JP4759700B2 - Exhaust structure - Google Patents

Description

  The present invention relates to an exhaust structure for a vehicle.

  In a general automobile exhaust structure, a muffler is coupled to a vehicle rear end portion of an exhaust pipe through which exhaust from the vehicle body side is sent out (see, for example, Patent Document 1).

  In this exhaust structure, the exhaust pipe and the muffler are generally connected to the entire circumference of the exhaust pipe by welding so that even when a load on the rear side of the vehicle is input to the muffler when the road surface of the vehicle interferes. Will not be released.

  However, the exhaust pipe and the muffler are wire joints, and it is necessary to take measures such as increasing the thickness by reducing the fatigue strength compared to other parts.

  Furthermore, due to variations in welding at the joint between the exhaust pipe and the muffler, the variation in the coupling strength between the exhaust pipe and the muffler is large.

  In addition, rust is likely to occur at the welded portion of the exhaust pipe and the muffler, resulting in poor appearance.

Therefore, a means for coupling the exhaust pipe and the muffler other than welding is desired, but there is no coupling means that can withstand load input when the muffler interferes with the road surface.
JP 2001-323809 A

  In consideration of the above-mentioned fact, the present invention combines the input exhaust pipe and the support exhaust pipe connected to the vehicle body by press-fitting, and when both axial loads are input to the input exhaust pipe. It is an object to obtain an exhaust structure capable of maintaining the coupling of the exhaust pipe.

The exhaust structure according to claim 1 sends exhaust from the vehicle body side , interferes with the road surface, and receives an input of an input exhaust pipe, and is press-fitted into an end of the input exhaust pipe along the load input direction. And a support exhaust pipe that is supported by a vehicle body at a portion other than the input exhaust pipe and allows exhaust to pass between the input exhaust pipe and the input exhaust pipe.

  The exhaust structure according to claim 2 is the exhaust structure according to claim 1, wherein a clearance is provided so that a press-fitting amount between the input exhaust pipe and the support exhaust pipe can be increased by an axial compression force. It is characterized by that.

  The exhaust structure according to claim 3 is the exhaust structure according to claim 1 or 2, wherein the exhaust structure is provided in the vicinity of a press-fitting position of at least one of the input exhaust pipe and the support exhaust pipe, and is press-fitted with an axial compressive force. It has the restriction part which restricts the amount of press-fitting to be characterized.

The exhaust structure according to claim 4 is coupled with an input exhaust pipe that sends exhaust from the vehicle body side , interferes with a road surface and receives a load, and is connected to the input exhaust pipe by press-fitting and seizure. A support exhaust pipe that is supported by the vehicle body at a portion other than the exhaust pipe and allows exhaust to pass between the input exhaust pipe and the input exhaust pipe.
The exhaust structure according to claim 5 is characterized in that, in the exhaust structure according to claim 4 , the input exhaust pipe and the support exhaust pipe are baked by exhaust of the engine due to operation of the vehicle.

  In the exhaust structure according to the first aspect, the input exhaust pipe and the support exhaust pipe are coupled, and the exhaust from the vehicle body side is sent out through the input exhaust pipe and the support exhaust pipe. Also, a load is input to the input exhaust pipe.

  Here, the support exhaust pipe is supported by the vehicle body at a portion other than the input exhaust pipe, and the support exhaust pipe is coupled to the end of the input exhaust pipe along the load input direction by press-fitting.

  For this reason, when a load is input to the input exhaust pipe, the load in the press-fitting direction acts on the press-fitting position of the input exhaust pipe and the support exhaust pipe in a state where the support exhaust pipe is prevented from moving. Thereby, the coupling | bonding of an input exhaust pipe and a support exhaust pipe can be maintained reliably.

  In the exhaust structure according to the second aspect, a clearance is provided so that the amount of press-fitting between the input exhaust pipe and the support exhaust pipe can be increased by an axial compression force (pressure input). For this reason, when a load is input to the input exhaust pipe, the amount of press-fitting between the input exhaust pipe and the support exhaust pipe increases, and an enlarged deformation force acts on either the input exhaust pipe or the support exhaust pipe. At the same time, a contraction deformation force acts on either the input exhaust pipe or the support exhaust pipe. Thereby, the coupling force between the input exhaust pipe and the support exhaust pipe is improved, and the coupling between the input exhaust pipe and the support exhaust pipe can be more reliably maintained.

  In the exhaust structure according to the third aspect, the limiting portion provided in the vicinity of the press-fitting position of at least one of the input exhaust pipe and the support exhaust pipe limits the press-fitting amount that is press-fitted by the axial compression force (press input). For this reason, when a load is input to the input exhaust pipe, the amount of press-fitting between the input exhaust pipe and the support exhaust pipe is limited, so that the relative position change between the input exhaust pipe and the support exhaust pipe can be suppressed. .

  In the exhaust structure according to the fourth aspect, the input exhaust pipe and the support exhaust pipe are coupled, and the exhaust from the vehicle body side is sent out through the input exhaust pipe and the support exhaust pipe. Also, a load is input to the input exhaust pipe.

  Here, the support exhaust pipe is supported by the vehicle body at a portion other than the input exhaust pipe, and the input exhaust pipe and the support exhaust pipe are coupled not only by press fitting but also by seizure.

  For this reason, when the support exhaust pipe is coupled to the end of the input exhaust pipe along the load input direction, when the load is input to the input exhaust pipe, the support exhaust pipe is prevented from moving. A load in the press-fitting direction acts on the press-fitting position of the input exhaust pipe and the support exhaust pipe. Thereby, the coupling | bonding of an input exhaust pipe and a support exhaust pipe can be maintained reliably.

  On the other hand, when the support exhaust pipe is coupled to the end of the input exhaust pipe along the counter-load input direction, the load is not moved when the load is input to the input exhaust pipe. Even if a load on the opposite side of the press-fitting direction acts on the press-fitting position of the input exhaust pipe and the support exhaust pipe, the connection between the input exhaust pipe and the support exhaust pipe can be maintained.

  FIG. 1 shows a side view of an exhaust structure 10 of a vehicle (automobile) according to an embodiment of the present invention as viewed from the left side of the vehicle, and FIG. 2 shows the exhaust structure 10 as viewed from the lower side of the vehicle. It is shown in the bottom view. In the drawings, the front of the vehicle is indicated by an arrow FR, and the rear of the vehicle is indicated by an arrow RE.

  The exhaust structure 10 according to the present embodiment includes a pair of circular front pipes 12 as support exhaust pipes, and one end 12A of each front pipe 12 is connected to an engine exhaust port (not shown) provided on the vehicle body side. It is fixed and supported on the vehicle body side. A catalytic converter 14 is provided at an intermediate portion of each front pipe 12, and exhaust gas sent from the exhaust port of the engine is purified by the catalytic converter 14.

  The other end 12B of each front pipe 12 is connected to one end 16A of a substantially elliptic cylindrical container-shaped main muffler 16 (silencer) as an input exhaust pipe. The main muffler 16 is made of rubber (not shown) as an elastic body. Is omitted).

  As shown in FIG. 3, a pair of circular intake pipes 17 as connecting pipes are provided in the main muffler 16, and each of the intake pipes 17 has one end 17 </ b> A from one end 16 </ b> A of the main muffler 16 to the outside. While projecting, the vicinity of one end 17 </ b> A is welded to the peripheral wall of the main muffler 16. The other end 12B of each front pipe 12 is coupled to one end 17A of each intake pipe 17, and the other end 12B of each front pipe 12 has a large load (for example, 2 to 4 tons) in one end 17A of each intake pipe 17. Press-fitted with a ton load) and surface bonded.

  In the main muffler 16, partition walls 18, 20, and 22 are provided in order from the vehicle front side, whereby the main muffler 16 is divided into compartments 24, 26, 28, and 30 in order from the vehicle front side. Each inlet pipe 17 penetrates the partition walls 18, 20, and 22, the other end 17 </ b> B edge of each inlet pipe 17 is closed, and a plurality of compartments 28 are arranged in the inlet pipe 17. A small hole (not shown) is formed through. A predetermined number of through holes (not shown) are formed through the partition walls 18 and 20.

  In the main muffler 16, a circular discharge pipe 32 is provided as a coupling pipe. The discharge pipe 32 passes through the partition walls 20 and 22, and one end 32 </ b> A is disposed in the compartment 26. The other end 32 </ b> B of the discharge pipe 32 protrudes from the other end 16 </ b> B of the main muffler 16, and the vicinity of the other end 32 </ b> B of the discharge pipe 32 is welded to the peripheral wall of the main muffler 16.

  For this reason, the exhaust gas sent from each front pipe 12 to each intake pipe 17 passes through a plurality of small holes, compartments 28, through holes in the partition walls 20 and compartments 26, or each The discharge pipe 32 passes through the plurality of small holes of the intake pipe 17, the compartment 28, the through hole of the partition wall 20, the compartment 26, the through hole of the partition wall 18, the compartment 24, the through hole of the partition wall 18, and the compartment 26. Is sent to. As a result, the exhaust is expanded, resonated, interfered, etc., and the engine exhaust noise is reduced.

  Each intake pipe 17 is press-fitted into the partition walls 18, 20, 22 with a light load, and the discharge pipe 32 is pressed into the partition walls 20, 22 with a light load. Generation of stress based on a difference in thermal expansion between the pipe 32 and the partition walls 18, 20, and 22 is alleviated.

  As shown in FIG. 4, the other end 32B of the discharge pipe 32 is formed with an enlarged taper portion 34 and a large diameter portion 36 as a restricting portion in order from the vehicle front side, and the other end 32B of the discharge pipe 32 is The diameter is gradually increased toward the rear side of the vehicle at the enlarged diameter tapered portion 34, and the same outer diameter is set at the large diameter portion 36.

  One end 38A of a circular rear pipe 38 as a support exhaust pipe is coupled to the other end 32B of the discharge pipe 32 at a large diameter portion 36. The one end 38A of the rear pipe 38 has a large load in the large diameter portion 36. It is press-fitted with a load (for example, a load of 2 to 4 tons) and surface-bonded. As a result, the exhaust sent from the discharge pipe 32 is sent to the rear pipe 38. One end 38 A of the rear pipe 38 is press-fitted into a part of the large diameter portion 36, and a clearance 39 is provided between the one end 38 A of the rear pipe 38 and the enlarged diameter tapered portion 34.

  As shown in FIGS. 1 and 2, one end 40A of a substantially cylindrical container-like sub muffler 40 (silencer) as an input exhaust pipe is coupled to the other end 38B of the rear pipe 38, and the other end 38B of the rear pipe 38 is connected. Are press-fitted into the one end 40A of the sub-muffler 40 with a large load (for example, a load of 2 to 4 tons) and are surface-bonded. The diameter of the central portion of the sub muffler 40 is made larger than the diameter of the rear pipe 38, whereby the exhaust delivered from the rear pipe 38 is expanded, resonated, interfered with, etc. by the sub muffler 40, and the exhaust noise of the engine is further reduced. . The other end 40B of the sub muffler 40 is formed with a reduced diameter taper portion 42 and a small diameter portion 44 as a restricting portion in order from the vehicle front side, and the other end 40B of the sub muffler 40 is connected to the rear of the vehicle by the reduced diameter taper portion 42. The diameter is gradually reduced toward the side, and the outer diameter is reduced at the small diameter portion 44.

  One end 46A of a circular tail pipe 46 as a support exhaust pipe is coupled to the small diameter portion 44 of the sub muffler 40, and the entire small diameter portion 44 of the sub muffler 40 has a large load (for example, within the end 46A of the tail pipe 46). It is press-fitted with a load of 2 to 4 tons and is surface-bonded. Thus, the exhaust gas sent from the sub muffler 40 is sent out of the vehicle from the other end 46B of the tail pipe 46 via the tail pipe 46. The tail pipe 46 is supported (fixed) on the vehicle body side by a support member 48, whereby the rear pipe 38 and the sub muffler 40 are supported on the vehicle body side via the tail pipe 46.

  Further, due to exhaust of the engine due to driving of the vehicle, a press-fit portion between one end 17A of each intake pipe 17 and the other end 12B of each front pipe 12, a press-fit portion between the other end 32B of the discharge pipe 32 and one end 38A of the rear pipe 38, The press-fit portion between one end 40A of the sub-muffler 40 and the other end 38B of the rear pipe 38 and the press-fit portion between the other end 40B of the sub-muffler 40 and one end 46A of the tail pipe 46 are heated to a predetermined temperature (for example, 400 ° C.) or higher. It is baked (the parts that are in contact with each other at the atomic level without being melted are joined by heating).

  Further, the lower surface of the main muffler 16 and the lower surface of the sub muffler 40 constitute the lowermost portion of the vehicle bottom. When the vehicle bottom interferes with the road surface while the vehicle is moving forward, the main muffler 16 and the sub muffler 40 are In this configuration, a load is input to the main muffler 16 and the sub muffler 40 to the rear side of the vehicle by interfering with the road surface.

  Next, the operation of the present embodiment will be described.

  In the exhaust structure 10 having the above configuration, each intake pipe 17 of the main muffler 16 is coupled to the other end 12B of each front pipe 12 whose one end 12A is connected to the exhaust port of the engine, and the exhaust pipe 32 of the main muffler 16. One end 38 </ b> A of the rear pipe 38 is coupled to the rear end. Further, one end 40A of the sub muffler 40 is coupled to the other end 38B of the rear pipe 38, and one end 46A of the tail pipe 46 is coupled to the other end 40B of the sub muffler 40. Thus, the exhaust from the exhaust port of the engine is purified by the catalytic converter 14 of each front pipe 12 through each front pipe 12, main muffler 16, rear pipe 38, sub muffler 40, and tail pipe 46, and exhaust sound is also emitted from the main muffler 16. And it is sent out of the vehicle while being reduced by the sub muffler 40.

  When the bottom of the vehicle interferes with the road surface while the vehicle is moving forward, the main muffler 16 and the sub muffler 40 interfere with the road surface, and a load is input to the main muffler 16 and the sub muffler 40 to the rear side of the vehicle.

  Here, one end 17A of each intake pipe 17 of the main muffler 16 and the other end 12B of each front pipe 12 having one end 12A (part other than the coupling surface with the intake pipe 17) supported on the vehicle body side are the main muffler. They are connected by press-fitting on the vehicle front side (anti-load input direction side) with respect to 16. On the other hand, the other end 32B of the discharge pipe 32 of the main muffler 16 and the rear pipe where the other end 38B (part other than the coupling surface with the discharge pipe 32) is supported by the support member 48 on the vehicle body side via the tail pipe 46 and the sub muffler 40. One end 38 </ b> A of 38 is coupled to the main muffler 16 by press-fitting on the vehicle rear side (load input direction side).

  Further, one end 40A of the sub muffler 40 and the other end 38B of the rear pipe 38 on which one end 38A (a portion other than the coupling surface with the sub muffler 40) is supported on the vehicle body via the front pipe 12 and the main muffler 16 are connected to the sub muffler 40. Further, they are coupled by press-fitting on the front side of the vehicle (on the side opposite to the load input direction). On the other hand, the other end 40A of the sub muffler 40 and one end 46A of the tail pipe 46 whose one end 46A (part other than the coupling surface with the sub muffler 40) is supported on the vehicle body side by the support member 48 are located on the vehicle rear side with respect to the sub muffler 40. They are connected by press-fitting at the (load input direction side).

  In addition, by exhausting the engine due to the operation of the vehicle, a press-fit portion between one end 17A of each intake pipe 17 and the other end 12B of each front pipe 12, a press-fit portion between the other end 32B of the discharge pipe 32 and one end 38A of the rear pipe 38, The press-fitted portion between one end 40A of the sub-muffler 40 and the other end 38B of the rear pipe 38 and the press-fitted portion between the other end 40B of the sub-muffler 40 and one end 46A of the tail pipe 46 are heated to a predetermined temperature or more and baked. It is tightly coupled.

  For this reason, when the main muffler 16 interferes with the road surface and a load is input to the main muffler 16 to the rear side of the vehicle, the main muffler 16 (each Even if a load on the opposite side of the press-fitting direction acts on the press-fitting position between the inlet pipe 17) and each front pipe 12, the connection between the main muffler 16 (each inlet pipe 17) and each front pipe 12 can be maintained.

  Further, when the main muffler 16 interferes with the road surface and a load is input to the main muffler 16 to the rear side of the vehicle, the main muffler 16 (discharge pipe) is kept in a state where the rear pipe 38 is prevented from moving to the rear side of the vehicle. 32) and a load (press input) in the press-fitting direction side act on the press-fitting position of the rear pipe 38. As a result, the connection between the main muffler 16 (discharge pipe 32) and the rear pipe 38 can be reliably maintained.

  Further, a clearance 39 is provided that can increase the amount of press-fit of the rear pipe 38 one end 38A to the other end 32B (large diameter portion 36) of the discharge pipe 32 by a load in the press-fitting direction. For this reason, the press-fitting amount increases, and an expansion deformation force acts on the other end 32B (large diameter portion 36) of the discharge pipe 32, and a contraction deformation force acts on the one end 38A of the rear pipe 38. Thus, the coupling force between the other end 32B of the discharge pipe 32 and the one end 38A of the rear pipe 38 is improved, and the coupling between the main muffler 16 (discharge pipe 32) and the rear pipe 38 can be maintained more reliably.

  In addition, the diameter-increasing taper portion 34 provided in the vicinity of the press-fitting position (large-diameter portion 36) of the discharge pipe 32 abuts on the edge of the one end 38A of the rear pipe 38, so that the amount of press-fitting due to the load in the press-fitting direction is increased. Can limit growth. Thereby, the relative position change of the main muffler 16 and the rear pipe 38 can be suppressed.

  On the other hand, when the sub muffler 40 interferes with the road surface and a load is input to the sub muffler 40 to the rear side of the vehicle, the press fitting position between the sub muffler 40 and the rear pipe 38 with the rear pipe 38 prevented from moving to the rear side of the vehicle. Even if a load on the opposite side of the press-fitting direction acts on the sub muffler 40, the connection between the sub muffler 40 and the rear pipe 38 can be maintained.

  Further, when the sub muffler 40 interferes with the road surface and a load is input to the sub muffler 40 to the rear side of the vehicle, the sub muffler 40 and the tail pipe 46 are in a state where the tail pipe 46 is prevented from moving to the rear side of the vehicle. A load (press input) in the press-fitting direction acts on the press-fitting position. Thereby, the coupling | bonding of the sub muffler 40 and the tail pipe 46 can be maintained reliably.

  Further, the diameter-reduced taper portion 42 provided in the vicinity of the press-fitting position (small-diameter portion 44) of the sub-muffler 40 comes into contact with the edge of the end 46A of the tail pipe 46, whereby one end 46A of the tail pipe 46 due to the load in the press-fitting direction. The increase in the amount of press-fitting of the other end 40B of the sub muffler 40 into the can be limited. Thereby, the relative position change of the sub muffler 40 and the tail pipe 46 can be suppressed.

  Further, as described above, each intake pipe 17 and each front pipe 12 are coupled by press-fitting instead of conventional welding, and the discharge pipe 32 and rear pipe 38 are coupled by press-fitting instead of conventional welding. . Further, the sub muffler 40 and the rear pipe 38 are coupled by press-fitting instead of the conventional welding, and the sub muffler 40 and the tail pipe 46 are coupled by press-fitting instead of the conventional welding.

  For this reason, unlike the conventional case, the connection portion between each intake pipe 17 and each front pipe 12, the connection portion between discharge pipe 32 and rear pipe 38, the connection portion between sub-muffler 40 and rear pipe 38, and sub-muffler 40 and tail pipe 46 The fatigue strength of each joint portion can be increased (e.g., 1.8 times that of the conventional joint), variation in the joint strength of each joint portion can be suppressed, and rust is generated in each joint portion. This can be suppressed.

  Further, as described above, by exhausting the engine by driving the vehicle, a press-fitting portion between each intake pipe 17 and each front pipe 12, a press-fitting portion between the discharge pipe 32 and the rear pipe 38, a press-fitting portion between the sub muffler 40 and the rear pipe 38, In addition, the press-fitted portions of the sub muffler 40 and the tail pipe 46 are heated and baked to a predetermined temperature or higher. For this reason, since each said press injection part closely_contact | adheres well, the leak of the exhaust gas from the said each press injection part can be suppressed or prevented.

  In the present embodiment, the exhaust of the engine due to the operation of the vehicle causes the press-fitted portion between each intake pipe 17 and each front pipe 12, the press-fitted portion between exhaust pipe 32 and rear pipe 38, and the press-fit between sub-muffler 40 and rear pipe 38. The portion and the press-fitted portion of the sub-muffler 40 and the tail pipe 46 are heated and baked to a predetermined temperature or more, but each press-fitted portion before the first operation of the vehicle (for example, immediately after the press-fitting operation of each press-fitted portion). It is good also as a structure which heated and baked to above predetermined temperature (especially 400 degreeC). Thereby, even before the first driving | running | working of a vehicle, the said each press injection part can be couple | bonded firmly.

  In the present embodiment, the enlarged diameter tapered portion 34 or the reduced diameter tapered portion 42 is provided in the vicinity of the press-fit position of the discharge pipe 32 with the rear pipe 38 or the press-fit position of the sub-muffler 40 with the tail pipe 46. In addition to or instead of this, the vicinity of the press-fitting position of the rear pipe 38 (support exhaust pipe) with the discharge pipe 32 (input exhaust pipe) or the tail pipe 46 (support exhaust pipe) with the sub-muffler 40 (input exhaust pipe). It is good also as a structure which provided the enlarged diameter taper part 34 or the reduced diameter taper part 42 (limitation part) in the position vicinity. In addition, the limiting portion is not limited to the enlarged diameter tapered portion 34 or the reduced diameter tapered portion 42, and may be a protruding portion, a bent portion, or the like.

  Further, in the present embodiment, the tail pipe 46 is supported on the vehicle body side by the support member 48 in addition to the sub muffler 40. However, the tail pipe 46 (support exhaust pipe) is supported only by the sub muffler 40 (input exhaust pipe). The vehicle body side may not be supported.

  Further, in the present embodiment, a connection portion between each intake pipe 17 and each front pipe 12, a connection portion between discharge pipe 32 and rear pipe 38, a connection portion between sub muffler 40 and rear pipe 38, and sub muffler 40 and tail pipe. The exhaust structure 60 shown in FIG. 5 may be applied to at least one of the coupling portions with the engine 46.

  In the exhaust structure 60, as in the present embodiment, the diameter-expanded taper portion 34 and the large-diameter portion 36 of the discharge pipe 32 are formed in a circular first pipe 62 (input exhaust pipe or support exhaust pipe), and the first A circular second pipe 64 (supporting exhaust pipe or input exhaust pipe) is press-fitted into one pipe 62, and a connecting portion (press-fitting portion) between the first pipe 62 and the second pipe 64 extends along the circumferential direction. A concave rib 66 is formed as an engaging portion. Further, for example, the rib 66 is disposed at the center of the press-fitting portion of the first pipe 62 and the second pipe 64 as shown in FIG. 5A, and the first pipe as shown in FIG. 5B. As shown in FIG. 5C, a pair of 62 and the second pipe 64 are arranged in the circumferential direction of the first pipe 62 and the second pipe 64 at equal intervals. Yes.

  Further, in the present embodiment, a connection portion between each intake pipe 17 and each front pipe 12, a connection portion between discharge pipe 32 and rear pipe 38, a connection portion between sub muffler 40 and rear pipe 38, and sub muffler 40 and tail pipe. The exhaust structure 70 shown in FIG. 6 may be applied to at least one of the coupling portions with the 46.

  In the exhaust structure 70, instead of the rib 66, a coupling portion (press-fit portion) between the first pipe 62 and the second pipe 64 similar to the exhaust structure 60 shown in FIG. A recess 72 is formed. Further, the recess 72 is disposed at the center of the press-fitting portion of the first pipe 62 and the second pipe 64 as shown in FIG. 6 (A), for example, as shown in FIG. The cross section along the axial direction of the second pipe 64 is substantially rectangular, and as shown in FIG. 6C, the circumference of the cross section along the circumferential direction of the first pipe 62 and the second pipe 64 is substantially arcuate, In addition, a pair is arranged at equal intervals along the circumferential direction of the first pipe 62 and the second pipe 64.

(Experimental example)
FIG. 7A is a cross-sectional view showing a coupling portion between the first pipe 62 and the second pipe 64 in the exhaust structure 80 to which the present invention used in this experimental example is applied.

  The exhaust structure 80 includes the first pipe 62 and the second pipe 64 similar to the exhaust structure 60 and the exhaust structure 70 (the rib 66 and the recess 72 are not formed), and the large diameter of the first pipe 62 is provided. The second pipe 64 is press-fitted into the portion 36 with a load of 27.5 KN, and the large-diameter portion 36 of the first pipe 62 and the second pipe 64 are surface-joined. Further, the outer peripheral diameter A of the first pipe 62 other than the enlarged diameter tapered portion 34 and the large diameter portion 36 is 48.6 mm, the peripheral wall thickness B of the first pipe 62 is 1.2 mm, and the enlarged diameter tapered portion of the first pipe 62. The length C of 34 is 15 mm, the length D of the large diameter portion 36 of the first pipe 62 is 45 mm, and the inner peripheral diameter E of the large diameter portion 36 of the first pipe 62 is 47.4 mm. On the other hand, the outer peripheral diameter F of the second pipe 64 is 48.6 mm, the peripheral wall thickness G of the second pipe 64 is 1.2 mm, the length H of the press-fitted portion of the second pipe 64 is 40 mm, and the outer peripheral diameter of the second pipe 64 The difference (press-fit allowance) between F and the inner peripheral diameter E of the large diameter portion 36 of the first pipe 62 is set to 1.2 mm.

  In this experimental example, the exhaust structure 60 and the exhaust structure 70 are also used. However, the press-fit loads and sizes of the first pipe 62 and the second pipe 64 of the exhaust structure 60 and the exhaust structure 70 are the same as those of the exhaust structure 80. ing.

  Further, as shown in FIG. 5B, the rib 66 in the exhaust structure 60 has a width I of 4.5 mm along the axial direction of the first pipe 62 and a maximum depth J on the outer peripheral surface of the first pipe 62. The radius of curvature K around the cross section along the axial direction of the first pipe 62 is 1.5 mm and 3 mm. Further, as shown in FIG. 5C, the rib 66 is formed on the outer peripheral surface of the first pipe 62 in a range L where the central angle of the first pipe 62 is 120 °.

  Further, as shown in FIG. 6B, the recess 72 in the exhaust structure 70 has a length M of the deepest portion along the axial direction of the first pipe 62 on the outer peripheral surface of the first pipe 62 of 4 mm. The radius of curvature N on both axial sides of the deepest first pipe 62 around the cross section along the axial direction of 62 is 1.8 mm. Furthermore, as shown in FIG. 6C, the recess 72 has a maximum depth P of 2 mm on the outer peripheral surface of the first pipe 62 and a radius of curvature Q around the cross section along the circumferential direction of the first pipe 62 of 1.. 8 mm.

  As shown in FIG. 8, in this experimental example, the opposite end of the second pipe 64 to the first pipe 62 is fixed to the jig 82, and the joint portion between the first pipe 62 and the second pipe 64 is set in the electric furnace 84. In the state in which the first pipe 62 is heated by being inserted into the first pipe 62, the first pipe 62 is pulled toward the second pipe 64 side by a hydraulic cylinder (not shown) at a speed of 10 mm / min. The unloading load between the pipe 62 and the second pipe 64 (the tensile load of the first pipe 62 when the first pipe 62 is unplugged from the joint between the first pipe 62 and the second pipe 64) was measured.

  The measurement of the unloading load between the first pipe 62 and the second pipe 64 is performed by controlling the electric furnace 84 to maintain the temperature of the atmosphere of the joint portion between the first pipe 62 and the second pipe 64 at the target temperature. This was performed when the temperature of the bonded portion was maintained at the target temperature and the bonded portion did not expand or contract.

  FIG. 9 shows the experimental results in this experimental example. The mark A in FIG. 9 indicates the unloading load between the first pipe 62 and the second pipe 64 when the joint portion between the first pipe 62 and the second pipe 64 that is not baked by heating in the exhaust structure 80 is set to various temperatures. Is shown. The mark B in FIG. 9 indicates the unloading load between the first pipe 62 and the second pipe 64 when the joint portion between the first pipe 62 and the second pipe 64 that is not baked by heating in the exhaust structure 60 is set to various temperatures. Is shown. The mark C in FIG. 9 shows the unloading load between the first pipe 62 and the second pipe 64 when the joint portions of the first pipe 62 and the second pipe 64 that are not baked by heating in the exhaust structure 70 are set to various temperatures. Is shown. The mark D in FIG. 9 shows the unloading load between the first pipe 62 and the second pipe 64 when the connecting portion between the first pipe 62 and the second pipe 64 in the exhaust structure 80 is heated to 400 ° C. and then returned to room temperature. Is shown. The mark E in FIG. 9 indicates the unloading load between the first pipe 62 and the second pipe 64 when the connecting portion of the first pipe 62 and the second pipe 64 in the exhaust structure 80 is heated to 500 ° C. and then returned to room temperature. Is shown.

  As shown in FIG. 9, in any case of the exhaust structure 80, the exhaust structure 60, and the exhaust structure 70, the joint portion between the first pipe 62 and the second pipe 64 that is not baked by heating is heated to 400 ° C. or more. When baked, the detachment load between the first pipe 62 and the second pipe 64 increased considerably.

  Further, when the first pipe 62 is removed from the joint portion between the first pipe 62 and the second pipe 64 in the normal temperature state without being heated in the exhaust structure 80, as shown in FIG. The second pipe 64 was hardly damaged 86 by the pipe 62. On the other hand, when the first pipe 62 is pulled out from the joint between the first pipe 62 and the second pipe 64 in the state heated to 400 ° C. in the exhaust structure 80, as shown in FIG. The pipe 62 damaged the second pipe 64 in a streak 86.

  As described above, the bonding portion between the first pipe 62 and the second pipe 64 is heated while the contact area at the atomic level is increased by pressurization and the recrystallization temperature of each metal is lowered. As a result, the dislocation (movement) of the atoms is assisted to increase the deformation and the atomic diffusion is promoted, and it is understood that they are joined (baked) by recrystallization or transformation (deformation).

  Here, the unloading load between the first pipe 62 and the second pipe 64 depends not only on the joining state of the first pipe 62 and the second pipe 64 but also on the strength of the base material of the first pipe 62 and the second pipe 64. Then it is understood.

  FIG. 11 shows the relationship between the tensile strength and the temperature of stainless steel (usually SUS409LT used for an exhaust pipe of a vehicle) that is a base material of the first pipe 62 and the second pipe 64. As shown in FIG. 11, the tensile strength of stainless steel decreases as the temperature increases. Note that the tensile strength of stainless steel sharply decreases particularly when the temperature exceeds 500 ° C.

  As shown in FIG. 9, in the exhaust structure 80, the exhaust structure 60, and the exhaust structure 70, the temperature of the joint portion between the first pipe 62 and the second pipe 64 exceeds 400 ° C. The unloading load with the pipe 64 was reduced. This is understood because the base material strength decreases as the temperature increases in the first pipe 62 and the second pipe 64.

  In addition, the detachment load between the first pipe 62 and the second pipe 64 in the exhaust structure 80 is obtained when the joint portion between the first pipe 62 and the second pipe 64 is heated to 400 ° C. or 500 ° C. and then returned to room temperature. However, it was larger than when the bonded portion was heated to 400 ° C or 500 ° C. The unloading load when the bonding portion was heated to 400 ° C. or 500 ° C. and then returned to room temperature was about four times the unloading load when the bonding portion was brought to room temperature without heating.

  Further, when the first pipe 62 is pulled out from the joint portion between the first pipe 62 and the second pipe 64 in a state where the exhaust structure 80 is heated to 400 ° C. and then returned to room temperature, the state shown in FIG. Thus, the second pipe 64 was damaged by the first pipe 62 in a thicker and streak form than in the case of FIG. 10B (a state heated to 400 ° C.).

  As for the above, although the said coupling | bond part is similarly baked in any case when it returned to normal temperature after heating to 400 degreeC or 500 degreeC, and when heated to 400 degreeC or 500 degreeC. It is understood that the base material strength of the first pipe 62 and the second pipe 64 is larger at room temperature than at 400 ° C. or 500 ° C.

It is the side view seen from the vehicle left side which shows the exhaust structure which concerns on embodiment of this invention. It is the bottom view seen from the vehicle lower side which shows the exhaust structure which concerns on embodiment of this invention. It is sectional drawing seen from the vehicle lower side which shows the main muffler in the exhaust structure which concerns on embodiment of this invention. It is the side view seen from the vehicle left side which shows the joint part of the discharge pipe and rear pipe in the exhaust structure which concerns on embodiment of this invention. It is a figure which shows the coupling | bond part (what formed the rib) of the 1st pipe and 2nd pipe which concern on the 1st another example of the exhaust structure which concerns on embodiment of this invention, (A) is a side view, ( (B) is an enlarged view of a portion B in (A), and (C) is a sectional view taken along the line CC in (A). It is a figure which shows the coupling | bond part (thing in which the recessed part was formed) of the 1st pipe and 2nd pipe which concern on the 2nd another example of the exhaust structure which concerns on embodiment of this invention, (A) is a side view, ( B is a cross-sectional view taken along the line BB of (A), and (C) is a cross-sectional view taken along the line CC of (A). It is sectional drawing which shows the coupling | bond part (thing in which the rib and the recessed part are not formed) of the 1st pipe and 2nd pipe to which this invention used by the experiment example in embodiment of this invention was applied. It is the partially broken side view which shows the experimental condition of the experiment example in embodiment of this invention. It is a graph which shows the experimental result of the experiment example in embodiment of this invention. It is a perspective view which shows the 2nd pipe when the 1st pipe is extracted from the connection part (one in which the rib and the recessed part are not formed) of the 1st pipe and the 2nd pipe in the experimental example in the embodiment of the present invention. , (A) is a case where the bonding part is brought to room temperature without being heated, (B) is a case where the bonding part is heated to 400 ° C., and (C) is a case where the bonding part is In this case, the temperature is returned to room temperature after being heated to 400 ° C. It is a graph which shows the relationship between the tensile strength of stainless steel (SUS409LT), and temperature.

Explanation of symbols

10 Exhaust structure 12 Front pipe (support exhaust pipe)
16 Main muffler (input exhaust pipe)
34 Expanded taper (restricted part)
38 Rear pipe (support exhaust pipe)
39 Clearance 40 Sub-muffler (input exhaust pipe)
42 Reduced diameter taper part (restriction part)
46 Tail pipe (support exhaust pipe)
60 Exhaust structure 62 First pipe (input exhaust pipe or support exhaust pipe)
64 Second pipe (support exhaust pipe or input exhaust pipe)
70 Exhaust structure 80 Exhaust structure

Claims (5)

An input exhaust pipe that sends exhaust from the vehicle body side and receives load by interfering with the road surface ;
A support exhaust pipe that is coupled to an end portion of the input exhaust pipe along the load input direction by press-fitting, is supported by a vehicle body at a portion other than the input exhaust pipe, and allows exhaust to pass between the input exhaust pipe and the input exhaust pipe; ,
Exhaust structure with   The exhaust structure according to claim 1, wherein a clearance is provided so that an amount of press-fitting between the input exhaust pipe and the support exhaust pipe can be increased by an axial compression force.   3. A limiting portion that is provided in the vicinity of a press-fitting position of at least one of the input exhaust pipe and the support exhaust pipe and limits a press-fitting amount that is press-fitted by an axial compression force. Exhaust structure. An input exhaust pipe that sends exhaust from the vehicle body side and receives load by interfering with the road surface ;
A support exhaust pipe that is coupled to the input exhaust pipe by press-fitting and seizure, is supported by a vehicle body at a portion other than the input exhaust pipe, and allows exhaust to pass between the input exhaust pipe;
Exhaust structure with The exhaust structure according to claim 4 , wherein the input exhaust pipe and the support exhaust pipe are baked by exhaust of an engine caused by driving of the vehicle .

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