JP2005225313A - Dynamic damper, and exhaust system structure equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a dynamic damper which can change its secondary resonance frequency without accompanying a great reduction of a primary resonance frequency of a bracket, a weight increase, and a strength decrease, and by which a sufficient vibration reducing effect can be obtained, and to provide an exhaust system equipped with the dynamic damper. <P>SOLUTION: For this exhaust system 100, a main bracket 1, a subsidiary bracket 2 which assists the main bracket 1, and this dynamic damper 10 having an inertial body 3 are attached to an exhaust pipe P. The main bracket 1 has a fastening section 15 which extends in an extending direction D1 and is connected with a vehicle main body. Also, the inertial body 3 has a protruding section 33 which extends in an extending direction D3 facing the approximately directly opposite direction (a crossing angle θ is approximate 180°) from the fastening section 15, and functions as a moment arm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a dynamic damper and an exhaust system structure including the same.

An exhaust pipe or muffler connected to an internal combustion engine such as a vehicle is generally provided with a so-called dynamic damper (dynamic vibration absorber) in order to reduce a large vibration near its natural frequency. For example, in Patent Document 1, a bracket obtained by bending a metal plate is fixed to a flange portion of an exhaust pipe, and a metal inertia body called “mass” is fixed to the other end of the bracket opposite to the fixed end. In addition, a dynamic damper for an exhaust pipe is described.
JP 2000-6673 A

  Normally, if the vibration transmitted to the exhaust pipe is a vibration different from the resonance frequency of the exhaust pipe (for example, vibration of the engine or the like), the entire exhaust pipe will not vibrate inconveniently. However, when the vibration transmitted to the exhaust pipe has a frequency near the resonance frequency of the exhaust system support structure, the vibration is amplified by the exhaust system support structure, and the vehicle interior noise is deteriorated. Under such circumstances, according to the above-described conventional dynamic damper, it is difficult to avoid a significant weight increase due to 'mass' in order to prevent deterioration of vehicle interior noise. Moreover, there is a concern that the strength may be lowered by attaching such a heavy 'mass'.

  Therefore, the present invention has been made in view of such circumstances, and by providing an inertial body employing a moment arm in the exhaust system support structure (bracket), a significant reduction in the primary resonance frequency of the exhaust system support structure ( In this case, for example, the vibration and resonance frequency of the engine or the like are likely to coincide with each other.) A dynamic damper that can change the secondary resonance frequency of the exhaust system support structure without increasing the weight and reducing the strength. And an exhaust system structure thereof.

  In order to solve the above problems, a dynamic damper according to the present invention is attached to a member constituting an exhaust system and connected to a member constituting an exhaust system (hereinafter referred to as “exhaust system constituent member”). Exhaust system connection portion formed so as to be able to be connected, and a bracket having a device connection portion which is bent from the exhaust system connection portion and extends in a predetermined direction and is formed so as to be connectable to the device main body, and to the bracket And a direction different from the extending direction of the device connection part, preferably a direction in which the crossing angle θ in the plane is several tens to three hundreds of degrees, more preferably about 90 ° to 270 °, particularly preferably Comprises an inertial body having a projecting portion extending so as to project in a direction of approximately 180 ° (substantially opposite direction). The inertial body may be joined to the bracket or may be formed integrally with the bracket.

  When the dynamic damper having such a configuration is used, the exhaust system connection portion of the bracket (exhaust system support structure) is connected to exhaust system components such as an exhaust pipe, a muffler, and a catalyst, and the device connection portion is a device such as a vehicle body. The exhaust system is held in the device while being connected to the device. Since the inertial body is joined to the bracket, a dynamic damper action is exerted, and vibrations at a resonance frequency and a frequency in the vicinity thereof that are input due to the operation of the internal combustion engine to which the exhaust system is connected are reduced. .

  At this time, the inertial body protrudes in a direction different from the extending direction of the device connecting portion, and functions as a moment arm. Therefore, as compared with the case where no projecting portion is provided as such, a portion where the device connection portion is supported from the device side, that is, a member length from the action point is ensured, and a moment ( (Moment of inertia) increases. As a result, a significant decrease in the primary resonance frequency of the bracket is suppressed, and even if the mass of the inertial body is significantly smaller than that of the conventional 'mass', the secondary resonance frequency can be easily changed significantly. A sufficient dynamic damper action can be obtained. Moreover, strength reduction is prevented by such weight reduction. In particular, it is more preferable that the projecting portion of the inertial body projects in a direction substantially opposite to the extending direction of the device connecting portion because the moment increase is extremely increased.

  Further, it is preferable that the inertial body has an exhaust system connection portion formed so as to be connectable to a member constituting the exhaust system.

  With such a configuration, the inertial body functions as a separate bracket, so that the exhaust system constituent members and thus the exhaust system retainability can be improved. In particular, when the dynamic damper is connected to a tubular member such as an exhaust pipe, for example, the tip of the exhaust system connection part of the bracket is formed to be bifurcated so as to grip the exhaust pipe. In this case, the number of parts of the bracket tends to be plural. However, since the inertial body has the exhaust system connection portion, the inertial body functions as another bracket, and thus the number of parts of the dynamic damper is reduced.

  More specifically, if the projecting portion of the inertial body has a rod shape, the moment from the force acting site as described above can be easily increased. This further reduces the weight of the dynamic damper. Moreover, if the joint part and bracket of a dynamic damper are also made into a rod-shaped member, it will become easy to join both.

  An exhaust system structure according to the present invention includes the dynamic damper according to the present invention and an exhaust system having a member connected to at least an exhaust system connection portion constituting a bracket.

  According to the dynamic damper of the present invention and the exhaust system structure including the dynamic damper, since the inertial body employing the moment arm is provided in the exhaust system support structure (bracket), the primary resonance frequency of the exhaust system support structure is significantly reduced. The secondary resonance frequency of the exhaust system support structure can be changed without increasing the weight and reducing the strength, and a sufficient vibration reduction effect can be realized.

  Hereinafter, embodiments of the present invention will be described in detail. The positional relationship such as up, down, left, and right is based on the positional relationship shown in the drawings unless otherwise specified. Further, the dimensional ratios in the drawings are not limited to the illustrated ratios.

  FIG. 1 is a side view schematically showing an embodiment of an exhaust system structure including a dynamic damper according to the present invention, and FIG. 2 is a front view thereof. The exhaust system 100 (exhaust system structure) is obtained by attaching a dynamic damper 10 to an exhaust pipe P such as a front pipe, a center pipe, and a tail pipe provided in a device such as a vehicle. The dynamic damper 10 is obtained by connecting an inertial body 3 to a bracket body constituted by a main bracket 1 and an auxiliary bracket 2.

  The main bracket 1 is formed of a rod-like member, and has an arcuate shape and a grip portion 11 that contacts the tube wall of the exhaust pipe P, an inclined portion 12 that extends obliquely upward in the drawing, and an auxiliary bracket that extends upward in the drawing and is described later. A locking portion 15 (equipment connecting portion) extending in the illustrated lateral direction from the joint portion 13 via the joint portion 13 and the bent portion 14 and connected to the vehicle main body (not shown). And a stopper 16 provided at the tip thereof. In this manner, the exhaust system connection portion is configured by the grip portion 11, the inclined portion 12, and the joint portion 13. Moreover, the site | part which continues to the latching | locking part 15 via the bending part 14 from the junction part 13 is formed in the substantially L shape, and the exhaust pipe P is extended in the extending direction D1 (refer FIG. 1) of the latching | locking part 15. FIG. It is substantially parallel to the extending direction.

  The auxiliary bracket 2 assists the main bracket 1. The auxiliary bracket 2 is formed of a rod-shaped member, and is disposed opposite to the grip portion 11 of the main bracket 1. The grip portion 21 forms an arc shape and comes into contact with the tube wall of the exhaust pipe P. It has an inclined portion 22 that is disposed opposite to the inclined portion 12 of the main bracket 1 and a joint portion 23 that extends upward in the drawing and is joined to the joint portion 13 of the main bracket 1. In the present embodiment, the auxiliary bracket 2 is formed of a member having a smaller diameter than the main bracket 1 from the viewpoint of weight reduction and assembling property.

  The inertial body 3 is formed of a rod-shaped member having a substantially L shape, and is connected to a joint portion 13 of the main bracket 1 and a joint portion 23 connected to the joint portion 23 of the auxiliary bracket 2 and a bent portion 32. It has a protruding portion 33 extending from the joint portion 31 in the illustrated horizontal direction. The protruding portion 33 is provided such that its extending direction D3 (see FIG. 1) is substantially opposite to the extending direction D1 of the locking portion 15 of the main bracket 1. That is, the locking portion 15 of the main bracket 1 and the protruding portion 33 of the inertial body 3 are arranged so that the crossing angle θ between the direction vectors in the extending directions D1 and D3 is an angle near 180 °. .

  In addition, the joining method in particular of joining part 13,23,31 is not restrict | limited, For example, if these are metal, it is preferable to join firmly by welding.

  In the exhaust system 100 configured as described above, the exhaust pipe P is gripped by the gripping portions 11 and 21, and the locking portion 15 of the main bracket 1 is connected to the vehicle body via, for example, a cushion rubber. The exhaust system 100 is held on the vehicle body by a plurality of supports (not shown) in addition to the support by the bracket. When the internal combustion engine of the vehicle is operated in this state, the vibration is transmitted to the vehicle main body via the exhaust pipe P, the main bracket 1 and the auxiliary bracket 2, and becomes one of the main noise factors in the vehicle interior. Further, when the high-order resonance frequency (for example, the secondary resonance frequency) of the main bracket 1 matches the resonance frequency of the internal combustion engine system including the exhaust system 100 (a turbo engine system depending on the vehicle), such a case. Noise vibration (NV) is likely to be amplified, and the vehicle interior noise may be increased.

  On the other hand, according to the exhaust system 100 of the present invention including the dynamic damper 10, the inertial body 3 including the protruding portion 33 is provided, so that the locking point (the locking point 15 of the locking portion 15 of the main bracket 1 in FIG. If the action point is F, the arm length L is sufficiently secured. Therefore, since the inertial body 3 functions as a moment arm, it is possible to significantly and sufficiently change the secondary resonance frequency while suppressing a significant decrease in the primary resonance frequency of the bracket. Therefore, noise vibration transmitted to the passenger compartment can be sufficiently reduced. Further, since the conventional heavy 'mass' is not required, weight reduction is realized, and further, the strength of the bracket and thus the exhaust system 100 can be prevented from being reduced.

  Further, the protruding portion 33 of the inertial body 3 extends in a direction different from that of the locking portion 15 of the main bracket 1. In particular, in this embodiment, the crossing angle θ is about 180 °, that is, the locking with the protruding portion 33. Since the portion 15 extends in the substantially opposite direction, a large arm length (member length) from the locking portion in the locking portion 15 is ensured. Therefore, the moment of inertia with the locking portion as a fulcrum can be further increased, so that the dynamic damper effect can be further enhanced and the noise vibration in the passenger compartment can be further reduced.

  Moreover, since the inertial body 3 is joined to the joint portion 13 in the vicinity of the bent portion 14 of the main bracket 1 at the joint portion 31, the rigidity of the bent portion 14 can be increased. On the other hand, if an attempt is made to join a thicker conventional 'mass' near the bent portion 14 without the protruding portion 33, the main bracket 1 is made thicker in order to obtain sufficient rigidity of the bent portion 14, or A treatment such as applying further reinforcement is required, and the total mass tends to further increase. Further, when the bracket having such a conventional structure is attached to the exhaust pipe P, there is a concern that the assemblability thereof is deteriorated. However, the dynamic damper 10 according to the present invention can realize the weight reduction, so Assembly can be improved. Therefore, the member cost and the number of assembly steps can be reduced and the economy can be improved.

  FIG. 3 is a side view schematically showing another embodiment of the exhaust system structure including the dynamic damper according to the present invention, and FIG. 4 is a front view thereof. Exhaust system 200 (exhaust system structure) is configured in the same manner as exhaust system 100 shown in FIGS. 1 and 2 except that dynamic damper 20 is connected to exhaust pipe P instead of dynamic damper 10. . The dynamic damper 20 is configured in the same manner as the dynamic damper 10 except that the inertial body 4 is provided instead of the auxiliary bracket 2 and the inertial body 3.

  The inertial body 4 has substantially the same shape as the main bracket 1. That is, the inertial body 4 is formed of a rod-like member, and is arranged facing the gripping portion 11 to form an arc shape and contact the pipe wall of the exhaust pipe P. Then, the inertial body 4 extends obliquely upward in the drawing to the inclined portion 12. It has an inclined portion 42 arranged oppositely, a joint portion 43 that extends upward in the figure and joined to the joint portion 13, and a protrusion 45 that extends in the lateral direction from the joint portion 43 via a bent portion 44. Yes. The protruding portion 45 is provided so as to be substantially opposite to the extending direction of the locking portion 15 of the main bracket 1.

  Also with the exhaust system 200 configured in this manner, the inertial body 4 constituting the dynamic damper 20 has the protrusion 45, so that the primary resonance frequency of the bracket is similar to the dynamic damper 10 and the exhaust system 100 including the dynamic damper 10. The secondary resonance frequency can be changed significantly and reliably while suppressing a significant decrease, and noise vibration due to input vibration from the internal combustion engine can be sufficiently reduced. Moreover, weight reduction can be achieved and strength reduction can be prevented. In addition, in order to avoid duplication description, the description about another similar and detailed effect is abbreviate | omitted. Further, since the inertial body 4 also serves as a bracket having the same function as the auxiliary bracket, the number of parts can be reduced. Therefore, further weight reduction can be realized and economic efficiency can be further improved.

  In addition, this invention is not limited to embodiment mentioned above, A various deformation | transformation is possible in the limit which does not change the summary. For example, if the inertia bodies 3 and 4 have protrusions, the shapes of the main bracket 1, the auxiliary bracket 2, and the inertia bodies 3 and 4 are not limited to a rod shape, and may be a plate shape, for example. Further, the inertial body 3 does not have to be substantially L-shaped, and may have a linear shape or a wavy shape as long as it has the protruding portion 33. In this case, the joining portion 31 located on the other end side of the protruding portion 33 may be joined to the locking portion 15 side of the main bracket 1. Further, the inertia bodies 3 and 4 may be formed integrally with the bracket body. Furthermore, the protrusions 33 and 45 may be provided so as to extend in a direction different from that of the locking part 15, and are not limited to the opposite direction. Furthermore, the dynamic dampers 10 and 20 may be connected to exhaust system components other than the exhaust pipe P, for example, mufflers, catalysts, members attached to them, and the like to configure the exhaust system.

  The dynamic damper and the exhaust system structure including the dynamic damper according to the present invention are provided with an inertial body employing a moment arm in the exhaust system support structure (bracket), so that the primary resonance frequency of the exhaust system support structure is significantly reduced and the weight is increased. In addition, the secondary resonance frequency of the exhaust system support structure can be changed without accompanied by a decrease in strength, and a sufficient vibration reduction effect due to an excellent dynamic damper action can be obtained. Therefore, the present invention can be widely used in equipment, motives, equipment, etc., such as a vehicle including an exhaust system connected to an internal combustion engine.

FIG. 1 is a side view schematically showing an embodiment of an exhaust system structure including a dynamic damper according to the present invention. FIG. 2 is a front view schematically showing an embodiment of an exhaust system structure including a dynamic damper according to the present invention. FIG. 3 is a side view schematically showing another embodiment of the exhaust system structure including the dynamic damper according to the present invention. FIG. 4 is a front view schematically showing another embodiment of the exhaust system structure including the dynamic damper according to the present invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Main bracket, 2 ... Auxiliary bracket, 3, 4 ... Inertial body, 10, 20 ... Dynamic damper, 11, 21, 41 ... Holding part, 12, 22, 42 ... Inclined part, 13, 23, 31, 43 ... Joint part, 14, 32, 44 ... bent part, 15 ... locking part (device connection part), 16 ... stop part, 33, 45 ... projecting part, 100, 200 ... exhaust system, D1, D3 ... extending direction, F: locking point, L: arm length, P: exhaust pipe (exhaust system component), θ: crossing angle.

Claims (4)

A dynamic damper attached to a member constituting the exhaust system,
An exhaust system connection portion formed so as to be connectable to a member constituting the exhaust system, and a device connection portion bent from the exhaust system connection portion and extending in a predetermined direction and formed so as to be connectable to the device body A bracket having
An inertial body having a projecting portion connected to the bracket and extending so as to project in a direction different from the extending direction of the device connecting portion;
Dynamic damper with The inertial body has an exhaust system connection portion formed so as to be connectable to a member constituting the exhaust system.
The dynamic damper according to claim 1. The protruding portion of the inertial body has a rod shape.
The dynamic damper according to claim 1 or 2. A dynamic damper according to any one of claims 1 to 3,
An exhaust system having at least a member connected to the exhaust system connection portion constituting the bracket;
Exhaust system structure with

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