JP2876419B2 - Soundproof structure in coffee mills, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Object of the Invention><Industrial application field> The present invention relates to a small household electric appliance such as a coffee mill having a vibration noise source such as a motor and a speaker therein, audio equipment and OA equipment. The present invention relates to a soundproof structure in a printer or the like.

<Background of the Invention> In a coffee mill or the like having a vibration noise source such as a motor, the noise of the rotation of the motor during operation or the sound generated by the vibration of the base on which the motor is mounted becomes a kind of noise, which can degrade the product image. is there. Such noise is transmitted directly through the air as a sound from the vibration source, or the vibration generated by the vibration source is transmitted to the outer case through the gantry, and the outer case vibrates to generate noise. For the latter noise, the following soundproofing measures have conventionally been taken. That is, at the connection between the frame where the vibration noise source is provided and the outer case,
A rubber material such as chloroprene rubber, butyl rubber, and natural rubber with a hardness of Hs 30 to 50 mm (JIS A), or a foamed material of this rubber material, or a vibration insulator called a bushing made of a foam material such as polyurethane foam is inserted. However, the vibration isolator blocks vibration from the gantry to reduce noise.
However, a rubber-made vibration isolator cannot provide a practically low hardness, and a low hardness rubber product filled with a large amount of oil has extremely large creep. Further, the vibration isolator made of a foam material has a large creep, and when a load is applied for a long period of time, so-called settling occurs and the elasticity is lost. As a result, the conventional vibration isolator had to be selected from either a material with an unnecessarily high elastic modulus or a material with a low elastic modulus and a spring constant that increased with time due to creep. Even with the material, the resonance frequency was high, and it was not possible to attenuate the vibration in the low frequency range, especially in the direction perpendicular to the mount. In addition, the vibration isolator 10 'conventionally called a bushing is
As shown in the figure, the bushing or grommet is provided between the holder 8 'provided in the outer casing 2' and the gantry 3 'and covers all the facing portions of these members. It had a power shape (hereinafter, this shape is called a grommet type). For this reason, stress concentrates near the intersection (represented by P in the figure) at the lower portion of the grommet type vibration isolator 10 ', so that even when used in combination with a material having a large vibration isolation effect, a sufficient vibration isolation effect is not necessarily obtained. I can't. Furthermore, in such a grommet type vibration isolator 10 ', there is a problem that the transmission of vibration in the horizontal plane direction of the gantry 3' is large.

<Technical matters attempted to be developed> The present invention has been made in view of such a background, and a material that can also attenuate vibration in a low frequency range is applied as a vibration isolator, and a part of the vibration isolator is used. An attempt was made to develop a soundproof structure in a coffee mill or the like having a structure that avoids stress concentration on the gantry and reduces the transmission of vibration in the horizontal direction of the gantry.

<< Structure of the Invention >><Means for Achieving the Object> The soundproofing structure in the coffee mill or the like according to the first invention of the present application involves directly or indirectly mounting a device serving as a vibration noise source on a support member thereof. In a holding structure in which a vibration isolator is interposed at the connection portion, the device serving as the vibration noise source is fixed to a pedestal having a connection hole,
Above and below this connection hole, a ring-shaped vibration isolator is provided so as to sandwich the gantry, while the support member is provided with a holder, and this holder is provided with the connection hole and the vibration isolator. The vibration isolator is provided so as to penetrate and not come into contact with the gantry, and is further arranged so as to form a space between the holding body and the gantry.

Further, the soundproofing structure in the coffee mill or the like according to the second invention according to the present application, in addition to the above requirements, of the ring-shaped vibration isolator provided so as to sandwich the gantry above and below the connection hole,
The upper vibration isolator is formed with a projection that fits into the connection hole, while the lower vibration isolator is flat.

Furthermore, the soundproofing structure in a coffee mill or the like according to the third invention according to the present application,
It is characterized by being made of silicone gel.

The present invention aims to achieve the above object.

<Function of the Invention> In the present invention, the device serving as a vibration noise source is fixed to a pedestal having a connection hole, and a ring-shaped vibration isolator is provided above and below the connection hole so as to sandwich the gantry. On the other hand, the support member includes a holding body, the holding body penetrates the connection hole and the vibration isolator, and is provided without being in contact with the gantry, and further includes the holding body, By taking a structure in which the vibration isolator is arranged so as to form a space between the gantry and the frame, a space is formed between the gantry and the holder, and transmission of vibration in the horizontal direction of the gantry is performed. The size can be reduced, and stress does not concentrate on a part of the vibration isolator.

Further, among the ring-shaped vibration isolators provided so as to sandwich the frame above and below the connection holes, the upper vibration isolators are formed with projections that fit into the connection holes, while the lower vibration isolators are formed. The flat shape facilitates positioning when the vibration isolator is attached to the gantry, and the projection is fixed to the connection hole, so that there is no deviation. Moreover, since the lower vibration isolator is flat, no stress is concentrated.

Furthermore, since the vibration isolator made of silicone gel has a resonance point with an extremely low frequency, transmission of vibration in a low frequency range in a direction perpendicular to the gantry can be greatly reduced.

<Example> Hereinafter, the present invention will be specifically described based on an illustrated example. FIG. 1 shows a structure in the vicinity of a motor M inside a coffee mill to which a soundproof structure in a coffee mill or the like according to the present invention is applied. In FIG. 1, reference numeral 1 denotes a soundproof structure in a coffee mill or the like according to the present invention. . This structure has a gantry 3 to which a motor M as a source of vibration and noise is fixed inside an outer box 2, and the gantry 3 is attached to a connection portion 4 provided inside the outer box 2. . Hereinafter, the side where the gantry 3 is attached to the outer box 2 will be defined as the upper side. The outer casing 2 is in a sealed state so that noise generated by rotation of the motor M, which is a vibration noise source, does not leak to the outside, and has a cylindrical support 5 formed inside. A support upper plate 6 is fixedly provided at an upper end portion of the support portion 5, and a holding cylinder 6 a as a holding body is formed upward from a center of the support upper plate 6. A female screw portion 6b is formed inside the holding cylinder 6a. A connecting portion 4 is provided between the holding cylinder 6a and the gantry 3 as a characteristic component of a soundproof structure in a coffee mill or the like according to the present invention. That is, the connection portion 4 is a portion where the gantry 3 is substantially connected to the outer box 2 via the support portion 5.
As a result, the vibration generated by the motor M fixed to the gantry 3 is attenuated to provide a soundproof effect. The structure of the connection part 4 is such that two ring-shaped vibration isolators in which the holding cylinder 6a penetrates the connection hole 3a formed in the gantry 3 and forms the hole part 11 in the center.
10 is provided so as to sandwich the gantry 3. Then, when the male screw portion 8a of the bolt 8 is screwed and tightened inside the holding cylinder 6a, the gantry 3 is fixed to the support portion 5 via the vibration isolator 10. In addition, the fixing structure of the connecting portion 4 may be a so-called stud bolt in which a screw portion 6c is further formed on the holding cylinder 6a as shown in FIG. 4 (a). 6d may be screwed and fixed, or the lower part of the holding cylinder 6a may be tapered as shown in FIG. 4 (b), and the rivet 9 may be fitted into the holding cylinder 6a. May be fixed. Further, as the bolt 8 in the embodiment shown in FIGS. 1 to 3, a self-tapping bolt as shown in FIG. 4 (c) may be applied. In the present invention, two upper and lower vibration isolators 10 are used with the frame 3 interposed therebetween. However, when the upper and lower vibration isolators are distinguished from each other, the upper vibration isolators 10a are used as the vibration isolators 10a. And the vibration isolator below the gantry 3 is designated as a vibration isolator 10b. Connection holes 3 formed in the gantry 3
Since a is set to be larger than the outer diameter of the holding cylinder 6a as a holding body, the edge of the connection hole 3a and the outer periphery of the holding cylinder 6a are supported when the gantry 3 is supported by being sandwiched between the vibration isolators 10. Surface is not in contact. Therefore, a space 12 is formed in a portion surrounded by both the vibration isolator 10 and the inner peripheral surface of the connection hole 3a and the outer peripheral surface of the holding cylinder 6a in the gantry 3. Incidentally, by forming the space portion 12 in this manner, the transmission of vibration of the gantry 3 in the horizontal direction can be reduced. Further, a protrusion 13 can be formed on the vibration isolator 10 as shown in FIG. That is, the projection 13 is provided around the hole 11 of the vibration isolator 10a located above the gantry 3, and is formed so as to fit into the connection hole 3a. By forming the projection 13 only on such an upper vibration isolator 10a, positioning when attaching the vibration isolator 10 to the gantry 3 is easy, and the projection 13 is fixed to the connection hole 3a. For,
There is no shift. Further, as a method of fixing the vibration isolator 10 to the gantry 3, as shown in FIG. 6, a groove 3b is formed around the connection hole 3a in the gantry 3, and the vibration isolator is fitted so as to fit into the groove 3b. The projection 13 may be formed on the body 10. Further, as the vibration isolator 10, a sheet-like one having a thickness of 1 to 30 mm can be applied. When the vibration isolator 10 is attached to the connection portion 4, it is used in a state where it is bent by 5 to 60% compared to the free state at the time of a static load. You. Further, the vibration isolator 10 may be used with its surface provided with irregularities as necessary, or covered with a thin plastic sheet, metal foil, or another foam material sheet. The motor M as a driving vibration source in this embodiment is first fixed on a common base 3 because of the axis alignment with a functional device driven by the motor M, and the base 3 is connected to another supporting member. In this case, the soundproof structure of the present invention is adopted. However, the present invention can be applied to a case where the motor M is directly mounted on the holding body without passing through such a gantry 3.

Next, the material of the vibration isolator 10 will be described. In this embodiment, a silicone gel is applied. By the way, if the vibration isolator 10 is made of silicone gel, the transmission of vibration in a low frequency range in the vertical direction with respect to the gantry 3 can be greatly reduced because the silicone gel has a very high damping property. The specific silicone gel used in this example is an addition-reaction type silicone gel comprising a vinylpolydimethylsiloxane component at both ends and a polyhydrogensiloxane component, and is crosslinked by a hydrosilylation reaction using a platinum-based catalyst as a catalyst.・ It is cured. The hardness of silicone gel is JI
SK-2207-1980 Penetration measured at 50 gr load is usually 5 to 5.
250, preferably in the range of 10 to 200 are used. Further, the silicone gel is obtained by directly reacting the above-mentioned gel raw material (hereinafter referred to as raw gel), or by hardening / crosslinking in a state in which open cells are sealed therein, or by mixing and dispersing particles that can be eluted such as salt. After hardening by hardening, the granules are eluted in water or the like to form trace pores (hereinafter referred to as porous gels), or raw gels or porous gels with fillers added . Examples of the filler to be added include general fillers such as organic and inorganic balloons, talc, mica, and lead powder, and metal, organic, and inorganic fibers and whiskers. Further, as the silicone gel to be used, a raw material composed of the above components may be prepared, but a commercially available silicone gel can also be used. Examples of such commercially available products include T-2, T-5, T-7, T-8 (Tore Dow Corning Silicone) and X32-902 / CAT58.
8, X32-902 / CAT1300 (Shin-Etsu Chemical Co., Ltd.) and the like. In this embodiment, the upper and lower vibration isolators 10 are used.
Both are composed of silicone gel,
The upper and lower vibration isolators 10 may be made of different materials, for example, one of the vibration isolators 10 may be made of silicone gel and the other of the vibration isolators 10 may be made of another material. . Incidentally, as such a combination, for example, an upper vibration isolator 10a made of chloroprene rubber is used, and a lower vibration isolator 10b made of silicone gel is used.

The soundproofing structure in the coffee mill and the like according to the present invention has the above-described structure. To confirm the effects of the present invention, the following three types of working samples and a conventional vibration isolator were used. Each type of comparative example was manufactured.

The three types of test samples used were coffee mills having a soundproof structure, and those incorporating the soundproof structure according to the present invention. Here, the structure of the coffee mill will be briefly described. A gantry 3 to which a motor M, a power transmission gear, and a mill for crushing coffee beans are fixed, and four support portions 5 for supporting the gantry 3 are formed inside. The connection part 4 between the gantry 3 and the support part 5 has a hardness Hs38 (JIS A), a grommet type shape, and a thickness of 2 mm.
In this case, the vibration isolator 10 made of chloroprene rubber is incorporated. This structure is the same as that shown in FIGS. 1 and 2 for one bearing 5.

[Execution sample I]

Using commercially available addition reaction type silicone gel raw material T-7 (Tore Dow Corning Silicone Co., Ltd.), gel hardness
A ring-shaped vibration isolator 10 of 110 (penetration), outer diameter 16 mm × inner diameter 6 mm × thickness 5 mm is manufactured, and this is replaced with the coffee mill vibration isolator. In this way, the working sample I in which the space 12 is formed around the holding cylinder 6a as the holding body is obtained. In addition, the vibration isolator 10 built in the lower part of the
30% compression on average due to the load received from

(Execution sample II)

Commercially available addition reaction type silicone gel raw material X-32-902 / CA
Using T-588 (manufactured by Shin-Etsu Chemical Co., Ltd.) and using porous gel having open cells inside (gel: bubble = 1: 1 by volume ratio), gel hardness 54 (penetration), Outer diameter 16mm ×
A ring-shaped vibration isolator 10b having an inner diameter of 6 mm and a thickness of 4 mm was manufactured and provided on the lower side of the gantry 3. On the other hand, a vibration isolator made of chloroprene rubber of a grommet type previously used in a coffee mill and a vibration isolator 10a cut in the horizontal direction at the center thereof were provided on the upper side of the gantry 3. still,
As a result, a working sample II in which the space 12 is formed only in the lower half around the holding cylinder 6a as the holding body is obtained. The vibration isolator 10 incorporated in the lower part of the gantry 3 is compressed on average by 25% by the load received from the gantry 3.

(Execution sample III)

A ring-shaped vibration isolator 10b manufactured using the porous gel used in the test sample II was provided on the lower side of the gantry 3. on the other hand,
A grommet type chloroprene rubber vibration isolator used in advance in the coffee mill and a chloroprene rubber vibration isolator 10a having the same shape as the vibration eliminator cut at the center in the horizontal direction. It was provided on the upper side.
Note that the state of the space 12 is the same as that of the sample II.

[Comparative Example I]

 The coffee mill was used as it was.

(Comparative Example II)

A ring-shaped vibration isolator 10b manufactured using the porous gel used in the test sample II was provided at the lower side of the gantry 3, and the shape used in the coffee mill was the same as that of the grommet type vibration isolator. The vibration body 10 was made of foamed chloroprene rubber, and was mounted on the vibration insulation body 10b.

<< Effects of the Invention >> The above Samples I to III and Comparative Examples I and II were placed in an anechoic box for noise measurement, and separated by 30 cm from the noise source by an integrated average sound level meter (NA-20 Rion Co., Ltd.). The vibration level (A characteristic) was measured at the position thus set. In addition, the absolute values of the test sample III and the comparative examples I and II were measured in an anechoic chamber. Table 1 shows the measurement results of the noise level.

As is clear from Table 1, the coffee mill to which the soundproof structure of the coher mill or the like according to the present invention is applied can reduce the noise level by 5 to 10 dB as compared with the conventional structure. This value is approximately 70 to the noise level of the conventional product.
This is equivalent to 90% noise reduction. Accordingly, the present invention is used as a soundproof structure for a coffee mill having a vibration noise source such as a motor and a speaker therein and a small household electric appliance having a vibration noise source such as a motor and a speaker therein, as well as a printer for audio equipment and OA equipment. By applying the soundproofing structure of the present invention, a high soundproofing effect can be obtained, and the noise does not impair the product image.

[Brief description of the drawings]

1 is a perspective view showing a soundproof structure in a coffee mill or the like of the present invention, FIG. 2 is a vertical sectional view of the same, FIG. 3 is an exploded perspective view of the same, and FIG. FIG. 5 is a longitudinal sectional view showing various embodiments, FIG. 5 is a longitudinal sectional view showing an embodiment in which the shape of a vibration isolator is changed, FIG. 6 is a longitudinal sectional view showing another embodiment, and FIG. It is a longitudinal section showing the soundproof structure in the conventional coffee mill etc. 1; soundproof structure in a coffee mill, etc. 2; outer box 3; gantry 3a; connection hole 3b; groove 4; connection 5; support 6; support upper plate 6a; holding cylinder (holding body) 6b; 6c; Thread 6d; Nut 7; Screw Hole 8; Bolt 8a; Male Thread 9; Rivet 10, 10a, 10b; Vibration Isolator 11; Hole 12; Space 13; Projection M; Motor

Claims (3)

(57) [Claims] When a device serving as a vibration noise source is directly or indirectly mounted on a support member thereof, the device serving as the vibration noise source is provided in a holding structure in which a vibration isolator is interposed at a connection portion between the two. Is fixed to a base with connection holes,
Above and below this connection hole, a ring-shaped vibration isolator is provided so as to sandwich the gantry, while the support member is provided with a holder, and this holder is provided with the connection hole and the vibration isolator. Wherein the vibration isolator is provided so as to penetrate and be in contact with the gantry, and further form a space between the holding body and the gantry. Construction. 2. A ring-shaped vibration isolator provided so as to sandwich a frame above and below said connection hole, a projection portion fitted into said connection hole is formed on an upper vibration isolator, and one lower portion is formed. The soundproofing structure in a coffee mill or the like according to claim 1, wherein the vibration isolator is flat. 3. The soundproof structure in a coffee mill or the like according to claim 1, wherein said vibration isolator is made of silicone gel.