member 6 to the insert member 4, the flange portion having a large outer diameter This eliminates the need to pass 5 and dramatically improves manufacturability. It is also possible to use a hollow structure as used in Example 2. However, since the outer diameter of the insert member 4 needs to be larger than the bolt seat surface diameter or the washer diameter to be used, the overall weight is slightly increased.

  In all of the first to third embodiments, the side having the vibration isolation device and the vibration isolation target have been described. However, the inner surface of the through hole provided in the insert member is threaded so that the vibration generation side is on the vibration generation side. The same effect can be obtained even if the device is mounted.

1 Electronic control unit
2 Vibration isolator
3 box
4 Insert material
5 Flange
6 Elastic member
7 Interface
8 volts
9 Interlocking area
10 Recess
11 Buttocks

Claims (3)

A cylindrical insert member integrally formed with a resin molded product and having a bolt fastening through hole;
Having a ring-shaped elastic member in a part of the space sandwiched between the resin molded product and the insert member;
The contact portion where the resin molded product and the insert member are in contact slides so that the resin molded product and the insert member can be displaced from each other,
The insert member has a thick portion where the outer diameter of at least a part is larger than the other part,
One of the surfaces perpendicular to the insert member axial direction of the elastic member is in contact with the thick portion. A vibration isolator according to claim 1,
The vibration isolator according to claim 1, wherein a recess is formed in a part of a portion of the outer peripheral surface of the insert member that contacts the elastic member. The vibration isolator according to claim 1 or 2,
An anti-vibration device, wherein an inner surface of the through hole is threaded.