JP6575619B2 - Electrical equipment - Google Patents

Description

  The present invention relates to a drive source, a driven device driven by the drive source, and an electric device including a housing, a cover, and the like.

  Various image forming apparatuses such as copiers, printers, facsimiles, or multifunction machines thereof, and electric devices such as projection display devices (including “electronic devices”; the same applies hereinafter) include driving sources such as motors and various actuators. And a driven device such as a fan, various rollers, a belt, a cam, and a polygon mirror driven by the driving source, a housing, an exterior cover, an interior cover, and an air duct.

  And when an electric device operates, sound is generated from its drive source and driven device. Such sounds are attracting attention, for example, in the case of an image forming apparatus, in which the discomfort is evaluated (Cited document 1). A Helmholtz silencer is often used for the purpose of reducing the sound generated from such an electric device.

  Here, an example of such a Helmholtz silencer is schematically shown in FIG. The Helmholtz silencer shown in FIG. 5 is a cylindrical shape having a hollow resonance box portion 20a, an opening having a diameter smaller than that of the inner space of the resonance box portion 20a at one end, and a tubular inner space communicating with the resonance box. And the neck portion 20b. Such a Helmholtz silencer reduces the sound of a specific frequency that enters the neck 20b. The derivation formula (1) for the frequency f is shown below.

  In equation (1), c is the speed of sound, S is the cross-sectional area of the neck, V is the volume of the resonance box, and L is the length of the neck. Δr is an open end correction, and generally a radius when the neck is circular is r, and 0.6r is used as Δr.

  As described above, a Helmholtz silencer can obtain a noise reduction effect without power consumption, and its use is proposed in Patent Document 2 relating to noise reduction of a photosensitive member driving unit of an image forming apparatus. However, in the case described in Patent Document 2, the actually obtained noise reduction effect was lower than expected.

  Moreover, in the example 30 of the conventional Helmholtz silencer (refer patent document 2) which shows an exploded view in FIG. 6, the some cylindrical protrusion part 31a provided by protruding from the plate-shaped part 31b of the outer side cover 31, A plurality of Helmholtz silencers are integrally formed by overlapping the inner cover 32 with a neck portion 32a provided at a position corresponding to the protruding portion 31a. With this configuration, this example is devised so that a plurality of Helmholtz silencers are formed without increasing the number of components.

  The inner cover 32 surface of the Helmholtz silencer 30 is installed, for example, so as to constitute a part of a wall of an air duct that is an air supply path by a motor-driven air fan of the projection display device. However, even in this example, the actually obtained noise reduction effect was lower than expected.

  Here, the projection display device is an electric device that projects an image on a screen in a presentation or a meeting, but usually includes a light emitting source with a large amount of light inside. The emission source generates a large amount of heat, and the exhaust noise from the fan that exhausts the heat to the outside of the device is large. Such a projection display device is often used in a quiet environment, and its quietness is desired.

  An object of the electrical device of the present invention is to solve the above-described conventional problem, that is, to provide an electrical device equipped with a Helmholtz silencer that is highly effective in reducing noise such as noise.

  In order to solve the above-described problems, an electrical device of the present invention includes, as described in claim 1, any one or more selected from a housing, an exterior cover, an interior cover, and an air duct, a drive source, An electrical apparatus having an apparatus member constituted by a driven apparatus driven by a drive source, comprising: a Helmholtz silencer including at least a resonance box and a neck having an opening at one end, the resonance box and the neck At least one of them is separated from the device member.

  The electrical device of the present invention has a Helmholtz silencer including at least a resonance box and a neck having an opening at one end thereof, and at least one of the resonance box and the neck is separated from the device member. It can be set as the electric equipment with the high sound reduction effect by a Helmholtz silencer.

It is a model figure which shows the state which attaches a Helmholtz silencer to the interior cover of an electric equipment. It is a model figure which shows an example of a Helmholtz silencer. It is a model figure which shows the cross section of the installation state of the Helmholtz silencer of FIG. It is a model figure which shows the cross section of the installation state of another Helmholtz silencer. It is a principle figure explaining the characteristic of the silencing effect by a Helmholtz silencer. It is a model figure which shows the example of the Helmholtz silencer of a prior art.

  When the present inventors examined the problems of the prior art, it was found that when the Helmholtz silencer is subjected to vibration, the effect of reducing sound such as noise is reduced. For example, in the technology described in Patent Document 2, a motor that is a vibration source and a noise source and an air fan are attached to an air duct in which a Helmholtz silencer is installed. For this reason, vibrations generated by the Helmholtz silencer are easily transmitted to the Helmholtz silencer. Therefore, it is difficult to obtain the original noise reduction effect of the Helmholtz silencer. The present invention has been conceived based on these findings.

  Here, examples of the device member that easily vibrates in the electronic device include a housing, an exterior cover, an interior cover, an air duct, a drive source, and a driven device driven by the drive source. Here, examples of the drive source include various motors and various actuators (solenoid actuators).

  Examples of the driven device include various rollers, various belts, gears, various link members, various fans, and the like. Here, the projection display device includes a fan as a driven device, and the image forming apparatus includes various rollers, various belts, gears, a fan, and the like.

  The housing is generally a box-like body that houses the electrical device itself or a part thereof. Examples of the exterior cover include a door, a lid, and an outer panel attached to the housing. The projection display apparatus and the image forming apparatus also have such a case and an exterior cover.

  The interior cover can be opened and closed by being provided inside the unit cover or the exterior cover that can be opened and closed when one or more of the device parts of the electrical device are combined into a unit. For example, a cover that covers the housing when the outer cover is opened. Here, in the case of an image forming apparatus, covers such as a developing unit, a fixing unit, a writing unit, a reading unit, and the like.

  The air duct is installed for the purpose of exhausting heat generated in the electrical equipment to the outside of the electrical equipment, or for collecting and removing ozone, dust, volatile organic compounds, and odors in the filter. Such an air duct is also provided in a projection display device and an image forming apparatus.

  FIG. 1 is an explanatory view showing a state in which a Helmholtz silencer 1 is attached to an interior cover 2 of an example (image forming apparatus) of an electrical apparatus of the present invention, FIG. 2 is an enlarged perspective view of the Helmholtz silencer 1, and FIG. The cross-sectional views in the plane including the neck 1c are shown.

  The Helmholtz silencer 1 is a composite type in which the upper surface portion 1b is fixed to the main body portion 1a with screws 1f, and has three Helmholtz silencers composed of a neck portion 1c and a resonance box portion 1e. It is a silencer. Each Helmholtz silencer has a different resonance box size and reduces sound of different frequencies. In addition, a space portion 1g is provided between the adjacent resonance box portions 1e so as not to interfere with each other's noise reduction effect.

  As can be understood from FIGS. 2 and 3, the Helmholtz silencer 1 has a leg portion that has a tip at a position away from the resonance box portion 1e and protrudes to the side opposite to the neck portion 1c side. There are four 1d in this example. And this Helmholtz silencer 1 is being fixed to the interior cover 2 of the electric equipment with the screw | thread 3 at the front-end | tip of these leg parts 1d. With such a configuration, the three resonance box portions 1 e and the neck portion 1 d of the Helmholtz silencer 1 are installed at positions separated from the interior cover 2. For this reason, vibration from the interior cover 2 is not easily transmitted to the resonance box part and the neck part, and the noise reduction effect of the Helmholtz silencer 1 is not easily disturbed by vibration.

  The noise reduction effect of the Helmholtz silencer decreases with increasing distance from the noise source.

  1-3, the Helmholtz silencer 1 is installed at a position closer to a noise source (not shown) than when the resonance box 1e is directly fixed to the interior cover 2 by the leg 1d. Therefore, a higher silencing effect can be obtained.

  Note that due to restrictions on the positional relationship between noise sources and other parts, the resonance box of the Helmholtz silencer is removed from the housing, exterior cover, interior cover, air duct, drive source, and driven equipment driven by the drive source. In some cases, there is not enough space for separation.

  Another example 4 of the Helmholtz silencer whose cross-sectional view is shown in FIG. 4 is a composite Helmholtz silencer having three Helmholtz silencers having different resonance box portions 1e as in the Helmholtz silencer 1. It is. A space portion 4g is provided between the resonance boxes 4e of the adjacent Helmholtz silencers as in the first example. In the vicinity of the two space portions 4g, the Helmholtz silencer 4 is installed on the interior panel 2 with screws 3 in a state of being separated from each other via a vibration damping material 5 made of an elastomer such as rubber. With such a configuration, propagation of vibration from the interior panel 2 to the resonance box 4e and the neck 4c of the Helmholtz silencer 4 can be reduced, and the silencing effect can be prevented from being hindered.

  Although the present invention has been described with reference to the preferred embodiment, the electric device of the present invention is not limited to the configuration of the above embodiment.

  A person skilled in the art can appropriately modify the electrical device of the present invention in accordance with conventionally known knowledge. Of course, such modifications are included in the scope of the present invention as long as the configuration of the electric apparatus of the present invention is provided.

JP 2007-205727 A JP 2003-43861 A JP 2007-47560 A

Claims (7)

In an electrical device having a drive source, a driven device driven by the drive source, and a device member provided with a cover that covers the drive source and the driven device,
Helmholtz silencer comprising a plurality of box portions (20a) forming an internal space, an opening having a smaller diameter than the internal space of the box portion, and a space portion (4g) formed between the plurality of box portions And
The Helmholtz silencer and the cover are configured separately, and have a damping material (5) provided between the space part (4g) of the Helmholtz silencer and the cover ,
The Helmholtz silencer is installed in the cover via the damping material (5) in a state of being separated from the cover .   The electric device according to claim 1, wherein the opening is formed by a neck portion which is a separate member from the box portion.   The electric device according to claim 1, wherein the damping material is rubber.   The electric device according to any one of claims 1 to 3, wherein the Helmholtz silencer is fixed to the cover with a screw through the damping material.   The said Helmholtz silencer is formed in multiple numbers, The said one opening part is formed with respect to one internal space which the said box part forms, The Claim 1 characterized by the above-mentioned. Electrical equipment. An image forming apparatus including an electrical device according to any one of claims 1 5. Projection display device equipped with electric apparatus according to any one of claims 1 5.

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