JP6029927B2 - Resonator - Google Patents

Description

  The present invention relates to a resonator provided in an intake system of an internal combustion engine.

  In an internal combustion engine mounted on a vehicle such as an automobile, a resonator is disposed in the middle of the intake duct in order to reduce intake noise generated when air is sucked through the intake duct. The resonator is a hollow box-like body, and reduces intake noise and the like using a resonance action by a resonance space defined inside the box-like body. In the resonator, water mixed with the air taken in from the outside by the intake duct or water generated by condensation accumulates in the resonance space, so a drain hole is formed at the bottom of the box-shaped body, and the water is removed through this drain hole. Configured to drain.

JP 2000-27719 A

  In the resonator, the volume of the resonance space is set according to the frequency of noise to be reduced. However, since the sound reduction characteristic is reduced by forming the water drain hole, it is necessary to increase the volume of the resonance space in order to ensure the equivalent sound reduction characteristic, leading to an increase in the size of the resonator. There are difficulties. In addition, the resonator in which the water drain hole is formed shifts to a higher frequency band where the sound can be reduced, and this frequency band shift is very difficult to obtain by simple analysis. For this reason, in the manufactured resonator, it takes time and effort to adjust the frequency aiming at sound reduction by adjusting the position, number and size of the drain holes, and the cost of correcting the mold of the resonator cannot be ignored.

  That is, the present invention has been proposed in order to suitably solve these problems inherent in the resonator according to the prior art, and the water drain hole does not change the sound reduction characteristics. An object of the present invention is to provide a resonator that can be drained through a wall.

In order to overcome the above-mentioned problems and achieve the intended object, the resonator according to the first aspect of the present invention provides:
A drain hole formed in the bottom wall of the recess formed by recessing the bottom of the resonance chamber in the downward direction,
An opening / closing means disposed in the recess for opening and closing the drain hole;
The opening / closing means includes
A weight portion having an insertion shaft that is inserted in the drain hole so as to be movable in the vertical direction;
The portion of the insertion shaft that extends to the inside of the resonance chamber is formed of a material having a specific gravity smaller than that of water, closes the drain hole from the inside of the resonance chamber, and collects water accumulated at the bottom of the resonance chamber. A float portion that floats on the water and opens the drain hole ,
The concave portion has a square shape with an opening shape,
The float portion has a circular shape in plan view and its maximum outer peripheral portion is opposed to the vertical wall of the recess,
The gist of the invention is that the vertical movement of the four concave walls restricts the lateral movement of the float .
According to the first aspect of the present invention, since the drain hole is closed by the float portion, the sound reduction characteristic is not changed by forming the drain hole. Further, when water accumulates in the resonance chamber, the float part floats so as to open the drain hole, so that the water accumulated in the resonance chamber can be discharged through the drain hole.

In the invention according to claim 2, the weight portion extends in a lateral direction of the insertion shaft at a portion of the insertion shaft that extends outside the resonance chamber and cannot be inserted into the drain hole. This is the summary.
According to the invention which concerns on Claim 2, it can prevent that an insertion shaft remove | deviates from a drain hole by a latching | locking part.

The gist of the invention according to claim 3 is that the insertion shaft is provided with a groove communicating with the inside and outside of the resonance chamber.
According to the invention of claim 3, in order to regulate the lateral movement of the insertion hole, even when the clearance between the drain hole and the insertion shaft is reduced, when the float portion opens the drain hole, Water can be discharged through a groove provided in the insertion shaft.

In the invention according to claim 4, the float part is accommodated in a concave part formed by denting the bottom part of the resonance chamber downward so as to be movable in the vertical direction,
The concave portion defines the concave portion over the displacement of the float portion between a state where the drain hole formed in the bottom wall of the concave portion is closed and a state where the concave portion floats on the water accumulated in the concave portion. The gist is that the vertical wall formed is formed at a depth opposite to the peripheral surface portion having the largest width of the float portion.
According to the invention which concerns on Claim 4, the attitude | position of the float part which moves to an up-down direction can be maintained with the vertical wall of a recessed part.

  According to the resonator according to the present invention, the water can be drained through the drain hole without changing the sound reduction characteristic by the drain hole.

1 is a front view showing a resonator according to a preferred embodiment of the present invention with a part broken away. It is explanatory drawing which shows the principal part of the resonator of an Example, (a) shows the case where an opening / closing means is in a normal state, (b) shows the case where an opening / closing means is in a drained state, (c) is a drained state The longitudinal section of the opening-and-closing means in is shown. (a) is a top view which shows the opening / closing means of an Example, (b) is the sectional view on the AA line of FIG. 2 (a) of an opening / closing means.

  Next, a preferred embodiment of the resonator according to the present invention will be described below with reference to the accompanying drawings. In addition, the direction of a resonator is designated on the basis of the installation attitude | position which connected the resonator to connection objects, such as an intake duct.

  As shown in FIG. 1, a resonator 10 according to an embodiment includes a resonance chamber 12 that defines a hollow resonance space 12a therein, and a cylinder that is provided in the upper portion of the resonance chamber 12 and that has a passage connected to the resonance space 12a. And an upper end portion of the connection portion 14 is connected to a connection target (not shown) such as an intake duct. The resonator 10 according to the embodiment has an opening of a box-like lower half 16 that opens above the resonance chamber 12 and a box-like upper half 18 that opens below the resonance chamber 12. The flange portions 16a and 18b extending at the edges are brought into contact with each other and assembled by engagement or adhesion with claws. The lower half 16 and the upper half 18 can be formed by molding a synthetic resin such as injection molding. In the resonator 10, a drain hole 22 is formed in the bottom portion of the resonance chamber 12 in the vertical direction, and an opening / closing means 30 capable of opening and closing the drain hole 22 is disposed at the bottom portion of the resonance chamber 12. In the embodiment, the drain hole 22 is formed in a circular shape.

  The bottom of the resonance chamber 12 where the water drain hole 22 is formed is a lowermost part of the resonance chamber 12, and the water that has entered the resonance chamber 12 is collected in the water drain hole 22. In the embodiment, the drain hole 22 is formed in the bottom wall 20a of the recess 20 formed by recessing the bottom of the resonance chamber 12 downward. The concave portion 20 of the embodiment has an opening shape opened upward to a regular square shape (see FIG. 3A), and four vertical walls 20b defining the concave portion extend in the vertical direction, and the bottom wall 20a is formed to extend in the horizontal direction (see FIG. 2).

  As shown in FIG. 2, the opening / closing means 30 includes a weight portion 32 having an insertion shaft 34 that is inserted in the drain hole 22 so as to be movable in the vertical direction, and a portion that extends inside the resonance chamber 12 in the insertion shaft 34. The float part 40 is provided. Further, the weight portion 32 is provided with a locking portion 36 that extends in the lateral direction of the insertion shaft 34 and cannot be inserted into the drain hole 22 at a portion of the insertion shaft 34 that extends to the outside of the resonance chamber 12. As described above, the weight portion 32 has the engaging portion 36 formed larger than the drain hole 22, and the engaging portion 36 is formed on the lower opening edge of the drain hole 22 (lower surface of the bottom wall 20 a of the recess 20). By abutting, the upward movement of the opening / closing means 30 is restricted. In the weight portion 32 of the embodiment, an annular locking portion 36 formed of a material having elasticity such as rubber is detachably fitted to the lower end portion of a rod-like insertion shaft 34 made of a solid body such as synthetic resin or metal. It is configured together. Here, the insertion shaft 34 can smoothly move in the vertical direction in the drain hole 22 by using a material having a small friction coefficient such as polyacetal or coating a material having a small friction coefficient such as a fluororesin. It is good to do so.

  The insertion shaft 34 is formed in such a shape that its outer peripheral surface is aligned with the drain hole 22. The insertion shaft 34 of the embodiment is in a symmetrical position across the center of the drain hole 22, and an arcuate outer peripheral surface matching the circular drain hole 22 abuts against a hole wall that defines the drain hole 22. Thus, movement in the lateral direction is restricted (see FIG. 2). Further, the insertion shaft 34 is provided with a shaft groove (groove) 35 extending in the vertical direction so as to be recessed inward in the radial direction with respect to the outer peripheral surface in contact with the hole wall. A gap is formed by the shaft groove 35 between the insertion shaft 34 inserted through the hole 22. In the insertion shaft 34 of the embodiment, four (a plurality of) shaft grooves 35 are formed in parallel at intervals of 90 ° in the circumferential direction (predetermined intervals).

  The locking portion 36 is provided with a radially extending locking groove 37 on the upper surface of the recess 20 facing the bottom wall 20a, and the recess 20 is in contact with the upper surface of the locking portion 36. A clearance is formed by the locking groove 37 between the bottom surface of the bottom wall 20a (see FIGS. 2B and 2C). In the locking portion 36 of the embodiment, four (a plurality of) locking grooves 37 are provided at intervals of 90 ° (predetermined intervals) with the insertion shaft 34 as the center, from the insertion shaft 34 to the locking portion 36. It is formed over the outer periphery, and each locking groove 37 is connected to the lower end of the shaft groove 35 at the corresponding position (see FIG. 3B). Thus, even if the weight portion 32 has a small clearance between the insertion shaft 34 and the drain hole 22 and restricts the movement in the lateral direction, the upper surface of the locking portion 36 contacts the lower surface of the bottom wall 20a of the recess 20. In the contacted state, a gap communicating with the inside and outside of the resonance chamber 12 is defined by the shaft groove 35 and the locking groove 37, and water can be discharged through this gap.

  The float 40 is formed of a material having a specific gravity smaller than that of water. As a material of the float part 40, a synthetic resin foam such as polypropylene foam or polystyrene foam, or a balsa material can be used. Further, the float part 40 is configured so as not to allow water to pass therethrough, for example, by using a closed cell structure in the case of a foam or by forming a coating layer on the surface even if it is a water-permeable material. . The float portion 40 is pulled by gravity applied to the weight portion 32 to close the drain hole 22 from the inside of the resonance chamber 12 and floats so as to open the drain hole 22 by buoyancy due to water accumulated in the recess 20. It is supposed to be configured. The float portion 40 of the embodiment is formed in a circular shape in plan view, and is formed in a spherical shape in which a lower portion 40a facing the bottom wall 20a of the recess 20 is convex downward (see FIG. 2). The lower portion 40 a of the float portion 40 is narrowed so as to incline downward from the radially outer side toward the inner side, and the base (lower portion) of the lower portion 40 a is smaller than the drain hole 22. That is, the float 40 has a base of the lower portion 40a in a normal state in which there is no water in the recess 20 or water that does not accumulate in the recess 20 so that buoyancy greater than the weight of the weight 32 acts on the float 40. Is configured to fit in the drain hole 22 and close the drain hole 22 (see FIG. 2A).

  The float portion 40 is formed such that a slight clearance is provided between a circumferential surface portion (maximum circumferential surface portion) having the largest lateral width (diameter) and the four vertical walls 20b that define the recess 20. The float portion 40 of the embodiment is configured such that the arcuate maximum outer peripheral portion is symmetrical with respect to the center of the recess 20 and is opposed to the corresponding vertical wall with a slight clearance. Here, the float 40 is not formed in the same outer shape as the recess 20, but is formed so that a gap is formed between the vertical wall 20b of the recess 20 and a size allowing water to flow. In the embodiment, the float 20 is formed. There are gaps at the four corners. Thus, the float 40 accommodated in the concave portion 20 in a state in which the vertical movement is possible is prevented from moving in the horizontal direction by the vertical wall 20b of the concave portion 20, and moves in the vertical direction while maintaining the posture. Retained. Further, the concave portion 20 extends over the vertical displacement of the float portion 40 between a state where the drain hole 22 formed in the bottom wall 20a of the concave portion 20 is closed and a state where it floats on the water accumulated in the concave portion 20. Thus, the vertical wall 20b of the recess 20 is formed with a depth facing the maximum peripheral surface portion of the float 40. In the opening / closing means 30 of the embodiment, since the upward displacement of the float portion 40 is restricted by the locking portion 36, the recessed portion 20 is larger than the vertical distance between the upper surface of the locking portion 36 and the maximum peripheral surface portion of the float portion 40. Is deeply formed. Thereby, even if the float 40 reaches the upper limit, the maximum outer peripheral portion of the float 40 does not come off from the vertical wall 20b of the recess 20, and even if the recess 20 is full, the lateral direction of the float 40 The movement can be suppressed by the vertical wall 20b.

  The opening / closing means 30 has an upper end portion of the insertion shaft 34 connected to the center of the circular float portion 40 in plan view and a lower end portion of the insertion shaft 34 connected to the center of the circular locking portion 36 in plan view ( (See FIG. 2). That is, the opening / closing means 30 is formed so that the insertion shaft 34 and the locking portion 36 of the weight portion 32 are symmetric with respect to the axis of the insertion shaft 34, and the float portion 40 about the axis of the insertion shaft 34. Are formed in a symmetric shape, and as a whole, a symmetric shape centered on the axis.

(Effects of Example)
Next, the operation of the resonator 10 according to the embodiment will be described. The opening / closing means 30 is configured so that the float 40 has the drain hole 22 in a normal state in which there is no water in the recess 20 or water that does not accumulate in the recess 20 so that buoyancy greater than the weight of the weight portion 32 acts on the float 40. Since it closes, the resonance chamber 12 is maintained to be a closed space (see FIG. 2A). When a required amount of water accumulates in the concave portion 20, the buoyancy acting on the float portion 40 becomes larger than the weight of the weight portion 32, and the float portion 40 floats upward so as to leave the drain hole 22 (FIG. 2 (b) and (See (c)). As a result, the float 40 opens the drain hole 22, and the water accumulated in the recess 20 is discharged from the drain hole 22 through the shaft groove 35. Here, even if the float 40 floats on the water accumulated in the recess 20, the opening / closing means 30 is engaged with the engaging portion 36 of the weight 32 on the bottom wall 20 a of the recess 20, so that the insertion shaft 34 extends from the drain hole 22. There is no escape. Even when the upper surface of the locking portion 36 is in contact with the lower surface of the bottom wall 20 a of the recess 20, the locking groove 37 is provided on the upper surface of the locking portion 36. Water can be discharged to the outside through the locking groove 37 facing the portion. When the water accumulated in the recess 20 is reduced and the buoyancy acting on the float 40 becomes smaller than the weight of the weight 32, the open / close means 30 closes the drain hole 22 and returns to the normal state. (See FIG. 2 (a)).

  Since the drain hole 22 is blocked by the float 40 of the opening / closing means 30 in the normal state, the resonator 10 is actually reduced from the set frequency to be reduced set in the design by the presence of the drain hole 22. The frequency does not shift, and the noise attenuation characteristic as designed is obtained. Thus, the resonator 10 can obtain the noise attenuation characteristics as designed, so that it is not necessary to increase the volume of the resonance chamber 12 as in the case where there is an open drainage hole as described in the conventional example. The resonance chamber 12 can be sized to a minimum while preventing water from accumulating in the chamber 12. In the resonator 10, the drain hole 22 can be closed by the opening / closing means 30, so that the resonance chamber 12 can be regarded as a closed space without the drain hole 22, and a set frequency can be set by a simple frequency calculation formula in designing. Can be calculated, and the deviation of the attenuation frequency between the model by analysis and the actual product can be reduced. And in order to match | combine with a design frequency, it does not require the effort which adjusts the position of the drain hole 22, etc., and the cost concerning correction | amendment of a shaping | molding die can be suppressed when shaping | molding a resonator by die shaping.

  In the opening / closing means 30, the horizontal movement of the float 40 is suppressed by the vertical wall 20b of the recess 20, and the horizontal movement of the insertion shaft 34 is also suppressed by the drain hole 22. In this state, the float 40 and The insertion shaft 34 moves up and down. That is, it is possible to prevent the posture of the float unit 40 and the insertion shaft 34 from being disturbed by vertical movement, and the float unit 40 can be operated smoothly. Moreover, even if the float part 40 is moved up and down, it can return so that the drain hole 22 is closed reliably, and noise can be reduced appropriately.

(Change example)
The present invention is not limited to the configuration of the embodiment described above, and can be modified as follows, for example.
(1) It is not always necessary to form a recess at the bottom of the resonance chamber. That is, the bottom of the resonance chamber may be flat.
(2) The insertion shaft may have an outer peripheral shape different from the opening shape of the water drain hole as long as it is configured to pass through the water drain hole so as to be movable in the vertical direction, for example, a quadrilateral inscribed in the circular water drain hole It may be a polygon such as. Further, the insertion shaft is not limited to the configuration inscribed in the drain hole, and may be formed smaller than the drain hole. In these cases, since a gap is formed between the drain hole and the outer peripheral surface of the insertion shaft, the shaft groove can be omitted.
(3) In the configuration in which the insertion shaft is inscribed in the drain hole, a through passage extending vertically is provided on the inner side of the insertion shaft, and the upper end of the through passage is located inside the resonance chamber when the float portion floats on water. It may be configured such that the lower end of the through-passage is opened at the lower surface of the weight portion facing the outside of the resonance chamber when the float portion floats on water while being opened at the facing circumferential surface.
(4) The locking portion of the weight portion may be omitted.

12 resonance chamber, 20 recess, 20a bottom wall, 20b vertical wall, 22 drain hole,
30 opening / closing means, 32 weight portion, 34 insertion shaft, 35 shaft groove (groove), 36 locking portion,
40 Float section

Claims (4)

A drain hole formed in the bottom wall of the recess formed by recessing the bottom of the resonance chamber in the downward direction,
An opening / closing means disposed in the recess for opening and closing the drain hole;
The opening / closing means includes
A weight portion having an insertion shaft that is inserted in the drain hole so as to be movable in the vertical direction;
The portion of the insertion shaft that extends to the inside of the resonance chamber is formed of a material having a specific gravity smaller than that of water, closes the drain hole from the inside of the resonance chamber, and collects water accumulated at the bottom of the resonance chamber. A float portion that floats on the water and opens the drain hole ,
The concave portion has a square shape with an opening shape,
The float portion has a circular shape in plan view and its maximum outer peripheral portion is opposed to the vertical wall of the recess,
A resonator having a structure in which lateral movement of the float portion is restricted by four vertical walls of the concave portion .   The weight portion is provided with a locking portion that extends in a lateral direction of the insertion shaft and cannot be inserted into the drain hole at a portion of the insertion shaft that extends outside the resonance chamber. Resonator.   The resonator according to claim 1 or 2, wherein the insertion shaft is provided with a groove communicating with the inside and outside of the resonance chamber. The float part is accommodated in a concave part formed by denting the bottom part of the resonance chamber downward so as to be movable in the vertical direction.
The concave portion defines the concave portion over the displacement of the float portion between a state where the drain hole formed in the bottom wall of the concave portion is closed and a state where the concave portion floats on the water accumulated in the concave portion. The resonator according to any one of claims 1 to 3, wherein the formed vertical wall is formed with a depth facing a peripheral surface portion having the largest lateral width of the float portion.

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