JP2008199692A - Noise reducing member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a noise reducing member having a saved space and capable of highly efficiently reducing a noise of a motor or a pair of gears. <P>SOLUTION: In a noise reducing bracket 60, a space is formed by a first plate-like member 61, a second plate-like member 62 and an occluding member 65. A plurality of through holes 71 are provided on the first plate-like member 61 so as to communicate with the space facing the pair of gears 30, 40. The through holes 71 allows to form an air layer by the space formed with the first plate-like member 61, the second plate-like member 62 and the occluding member 65. Also, the through holes 71 provided on the first plate-like member 61 and the air layer work as a resonator, and the noise of the pair of gears 30, 40 can be reduced. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a noise reduction member that reduces noise generated by a motor and a pair of gears that transmit the rotational force of the motor.

  High-speed rotating motors and gears are used in DVD (Digital Versatile Disc), AV (Audio Visual) equipment, HDD (Hard Disk Drive), OA (Office Automation) equipment, and the like.

  In recent years, by further increasing the speed of rotation of these motors and gears, high performance and high functionality of AV and OA devices have been realized. However, the increase in vibration caused by this has deteriorated the reading accuracy of DVD. This leads to an increase in noise generated from the equipment. For this reason, it is desired to reduce vibration noise caused by a motor rotating at high speed.

  In particular, there is noise caused not only by the motor but also by the engagement of gears. The noise due to the meshing of the gears is caused by the excitation force due to the contact between the teeth of the pair of gears. As countermeasures for reducing the gear noise itself, there is a gear tooth profile correction and the like, but there is a limit to the improvement of the tooth profile size, and development of a further method for reducing gear noise is desired.

  For example, Patent Document 1 discloses an image carrier driving unit capable of reducing noise and an image forming apparatus using the image carrier driving unit. According to the image carrier driving unit and the like disclosed in Patent Document 1, a new resonator is provided to reduce noise generated in the rotation of the motor and the gear portion, thereby realizing noise reduction.

Patent Document 2 discloses a laser printer apparatus that can reduce noise in the gear portion. According to the laser printer device disclosed in Patent Document 2, a noise reduction cover and a silencer that encloses the gear portion are newly provided to reduce the noise of the gear portion.
JP 2002-244380 A Japanese Patent Laid-Open No. 04-000469

  However, in any of the devices described in Patent Document 1 and Patent Document 2, it is necessary to newly provide a resonator, a large soundproof cover, a silencer, etc., and there is a problem that it cannot be applied to a structure having a small space. It was.

  Further, since the noise of the motor and gear spreads radially as a point sound source, there is a problem that when the sound is silenced by the resonator, the position near the sound source and the sound absorbing surface must be enlarged as much as possible.

  The objective of this invention is providing the noise reduction member which can reduce the noise of a motor and / or a pair of gears efficiently in space-saving.

  Another object of the present invention is to reduce the space and cost by a simple structure and to improve the efficiency by increasing the sound absorption area, and to install as close as possible to the noise source of the motor and / or a pair of gears. It is providing the noise reduction member which can do.

(1)
A noise reduction member according to the present invention is a noise reduction member provided to reduce noise caused by a motor or a pair of gears that transmit a rotational force from the motor, and the noise reduction member includes a motor and a pair of gears. Between the first plate member disposed so as to face at least one of the first plate member and a plurality of through-holes, and disposed in parallel with the first plate member. And a second plate member capable of forming a space.

  In the noise reduction member according to the present invention, a space is formed by the first plate member and the second plate member, and the plurality of through holes of the first plate member face at least one of the motor and the pair of gears. It is arranged as follows.

  In this case, the space (air layer) formed by the first plate member and the second plate member and the plurality of through holes provided in the first plate member function as a resonator, and the motor or the pair of gears. Noise can be reduced. That is, when sound waves are incident, resonance occurs between the air in the plurality of through holes and the internal space (air layer), and the air in the through hole vibrates violently. As a result, frictional damping occurs on the wall surface of the through hole, and sound energy is converted to heat energy, thereby reducing sound.

(2)
The first plate member may be disposed to face the motor.

  In this case, since the plurality of through holes form a large sound absorbing surface, the noise of the motor can be suitably reduced.

(3)
The first plate member may be disposed to face the pair of gears.

  In this case, since the plurality of through holes form a large sound absorbing surface in this case, the noise of the pair of gears can be suitably reduced.

(4)
The aperture ratio of the through hole of the first plate member, the hole diameter of the through hole of the first plate member, the plate thickness of the first plate member, and the distance between the parallel members of the first plate member and the second plate member are the aperture ratio of the through hole. Is β, the hole diameter of the through hole is d, the plate thickness of the first plate member is t, the distance between the parallel members of the first plate member and the second plate member is L, and the speed of sound is c, It is preferable that the design frequency f0 determined in (2) is designed so as to match or approximate the noise frequency f of the motor or the pair of gears.

  In this case, since the design frequency f0 is designed to match or approximate the noise frequency f of the motor or the pair of gears, the noise of the motor or the pair of gears can be most effectively reduced. In particular, since the noise of the motor or the pair of gears has a single frequency, the single frequency can be reduced, and the noise can be reliably reduced.

(5)
The space formed by the first plate member and the second plate member further includes one or more core members provided substantially orthogonal to the first plate member and the second plate member, and the one or more core members are motors And / or may be provided at an interval of less than half the wavelength of the noise frequency f of the pair of gears.

  In this case, by providing the core material at an interval of less than half the wavelength of the noise frequency f, the sound wave can easily travel perpendicular to the first plate member, so that the resonance effect can be improved. As a result, noise reduction can be suitably achieved.

(6)
The first plate member and the second plate member may be provided in a space region between the motor and the pair of gears.

  In this case, the noise of at least one of the motor and the pair of gears can be efficiently reduced. In addition, an empty space (dead space) inevitably generated in design between the motor and the pair of gears can be effectively used. As a result, space saving can be achieved.

(7)
The third plate member may further include a third plate member disposed in parallel to the first plate member, and the third plate member may be provided with a plurality of through holes.

  In this case, in addition to the plurality of through holes in the first plate member, a plurality of through holes in the third plate member are formed. A plurality of spaces (air layers) are formed by the first plate member, the second plate member, and the third plate member. As a result, it acts as a resonator for a plurality of frequencies, and a plurality of noises can be reduced. That is, the noise of the motor or the pair of gears can be more reliably reduced.

(8)
The third plate member may be provided in a space formed between the first plate member and the second plate member, and the space may be divided into a plurality.

  In this case, a plurality of spaces (air layers) can be provided between the first plate member and the second plate member, and a resonator having a plurality of resonance frequencies can be formed. Thereby, a plurality of noises can be reduced efficiently.

(9)
The third plate member is provided in a direction different from the first plate member provided to face the second plate member, and the second plate has a space different from the space formed by the first plate member and the second plate member. You may form with a member and a 3rd board member. That is, you may provide a 3rd board member on the opposite side (opposite side) with respect to a 1st board member centering on a 2nd board member.

  In this case, apart from the space (air layer) formed by the first plate member and the second plate member, a separate space (air layer) can be provided by the second plate member and the third plate member. As a result, a resonator facing each of the motor and the pair of gears can be formed, and a plurality of noises of the motor and the pair of gears can be simultaneously reduced. Specifically, the first plate member is opposed to the pair of gears, and the third plate member is opposed to the motor, or vice versa, thereby efficiently reducing a plurality of noises of the motor and the pair of gears. be able to.

(10)
The third plate member is provided in a different direction from the second plate member disposed to face the first plate member, and the first plate has a space different from the space formed by the first plate member and the second plate member. You may form with a board member and a 3rd board member. That is, you may provide a 3rd board member on the opposite side (opposite side) with respect to a 2nd board member centering on a 1st board member.

  In this case, apart from the space (air layer) formed by the first plate member and the second plate member, a separate space (air layer) can be provided by the first plate member and the third plate member. As a result, a resonator specialized for one of the motor and the pair of gears can be formed, and noise can be reliably reduced.

(11)
The third plate member may be composed of one or a plurality of plate members.

  In this case, a resonator having a plurality of resonance frequencies can be provided. As a result, it is possible to simultaneously reduce a plurality of noises having a plurality of frequencies.

(12)
A plurality of spaces formed by the first plate member, the second plate member, and the third plate member to match or approximate the noise frequency of the motor and / or the pair of gears, and the first plate member and the third plate member A resonator having a plurality of degrees of freedom resonance system may be equivalently formed by the plurality of through holes formed by the above.

  In this case, by setting the third plate member to N sheets via a plurality of spaces (air layers), N air masses in the through holes and N + 1 springs due to the plurality of spaces (air layers) A resonance system with N + 1 degrees of freedom can be formed, and N + 1 frequencies can be absorbed.

  As a result, a resonator that matches or approximates the noise frequency of the motor and / or the pair of gears can be formed by changing each parameter such as the size of the space (air layer) and the diameter of the plurality of through holes. Noise can be reduced reliably.

(13)
One or more provided at least partially in the plurality of spaces formed by the first plate member, the second plate member, and the third plate member so as to be substantially orthogonal to the first plate member, the second plate member, and the third plate member. The one or more core members may be provided at an interval of less than half the wavelength of the noise frequency f of the motor and / or the pair of gears.

  In this case, by providing the core material at an interval of less than ½ of the wavelength of the noise frequency f, the sound wave can easily travel perpendicularly to the first plate member and / or the third member, thereby improving the resonance effect. Can do. As a result, noise reduction can be suitably achieved.

(14)
An occluding member may be further included, and the occluding member may be disposed so that at least one of the plurality of spaces can be sealed.

  In this case, the space (air layer) formed by the first plate member and the second plate member can be a sealed space, and is formed by the first plate member, the second plate member, and the third plate member. The space (air layer) can be a sealed space. Thereby, the diffusion of sound in the air layer can be further prevented, and the noise of the motor and the pair of gears can be reliably reduced. In addition, even if it is not completely sealed, noise can be basically reduced, but noise can be surely reduced by completely sealing.

(15)
The first plate member, the second plate member, and the third plate member may be provided in a space region between the motor and the pair of gears.

  In this case, the noise of either the motor or the pair of gears, or the noise of the motor and the pair of gears can be efficiently reduced at the same time. In addition, an empty space (dead space) inevitably generated in design between the motor and the pair of gears can be effectively used. As a result, space saving can be achieved.

(16)
The closing member may have a bracket function provided to support at least one of the motor and / or the pair of gears.

  In this case, since the closing member has a bracket function, the bracket that holds the motor and / or gear is provided with the function of a resonator. Therefore, a large sound absorbing surface by the resonator can be arranged near the sound source without providing a new resonator. As a result, the noise of the motor and / or the pair of gears can be efficiently reduced in a space-saving manner.

(17)
The closing member may have a cover function provided so as to surround at least one of the pair of gears and / or the motor.

  In this case, since the closing member has a cover function, the function of the resonator is provided in the cover surrounding the pair of gears. Therefore, a large sound absorbing surface by the resonator can be arranged near the sound source without providing a new resonator. As a result, the noise of the motor and / or the pair of gears can be efficiently reduced in a space-saving manner.

  Embodiments according to the present invention will be described below. Hereinafter, a drive device including a noise reduction bracket in the first to fourth embodiments will be described as an example of the noise reduction member according to the present invention, and a noise reduction cover in the fifth to eighth embodiments. An example of a drive device including

(First embodiment)
FIG. 1 is a schematic cross-sectional view showing an example of a drive device 100 using the noise reduction bracket according to the first embodiment.

  1 includes a motor 10, a drive shaft 20, a pair of gears 30 and 40, a transmission shaft 50, and a noise reduction bracket 60.

  The noise reduction bracket 60 has a support portion (not shown) that supports the motor 10 and is disposed so as to surround the motor 10. Furthermore, it includes a first plate member 61 having a plate shape, a second plate member 62 having a plate shape, and a closing member 65 for connecting the peripheral edges of the first plate member 61 and the second plate member 62. In addition, the surrounding in this invention means the state of enclosing or covering, and is not limited to what surrounds the whole, The state of enclosing or covering a part is also included.

  The first plate member 61 and the second plate member 62 are disposed substantially parallel to each other at a distance L1. Both the first plate member 61 and the second plate member 62 may be made of various other arbitrary materials such as a metal such as iron or aluminum or a resin. The first plate member 61 and the second plate member 62 are preferably made of the same material. Further, the closing member 65 is preferably made of the same material as the first plate member 61 and the second plate member 62.

  Thus, a space is formed by the first plate member 61, the second plate member 62, and the closing member 65. Hereinafter, this space is called an air layer.

  As shown in FIG. 1, the first plate member 61 is disposed to face the pair of gears 30 and 40, and is provided with a plurality of through holes 71. Thereby, the periphery of the pair of gears 30 and 40 communicates with the air layer via the plurality of through holes 71.

  In the first embodiment, for example, the plate thickness t1 of the first plate member 61 is not less than 0.3 mm and not more than 3 mm, and the plate thickness t2 of the second plate member 62 is not less than 0.3 mm and not more than 3 mm. The plate thickness t5 of the member 65 is not less than 0.3 mm and not more than 3 mm, the hole diameter (diameter φ) d1 of the through hole 71 provided in the first plate member 61 is not less than 0.3 mm and not more than 15 mm, and the first plate member The opening ratio β1 of the through hole provided in 61 is 0.1% or more and 10% or less, and the distance L1 between the parallel members between the first plate member 61 and the second plate member 62 is 1 mm or more and 50 mm or less.

  Next, the operation of the driving device 100 in FIG. 1 will be described. As the motor 10 rotates, the drive shaft 20 rotates. Accordingly, the gear 30 provided on the drive shaft 20 rotates, and at the same time, the gear 40 provided so as to mesh with the gear 30 rotates dependently. Thereby, the transmission shaft 50 provided in the gear 40 rotates. In this case, a motor 10 sound is generated from the motor 10, and a gear sound is generated in the pair of gears 30 and 40 due to the meshing of the teeth of each other.

  Here, in the first embodiment, a case is considered in which the gear noise is larger than the noise of the motor 10 and the gear noise is reduced. Each parameter is set so that the design frequency f0 satisfying the following expression is obtained with respect to the frequency f of the gear noise.

ここで、β１は第１板部材６１の貫通孔の開口率を示し、ｄ１は第１板部材６１の貫通孔の孔径を示し、ｔ１は第１板部材６１の板厚を示し、Ｌ１は第１板部材６１および第２板部材６２の並行部材間距離を示し、ｃは音速を示す。

Here, β1 indicates the aperture ratio of the through hole of the first plate member 61, d1 indicates the diameter of the through hole of the first plate member 61, t1 indicates the plate thickness of the first plate member 61, and L1 indicates the first thickness. The distance between the parallel members of the first plate member 61 and the second plate member 62 is indicated, and c indicates the speed of sound.

  Thus, since the design frequency f0 is provided so as to match or approximate the gear noise frequency f, the gear noise can be reduced.

  That is, the air mass in the plurality of through holes formed in the first plate member 61 forms a virtual mass system, and the air layer formed by the first plate member 61, the second plate member 62, and the closing member 65. Forms a virtual spring system. Therefore, a one-degree-of-freedom resonance system can be formed in the vicinity of the pair of gears 30 and 40.

  The virtual mass m is determined by the thickness t1 of the first plate member 61, the hole diameter φd1 of the plurality of through holes 71, the opening ratio β1, and the air density ρ. The virtual spring system k includes the parallel member distance L1, air It is determined by density ρ and sound speed c.

  Therefore, by adjusting the parameters of the virtual mass m and the virtual spring system k, a resonator that matches or approximates the resonance frequency of the noise of the pair of gears 30 and 40 can be formed. Therefore, when the noise of the pair of gears 30 and 40 enters the air layer through the plurality of through holes 71, a resonance phenomenon occurs and the sound is absorbed.

  As described above, in the noise reduction bracket 60 according to the first embodiment, an air layer is formed by the space formed by the first plate member 61, the second plate member 62, and the closing member 65, and the first plate Together with the plurality of through holes 71 provided in the member 61, it acts as a resonator, and the noise of the pair of gears 30 and 40 can be reduced.

  Moreover, since the several through-hole 71 is provided facing a pair of gears 30 and 40, a big sound absorption surface can be formed and the noise of a pair of gears 30 and 40 can be reduced suitably.

  Furthermore, in the noise reduction bracket 60 according to the first embodiment, a noise can be reduced by providing a resonator in the bracket that holds the motor 10, so that the motor 10 can be provided without newly providing a resonator or the like. The noise reduction bracket 60 having a large sound absorbing surface in the vicinity of the sound source can be disposed in an empty space (dead space) inevitably generated in design between the gear 30 and the pair of gears 30 and 40. As a result, the noise of the motor 10 or the pair of gears 30 and 40 can be efficiently reduced in a space-saving manner.

  Further, as described above, the design frequency f0 set by the parameters such as the thickness L1 of the air layer and the diameter d1 of the plurality of through holes 71 of the first plate member 61 coincides with the noise frequency f of the pair of gears 30 and 40. Or since it is provided so that it may approximate, the noise of a pair of gears 30 and 40 can be reduced most effectively. In particular, since the noise of the pair of gears 30 and 40 has a single frequency, the single frequency can be reduced by the configuration of the plurality of through holes 71 and the air layer, and the noise can be reliably reduced. .

  In the above embodiment, the first plate member 61, the second plate member 62, and the closing member 65 are configured as separate members. However, the present invention is not limited to this, and the first plate member 61, the second plate are not limited thereto. Any one or more or all of the member 62 and the closing member 65 may be formed from one member.

(Second Embodiment)
Next, the driving device 100a according to the second embodiment will be described. FIG. 2 is a schematic cross-sectional view showing an example of a drive device 100a using the noise reduction bracket according to the second embodiment.

  The driving device 100a according to the second embodiment is different from the driving device 100 according to the first embodiment in the following points.

  The drive device 100a according to the second embodiment includes a noise reduction bracket 60a instead of the noise reduction bracket 60 of the drive device 100 according to the first embodiment. The noise reduction bracket 60 a further includes one or more third plate members 63 in the noise reduction bracket 60. In the second embodiment, a case where there is one third plate member 63 will be described.

  The third plate member 63 is provided between the first plate member 61 and the second plate member 62. The third plate member 63 may be made of various other materials such as a metal such as iron or aluminum or a resin. In addition, it is preferable that the material of the 1st board member 61, the 2nd board member 62, and the 3rd board member 63 consists of the same raw material. The closing member 65 is preferably made of the same material as the first plate member 61, the second plate member 62, and the third plate member 63.

  As shown in FIG. 2, the space surrounded by the first plate member 61, the third plate member 63 and the closing member 65, and the space surrounded by the third plate member 63, the second plate member 62 and the closing member 65 The two air layers are formed.

  A plurality of through holes 71 are formed in the first plate member 61, and a plurality of through holes 73 are also formed in the third plate member 63. Accordingly, the periphery of the gears 30 and 40 communicates with the air layer surrounded by the third plate member 63 and the first plate member 61 through the plurality of through holes 71, and the second through the plurality of through holes 73. The air layer surrounded by the plate member 62 and the third plate member 63 communicates with the air layer.

  In the second embodiment, for example, the plate thickness t1 of the first plate member 61 is not less than 0.3 mm and not more than 3 mm, the plate thickness t2 of the second plate member 62 is not less than 0.3 mm and not more than 3 mm, The plate thickness t3 of the three plate members 63 is not less than 0.3 mm and not more than 3 mm, the plate thickness t of the closing member 65 is not less than 0.3 mm and not more than 3 mm, and the diameter of the through hole 71 provided in the first plate member 61 ( The diameter φ) d1 is not less than 0.3 mm and not more than 15 mm, and the opening ratio β1 of the through hole provided in the first plate member 61 is not less than 0.1% and not more than 10%, and is provided in the third plate member 63. The through hole has a hole diameter (diameter φ) d3 of not less than 0.3 mm and not more than 15 mm, and an opening ratio β3 of the through hole provided in the third plate member 63 is not less than 0.1% and not more than 10%. The distance L2 between the parallel members between the plate member 62 and the third plate member 63 is 1 mm or more. And at 0mm or less, parallel members distance L3 between the first plate member 61 and the third plate member 63 is 1mm or more 50mm or less.

  In the second embodiment, similar to the first embodiment, the noise of the pair of gears 30 and 40 is larger than the noise of the motor 10, and the noise of the pair of gears 30 and 40 is reduced. Consider the case of reduction.

  That is, air masses in the plurality of through holes 71 formed in the first plate member 61 form a virtual mass system m1, and air masses in the plurality of through holes 73 formed in the third plate member 63 A virtual mass system m3 is formed, and an air layer formed by the second plate member 62, the third plate member 63, and the closing member 65 forms a virtual spring system k23, and the first plate member 61, the third plate The air layer formed by the plate member 63 and the closing member 65 forms a virtual spring system k13. Therefore, a two-degree-of-freedom resonance system can be formed in the vicinity of the pair of gears 30 and 40.

  The virtual mass m1 is determined by the thickness t1 of the first plate member 61, the hole diameter φd1 of the plurality of through holes 71, the aperture ratio β1, and the air density ρ. The virtual mass m3 is the thickness t3 of the third plate member 63. The virtual spring system k23 is determined by the distance L2 between the parallel members, the air density ρ, and the sound velocity c, and the virtual spring system k13 is , Determined by the distance L3 between the parallel members, the air density ρ, and the speed of sound c.

  Therefore, by adjusting the parameters of the virtual masses m1 and m3 and the virtual spring systems k23 and k13, the frequency of noise of not only the pair of gears 30 and 40 but also other adjacent gears (not shown). It is possible to form a resonator having a plurality of resonance frequencies that match or approximate. Therefore, noises of other frequencies generated by the pair of gears 30 and 40 and other gears are absorbed by the resonance phenomenon in the air and air layers of the plurality of through holes 71 and 73.

  As described above, in the noise reduction bracket 60a according to the second embodiment, two spaces are formed by the space formed by the first plate member 61, the second plate member 62, the third plate member 63, and the closing member 65. An air layer is formed, and combined with the plurality of through holes 71 and the plurality of through holes 73, acts as a resonator having a plurality of resonance frequencies, and effectively reduces noise of the pair of gears 30, 40 and other gears. can do.

  Further, since the plurality of through holes 71 and the plurality of through holes 73 are provided so as to face the pair of gears 30 and 40, a large sound absorbing surface is formed to suitably reduce the noise of the pair of gears 30 and 40. Can do.

  Furthermore, in the noise reduction bracket 60a according to the second embodiment, a resonator having a plurality of resonance frequencies can be provided on the bracket that holds the motor 10, so that noise can be reduced. Without being provided, it is possible to dispose the noise reduction bracket 60a having a large sound absorbing surface in the vicinity of the sound source in an empty space (dead space) which is unavoidably generated due to the design between the motor 10 and the pair of gears 30 and 40. it can. As a result, the noise of the motor 10 or the pair of gears 30 and 40 can be efficiently reduced in a space-saving manner.

  The design frequency f0 set by parameters such as the air layer thicknesses L2 and L3 and the diameters of the plurality of through holes 71 and 73 is the noise frequency f of the pair of gears 30 and 40 and the noise of other adjacent gears. Since it is provided so as to match or approximate the frequency f2, the noise of the pair of gears 30 and 40 and the adjacent gear can be reduced.

In the above embodiment, the first plate member 61, the second plate member 62, the third plate member 63, and the closing member 65 are configured as separate members. However, the present invention is not limited to this, and the first plate Any one or more of the member 61, the second plate member 62, the third plate member 63, and the closing member 65 may be formed from a single member.
Further, although the closing member 65 may seal only one of the two air layers, it is preferable to seal the two air layers.

(Third embodiment)
Next, a driving device 100b according to a third embodiment of the present invention will be described. FIG. 3 is a schematic cross-sectional view showing an example of a drive device 100b using the noise reduction bracket according to the third embodiment. The driving device 100b according to the third embodiment is different from the driving device 100 according to the first embodiment in the following points.

  The third embodiment includes a noise reduction bracket 60b instead of the noise reduction bracket 60 of the drive device 100 according to the first embodiment. As shown in FIG. 3, the noise reduction bracket 60 b includes a first plate member 61 provided on the motor 10 side, and a plurality of through holes 71 are formed in the first plate member 61. Accordingly, the periphery of the motor 10 communicates with the air layer surrounded by the first plate member 61, the second plate member 62, and the closing member 65 through the plurality of through holes 71.

  In the third embodiment, for example, the plate thickness t1 of the first plate member 61 is not less than 0.3 mm and not more than 3 mm, and the plate thickness t2 of the second plate member 62 is not less than 0.3 mm and not more than 3 mm. The plate thickness t of the member 65 is not less than 0.3 mm and not more than 3 mm, and the diameter d1 of the through hole 71 provided in the first plate member 61 is not less than 0.3 mm and not more than 15 mm, and is provided in the first plate member 61. The opening ratio β1 of the through holes is 0.1% or more and 10% or less, and the distance L4 between the parallel members between the first plate member 61 and the second plate member 62 is 1 mm or more and 50 mm or less.

  In the third embodiment, unlike the first embodiment, the case where the noise of the motor 10 is larger than the gear noise and the noise of the motor 10 is reduced is considered. Accordingly, the design frequency f0 is provided so as to match or approximate the noise frequency f of the motor 10 (see Equation 3).

  That is, a mass of air in the plurality of through holes 71 formed in the first plate member 61 forms a virtual mass system m1, and an air layer formed by the first plate member 61 and the second plate member 62 is virtual. A typical spring system k1 is formed. Therefore, a one-degree-of-freedom resonance system can be formed in the vicinity of the motor 10.

  The virtual mass m1 is determined by the thickness t1 of the first plate member 61, the hole diameter φd1 of the plurality of through holes 71, the opening ratio β1, and the air density ρ. The virtual spring system k1 includes the distance L4 between the parallel members, the air It is determined by density ρ and sound speed c.

  Therefore, by adjusting the parameters of the virtual mass m1 and the virtual spring system k1, a resonator that matches or approximates the resonance frequency of the noise of the motor 10 can be formed. Therefore, when the noise of the motor 10 enters the air layer through the plurality of through holes 71, a resonance phenomenon occurs and the sound is absorbed.

  As described above, in the noise reduction bracket 60b according to the third embodiment, an air layer is formed by the space formed by the first plate member 61, the second plate member 62, and the closing member 65, and the first plate Together with the plurality of through holes 71 provided in the member 61, it acts as a resonator, and the noise of the motor 10 can be reduced.

  Moreover, since the several through-hole 71 is provided facing the motor 10, a big sound absorption surface can be formed and the noise of the motor 10 can be reduced suitably.

  Further, in the noise reduction bracket 60b according to the present invention, a noise can be reduced by providing a resonator in the bracket that holds the motor 10, so that the motor 10 and the pair of gears can be provided without newly providing a resonator or the like. It is possible to dispose a noise reduction bracket 60b having a large sound absorbing surface in the vicinity of the sound source in an empty space (dead space) that is unavoidably generated due to the design between 30 and 40. As a result, the noise of the motor 10 can be efficiently reduced in a space-saving manner.

  Further, the design frequency f0 set by each parameter such as the air layer thickness L4 and the diameters of the plurality of through holes 71 of the first plate member 61 is provided so as to match or approximate the noise frequency f of the motor 10. The noise of the motor 10 can be reduced most effectively. In particular, since the noise of the motor 10 has a single frequency, the single frequency can be reduced by the configuration of the plurality of through holes 71 and the air layer, and the noise can be reliably reduced.

  In the above embodiment, the first plate member 61, the second plate member 62, and the closing member 65 are configured as separate members. However, the present invention is not limited to this, and the first plate member 61, the second plate are not limited thereto. Any one or more or all of the member 62 and the closing member 65 may be formed from one member.

(Fourth embodiment)
Next, a driving apparatus 100c according to a fourth embodiment of the present invention will be described. FIG. 4 is a schematic cross-sectional view showing an example of a drive device 100c using the noise reduction bracket according to the fourth embodiment.

  The driving device 100c according to the fourth embodiment is different from the driving device 100 according to the first embodiment in the following points.

  The noise reduction bracket 60 c of the fourth embodiment further includes a core member 80 in addition to the first noise reduction bracket 60.

  The first plate member 61, the second plate member 62, and the core member 80 may all be made of various other materials such as a metal such as iron or aluminum or a resin. The first plate member 61, the second plate member 62, and the core member 80 are preferably made of the same material.

  The core member 80 is provided so as to divide the air layer formed by the first plate member 61 and the second plate member 62 into a plurality of pieces. As shown in FIG. 4, the core member 80 in the present embodiment is provided substantially perpendicular to the cross sections of the first plate member 61 and the second plate member 62.

  As shown in FIG. 4, the first plate member 61 is provided with a plurality of through holes 71 on the surface with respect to the gears 30 and 40. Thereby, the periphery of the gears 30 and 40 communicates with each air layer partitioned by the core member 80 through the plurality of through holes 71.

  In the fourth embodiment, for example, the plate thickness t1 of the first plate member 61 is not less than 0.3 mm and not more than 3 mm, the plate thickness t2 of the second plate member 62 is not less than 0.3 mm and not more than 3 mm, The hole diameter (diameter φ) d1 of the through hole provided in the first plate member 61 is 0.3 mm or more and 15 mm or less, and the opening ratio β1 of the through hole provided in the first plate member 61 is 0.1% or more and 10 %, The plate thickness t8 of the core member 80 is not less than 0.3 mm and not more than 3 mm, the distance L5 between the parallel members between the first plate member 61 and the second plate member 62 is not less than 1 mm and not more than 50 mm, The arrangement interval L8 of 80 is 1 mm or more and 50 mm or less.

  Then, the formation method of the core material 80 is demonstrated. FIG. 5 is a diagram showing an example of a manufacturing method of the noise reduction bracket 60c shown in FIG. FIG. 5A shows a case where an air layer is formed by using the core member 80 as a separate member as shown in FIG. 4, and FIGS. 5B and 5C show 2 in which a plurality of through holes 71 are already formed. The case where the core material 80 is formed by bending a single metal plate by pressing is shown.

  As shown in FIG. 5A, when the core member 80 is newly provided in the bracket 60c, it is necessary to employ a method such as adhesion, which is troublesome and tends to increase the manufacturing cost.

  However, as shown in FIG. 5 (b), the direction of the arrow X2 with respect to the dual-structure plate member in which the first plate member 61 has a plurality of through holes 71 and the second plate member 62 is formed. Thus, the core member 80 can be easily formed by pressing the first plate member 61.

  Similarly, as shown in FIG. 5C, a double-structure plate member in which a plurality of through holes 71 are formed in the first plate member 61 and the second plate member 62 is formed is indicated by an arrow X3. The core member 80 may be easily formed by pressing the second plate member 62 in the direction.

  As a result, the core member 80 can be easily formed on the first plate member 61 and the second plate member 62.

  In the fourth embodiment, similar to the first embodiment, the noise of the pair of gears 30 and 40 is larger than the noise of the motor 10, and the noise of the pair of gears 30 and 40 is reduced. Consider the case of reduction. Therefore, similarly to the first embodiment, the design frequency f0 is provided so as to match or approximate the noise frequency f of the pair of gears 30 and 40 (see Equation 3).

  That is, a mass of air in the plurality of through holes 71 formed in the first plate member 61 forms a virtual mass system m1, and is formed by the first plate member 61, the second plate member 62, and the core member 80. The air layer forms a virtual spring system k81. The virtual mass m1 is determined by the thickness t1 of the first plate member 61, the hole diameter φd1 of the plurality of through holes 71, the opening ratio β1, and the air density ρ. The virtual spring system k8 includes the distance L5 between the parallel members, the core It is determined by the arrangement interval L8 of the material 80, the air density ρ, and the sound velocity c.

  Therefore, by adjusting the parameters of the virtual mass m1 and the virtual spring system k8, a resonator that matches or approximates the resonance frequency of the noise of the pair of gears 30 and 40 can be formed. Therefore, when the noise of the pair of gears 30 and 40 enters the air layer through the plurality of through holes 71, a resonance phenomenon occurs and the sound is absorbed. It further includes a plurality of core members 80 provided between the first plate member 61 and the second plate member 62, and the adjacent core members 80 are less than half the wavelength of the noise frequency f of the pair of gears 30 and 40. Since they are provided at intervals, it is possible to suitably reduce noise.

  Further, since the plurality of through holes 71 are provided to face the pair of gears 30 and 40, a large sound absorbing surface can be formed, and the noise of the pair of gears 30 and 40 can be suitably reduced.

  Furthermore, in the noise reduction bracket 60c according to the fourth embodiment, the noise can be reduced by providing a resonator in the bracket that holds the motor 10, so that the motor 10 can be provided without newly providing a resonator or the like. The noise reduction bracket 60c having a large sound absorbing surface can be disposed in the vicinity of the sound source, which is a vacant space (dead space) inevitably generated in design between the gear 30 and the pair of gears 30 and 40. As a result, the noise of the motor 10 or the pair of gears can be efficiently reduced in a space-saving manner.

  Further, the design frequency f0 set by parameters such as the air layer thickness L5, the core material arrangement interval L8, and the diameters of the plurality of through holes 71 of the first plate member 61 is the noise frequency f of the pair of gears 30 and 40. Therefore, the noise of the pair of gears 30 and 40 can be reduced most effectively. In particular, since the noise of the pair of gears 30 and 40 has a single frequency, the single frequency can be reduced by the configuration of the plurality of through holes 71 and the air layer, and the noise can be reliably reduced. .

(Fifth embodiment)
FIG. 6 is a schematic cross-sectional view showing an example of a drive device 100d using the noise reduction cover according to the first embodiment.

  The drive device 100d of FIG. 6 includes a motor 10, a drive shaft 20, a pair of gears 30 and 40, a transmission shaft 50, and a noise reduction cover 90.

  The noise reduction cover 90 is disposed so as to surround the pair of gears 30, 40, has a support portion (not shown) that supports the pair of gears 30, 40, and further has a plate-like first plate It includes a member 91, a plate-like second plate member 92, and a first plate member 91 and a closing member 95 that connects the peripheral edges of the second plate member 92. In addition, the surrounding in this invention means the state of enclosing or covering, and is not limited to what surrounds the whole, The state of enclosing or covering a part is also included.

  The first plate member 91 and the second plate member 92 are disposed substantially parallel to each other at a distance L1. Both the first plate member 91 and the second plate member 92 may be made of various other materials such as a metal such as iron or aluminum, or a resin. The first plate member 91 and the second plate member 92 are preferably made of the same material. Further, the closing member 95 is preferably made of the same material as the first plate member 91 and the second plate member 92.

  Thus, a space is formed by the first plate member 91, the second plate member 92, and the closing member 95. Hereinafter, this space is called an air layer.

  As shown in FIG. 6, the first plate member 91 is provided with a plurality of through holes 71 on the surface with respect to the pair of gears 30 and 40. Thereby, the periphery of the pair of gears 30 and 40 communicates with the air layer via the plurality of through holes 71. The first plate member 91 has a shape that can support the drive shaft 20 and the transmission shaft 50 of the pair of gears 30 and 40.

  In the fifth embodiment, for example, the plate thickness t1 of the first plate member 91 is not less than 0.3 mm and not more than 3 mm, and the plate thickness t2 of the second plate member 92 is not less than 0.3 mm and not more than 3 mm. The plate thickness t5 of the member 95 is not less than 0.3 mm and not more than 3 mm, the hole diameter (diameter φ) d1 of the through hole 71 provided in the first plate member 91 is not less than 0.3 mm and not more than 15 mm, and the first plate member The opening ratio β1 of the through hole provided in 91 is 0.1% or more and 10% or less, and the distance L1 between the parallel members between the first plate member 91 and the second plate member 92 is 1 mm or more and 50 mm or less.

  Next, the operation of the driving device 100d in FIG. 6 will be described. As the motor 10 rotates, the drive shaft 20 rotates. Accordingly, the gear 30 provided on the drive shaft 20 rotates, and at the same time, the gear 40 provided so as to mesh with the gear 30 rotates dependently. Thereby, the transmission shaft 50 provided in the gear 40 rotates. In this case, a motor 10 sound is generated from the motor 10, and a gear sound is generated in the pair of gears 30 and 40 due to the meshing of the teeth of each other.

  Here, in the fifth embodiment, the case where the noise of the gears 30 and 40 is larger than the noise of the motor 10 and the noise of the gears 30 and 40 is reduced is considered. Each parameter is set so that the design frequency f0 satisfying the following expression is obtained with respect to the noise frequency f of the gears 30 and 40.

ここで、β１は第１板部材９１の貫通孔の開口率を示し、ｄ１は第１板部材９１の貫通孔の孔径を示し、ｔ１は第１板部材９１の板厚を示し、Ｌ１は第１板部材９１および第２板部材９２の並行部材間距離を示し、ｃは音速を示す。

Here, β1 represents the aperture ratio of the through hole of the first plate member 91, d1 represents the hole diameter of the through hole of the first plate member 91, t1 represents the plate thickness of the first plate member 91, and L1 represents the first The distance between the parallel members of the 1 plate member 91 and the 2nd plate member 92 is shown, c shows the speed of sound.

  Thus, since the design frequency f0 is provided so as to match or approximate the noise frequency f of the gears 30 and 40, the noise of the gears 30 and 40 can be reduced.

  That is, the air mass in the plurality of through holes formed in the first plate member 91 forms a virtual mass system, and the air layer formed by the first plate member 91, the second plate member 92, and the closing member 95. Forms a virtual spring system. Therefore, a one-degree-of-freedom resonance system can be formed in the vicinity of the pair of gears 30 and 40.

  The virtual mass m is determined by the thickness t1 of the first plate member 91, the hole diameter φd1 of the plurality of through holes 71, the opening ratio β1, and the air density ρ. The virtual spring system k includes the distance L1 between the parallel members, the air It is determined by density ρ and sound speed c.

  Therefore, by adjusting the parameters of the virtual mass m and the virtual spring system k, a resonator that matches or approximates the resonance frequency of the noise of the pair of gears 30 and 40 can be formed. Therefore, when the noise of the pair of gears 30 and 40 enters the air layer through the plurality of through holes 71, a resonance phenomenon occurs and the sound is absorbed.

  As described above, in the noise reduction cover 90 according to the fifth embodiment, an air layer is formed by the space formed by the first plate member 91, the second plate member 92, and the closing member 95, and the first plate Together with the plurality of through holes 71 provided in the member 91, it acts as a resonator, and the noise of the pair of gears 30 and 40 can be reduced.

  Moreover, since the several through-hole 71 is provided facing a pair of gears 30 and 40, a big sound absorption surface can be formed and the noise of a pair of gears 30 and 40 can be reduced suitably.

  Furthermore, in the noise reduction cover 90 according to the fifth embodiment, since a resonator can be provided in the cover surrounding the pair of gears 30 and 40 to reduce noise, a new resonator or the like is provided. In addition, it is possible to dispose the noise reduction cover 90 having a large sound absorbing surface in the vicinity of the sound source in an empty space (dead space) inevitably generated in design between the motor 10 and the pair of gears 30 and 40. As a result, the noise of the motor 10 or the pair of gears 30 and 40 can be efficiently reduced in a space-saving manner.

  Further, as described above, the design frequency f0 set by the parameters such as the thickness L1 of the air layer and the diameter d1 of the plurality of through holes 71 of the first plate member 91 coincides with the noise frequency f of the pair of gears 30 and 40. Or since it is provided so that it may approximate, the noise of a pair of gears 30 and 40 can be reduced most effectively. In particular, since the noise of the pair of gears 30 and 40 has a single frequency, the single frequency can be reduced by the configuration of the plurality of through holes 71 and the air layer, and the noise can be reliably reduced. .

In the above embodiment, the first plate member 91, the second plate member 92, and the closing member 95 are configured as separate members. However, the present invention is not limited to this, and the first plate member 91, the second plate are not limited thereto. One or more of the member 92 and the closing member 95 may be formed from one member.
Further, the closing member 95 may seal only one of the two air layers, but it is preferable to seal the two air layers.

(Sixth embodiment)
Next, a driving device 100e according to a sixth embodiment will be described. FIG. 7 is a schematic cross-sectional view showing an example of a drive device 100e using the noise reduction cover according to the sixth embodiment.

  The driving device 100e according to the sixth embodiment is different from the driving device 100d according to the fifth embodiment in the following points.

  The drive device 100e according to the sixth embodiment includes a noise reduction cover 90a instead of the noise reduction cover 90 of the drive device 100d according to the fifth embodiment. The noise reduction cover 90 a further includes one or a plurality of third plate members 93 in the noise reduction cover 90. In the sixth embodiment, a case where there is one third plate member 93 will be described.

  The third plate member 93 is provided between the first plate member 91 and the second plate member 92. In addition, the 3rd board member 93 may consist of other various raw materials, such as metals, such as iron and aluminum, or resin.

  As shown in FIG. 7, the space surrounded by the first plate member 91, the third plate member 93 and the closing member 95, and the space surrounded by the third plate member 93, the second plate member 92 and the closing member 95 The two air layers are formed.

  A plurality of through holes 71 are formed in the first plate member 91, and a plurality of through holes 73 are also formed in the third plate member 93. Thereby, the periphery of the gears 30 and 40 communicates with the air layer surrounded by the third plate member 93 and the first plate member 91 through the plurality of through holes 71, and the second through the plurality of through holes 73. The air layer surrounded by the plate member 92 and the third plate member 93 communicates with the air layer.

  In the sixth embodiment, for example, the plate thickness t1 of the first plate member 91 is not less than 0.3 mm and not more than 3 mm, the plate thickness t2 of the second plate member 92 is not less than 0.3 mm and not more than 3 mm, The plate thickness t3 of the three plate member 93 is not less than 0.3 mm and not more than 3 mm, the plate thickness t of the closing member 95 is not less than 0.3 mm and not more than 3 mm, and the diameter of the through hole 71 provided in the first plate member 91 ( The diameter φ) d1 is not less than 0.3 mm and not more than 15 mm, and the opening ratio β1 of the through-hole provided in the first plate member 91 is not less than 0.1% and not more than 10%, and is provided in the third plate member 93. The hole diameter (diameter φ) d3 of the through hole is 0.3 mm or more and 15 mm or less, the opening ratio β3 of the through hole provided in the third plate member 93 is 0.1% or more and 10% or less, and the second The distance L2 between the parallel members between the plate member 92 and the third plate member 93 is 1 mm or more. And at 0mm or less, parallel members distance L3 between the first plate member 91 and the third plate member 93 is 1mm or more 50mm or less.

  In the sixth embodiment, as in the fifth embodiment, the noise of the pair of gears 30 and 40 is larger than the noise of the motor 10, and the noise of the pair of gears 30 and 40 is reduced. Consider the case of reduction.

  That is, air masses in the plurality of through holes 71 formed in the first plate member 91 form a virtual mass system m1, and air masses in the plurality of through holes 73 formed in the third plate member 93 A virtual mass system m3 is formed, and an air layer formed by the second plate member 92, the third plate member 93, and the closing member 95 forms a virtual spring system k23, and the first plate member 91, the third plate The air layer formed by the plate member 93 and the closing member 95 forms a virtual spring system k13. Therefore, a two-degree-of-freedom resonance system can be formed in the vicinity of the pair of gears 30 and 40.

  The virtual mass m1 is determined by the thickness t1 of the first plate member 91, the hole diameter φd1 of the plurality of through holes 71, the aperture ratio β1, and the air density ρ. The virtual mass m3 is the thickness t3 of the third plate member 93. The virtual spring system k23 is determined by the distance L2 between the parallel members, the air density ρ, and the sound velocity c, and the virtual spring system k13 is , Determined by the distance L3 between the parallel members, the air density ρ, and the speed of sound c.

  Therefore, by adjusting the parameters of the virtual masses m1 and m3 and the virtual spring systems k23 and k13, the frequency of noise of not only the pair of gears 30 and 40 but also other adjacent gears (not shown). It is possible to form a resonator having a plurality of resonance frequencies that match or approximate. Therefore, noises of other frequencies generated by the pair of gears 30 and 40 and other gears are absorbed by the resonance phenomenon in the air and air layers of the plurality of through holes 71 and 73.

  As described above, in the noise reduction cover 90a according to the sixth embodiment, two spaces are formed by the space formed by the first plate member 91, the second plate member 92, the third plate member 93, and the closing member 95. An air layer is formed, and combined with the plurality of through holes 71 and the plurality of through holes 73, acts as a resonator having a plurality of resonance frequencies, and effectively reduces noise of the pair of gears 30, 40 and other gears. can do.

  Further, since the plurality of through holes 71 and the plurality of through holes 73 are provided so as to face the pair of gears 30 and 40, a large sound absorbing surface is formed to suitably reduce the noise of the pair of gears 30 and 40. Can do.

  Furthermore, in the noise reduction cover 90a according to the sixth embodiment, since a resonator having a plurality of resonance frequencies can be provided on the cover surrounding the pair of gears 30 and 40, noise reduction can be achieved. A noise reduction cover 90a having a large sound-absorbing surface in the vicinity of the sound source is a vacant space (dead space) that is inevitably generated by design between the motor 10 and the pair of gears 30 and 40 without providing a resonator or the like. Can be arranged. As a result, the noise of the motor 10 or the pair of gears 30 and 40 can be efficiently reduced in a space-saving manner.

  The design frequency f0 set by parameters such as the air layer thicknesses L2 and L3 and the diameters of the plurality of through holes 71 and 73 is the noise frequency f of the pair of gears 30 and 40 and the noise of other adjacent gears. Since it is provided so as to match or approximate the frequency f2, the noise of the pair of gears 30 and 40 and the adjacent gear can be reduced.

  In the above embodiment, the first plate member 91, the second plate member 92, the third plate member 93, and the closing member 95 are configured as separate members. However, the present invention is not limited to this, and the first plate Any one or more of the member 91, the second plate member 92, the third plate member 93, and the closing member 95 may be formed from one member.

(Seventh embodiment)
Next, a driving device 100f according to a seventh embodiment of the present invention will be described. FIG. 8 is a schematic cross-sectional view showing an example of a drive device 100f using the noise reduction cover according to the seventh embodiment. The driving device 100f according to the seventh embodiment is different from the driving device 100d according to the fifth embodiment in the following points.

  The seventh embodiment includes a noise reduction cover 90b instead of the noise reduction cover 90 of the drive device 100d according to the fifth embodiment. As shown in FIG. 8, the noise reduction cover 90 b includes a first plate member 91 provided on the motor 10 side, and a plurality of through holes 71 are formed in the first plate member 91. Accordingly, the periphery of the motor 10 communicates with the air layer surrounded by the first plate member 91, the second plate member 92, and the closing member 95 through the plurality of through holes 71.

  In the seventh embodiment, for example, the plate thickness t1 of the first plate member 91 is not less than 0.3 mm and not more than 3 mm, and the plate thickness t2 of the second plate member 92 is not less than 0.3 mm and not more than 3 mm. The plate thickness t of the member 95 is not less than 0.3 mm and not more than 3 mm, and the hole diameter d1 of the through hole 71 provided in the first plate member 91 is not less than 0.3 mm and not more than 15 mm, and is provided in the first plate member 91. The opening ratio β1 of the through holes is 0.1% or more and 10% or less, and the distance L4 between the parallel members between the first plate member 91 and the second plate member 92 is 1 mm or more and 50 mm or less.

  In the seventh embodiment, unlike the fifth embodiment and the sixth embodiment, the noise of the motor 10 is larger than the gear noise, and the noise of the motor 10 is reduced. think of. Therefore, the design frequency f0 is provided so as to match or approximate the noise frequency f of the motor 10 (see Equation 4).

  That is, a mass of air in the plurality of through holes 71 formed in the first plate member 91 forms a virtual mass system m1, and an air layer formed by the first plate member 91 and the second plate member 92 is virtual. A typical spring system k1 is formed. Therefore, a one-degree-of-freedom resonance system can be formed in the vicinity of the motor 10.

  The virtual mass m1 is determined by the thickness t1 of the first plate member 91, the hole diameter φd1 of the plurality of through holes 71, the opening ratio β1, and the air density ρ. The virtual spring system k1 includes the distance L4 between the parallel members, the air It is determined by density ρ and sound speed c.

  Therefore, by adjusting the parameters of the virtual mass m1 and the virtual spring system k1, a resonator that matches or approximates the resonance frequency of the noise of the motor 10 can be formed. Therefore, when the noise of the motor 10 enters the air layer through the plurality of through holes 71, a resonance phenomenon occurs and the sound is absorbed.

  As described above, in the noise reduction cover 90b according to the seventh embodiment, an air layer is formed by the space formed by the first plate member 91, the second plate member 92, and the closing member 95, and the first plate Together with the plurality of through holes 71 provided in the member 91, it acts as a resonator, and the noise of the motor 10 can be reduced.

  Moreover, since the several through-hole 71 is provided facing the motor 10, a big sound absorption surface can be formed and the noise of the motor 10 can be reduced suitably.

  Furthermore, in the noise reduction cover 90f according to the present invention, a noise can be reduced by providing a resonator in the cover surrounding the pair of gears 30 and 40. Therefore, the motor 10 can be provided without newly providing a resonator or the like. The noise reduction cover 90f having a large sound absorbing surface in the vicinity of the sound source can be disposed in an empty space (dead space) inevitably generated in design between the gear 30 and the pair of gears 30 and 40. As a result, the noise of the motor 10 can be efficiently reduced in a space-saving manner.

  In addition, since the design frequency f0 set by each parameter such as the thickness L4 of the air layer and the diameters of the plurality of through holes 71 of the first plate member 91 is provided so as to match or approximate the noise frequency f of the motor 10, The noise of the motor 10 can be reduced most effectively. In particular, since the noise of the motor 10 has a single frequency, the single frequency can be reduced by the configuration of the plurality of through holes 71 and the air layer, and the noise can be reliably reduced.

  In the above embodiment, the first plate member 91, the second plate member 92, and the closing member 95 are configured as separate members. However, the present invention is not limited to this, and the first plate member 91, the second plate are not limited thereto. One or more of the member 92 and the closing member 95 may be formed from one member.

(Eighth embodiment)
Next, a driving device 100g according to an eighth embodiment of the present invention will be described. FIG. 9 is a schematic cross-sectional view showing an example of a drive device 100g using the noise reduction cover according to the eighth embodiment.

  The driving device 100g according to the eighth embodiment is different from the driving device 100d according to the fifth embodiment in the following points.

  The noise reduction cover 90c of the eighth embodiment further includes a core member 80 in addition to the fifth noise reduction cover 90.

  The first plate member 91, the second plate member 92, and the core member 80 may all be made of various other materials such as a metal such as iron or aluminum or a resin. The first plate member 91, the second plate member 92, and the core member 80 are preferably made of the same material.

  The core member 80 is provided so as to divide the air layer formed by the first plate member 91 and the second plate member 92 into a plurality of pieces. As shown in FIG. 9, the core member 80 in the present embodiment is provided substantially perpendicular to the cross sections of the first plate member 91 and the second plate member 92.

  As shown in FIG. 9, the first plate member 91 is provided with a plurality of through holes 71 on the surface with respect to the gears 30 and 40. Thereby, the periphery of the gears 30 and 40 communicates with each air layer partitioned by the core member 80 through the plurality of through holes 71.

  In the eighth embodiment, for example, the plate thickness t1 of the first plate member 91 is not less than 0.3 mm and not more than 3 mm, the plate thickness t2 of the second plate member 92 is not less than 0.3 mm and not more than 3 mm, The hole diameter (diameter φ) d1 of the through hole provided in the first plate member 91 is 0.3 mm or more and 15 mm or less, and the opening ratio β1 of the through hole provided in the first plate member 91 is 0.1% or more and 10 %, The plate thickness t8 of the core member 80 is not less than 0.3 mm and not more than 3 mm, the distance L5 between the parallel members between the first plate member 91 and the second plate member 92 is not less than 1 mm and not more than 50 mm, The arrangement interval L8 of 80 is 1 mm or more and 50 mm or less.

  Then, the formation method of the core material 80 is demonstrated. FIG. 10 is a diagram showing an example of a method for manufacturing the noise reduction cover 90c shown in FIG. FIG. 10A shows a case where an air layer is formed by using the core member 80 as a separate member as shown in FIG. 9, and FIGS. 10B and 10C show a case where a plurality of through holes 71 are already formed. The case where the core material 80 is formed by bending a single metal plate by pressing is shown.

  As shown in FIG. 10A, when a core member 80 is newly provided in the cover 90c, it is necessary to employ a method such as adhesion, which is troublesome and tends to increase manufacturing costs.

  However, as shown in FIG. 10 (b), the direction of the arrow X2 with respect to the dual-structure plate member in which the plurality of through holes 71 are formed in the first plate member 91 and the second plate member 92 is formed. The core material 80 can be easily formed by pressing.

  Similarly, as shown in FIG. 10C, the double plate member in which the plurality of through holes 71 are formed in the first plate member 91 and the second plate member 92 is formed is indicated by an arrow X3. The core material 80 may be easily formed by pressing in the direction.

  As a result, the core member 80 can be easily formed on the first plate member 91 and the second plate member 92.

  In the eighth embodiment, as in the fifth embodiment, the noise of the pair of gears 30 and 40 is larger than the noise of the motor 10, and the noise of the pair of gears 30 and 40 is reduced. Consider the case of reduction. Therefore, similarly to the fifth embodiment, the design frequency f0 is provided so as to match or approximate the noise frequency f of the pair of gears 30 and 40 (see Equation 4).

  That is, a mass of air in the plurality of through holes 71 formed in the first plate member 91 forms a virtual mass system m1, and is formed by the first plate member 91, the second plate member 92, and the core member 80. The air layer forms a virtual spring system k81. The virtual mass m1 is determined by the thickness t1 of the first plate member 91, the hole diameter φd1 of the plurality of through holes 71, the opening ratio β1, and the air density ρ. The virtual spring system k8 includes the parallel member distance L5, the core It is determined by the arrangement interval L8 of the material 80, the air density ρ, and the sound velocity c.

  Therefore, by adjusting the parameters of the virtual mass m1 and the virtual spring system k8, a resonator that matches or approximates the resonance frequency of the noise of the pair of gears 30 and 40 can be formed. Therefore, when the noise of the pair of gears 30 and 40 enters the air layer through the plurality of through holes 71, a resonance phenomenon occurs and the sound is absorbed. It further includes a plurality of core members 80 provided between the first plate member 91 and the second plate member 92, and the core member 80 is at an interval of less than ½ of the wavelength of the noise frequency f of the pair of gears 30 and 40. Since it is provided, noise reduction can be suitably achieved.

  Further, since the plurality of through holes 71 are provided to face the pair of gears 30 and 40, a large sound absorbing surface can be formed, and the noise of the pair of gears 30 and 40 can be suitably reduced.

  Furthermore, in the noise reduction cover 90c according to the eighth embodiment, a resonator can be provided on the cover surrounding the pair of gears 30 and 40 so as to reduce noise, so that a new resonator or the like is provided. In addition, it is possible to dispose a noise reduction cover 90c having a large sound absorbing surface in an empty space (dead space) inevitably generated in design between the motor 10 and the pair of gears 30 and 40 and in the vicinity of the sound source. As a result, the noise of the motor 10 or the pair of gears can be efficiently reduced in a space-saving manner.

  Further, the design frequency f0 set by parameters such as the air layer thickness L5, the core material arrangement interval L8, and the diameters of the plurality of through holes 71 of the first plate member 91 is the noise frequency f of the pair of gears 30 and 40. Therefore, the noise of the pair of gears 30 and 40 can be reduced most effectively. In particular, since the noise of the pair of gears 30 and 40 has a single frequency, the single frequency can be reduced by the configuration of the plurality of through holes 71 and the air layer, and the noise can be reliably reduced. .

In the above embodiment, the first plate member 91, the second plate member 92, and the closing member 95 are configured as separate members. However, the present invention is not limited to this, and the first plate member 91, the second plate are not limited thereto. One or more of the member 92 and the closing member 95 may be formed from one member.
Further, the closing member 95 may seal only one of the two air layers, but it is preferable to seal the two air layers.

(Other examples)
FIG. 11 is a schematic diagram for explaining a case where the noise reduction brackets according to the first to fourth embodiments and the noise reduction cover according to the fifth to eighth embodiments are integrated.

  11 includes a second plate member 62 provided between the motor 10 and the pair of gears 30 and 40, and a first plate member 61 facing one side of the second plate member 62. The noise reduction member 100h illustrated in FIG. A third plate member 63 is provided opposite to the opposite side of the second plate member 62.

  The first plate member 61 and the third plate member 63 are provided with a plurality of through holes 71 and 73. Accordingly, the periphery of the pair of gears 30 and 40 is provided in communication with the air layer through the plurality of through holes 73, and the periphery of the motor 10 is in communication with the air layer through the plurality of through holes 71. Provided.

  That is, air masses in the plurality of through holes 71 formed in the first plate member 61 form a virtual mass system m1, and air masses in the plurality of through holes 73 formed in the third plate member 63 A virtual mass system m3 is formed, and an air layer formed by the second plate member 62, the third plate member 63, and the closing member 65 forms a virtual spring system k23, and the first plate member 61, the third plate The air layer formed by the plate member 63 and the closing member 65 forms a virtual spring system k13. Therefore, a one-degree-of-freedom resonance system can be formed in the vicinity of the pair of gears 30 and 40, and a one-degree-of-freedom resonance system can be formed in the vicinity of the motor 10.

  The virtual mass m1 is determined by the thickness t1 of the first plate member 61, the hole diameter φd1 of the plurality of through holes 71, the aperture ratio β1, and the air density ρ. The virtual mass m3 is the thickness t3 of the third plate member 63. The virtual spring system k23 is determined by the inter-member distance L12, the air density ρ, and the sound velocity c, and the virtual spring system k13 is determined by the hole diameter φd3, the opening ratio β3, and the air density ρ of the plurality of through holes 73. , Determined by the distance L13 between the parallel members, the air density ρ, and the speed of sound c.

  Therefore, by adjusting the parameters of the virtual masses m1 and m3 and the virtual spring systems k23 and k13, a plurality of resonances that match or approximate the noise frequencies of both the pair of gears 30 and 40 and the motor 10 are obtained. A resonator having a frequency can be formed. Therefore, noises having a plurality of frequencies generated by the pair of gears 30 and 40 and the motor 10 are absorbed by the resonance phenomenon in the air and the air layer of the plurality of through holes 71 and 73.

  As described above, in the noise reduction member, two air layers are formed by the space formed by the first plate member 61, the second plate member 62, the third plate member 63, and the closing member 65, and a plurality of air layers are formed. Together with the through-hole 71 and the plurality of through-holes 73, it acts as a resonator having a plurality of resonance frequencies, and the noise of the pair of gears 30 and 40 and the motor 10 can be effectively reduced.

  In addition, since the plurality of through holes 71 are provided to face the motor 10 and the plurality of through holes 73 are provided to face the pair of gears 30 and 40, a large sound absorbing surface is formed, and the motor 10 and the pair of pairs are formed. The noise of the gears 30 and 40 can be suitably reduced.

  Furthermore, in the noise reduction member, a resonator having a plurality of resonance frequencies can be provided on the bracket surrounding the motor 10 and the cover surrounding the gear, so that noise can be reduced. Therefore, it is possible to dispose a noise reduction member having a large sound absorbing surface in the vicinity of the sound source in an empty space (dead space) inevitably generated in design between the motor 10 and the pair of gears 30 and 40. . As a result, the noise of the motor 10 or the pair of gears 30 and 40 and the motor 10 can be efficiently reduced in a space-saving manner.

  In addition, the design frequency f0 set by each parameter such as the thickness of the air layer and the diameters of the plurality of through holes 71 and 73 matches or approximates the noise frequency f of the pair of gears 30 and 40 and the noise frequency f2 of the motor 10. Therefore, the noise of the pair of gears 30 and 40 and the motor 10 can be reduced.

  In the other examples, the first plate member 61, the second plate member 62, the third plate member 63, and the closing member 65 are configured as separate members. However, the present invention is not limited to this, and the first plate Any one or more of the member 61, the second plate member 62, the third plate member 63, and the closing member 65 may be formed from a single member.

  Further, the core member 80 may be provided in the air layer formed from the first plate member 61 and the second plate member 62, and the core member 80 may be provided in the air layer formed from the second plate member 62 and the third plate member 63. May be provided.

  In the first to eighth embodiments, the motor 10 corresponds to the motor 10, the gears 30 and 40 correspond to a pair of gears, and the noise reduction brackets 60, 60a, 60b, and 60c are noise reduction members and brackets. The noise reduction covers 90, 90a, 90b, 90c correspond to the noise reduction member and the cover function, the closing members 65, 95 correspond to the closing member, and the first plate members 61, 91 correspond to the first plate member. The second plate members 62, 92 correspond to the second plate member, the plurality of through holes 71, 72, 73 correspond to the plurality of through holes, and the aperture ratios β, β1, β3 of the through holes pass through. The hole diameter (diameter φ) d, d1, d3 of the through hole corresponds to the hole diameter of the through hole, and the plate thicknesses t1, t2, t of the first plate member, the second plate member, and the blocking member Corresponds to the plate thickness, and the distances L1, ~, L5 between the parallel members L12 and L13 correspond to the distance between any two parallel members of the first plate member, the second plate member, and the third plate member, the design frequency f0 corresponds to the design frequency, and the noise frequency f corresponds to the noise frequency. The core material 80 corresponds to the core material.

  Although the present invention has been described in the first to eighth preferred embodiments described above, the present invention is not limited thereto. It will be understood that various other embodiments may be made without departing from the spirit and scope of the invention. Furthermore, in this embodiment, although the effect | action and effect by the structure of this invention are described, these effect | actions and effects are examples and do not limit this invention.

  For example, the air layer formed by the first plate member 61, the second plate member 62, the third plate member 63, and the closing member 65 between the motor 10 and the pair of gears 30 and 40 and the arrangement of the plurality of through holes are as follows. The cases of Examples 1 to 8 below may be used. In addition, also in the following Examples 1 to 8, a case where the second plate member 62 is not provided with a plurality of through holes, and the first plate member 61 and the third plate member 63 are provided with a plurality of through holes will be described. .

(Example 1)
The motor 10, the first plate member 61, the second plate member 62, and the pair of gears 30 and 40 are arranged in this order.

(Example 2)
The motor 10, the second plate member 62, the first plate member 61, and the pair of gears 30 and 40 are arranged in this order.

(Example 3)
The motor 10, the first plate member 61, the second plate member 62, the third plate member 63, and the pair of gears 30 and 40 are arranged in this order.

(Example 4)
The motor 10, the first plate member 61, the plurality of third plate members 63, the second plate member 62, and the pair of gears 30 and 40 are arranged in this order.

(Example 5)
The motor 10, the second plate member 62, the first plate member 61, the plurality of third plate members 63, and the pair of gears 30 and 40 are arranged in this order.

(Example 6)
The motor 10, the first plate member 61, the second plate member 62, the plurality of third plate members 63, and the pair of gears 30 and 40 are arranged in this order.

(Example 7)
The motor 10, the plurality of third plate members 63, the second plate member 62, the first plate member 61, and the pair of gears 30 and 40 are arranged in this order.

(Example 8)
The motor 10, the plurality of first plate members 61, the second plate member 62, the plurality of third plate members 63, and the pair of gears 30 and 40 are arranged in this order.

  The arrangement of the first plate member 61, the second plate member, and the third plate member as shown in Examples 1 to 8 above may be used. Instead of the first plate member 61, the second plate member 62, and the third plate member 63, the first plate member 91, the second plate member 92, and the third plate member 93 may be used. Even in this case, the noise of the motor 10 or the pair of gears 30 and 40 can be efficiently reduced in a space-saving manner.

<Example>
The drive device according to the above embodiment was manufactured, and the noise reduction was measured. This will be described below.

(Example 1)
In Example 1, the drive device 100 including the noise reduction bracket 60 illustrated in FIG. 1 was manufactured. The plate thickness t1 of the first plate member 61 is 1 mm, the plate thickness t2 of the second plate member 62 is 1 mm, the hole diameter d of the through hole provided in the first plate member 61 is φ4 mm, The aperture ratio β of the through hole provided in the first plate member 61 is 0.4%, and the parallel distance L between the first plate member 61 and the second plate member 62 is 5 mm. The noise reduction bracket 60 was provided at a portion 1 mm away from the gears 30 and 40.

(Example 2)
Next, in Example 2, the driving device 100a including the noise reduction bracket 60a illustrated in FIG. 2 was manufactured. The plate thickness t1 of the first plate member 61 is 1 mm, the plate thickness t2 of the second plate member 62 is 1 mm, the plate thickness t3 of the third plate member 63 is 1 mm, and the first plate member 61 is provided on the first plate member 61. The diameter (diameter φ) d1 of the formed through hole is 4 mm, the opening ratio β1 of the through hole provided in the first plate member 61 is 0.3%, and the through hole provided in the third plate member 63 Has a hole diameter (diameter φ) d3 of 4 mm, and the aperture ratio β3 of the through hole provided in the third plate member 63 is 0.1%. The noise reduction bracket 60a was provided at a portion 1 mm away from the gears 30 and 40.

(Comparative Example 1)
In Comparative Example 1, a drive device similar to that of Example 1 was manufactured except for a portion where the plurality of through holes 71 of the first plate member 61 of the noise reduction bracket 60 manufactured in Example 1 were not formed. The noise reduction bracket was provided at a portion 1 mm away from the gears 30 and 40.

(Comparative Example 2)
In Comparative Example 2, the following drive device was created. FIG. 12 is a diagram showing a driving device of Comparative Example 2. As shown in FIG. 12, in Comparative Example 2, a bracket 60 is provided between the motor 10 and the gears 30 and 40, and a thickness t (5 mm, 64 kg / m ³ ) is provided on one surface of the bracket facing the gears 30 and 40. Glass wool 90 was formed. The noise reduction bracket was provided at a portion 1 mm away from the gears 30 and 40.

(Evaluation 1)
FIG. 13 is a diagram showing the results of measuring the meshing noise of the gears in Example 1 and Comparative Example 1. The vertical axis in FIG. 13 indicates the noise level (dB (A)), and the horizontal axis indicates the frequency (Hz).

  As shown in FIG. 13, at a frequency of 800 Hz, the noise level in Comparative Example 1 is 40 dB (A), but in Example 1, the noise level is reduced to 35 dB (A). That is, in other frequency regions, the noise level cannot be reduced, but the noise level of the gears 30 and 40 at the frequency of 800 Hz, which is the largest noise, can be reduced by about 5 dB. Thereby, it was found that the largest noise of the gears 30 and 40 can be reduced.

(Evaluation 2)
FIG. 14 is a diagram showing the measurement results of the sound absorption coefficient in Example 1, Example 2, and Comparative Example 2. The vertical axis in FIG. 14 indicates the sound absorption coefficient, and the horizontal axis indicates the frequency (Hz).

  As shown in FIG. 14, the sound absorption coefficient of the glass wool in Comparative Example 1 was 0.2 or less at a frequency between 0 Hz and 2 KHz.

  On the other hand, the sound absorption coefficient of the noise reduction blanket 60 in Example 1 was approximately 1.0 when the frequency was about 800 Hz.

  In addition, the sound absorption coefficient of the noise reduction blanket 60a in Example 2 was approximately 0.9 when the frequency was about 450 Hz and about 1020 Hz.

  Accordingly, in the case of Example 1, noise having a frequency of about 800 Hz can be completely reduced in one air layer, and in the case of Example 2, about 450 Hz and about 1020 Hz in two air layers can be achieved. It was found that the noise can be reduced almost. Therefore, it was found that a plurality of noises can be reduced by adjusting the design frequency.

  Although the present invention has been described in the first to eighth preferred embodiments described above, the present invention is not limited thereto. It will be understood that various other embodiments may be made without departing from the spirit and scope of the invention. Furthermore, in this embodiment, although the effect | action and effect by the structure of this invention are described, these effect | actions and effects are examples and do not limit this invention.

Typical sectional drawing which shows an example of the drive device using the noise reduction bracket which concerns on 1st Embodiment. Typical sectional drawing which shows an example of the drive device using the noise reduction bracket which concerns on 2nd Embodiment. Typical sectional drawing which shows an example of the drive device using the noise reduction bracket which concerns on 3rd Embodiment. Typical sectional drawing which shows an example of the drive device using the noise reduction bracket which concerns on 4th Embodiment. The figure which shows an example of the manufacturing method of the noise reduction bracket shown in FIG. Typical sectional drawing which shows an example of the drive device using the noise reduction bracket which concerns on 5th Embodiment. Typical sectional drawing which shows an example of the drive device using the noise reduction bracket which concerns on 6th Embodiment. Typical sectional drawing which shows an example of the drive device using the noise reduction bracket which concerns on 7th Embodiment. Typical sectional drawing which shows an example of the drive device using the noise reduction bracket which concerns on 8th Embodiment. The figure which shows an example of the manufacturing method of the noise reduction bracket shown in FIG. Schematic diagram showing an example of a noise reduction member including a noise reduction bracket and a noise reduction cover The figure which shows the drive device of the comparative example 2. The figure which shows the result of having measured the meshing noise of the gear in Example 1 and Comparative Example 1 The figure which shows the measurement result of the sound absorption rate in Example 1, Example 2, and Comparative Example 2

Explanation of symbols

10 Motor 10
30, 40 Gear 60, 60a, 60b, 60c Noise reduction bracket 61 First plate member 62 Second plate member 65 Closure member 71, 72, 73 Multiple through holes 80 Core material d Diameter of through hole f Noise frequency f0 Design frequency L1, ..., L5, L12, L13 Distance between parallel members t Plate thickness β Opening ratio of through-hole

Claims (17)

A noise reduction member provided to reduce noise caused by a motor or a pair of gears that transmit rotational force from the motor,
The noise reduction member is
A first plate member disposed to face at least one of the motor and the pair of gears, and provided with a plurality of through holes;
A noise reduction member, comprising: a second plate member that is disposed in parallel with the first plate member so that a space can be formed between the first plate member and the second plate member. The first plate member is
The noise reduction member according to claim 1, wherein the noise reduction member is disposed to face the motor. The first plate member is
The noise reduction member according to claim 1, wherein the noise reduction member is disposed to face the pair of gears. The aperture ratio of the through hole of the first plate member, the hole diameter of the through hole of the first plate member, the plate thickness of the first plate member, and the distance between the parallel members of the first plate member and the second plate member are ,
The opening ratio of the through hole is β, the diameter of the through hole is d, the plate thickness of the first plate member is t, and the distance between the parallel members of the first plate member and the second plate member is L. The design frequency f0 determined by the following equation (1) when the sound speed is c is designed to be equal to or approximate to the noise frequency f of the motor or the pair of gears. The noise reduction member according to claim 3.

And further including one or more core members provided substantially orthogonal to the first plate member and the second plate member in a space formed by the first plate member and the second plate member,
The one or more core material, any one of claims 1 to 4, characterized in that provided at less than 1/2 of the wavelength interval of the motor and / or the noise frequency f of the pair of gears The noise reduction member according to item 1.   6. The device according to claim 1, wherein the first plate member and the second plate member are provided in a space region between the motor and the pair of gears. Noise reduction member. A third plate member disposed in parallel with the first plate member;
The noise reduction member according to any one of claims 1 to 6, wherein the third plate member is provided with a plurality of through holes. The third plate member is
The noise reduction member according to claim 7, wherein the noise reduction member is provided in a space formed between the first plate member and the second plate member, and the space is divided into a plurality of portions. The third plate member is
A space different from the space formed by the first plate member and the second plate member is provided in a direction different from the first plate member provided facing the second plate member, and the second plate member The noise reduction member according to claim 7, wherein the noise reduction member is formed by the third plate member. The third plate member is
A space different from the space formed by the first plate member and the second plate member is provided in a direction different from the second plate member disposed to face the first plate member. The noise reduction member according to claim 7, wherein the noise reduction member is formed by a member and the third plate member. The third plate member is
The noise reduction member according to any one of claims 7 to 10, comprising one or a plurality of plate members. To match or approximate the noise frequency of the motor and / or a pair of gears,
A plurality of spaces formed by the first plate member, the second plate member, and the third plate member;
12. A resonator having a plurality of degrees of freedom resonance systems is equivalently formed by a plurality of through holes formed by the first plate member and the third plate member. The noise reduction member according to any one of the above. At least part of a plurality of spaces formed by the first plate member, the second plate member, and the third plate member is substantially orthogonal to the first plate member, the second plate member, and the third plate member. And one or more core materials provided
Wherein the one or more core material, any one of claims 12 to claim 7, characterized in that provided at less than 1/2 of the wavelength interval of the motor and / or the noise frequency f of the pair of gears The noise reduction member according to item 1. Further comprising an occluding member;
The noise reducing member according to claim 12 or 13, wherein the closing member is disposed so that at least one of the plurality of spaces can be sealed.   The first plate member, the second plate member, and the third plate member are provided in a space region between the motor and the pair of gears. The noise reduction member according to claim 1. The closing member is
The noise reduction member according to claim 14 or 15, further comprising a bracket function provided to support at least one of the motor and / or the pair of gears. The closing member is
The noise reduction member according to claim 14 or 15, further comprising a cover function provided so as to surround at least one of the pair of gears and / or the motor.

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