Muffler

Abstract

A muffler (10) comprises: a muffler body (20); a sixth baffle plate (50) which is a baffle plate partitioning the interior of the muffler body (20); and a connection pipe (82) extending from the sixth baffle plate (50). The sixth baffle plate (50) comprises: a partition surface (100) that partitions the interior of the muffler body (20) into one side (I) and the other side (T); and an opening (104), that is formed in the partition surface (100) and allows an exhaust gas (G) to flow to a seventh space (72) which is a space on the one side (I). The partition surface (100) of the sixth baffle plate (50) has a funnel shape that is recessed toward the other side (T). The sixth baffle plate (50) has a funnel shape in which the partition surface (100) is recessed toward the other side (T), and has a guide part (106) that guides exhaust gas (G) in a seventh space (72) as one side space to a connection pipe (82) projecting toward the other side (T).

Description

Silencer

[0001] The present invention relates to a silencer.

[0002] JP2015-209829A discloses a silencer. The silencer includes a lid that closes an exhaust inlet opening at an exhaust inflow side end of an outlet pipe. An exhaust inlet provided with a valve body is formed in the lid, and the exhaust inlet is opened and closed according to the engine rotation speed.

[0003] In the silencer of Patent Document 1, when the exhaust gas flowing into the outlet pipe passes through the exhaust inlet of the lid, a constriction flow and a vortex occur, resulting in a problem that the airflow sound becomes large.

[0004] The present invention has been made in view of the above problems, and an object thereof is to be able to suppress the generation of airflow sound.

[0005] According to an aspect of the present invention, the silencer includes a silencer body, a baffle plate that partitions the inside of the silencer body, and a pipe that extends from the baffle plate. The baffle plate has a partition surface that partitions the inside of the silencer body into one side and the other side, an opening formed in the partition surface for allowing exhaust gas to flow into the one-side space on the one side, and a funnel shape in which the partition surface is recessed toward the other side, and a guide portion that guides the exhaust gas in the one-side space to the pipe that extends toward the other side.

[0006] In the above aspect, the exhaust gas sent to the one-side space on one side of the partition surface of the baffle plate is guided to the connection pipe by the funnel-shaped guide portion formed in the partition surface. At this time, the exhaust gas in the one-side space is collected in the central portion by the guide portion whose opening portion expands in a funnel shape, so that the constriction flow of the exhaust gas passing through the opening portion is suppressed. As a result, the generation of vortices generated in the constriction portion is reduced.

[0007] Therefore, the silencer can suppress the generation of airflow sound as compared with a case where the generation of vortices caused by the constriction flow of the exhaust gas passing through the opening portion cannot be suppressed.

[0008] Figure 1 is a perspective view showing the inside of a silencer according to an embodiment of the present invention. Figure 2 is a side view of the baffle plate. Figure 3 is a front view of the baffle plate. Figure 4 is a cross-sectional view showing the baffle plate with the connecting pipe fitted inside. Figure 5 is a cross-sectional view showing the baffle plate with the connecting pipe fitted outside. Figure 6 is a diagram showing the evaluation results. Figure 7 is an explanatory diagram for explaining the flow of exhaust gas. Figure 8 is a diagram showing the relationship between engine speed and airflow noise. Figure 9 is a cross-sectional view showing a first modified example. Figure 10 is a side view of the baffle plate of the first modified example. Figure 11 is a side view of the baffle plate of the second modified example. Figure 12 is a cross-sectional view showing a third modified example.

[0009] Hereinafter, a silencer 10 according to an embodiment of the present invention will be described with reference to the drawings.

[0010] First, the overall configuration of the silencer 10 will be described with reference to Figure 1. Figure 1 is a perspective view showing the inside of the silencer 10 according to an embodiment of the present invention.

[0011] As shown in Figure 1, the silencer 10 is a device installed, for example, in the exhaust path of an automobile to reduce the exhaust noise emitted from the engine. In this embodiment, the case in which the silencer 10 is used in the exhaust path of an automobile is given as an example, but the use of the silencer 10 is not limited to this. The silencer 10 may also be used by connecting it to, for example, factory piping (ducts), air conditioning system piping, or other fluid system piping.

[0012] The silencer 10 comprises a silencer body 20, an inlet pipe 22 that guides exhaust gas G into the silencer body 20, and a plurality of baffle plates (40, 42, 44, 46, 48, 50) that partition the inside of the silencer body 20.

[0013] The baffle plate is composed of a first baffle plate 40, a second baffle plate 42, a third baffle plate 44, a fourth baffle plate 46, a fifth baffle plate 48, and a sixth baffle plate 50. Each baffle plate 40, 42, 44, 46, 48, and 50 is a press-formed product formed by press molding. Each baffle plate 40, 42, 44, 46, 48, and 50 may be formed by a 3D printer or other manufacturing method.

[0014] The first baffle plate 40, the second baffle plate 42, the third baffle plate 44, the fourth baffle plate 46, and the fifth baffle plate 48 are formed to be substantially the same shape. The sixth baffle plate 50 has a different shape from each of the baffle plates 40, 42, 44, 46, and 48. Details of the sixth baffle plate 50 will be described later.

[0015] (Silencer body) The silencer body 20 has a cylindrical portion 34 formed in a cylindrical shape, an end plate 38 provided at one end of the cylindrical portion 34 to close the end opening on that end, and an end plate 36 provided at the other end of the cylindrical portion 34 to close the end opening on the other end. The inlet pipe 22 described above is connected to the cylindrical portion 34 of the silencer body 20, and exhaust gas G discharged from the engine is introduced into the silencer body 20 via the inlet pipe 22.

[0016] The silencer body 20 has baffle plates 40, 42, 44, 46, 48, and 50 arranged sequentially at intervals along the longitudinal direction of the silencer body 20. Inside the silencer body 20, a first space 60, a second space 62, a third space 64, a fourth space 66, a fifth space 68, a sixth space 70, and a seventh space 72 are formed, each partitioned by the baffle plates 40, 42, 44, 46, 48, and 50.

[0017] The first baffle plate 40, the second baffle plate 42, the third baffle plate 44, the fourth baffle plate 46, and the fifth baffle plate 48 have communication holes (not shown) that connect adjacent spaces (60, 62, 64, 66, 68, 70). As a result, some of the exhaust gas G guided from the inlet pipe 22 into the fifth space 68 flows into the sixth space 70, while the rest flows into the first space 60 via the fourth space 66, the third space 64, and the second space 62.

[0018] Inside the silencer body 20, there is a cylindrical introduction pipe 80 through which each of the baffle plates 40, 42, 44, 46, and 48 is inserted, guiding the exhaust gas G in the first space 60, which is the upstream side, to the seventh space 72, which is the side space. Also inside the silencer body 20, there is a connecting pipe 82, which is a cylindrical pipe that is constructed separately from each of the baffle plates 40, 42, 44, 46, 48, and 50, and extends from the sixth baffle plate 50, specifically connected to the sixth baffle plate 50.

[0019] The connecting pipe 82 passes through each of the baffle plates 40, 42, 44, 46, and 48, and extends outside the silencer body 20 by passing through the end plate 36 on the other end. A tailpipe 84 is connected to the end of the connecting pipe 82 that extends outside the silencer body 20. The tailpipe 84 discharges the exhaust gas G flowing in from the connecting pipe 82 through an outlet 86 that is open to the outside.

[0020] (Sixth Baffle Plate) Next, the sixth baffle plate 50, to which the introduction pipe 80 is inserted and the connecting pipe 82 is connected, will be described in detail using Figures 2 to 5.

[0021] Figure 2 is a side view of the sixth baffle plate 50 as a baffle plate. Figure 3 is a front view of the sixth baffle plate 50 as a baffle plate. Figure 4 is a cross-sectional view showing the sixth baffle plate 50 with the connecting pipe 82 fitted inside. Figure 5 is a cross-sectional view showing the sixth baffle plate 50 with the connecting pipe 82 fitted outside.

[0022] As shown in Figures 2 and 3, the sixth baffle plate 50 has a partition surface 100 that divides the inside of the silencer body 20 into one side I, the seventh space 72 side, and the other side T, the sixth space 70. The partition surface 100 is formed in the same shape as the cross-sectional shape of the silencer body 20 (see Figure 3). A flange 102 extending toward the seventh space 72 side is formed around the entire periphery of the partition surface 100 (see Figures 1 and 2). The flange 102 is fixed to the inner surface of the silencer body 20 when the sixth baffle plate 50 is placed inside the silencer body 20 (see Figure 1).

[0023] As shown in Figure 3, a circular opening 104 is formed on the lower side of Figure 3, with the longitudinal center of the partition surface 100 as the boundary, for allowing exhaust gas G to flow into the seventh space 72, which is the one-sided space of one side I. The opening 104 allows the aforementioned introduction pipe 80 to be inserted, and the introduction pipe 80 is fixed to the sixth baffle plate 50 (see Figure 1).

[0024] As shown in Figures 2 and 3, a guide portion 106 is formed in the longitudinal center of the partition surface 100. The guide portion 106 is positioned offset to one side from the short-side center of the partition surface 100. Note that the guide portion 106 can also be located in the center of the partition surface 100 to obtain the effects described later.

[0025] The guide section 106 is formed in a funnel shape with the partition surface 100 recessed toward the sixth space 70, which is the other side T. As a result, the exhaust gas G that flows from the introduction pipe 80 into the seventh space 72 is guided to the guide section 106 along the surface of the partition surface 100 of the sixth baffle plate 50. The guide section 106 then guides the guided exhaust gas G to the connecting pipe 82 which is connected to the end that protrudes toward the sixth space 70, which is the other side T.

[0026] Specifically, the guide portion 106 has a cylindrical portion 110 to which the connecting pipe 82 is connected, a flared portion 112 that widens in diameter from the cylindrical portion 110 toward the partition surface 100, and a rounded curved portion 114 formed between the cylindrical portion 110 and the flared portion 112. Note that the guide portion 106 may also have a structure without the curved portion 114, as will be described later (see Figure 9).

[0027] (Cylindrical section) The cylindrical section 110 is formed in a cylindrical shape. A cylindrical connecting pipe 82 is connected to the cylindrical section 110. Methods for connecting the cylindrical section 110 and the connecting pipe 82 include fitting the end of the connecting pipe 82 into the cylindrical section 110 (see Figure 4) and fitting the end of the connecting pipe 82 into the cylindrical section 110 (see Figure 5).

[0028] (Flared section) The flared section 112 is positioned offset to one side from the center of the partition surface 100 in the short direction. Therefore, the first length N1 on one side of the partition surface 100 in the short direction is shorter than the second length N2 on the other side of the partition surface 100 in the short direction (see Figure 3).

[0029] The flare angle α, which is the angle formed between the central axis C of the connecting pipe 82 connected to the guide section 106 and the inner surface 112A of the flared section 112, is set within the range of 20 degrees to 70 degrees. Preferably, this flare angle α is set within the range of 30 degrees to 50 degrees.

[0030] Furthermore, if the flare angle α of the flared portion 112 exceeds 70 degrees, the flared portion 112 may come into contact with the outer edge of the partition surface 100, or the widened flared portion 112 may reach the adjacent opening 104. For this reason, the upper limit of the flare angle α is set to 70 degrees in order to ensure an appropriate shape for the flared portion 112.

[0031] (Curved surface) The curved surface 114 has an angle radius (R) that indicates the curvature of the curved surface 114, which is set within the range of R3 to R40. It is preferable that this angle radius be set to the largest value within the range of R3 to R40, which is R40.

[0032] R3 represents the curve represented by a circular arc with a radius of 3 mm. R40 represents the curve represented by a circular arc with a radius of 40 mm.

[0033] Furthermore, if the radius of the corner of the curved portion 114 exceeds R40, the curved portion 114 will encroach upon the area of ​​the flared portion 112. For this reason, the upper limit of the radius of the corner of the curved portion 114 is set to R40 in order to properly form the curved portion 114 and maintain the shape of the flared portion 112.

[0034] (Evaluation Results) Figure 6 shows the evaluation results, which are obtained from the perspective of the flare angle α and angle R of the guide portion 106.

[0035] [Noise Reduction Evaluation Test] In the noise reduction evaluation test, a comparative product was set in the silencer 10, in which a cylindrical pipe was inserted through a baffle plate and the tip of the cylindrical pipe, which had multiple small holes formed on its circumferential surface, protruded from the baffle plate. The airflow noise was measured in the silencer 10 in which the comparative product was set.

[0036] Furthermore, a sixth baffle plate 50 with a predetermined flare angle α of the guide section 106 and a predetermined angle R was used as a simulation product. The airflow noise generated in the silencer 10 with the simulation product installed was analyzed by simulation and compared with a comparative product.

[0037] The predetermined angles for flare angle α were set to 5 degrees, 10 degrees, 20 degrees, 30 degrees, 35 degrees, 40 degrees, 50 degrees, 60 degrees, and 70 degrees. The predetermined values ​​for angle R at each flare angle α were set to R3, R10, R15, R20, and R40. The generated airflow noise was calculated based on the magnitude of vorticity analyzed for each simulated product.

[0038] In the noise reduction evaluation test, a silencer 10 equipped with the simulation product was deemed to pass if the loudness of the airflow noise generated was -3 dB(A) or less than the loudness of the airflow noise generated by the silencer 10 equipped with the comparison product.

[0039] As a result, the airflow noise level of all silencers 10 equipped with the simulation product was -3 dB(A) or less than that of the silencer 10 equipped with the comparison product, and was therefore deemed acceptable.

[0040] In other words, it was found that a silencer 10 in which the flare angle α of the guide portion 106 is within the range of 5 degrees to 70 degrees, and the corner radius R of the guide portion 106 is within the range of R3 to R40, has a higher sound-reducing effect than a silencer 10 with a comparative product installed.

[0041] Furthermore, it was found that the sound-dampening effect of the silencer 10 with the simulated product installed was particularly high when the angle radius was R40 and the flare angle α was between 40 and 60 degrees.

[0042] [Manufacturability Test] The manufacturability test is a test for evaluating manufacturability based on the sheet thickness reduction rate when a flat blank material is press-formed to form the sixth baffle plate 50.

[0043] In the manufacturability test, the reduction rate of the sheet thickness when press-forming the blank material with the flare angle α of the guide part 106 set to a predetermined angle and the corner R set to a predetermined value is analyzed by simulation.

[0044] In the table T of FIG. 6, the predetermined angles of the flare angle α are 5 degrees, 10 degrees, 20 degrees, 30 degrees, 35 degrees, 40 degrees, 50 degrees, 60 degrees, 70 degrees, and the results based on the reduction rate of the sheet thickness when the predetermined values of the corner R at each flare angle α are R3, R10, R15, R20, R40 are shown.

[0045] In the table T, the specific values of the reduction rate of the sheet thickness are omitted, and the qualified area P where the reduction rate of the sheet thickness is 30% or less is indicated by diagonal lines.

[0046] According to this manufacturability test, it was found that the muffler 10 in which the flare angle α of the guide part 106 is within the range of 20 degrees or more and 70 degrees or less and the corner R is set within the range of R3 or more and R15 or less becomes a qualified product. Also, if the flare angle α of the guide part 106 is within the range of 30 degrees or more and 50 degrees or less, it was found that all mufflers 10 become qualified products regardless of the range in which the corner R is set from R3 or more to R40 or less.

[0047] Considering the condition that the corner R is R40 and the flare angle α is within the range of 40 degrees or more and 60 degrees or less, where the muffling effect is particularly high in the muffling evaluation test, it was found that it is desirable to set the guide part 106 in the high-effect area K where the corner R is R40 and the flare angle α is within the range of 40 degrees or more and 50 degrees or less.

[0048] (Function and Effect) According to the above embodiment, the following effects are achieved. The function and effect of this embodiment will be described while referring to FIGS. 7 and 8. FIG. 7 is an explanatory diagram for explaining the flow of the exhaust gas G. FIG. 8 is a diagram showing the relationship between the engine speed and the airflow noise.

[0049] The silencer 10 of this embodiment comprises a silencer body 20, a sixth baffle plate 50 as a baffle plate that partitions the inside of the silencer body 20, and a connecting pipe 82 extending from the sixth baffle plate 50. The sixth baffle plate 50 comprises a partition surface 100 that partitions the inside of the silencer body 20 into one side I and the other side T, and an opening 104 formed in the partition surface 100 for allowing exhaust gas G to flow into the seventh space 72, which is the one-side space of the one-side I. The sixth baffle plate 50 has a funnel shape with the partition surface 100 recessed toward the other side T, and has a guide portion 106 that guides the exhaust gas G from the seventh space 72, which is the one-side space, to the connecting pipe 82 that protrudes toward the other side T.

[0050] In this configuration, the exhaust gas G sent to the seventh space 72 on one side I of the partition surface 100 of the sixth baffle plate 50 is guided to the connecting pipe 82 by a funnel-shaped guide portion 106 formed on the partition surface 100 (see Figure 7).

[0051] The exhaust gas G in the seventh space 72 is gently collected towards the center along the inner surface 112A of the guide portion 106, which has a funnel-shaped opening that opens into the seventh space 72. Furthermore, the opening of the guide portion 106 that opens into the seventh space 72 is wider than the pipe opening 82A at the end of the connecting pipe 82 (see Figure 7). As a result, the constriction 130 of the exhaust gas G that passes through the opening of the guide portion 106 is suppressed. Consequently, the generation of vortices 132 in the constricted portion is reduced.

[0052] Therefore, the silencer 10 can suppress the generation of airflow noise compared to a case where, for example, an opening without a guide portion 106 cannot suppress the generation of vortices 132 caused by the constriction 130 of exhaust gas G passing through the opening.

[0053] Figure 8 shows the relationship between the engine speed of the engine into which the exhaust gas G is introduced and the generated airflow noise for the porous structure silencer 140 and the silencer 10 of this embodiment. In the porous structure silencer 140, a connecting pipe 82 is inserted through a sixth baffle plate 50 which does not have a guide portion 106, and a plurality of small holes are formed on the circumferential surface of the connecting pipe 82 that protrudes from the sixth baffle plate 50.

[0054] Figure 8 confirms that the silencer 10 of this embodiment can reduce airflow noise in the high-speed region 144 compared to the porous silencer 140.

[0055] Furthermore, even when the flare angle α of the guide portion 106 of the silencer 10 was varied within the range of 20 degrees to 70 degrees and the angle R being between R3 and R40, characteristics equivalent to those shown in Figure 8 were obtained.

[0056] The silencer 10 of this embodiment further includes an introduction pipe 80 that is inserted into the opening 104 and guides the exhaust gas G flowing in from the upstream side to the seventh space 72, which is a one-sided space. The guide section 106 guides the exhaust gas G that has flowed from the introduction pipe 80 into the seventh space 72, which is a one-sided space, along the surface of the sixth baffle plate 50.

[0057] In this configuration, exhaust gas G from the upstream side is introduced into the seventh space 72 via an introduction pipe 80 inserted into the opening 104 of the sixth baffle plate 50. This allows exhaust gas G from the first space 60, which is far from the seventh space 72, to be introduced into the seventh space 72 via the introduction pipe 80.

[0058] In the silencer 10 of this embodiment, the guide portion 106 has a cylindrical portion 110 that is continuous with the connecting pipe 82, and a flared portion 112 that expands in diameter as it moves from the cylindrical portion 110 toward the partition surface 100.

[0059] In this configuration as well, the silencer 10 can suppress the generation of airflow noise.

[0060] In the silencer 10 of this embodiment, the flare angle α, which is the angle formed between the central axis C of the connecting pipe 82 as a pipe and the inner surface 112A of the flared portion 112, is 20 degrees or more and 70 degrees or less (see Figure 2).

[0061] In this configuration, even if the corner radius of the guide portion 106 of the silencer 10 is set within the range of R3 to R15, it is possible to suppress the reduction in plate thickness when pressing a flat blank material to form the sixth baffle plate 50 to 30% or less. This makes it possible to guarantee the quality of the press-formed sixth baffle plate 50.

[0062] Furthermore, compared to the case where the flare angle α is set to less than 20 degrees, the silencer 10 can suppress the flow velocity of the exhaust gas G in the connecting pipe 82 and the vorticity of the vortices 132 generated in the connecting pipe 82, thereby suppressing the generated airflow noise.

[0063] Furthermore, since the flare angle α can be adjusted over a wide range of 20 to 70 degrees, it is possible to tune the airflow noise reduction effect while suppressing the generated airflow noise.

[0064] Furthermore, in the silencer 10 of this embodiment, the flare angle α is 30 degrees or more and 50 degrees or less.

[0065] In this configuration, even if the corner radius of the guide portion 106 of the silencer 10 is set within the range of R3 to R40, it is possible to suppress the reduction in plate thickness when pressing a flat blank material to form the sixth baffle plate 50 to 30% or less. This makes it possible to guarantee the quality of the press-formed sixth baffle plate 50.

[0066] Furthermore, the silencer 10 allows for a wider range of selectable angles (R) compared to when the flare angle α is set to between 20 and 70 degrees.

[0067] Furthermore, by setting the flare angle α of the silencer 10 to 30 degrees or more and 50 degrees or less, the vorticity of the vortices 132 generated in the connecting pipe 82 can be further suppressed, thereby enabling further reduction of the generated airflow noise.

[0068] In the silencer 10 of this embodiment, the guide portion 106 further has a curved portion 114 provided between the cylindrical portion 110 and the flared portion 112.

[0069] In this configuration, even if the silencer 10 has a curved surface portion 114 between the cylindrical portion 110 and the flared portion 112 of the guide portion 106, it is possible to suppress the generation of airflow noise in the same way as described above.

[0070] Furthermore, in the silencer 10 of this embodiment, the corner radius of the curved portion 114 is R3 or more and R40 or less.

[0071] In this configuration, the silencer 10 can suppress the flow velocity of the exhaust gas G in the connecting pipe 82 and the vorticity of the vortices 132 generated in the connecting pipe 82, compared to the case where the corner radius R of the curved portion 114 of the guide portion 106 is set to less than R3. This makes it possible to suppress the generated airflow noise.

[0072] Furthermore, since the radius of the corner of the curved portion 114 can be adjusted over a wide range of R3 to R40, it becomes possible to tune the airflow noise reduction effect while suppressing the generated airflow noise.

[0073] In this embodiment, the muffler 10, specifically the sixth baffle plate 50, is a press-formed product formed by press molding.

[0074] In this configuration, since the sixth baffle plate 50 is a press-formed product, when press-forming the sixth baffle plate 50, it is possible to form a funnel-shaped guide portion 106 recessed to one side I and an opening 104 on the partition surface 100.

[0075] In this embodiment, an example of the configuration of the sixth baffle plate 50 of the silencer 10 is shown, but the sixth baffle plate 50 is not limited to this shape and may be configured as shown below.

[0076] (First Modified Example) Figure 9 is a cross-sectional view showing the first modified example. Figure 10 is a side view of the baffle plate (50) of the first modified example. Figure 9 shows an enlarged cross-sectional view of the sixth baffle plate 50.

[0077] As shown in Figures 9 and 10, the sixth baffle plate 50 of the silencer 200 according to the first modified example eliminates the curved portion 114 provided between the cylindrical portion 110 and the flared portion 112 of the guide portion 106, compared to the embodiment. Furthermore, in the sixth baffle plate 50 of the silencer 200 according to the first modified example, the flared portion 112 constituting the guide portion 106 is made of a curved surface.

[0078] To explain in more detail, the flared portion 112 of the sixth baffle plate 50 is formed in a curved shape such that, when a plane is imagined passing through the central axis C of the connecting pipe 82 (see Figure 9), the cross-sectional shape along this plane protrudes toward the central axis C of the connecting pipe 82.

[0079] In the first modified example, the flare angle α is represented by the angle between the straight line 206 passing through the first contact point 202 where the flared portion 112 and the cylindrical portion 110 are in contact, and the second contact point 204 where the flared portion 112 and the partition surface 100 are in contact, and the central axis C of the connecting pipe 82.

[0080] The flare angle α is set within the range of 20 degrees to 70 degrees, similar to the embodiment. Preferably, this flare angle α is set within the range of 30 degrees to 50 degrees.

[0081] In this modified example, the same effects and advantages as in the previously described embodiment can be obtained, except for the portion where the curved surface portion 114 is formed between the cylindrical portion 110 and the flared portion 112.

[0082] Furthermore, in the silencer 10 of this embodiment, the flared portion 112 is formed in a curved shape with a cross-sectional shape that follows a plane passing through the central axis C of the connecting pipe 82, and protrudes toward the central axis C of the connecting pipe 82.

[0083] This configuration allows the silencer 10 to smoothly guide the exhaust gas G along the flared section 112.

[0084] Furthermore, in the silencer 10 of this embodiment, the flare angle α is the angle formed by the straight line 206 passing through the first contact point 202 where the flared portion 112 and the cylindrical portion 110 are in contact and the second contact point 204 where the flared portion 112 and the partition surface 100 are in contact, and the central axis C of the connecting pipe 82 as a pipe.

[0085] In this configuration, the silencer 10 can express the flare angle α as the angle formed by the aforementioned straight line 206 and the central axis C of the connecting pipe 82.

[0086] (Second modified example) Figure 11 is a side view of the baffle plate (50) of the second modified example.

[0087] As shown in Figure 11, the guide portion 106 of the sixth baffle plate 50 of the silencer 210 according to the second modified example has a shorter length of the flared portion 112 in the axial direction of the connecting pipe 82 compared to the first modified example.

[0088] In this modified example, the same effects and benefits as in the second modified example can be obtained.

[0089] (Third Modification) Figure 12 is a cross-sectional view showing the third modification.

[0090] In the third modified silencer 220, the sixth baffle plate 50 of the guide portion 106 expands in diameter as it approaches the connecting pipe 82. As a result, the cross-sectional shape of the cylindrical portion 110 becomes a curve or a free curve.

[0091] In this modified example, the same effects and advantages as those of the previously described embodiment can be obtained.

[0092] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments.

[0093] In other words, although the above-described embodiment explained the case in which the sixth baffle plate 50 and the connecting pipe 82 extending from the sixth baffle plate 50 are configured as separate components, the sixth baffle plate 50 and the connecting pipe 82 may be configured as a single unit.

[0094] This application claims priority based on Japanese Patent Application No. 2024-213324, filed with the Japan Patent Office on December 6, 2024, the entire contents of which application are incorporated herein by reference. This application also claims priority based on Japanese Patent Application No. 2025-190477, filed with the Japan Patent Office on November 11, 2025, the entire contents of which application are incorporated herein by reference.

Claims

1. A silencer comprising: a silencer body; a baffle plate partitioning the inside of the silencer body; and a pipe extending from the baffle plate, wherein the baffle plate has: a partition surface dividing the inside of the silencer body into one side and the other side; an opening formed in the partition surface for allowing exhaust gas to flow into the one side space; and a guide portion which is funnel-shaped with the partition surface recessed toward the other side, for guiding the exhaust gas from the one side space to the pipe extending toward the other side.

2. A silencer according to claim 1, further comprising an introduction pipe inserted into the opening and guiding exhaust gas flowing in from the upstream side into the one-side space, wherein the guide portion guides the exhaust gas flowing in from the introduction pipe into the one-side space along the surface of the baffle plate.

3. A silencer according to claim 1, wherein the guide portion comprises a cylindrical portion continuous with the pipe and a flared portion that expands in diameter from the cylindrical portion toward the partition surface.

4. A silencer according to claim 3, wherein the flared portion is formed in a curved shape.

5. A silencer according to claim 4, wherein the flared portion is formed in a curved shape with a cross-sectional shape along a plane passing through the central axis of the pipe that protrudes toward the central axis of the pipe.

6. A silencer according to claim 3 or claim 4, wherein the flare angle formed by the central axis of the pipe and the inner surface of the flared portion is 20 degrees or more and 70 degrees or less.

7. A silencer according to claim 6, wherein the flare angle is 30 degrees or more and 50 degrees or less.

8. A silencer according to claim 6, wherein the flare angle is the angle formed by a straight line passing through a first contact point where the flared portion and the cylindrical portion are in contact and a second contact point where the flared portion and the partition surface are in contact, and the central axis of the pipe.

9. A silencer according to claim 3, wherein the guide portion further comprises a curved portion provided between the cylindrical portion and the flared portion.

10. A silencer according to claim 9, wherein the radius of the curved portion is R3 or more and R40 or less.

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