JP2006188975A - Heat protective device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify a constitution, and to reduce manufacturing manhours, by improving reliability of an internal combustion engine. <P>SOLUTION: This invention includes an exhaust manifold gasket 26 interposed between an exhaust port hole 25 and an exhaust manifold 27 of an engine 22, and a heat insulator 28 composed of a light metal plate arranged by at least partially surrounding the exhaust manifold 27. A connecting piece 31 extending to the heat insulator 28 side is arranged in the exhaust manifold gasket 26 integrally with the gasket 26, and the connecting piece 31 and the heat insulator 28 are mutually connected by a hook member 32. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a thermal protection device for an internal combustion engine configured by integrating a metal exhaust manifold gasket interposed between an internal combustion engine and an exhaust manifold as an example, and a heat insulator provided to cover the exhaust manifold. Is.

  Conventionally, in order to suppress the situation where heat or noise is dissipated outside from a heat source or a sound source such as an internal combustion engine or an exhaust manifold (hereinafter referred to as an exhaust manifold) connected to the internal combustion engine, for example, Various heat insulators (hereinafter referred to as insulators) are used as thermal protection devices for sound sources. As an example, the exhaust manifold of an automobile engine has a high temperature flue gas that reaches several hundred degrees as the engine operates, and flows at a pulsating pressure of several thousand cycles per minute in the case of high engine rotation. Heat and noise are dissipated or transmitted inside the engine room and outside the vehicle. Such heat dissipation may cause heat damage to various harnesses and ducts in the engine room. In order to suppress the occurrence of such problems, the insulator is used as a thermal protection device.

  On the other hand, in order to prevent combustion exhaust gas from leaking between the engine and the exhaust manifold, an exhaust manifold gasket is mounted between the engine and the exhaust manifold. As a conventional technique related to such an exhaust manifold gasket and an insulator, there is a technique described in the publication of Patent Document 1 below.

  FIG. 4 is a sectional view of the engine 1 in the prior art of this thermal protection device. Hereinafter, this prior art will be described with reference to FIG. In this prior art, the engine 1 has a configuration in which a cylinder head 2 is fastened to an upper surface of a cylinder block (not shown). In the cylinder head 2, an exhaust manifold 4 is attached to one side surface 3 so as to communicate with the exhaust port 5, and an insulator 6 is attached to the exhaust manifold 4 as a thermal protection device so as to cover the exhaust manifold 4. It has been. The insulator 6 mounted in this way suppresses heat radiation from the inside of the exhaust manifold 4 and noise emission to the outside.

  Further, an exhaust manifold gasket 7 formed of, for example, a thin metal plate having a spring property is disposed between the exhaust port 5 and the exhaust manifold 4 of the engine 1, and a bolt (see FIG. Etc.). The exhaust manifold gasket 7 prevents the combustion exhaust gas from leaking from the joint surface between the engine 1 and the exhaust manifold 4.

  FIG. 5 is a perspective view of an insulator 6a in the second prior art of the thermal protection device. This second prior art is disclosed in Patent Document 2 below. Hereinafter, the second prior art will be described with reference to FIG. This prior art relates to a thermal protection device including an insulator 6a provided so as to cover an exhaust manifold (not shown) of an engine as in the first prior art.

  In the prior art, the insulator 6 a is configured integrally with the exhaust manifold gasket 7. Exhaust manifold gasket 7 is configured, for example, by forming through holes 9 through which combustion exhaust gas flows in metal plate 8 such as a stainless steel plate.

  Such an exhaust manifold gasket 7 is mutually connected with the connection member 10 which consists of metal materials which have flexibility, such as an expanded metal and a metal mesh material, with a volt | bolt, spot welding, or the rivet 12, for example. The insulator 6 a is connected to the connecting member 10 by connecting means such as the rivet 12.

  Further, in the insulator 6a, one end on the side of the exhaust manifold 7 is fixed to the exhaust manifold 6a via the connecting member 10 as described above. On the other hand, one bolt hole 13 is formed in the vicinity of the end of the insulator 6a opposite to the exhaust manifold 7 as an example, and the insulator 6a is fastened to the exhaust manifold 3 with a bolt (not shown). That is, the insulator 6a is attached to the engine and the exhaust manifold by the connecting member 10 and the bolt. Such an insulator 6a is formed from a metal plate of a light metal material such as an aluminum alloy as shown in Patent Document 2 below for weight reduction. Further, the insulator 6 and the exhaust manifold 7 are integrated, and a thermal protection device is configured including both.

JP-A-8-319886 (FIG. 4 and paragraphs 0009 to 0011) Japanese Unexamined Patent Publication No. 2000-293765 (FIG. 1 and paragraphs 0025 to 0026)

  In the conventional insulators 6 and 6 a, there is a problem that the insulators 6 and 6 a are thermally deteriorated by the heat from the exhaust manifold 4. Further, the vibration transmitted from the exhaust manifold 4 may cause cracks in the attachment seat portions of the insulators 6 and 6a to which the bolts for attaching the insulators 6 and 6a to the exhaust manifold 4 and the like are fastened. Moreover, the crack of this attachment seat site | part becomes a cause, and the malfunction that a crack generate | occur | produces also in the other site | parts of the insulators 6 and 6a generate | occur | produces.

  Further, as shown in FIG. 5, when the insulator 6a and the exhaust manifold 7 are integrally formed, as described above, when the insulator 6a and the exhaust manifold 7 are connected, the insulator 6a, the connecting member 10, and the exhaust manifold 2 are connected. Need to be connected by bolts, spot welding or rivets. Due to such work, there are problems that the number of work steps increases and the cost of the insulator 6a increases.

  Such a problem becomes prominent when the insulator 6a surrounds the exhaust manifold 4 over the entire circumference. Here, a configuration in which the insulator surrounds the exhaust manifold over the entire circumference will be described. In the prior art shown in FIG. 4, the insulator 6 covers the exhaust manifold 4 from above in FIG. 5 in a state spaced from the exhaust manifold 4. Another insulator is also provided on the lower side of the exhaust manifold 4, and the insulator 6 and the other insulator are connected on the outer periphery thereof. In this way, the exhaust manifold 4 can be surrounded over the entire circumference by the insulator 6 and the other insulator. Such a configuration is used to shield not only the upper side of the exhaust manifold 4 but also the lower side thereof against the heat from the exhaust manifold 4.

  When such a configuration is adopted, the insulator 6 and the other insulator are assembled to the exhaust manifold 4 with respect to the exhaust manifold 4 as shown in FIG. 4, and the insulator 6 and the other insulator are connected to each other. , And need to be connected to each other at the outer periphery. As means for realizing this connection, the above-described bolt, spot welding, rivet or the like is used.

  Since such an operation is performed on the exhaust manifold 4 assembled in the engine 1, a space required for the operation is narrow, and it is difficult to use a bolt fastening machine, a welding machine, or a rivet driving machine. In addition, when it is performed manually, there is a problem that the production efficiency is lowered.

  Further, in the prior art insulators 6 and 6a, as shown in FIG. 4, taper from the gap between the insulator 6 and the engine 1 or from the insulator 6a to the gasket 7 as shown in FIG. The heat generated in the exhaust manifold 4 rises from both sides of the connecting piece 10 as shown by the arrow A1. A cylinder head cover 11 made of synthetic resin is mounted on the upper part of the cylinder head 3 of the engine 1 via a rubber seal 11a. The cylinder head cover 11 and the rubber seal 11a are disadvantageously thermally damaged by the heat from the exhaust manifold 4.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to improve the reliability of the internal combustion engine by preventing the occurrence of heat damage in the components of the internal combustion engine. It is intended to provide a thermal protection device for an internal combustion engine in which the number of manufacturing steps is greatly reduced and the reliability is improved.

  The invention according to claim 1 is provided between the exhaust port of the internal combustion engine and the exhaust manifold, and is provided with a gasket formed of a metal plate having elasticity and spring property, and at least partially surrounding the exhaust manifold. A heat insulator configured to include a light metal plate, and a connection piece that integrally connects the gasket and the heat insulator, and at least the connection piece and the vicinity of the end of the heat insulator on the gasket side. The internal combustion engine is connected to each other via a hook member, and the vicinity of the end of the heat insulator opposite to the gasket is fastened to the exhaust manifold via a metal fastener. It is a thermal protection device.

  The invention according to claim 2 is the internal combustion engine according to claim 1, wherein the connecting piece is formed by extending the metal plate toward the heat insulator at the outer peripheral portion of the gasket. It is an engine thermal protection device.

  According to a third aspect of the present invention, in the first aspect of the present invention, the shape and size of the connecting piece is such that the heat from the exhaust manifold moves upward between the heat insulator and the internal combustion engine above the internal combustion engine. Is a thermal protection device for an internal combustion engine, characterized in that it is defined in a substantially damped manner.

  According to a fourth aspect of the present invention, in the first aspect of the invention, the heat insulator includes a plurality of constituent members including a plurality of panel members formed by laminating a plurality of light metal plates, and is connected to each other. The plurality of power components are connected to each other via the hook member, and are a thermal protection device for an internal combustion engine.

  According to a fifth aspect of the present invention, in the invention of the fourth aspect, the plurality of panel members are arranged in a manner that surrounds the exhaust manifold almost entirely, and a flange portion provided on the outer periphery of each panel member, The plurality of panel members are connected to each other using the plurality of hook members.

  The operation of each invention will be described below.

  In the first aspect of the present invention, the gasket and the heat insulator attached to the exhaust manifold are integrated using a connecting piece. Further, at least the connecting piece and the vicinity of the end portion on the gasket side of the heat insulator are connected to each other using a hook member. The connection between the gasket, the heat insulator and the connecting piece, at least the connection between the heat insulator and the connecting piece in the vicinity of the end portion on the gasket side, is realized by an operation of pressing the hook members of the heat insulator and the connecting piece. Also, the vicinity of the end of the heat insulator opposite to the gasket is fastened to the exhaust manifold via a metal fastener, and the other part that needs to be attached to another member of the heat insulator is the connecting piece. Connected to the gasket.

  In a second aspect of the present invention, a connecting piece formed by extending the outer peripheral portion of the metal plate constituting the gasket toward the heat insulator is connected to the heat insulator using the hook member.

  According to the third aspect of the present invention, the connecting piece substantially dams the moving path in which the heat from the exhaust manifold moves upward between the heat insulator and the internal combustion engine based on the shape and size thereof. .

  In a fourth aspect of the present invention, among a plurality of constituent members included in the heat insulator, a plurality of constituent members to be connected to each other are connected to each other via a hook member.

  In the invention according to claim 5, in the flange portion provided on the outer periphery of the heat insulator including a plurality of panel members, the plurality of panel members are connected to each other using a plurality of hook members. That is, a plurality of panel members are connected to each other by combining the plurality of panel members and pressing the flange portions against each other.

  According to the first aspect of the present invention, the gasket and the heat insulator attached to the exhaust manifold are integrated using the connecting piece, and at least the connecting piece and the vicinity of the gasket side end of the heat insulator are: They are connected to each other via a hook member. Therefore, when connecting the connecting piece and the heat insulator, etc., compared to the case of connecting by rivet or spot welding, no special large work machine is required, and the connecting operation process is simplified and manufactured. Man-hours are reduced.

  Further, according to the present invention, the vicinity of the end of the heat insulator opposite to the gasket is fastened to the exhaust manifold via the metal fastener, and the other place where the heat insulator needs to be attached to another member. Is connected to the gasket by the connecting piece. Thereby, in the attachment operation | work to the other member of a heat insulator, the fastening operation | work using the said metal fastener can be reduced. In this respect, the number of manufacturing steps can be reduced.

  Further, according to the present invention, since the heat insulator is made of a light metal plate, the heat insulator can be remarkably reduced in weight, and it is possible to reduce the number of attachment points that are reinforcing parts when attaching to the exhaust manifold. is there. Therefore, in the manufacturing process in which the exhaust manifold is assembled to the exhaust port of the internal combustion engine and the heat insulator is further assembled to the exhaust manifold, the number of manufacturing steps can be reduced and the cost can be reduced.

  In addition, since the heat insulator is lighter, even when high-temperature heat is transmitted from an exhaust manifold or the like and vibration is transmitted and the heat insulator itself vibrates, the heat insulator vibrates to the exhaust manifold of the heat insulator. The magnitude of the stress applied to the mounting location can be reduced, and the occurrence of cracks in the heat insulator is prevented. Thereby, the reliability of the thermal protection apparatus of the present invention is remarkably improved.

  Further, in the present invention, the exhaust manifold gasket and the heat insulator attached to the exhaust manifold are integrally connected using the connecting piece. Therefore, the gasket included in the present invention is connected to the exhaust port hole of the internal combustion engine. In the process of being sandwiched and fixed between the exhaust manifold, the heat insulator is partially fixed. Thereby, the manufacturing process required for mounting the heat insulator to the exhaust manifold can be simplified, and this can also reduce the cost.

  The exhaust manifold is a heat source because combustion exhaust gas from the internal combustion engine flows through. The heat insulator of the present invention is formed from a light metal plate. The heat conductivity of such a light metal plate is much higher than that of an aluminum-plated steel plate or the like that is often used as a material for heat-heat insulators, so the heat distribution in the heat-insulator is easily equalized. And a situation where a heat spot having a higher temperature than other portions is locally formed on the heat insulator is prevented.

  Therefore, in the heat insulator, it is possible to prevent the occurrence of undesired deformation and cracking due to a decrease in strength at the heat spot portion when the occurrence of the heat spot is assumed. Thereby, the reliability of the heat insulator is greatly improved.

  Further, in the present invention, since undesirable deformation and cracking of the heat insulator are prevented, in order to achieve this, the thickness of the metal plate constituting the heat insulator is increased or a reinforcing member is added. Thus, the need to increase the rigidity of the heat insulator or increase the number of support points for the exhaust manifold of the heat insulator is eliminated. As a result, an increase in the possibility of cracking in the vicinity of the support portion due to an increase in the weight of the heat insulator assumed when the rigidity of the heat insulator is increased, or an increase in the support portion of the heat insulator is assumed. Generation of cracks due to thermal strain can be prevented. In these respects, the reliability of the heat insulator is greatly improved.

  The heat insulator is connected to the internal combustion engine via a connecting piece. The gasket that is integrally formed with the connecting piece is provided facing the exhaust port hole of the internal combustion engine. At the same time, the gasket is in contact with the entire surface of the gasket. It gets colder.

  The connecting piece is formed integrally with the gasket by extending a metal plate constituting the gasket at the outer periphery of the gasket. Therefore, the temperature of the connecting piece is about the temperature in the vicinity of the outer peripheral portion of the gasket, and is lower than a fastener such as a bolt connecting the heat insulator to the exhaust manifold.

  Therefore, the heat dissipation from the connecting piece connecting the internal combustion engine and the heat insulator is significantly suppressed compared to the heat dissipation from the fastener. Moreover, regarding the degree to which heat is transmitted to the heat insulator and the temperature of the heat insulator is increased, the temperature increase by the connecting piece can be remarkably suppressed as compared with the temperature increase by the fastener. Thereby, heat dissipation by the heat insulator can be remarkably suppressed.

  In addition, since the connecting piece is formed of a metal plate having elasticity and spring property constituting the gasket, vibration transmitted from the internal combustion engine to the heat insulator side is converted into a bending motion of the connecting piece itself, and the insulator The degree to which vibration is transmitted to the main body can be remarkably suppressed.

  Moreover, in this invention, in order to fix a heat insulator, a part of connection location where a heat insulator is connected with an exhaust manifold is replaced with the connection to the gasket via the said connection piece. As described above, by using this connecting piece, as described above, the degree to which heat and vibration are transmitted to the heat insulator is suppressed.

  As a result, in the present invention, transmission of heat and vibration from the vibration manifold and the exhaust manifold, which is the heat source, to the heat insulator is efficiently suppressed, so that the heat insulator resonates due to the transmitted vibration or the bolt of the heat insulator It is possible to suppress the occurrence of metal fatigue in the vicinity of the attachment site, and to eliminate the increase of noise and the occurrence of cracks in the heat insulator, which can greatly improve the quality of the heat insulator. it can. In addition, since heat transfer from the exhaust manifold can be efficiently suppressed, the quality can be improved in this respect.

  Thereby, when using the heat insulator of the present invention, hoses and ducts made of various electrical equipment, harnesses or synthetic resin materials arranged around the internal combustion engine are excessively heated by the heat radiation, It is possible to prevent the occurrence of a heat damage such as a characteristic change or thermal deterioration, a problem that the quietness in the vehicle interior is impaired, or an external noise level is increased.

  According to the second aspect of the present invention, in the first aspect of the present invention, the connecting piece is configured such that the outer peripheral portion of the metal plate constituting the gasket is extended toward the heat insulator. Therefore, the present invention has the following effects in addition to the effects of the invention of claim 1. Regarding the configuration of the thermal protection device of the present invention, it is not necessary to prepare the connecting piece as a separate part other than the heat insulator and the gasket, and the configuration of the thermal protection device can be simplified. Moreover, the attachment work to the gasket of the connection piece assumed when a connection piece is the said another part becomes unnecessary, and reduction of a manufacturing man-hour can be aimed at.

  According to the third aspect of the present invention, in the first aspect of the present invention, the connecting piece moves from between the heat insulator and the internal combustion engine to above the internal combustion engine based on the shape and size of the connecting piece. A function of substantially stopping the moving route. Thereby, in addition to the effect of invention of Claim 1, this invention has the following effects. A situation in which heat from the exhaust manifold causes heat damage to components such as a cylinder head cover above the internal combustion engine is prevented, and the reliability of the internal combustion engine to which the thermal protection device is mounted is greatly improved.

  According to a fourth aspect of the invention, in the first aspect of the invention, among the plurality of constituent members included in the heat insulator, the plurality of constituent members to be connected to each other are connected to each other via a hook member. Is done. Thereby, in addition to the effect of invention of Claim 1, this invention has the following effects. Therefore, compared with the case where these structural members are connected by rivets, spot welding or the like, a special large work machine is not required, the connecting work process is simplified, and the number of manufacturing steps is reduced.

  According to the invention of claim 5, in the invention of claim 4, in the flange portion provided on the outer periphery of the heat insulator configured to include a plurality of panel members, the plurality of panel members use a plurality of hook members. Connected to each other. That is, a plurality of panel members are connected to each other by combining the plurality of panel members and pressing the flange portions against each other. Thereby, in addition to the effect of invention of Claim 1, this invention has the following effects.

  When assembling a heat insulator including a plurality of panel members arranged so as to surround almost the entire circumference of the exhaust manifold to the exhaust manifold, the panel members are connected to each other by bolts, spot welding, rivets, etc. This eliminates the need for a special large work machine, simplifies the connecting process and reduces the number of manufacturing steps.

  The connecting piece that is integral with the exhaust manifold gasket and extends to the heat insulator side and the heat insulator are connected to each other by a hook member, so that it is possible to reduce the number of manufacturing steps when manufacturing the thermal protection device of the internal combustion engine. it can.

  The present invention will be described below with reference to examples. 1 and 2 show a first embodiment of the present invention. FIG. 1 is an exploded perspective view of the thermal protection device 21 of the engine 22 of this embodiment, and FIG. 2 is a cross-sectional view of the thermal protection device 21.

  Hereinafter, the configuration of the thermal protection device 21 of this embodiment will be described with reference to FIGS. 1 and 2 together. As an example of an internal combustion engine, an automobile engine 22 includes a cylinder head 23 and a cylinder block 24 joined to each other with a cylinder head gasket (not shown) interposed therebetween. An exhaust port hole 25 through which combustion exhaust gas is discharged is formed in the cylinder head 23, and an exhaust manifold 27 is joined to the exhaust port hole 25 via an exhaust manifold gasket 26 that is a gasket of the present invention. A heat insulator 28 is provided so as to cover the exhaust manifold 27. Further, a cylinder head cover 40 made of synthetic resin, for example, is attached to the cylinder head 23 via a rubber seal 40a.

  The exhaust manifold 26 is configured by, for example, laminating one or a plurality of metal plates having elasticity and spring properties, such as a stainless steel thin plate, and forming a sealing bead around the exhaust port hole 25. The heat insulator 28 is formed by laminating one or a plurality of light metal plates (for example, NIMBUS manufactured by Federal Mogal) made of a light metal such as an aluminum alloy. In this embodiment, the light metal plate includes an aluminum foil or an aluminum alloy foil, and a thin plate made of aluminum or an alloy thereof.

  One or a plurality of connecting pieces 31 having a structure in which a metal plate constituting the exhaust manifold 26 is extended to a heat insulator 28 side at an outer peripheral portion thereof at a predetermined portion of the exhaust manifold 26 are integrally formed with the exhaust manifold 26. It is formed. In this embodiment, as shown in FIG. 1, connection pieces 31 are formed at two places in total in the vicinity of both ends in the left-right direction of FIG.

  Each connecting piece 31 is preferably stamped and formed at the same time when the metal plate constituting the exhaust manifold 26 is stamped or press-molded. The thermal protection device 21 in the present embodiment is configured to include the exhaust manifold gasket 26, the heat insulator 28, and the connecting piece 31.

  The length L1 of the connecting piece 31 shown in FIG. 1 is such that the vicinity of its tip reaches the heat insulator 28 in a state where the exhaust manifold 27 and the thermal protection device 21 are assembled to the engine 22 as shown in FIG. The range is selected. As an example, a male part 33 constituting a part of the hook member 32 is mounted near the tip of each connecting piece 31. Further, in the vicinity of the end portion of the heat insulator 28 on the side of the exhaust gasket 26 and corresponding to each tip portion of the connecting piece 31, a female part 34, for example, constituting another part of the hook member 32 is provided. Each is attached.

  The number of the connecting pieces 31 can be appropriately determined in accordance with the size and size of the heat insulator 28 and the exhaust gasket 26, or the distribution and amplitude of the vibration frequency band that varies depending on the type of the engine 22, and is shown in FIG. The two examples are just examples. Moreover, since the connection piece 31 is formed from the metal plate which comprises the said exhaust manifold 26, the connection piece 31 has a characteristic as an elastic body which has flexibility and is easily elastically deformed.

  The heat insulator 28 includes a lower member 35 attached to the exhaust manifold 27 on the lower side of FIGS. 1 and 2, and an upper member 36 attached to the exhaust manifold 27 on the upper side of FIGS. 1 and 2. Consists of. The lower member 35 and the upper member 36 are each formed of NIMBUS manufactured by Federal Mogal Co., Ltd., respectively, constitute a panel member, and are included in the constituent members in the present invention. Moreover, it has the structure by which the some light metal plate each formed from light metals, such as an aluminum alloy, as an example was laminated | stacked, respectively.

  In this embodiment, the heat insulator 28 includes the lower member 35 and the upper member 36. The lower member 35 and the upper member 36 are provided with flange portions 35a and 36a, respectively. The flange portion 35a of the lower member 35 is provided with, for example, male parts 33 of the hook member 32 at a plurality of locations. A female part 34 is provided at a position corresponding to the male part 33 in the flange portion 36 a of 36.

  Further, a bolt 37 is inserted in the vicinity of the opposite side of the exhaust member 26 of the upper member 36 of the heat insulator 28, and a fastening portion 39 which is a bolt fastening seat for fastening the upper member 36 to the mounting member 29 of the exhaust manifold 27. Provided.

  Hereinafter, an example of a method for assembling the thermal protection device 21 of this embodiment to the engine 22 will be described. The exhaust manifold 26 is formed by punching and pressing the metal plate. At this time, the connecting piece 31 is simultaneously formed into a predetermined shape in the forming process of the exhaust manifold 26.

  Next, the lower member 35 and the upper member 36 constituting the heat insulator 28 are punched and formed into a three-dimensional shape from the light metal plate, respectively. At this time, the flange portions 35a and 36a are also formed at the same time. A male part 33 and a female part 34 constituting the hook member 32 are mounted on the flange portions 35a and 36a, respectively. In addition, female parts 34 constituting the hook member 32 are respectively attached to a plurality of portions of the upper member 36 facing the connecting piece 31.

  Next, the exhaust manifold gasket 26 is sandwiched between the exhaust manifold 27 and the engine 22, and the exhaust manifold 27 is fastened to the engine 22 with bolts (not shown). At this time, as described above, since the connecting piece 31 is formed of a metal material having elasticity, when the exhaust manifold gasket 26 is assembled, the connecting piece 31 is bent to prevent the bolt from being tightened. It is possible to evacuate from the range necessary for work so that it does not become.

  Next, the exhaust manifold 26 and the upper member 36 are connected to each other via the connecting piece 31. As an example of the connecting step, the connecting piece 31 is bent from the engine 22 side toward the upper member 36 as shown in FIG. 2, and the male part 33 attached to the connecting piece 31 and the female attached to the upper member 36 are used. The mold parts 34 are fastened to each other by pressing each other. Thereby, the upper member 36 and the exhaust manifold 26 are connected to each other via the connecting piece 31. Further, the upper member 36 is fastened to the exhaust manifold 27 using bolts 37. In this way, the upper member 36 is attached to the exhaust manifold 27.

  Next, the lower member 35 is attached to the exhaust manifold 27 from the lower side of FIGS. 1 and 2, the flange portions 35a and 36a of the lower member 35 and the upper member 36 are brought into contact with each other, and attached to the flange portions 35a and 36a. The male part 33 and the female part 34 are connected to each other. In this way, the lower member 35 and the upper member 36 are connected to each other by the hook member 32. Thereby, the thermal protection device 21 is attached to the engine 22.

  As described above, according to this embodiment, the exhaust manifold 26 and the heat insulator 28 attached to the exhaust manifold 27 are integrated using the connection piece 31, and the connection piece 31 and the gasket side of the heat insulator 28 are further integrated. The vicinity of the end is connected to each other via the hook member 32. Therefore, when performing the connecting operation between the connecting piece 31 and the upper member 36 and the connecting operation between the lower member 35 and the upper member 35, etc., compared to the case of connecting by rivets, spot welding, etc., a particularly large work No machine is required, the connecting work process is simplified, and the number of manufacturing steps is reduced.

  Further, according to the present embodiment, the vicinity of the end of the upper member 36 opposite to the exhaust manifold 26 is fastened to the exhaust manifold 27 via the bolt 37, and the upper member 36 is attached to other members such as the exhaust manifold 27. The other attachment points that require this are connected to the exhaust manifold 26 by the connecting piece 31. Thereby, the fastening operation | work which uses the volt | bolt 37 in the installation operation | work to the exhaust manifold 27 etc. of the upper member 36 can be reduced. In this respect, the number of manufacturing steps can be reduced.

  As described above, according to the present embodiment, the heat insulator 28 includes an aluminum alloy. Accordingly, the heat insulator 28 is significantly reduced in weight as compared with the case where an iron plate or the like is used, and the attachment strength can be suppressed when the heat insulator 28 is attached to the exhaust manifold 27. Therefore, the attachment location can be reduced. Since the number of attachment points can be reduced, in the manufacturing process in which the exhaust manifold 27 is assembled to the engine 22 and the heat insulator 28 is assembled to the exhaust manifold 27, the number of fastening points using the bolts 37 can be reduced. The number of manufacturing steps for attaching the thermal protection device 21 can be reduced, and the cost can be reduced.

  In addition, since the heat insulator 28 included in the thermal protection device 21 is reduced in weight, even when high-temperature heat is transmitted from the exhaust manifold 27 or the like, high-frequency vibration is transmitted, and the heat insulator 28 itself vibrates, The magnitude of the stress applied to the place where the heat insulator 28 is attached to the exhaust manifold 27 due to the vibration of the insulator 28 can be reduced, and the occurrence of cracks in the mounting portion 39 which is the bolt mounting seat of the upper member 36 can be prevented. Can do. Furthermore, it is possible to prevent the occurrence of cracks in other parts of the upper member 36 that are caused by cracks in the attachment portion 39.

  Further, in the present embodiment, the exhaust manifold gasket 26 and the heat insulator 28 attached to the exhaust manifold 27 are integrally connected using the connecting piece 31, so that the exhaust manifold gasket 26 is connected to the exhaust port hole 25 of the engine 22. In this process, the heat insulator 28 is partially fixed. Thereby, the manufacturing process required for the attachment of the heat insulator 28 to the exhaust manifold 27 can be simplified, and this can also reduce the cost.

  Further, the exhaust manifold 27 serves as a heat source because combustion exhaust gas from the engine 22 flows through. The heat insulator 28 of the present embodiment is made of a light alloy such as an aluminum alloy. Since the heat conductivity of such an aluminum alloy has a much higher heat conductivity than an aluminum-plated steel sheet or the like that has been conventionally used as a material for heat insulators, the heat distribution in the heat insulator 28 is easy. Thus, a situation in which a heat spot having a temperature higher than that of other portions is locally formed on the heat insulator 28 is prevented. Accordingly, in the heat insulator 28, it is possible to prevent the occurrence of undesired deformation and cracking due to a decrease in strength at the heat spot portion when the occurrence of the heat spot is assumed. Thereby, the reliability of the thermal protection device 21 is remarkably improved.

  Further, in this embodiment, since undesirable deformation and cracking of the heat insulator 28 are prevented, in order to achieve this, the thickness of the metal plate constituting the heat insulator 28 is increased or a reinforcing member is used. The necessity of increasing the rigidity of the heat insulator 28 or increasing the attachment position of the insulator 28 to the exhaust manifold 27 is eliminated.

  As a result, when the rigidity of the heat insulator 28 is increased, the possibility of cracking in the vicinity of the attachment location due to the increase in the weight of the heat insulator 28 is increased, or when the attachment location of the heat insulator 28 is increased. Generation of cracks due to assumed thermal strain can be prevented. Also in these points, the reliability of the thermal protection device 21 is significantly improved.

  As described above, the heat insulator 28 is coupled to the cylinder head 23 via the coupling piece 31. The exhaust manifold 26 integrally formed with the connecting piece 31 is provided facing the exhaust port hole 25 of the cylinder head 23. At the same time, the exhaust manifold gasket 26 is in contact with the entire surface of the exhaust gasket 26. The temperature distribution of the exhaust manifold 26 becomes lower as it is closer to the periphery.

  The connecting piece 31 is formed integrally with the exhaust manifold 26 by extending a stainless steel plate or the like constituting the exhaust manifold 26 at the outer periphery of the exhaust manifold 26. Accordingly, the temperature of the connecting piece 31 is about the temperature near the outer peripheral portion of the exhaust manifold 26 and is lower than the bolt 37 directly connected to the exhaust manifold 27.

Therefore, the heat dissipation from the connecting piece 31 that connects the engine 22 and the heat insulator 28 is much lower than the heat dissipation from the bolt 37. Further, regarding the extent to which heat is transmitted to the heat insulator 28 and the temperature of the heat insulator 28 rises, the temperature rise due to heat conduction from the connecting piece 31 is higher than the temperature rise due to heat conduction from the bolt 37. The degree can be greatly reduced. Thereby, the outward heat dissipation by the thermal protection device 21 can be remarkably suppressed.
Further, since the connecting piece 31 of the thermal protection device 21 is formed of a metal plate having elasticity and spring properties such as a stainless thin plate constituting the exhaust manifold gasket 26, vibration transmitted from the cylinder head 23 to the heat insulator 28 side. Can be remarkably suppressed to the extent that vibration is transmitted to the heat insulator 28 by being converted into the bending motion of the connecting piece 31 itself.

  In this embodiment, the heat insulator 28 is directly connected to the exhaust manifold 27 at one place, and the other two places are connected to the exhaust manifold gasket 26 by the connecting piece 31. By using the connecting piece 31, as described above, the degree to which heat and vibration are transmitted to the heat insulator 28 is suppressed.

  As a result, in this embodiment, transmission of vibration from the exhaust manifold 27 serving as the vibration source and heat source to the heat insulator 28 is efficiently suppressed, so that the heat insulator 28 resonates due to the transmitted vibration or the bolt 37 It is possible to suppress the occurrence of metal fatigue in the vicinity of the attachment portion 39 of the heat insulator 28 to which the heat insulator 28 is attached, and it is possible to eliminate an increase in noise and the occurrence of cracks in the heat insulator 28. The quality of the can be greatly improved. In addition, since the heat transfer from the exhaust manifold 27 can be efficiently suppressed, the quality can be improved also in this respect.

  As a result, when the thermal protection device 21 of the present embodiment is used, hoses and ducts made of various electrical equipment, harnesses, synthetic resin materials, etc. disposed around the engine 22 are excessively raised by the thermal radiation. It is possible to prevent the occurrence of problems such as heating, thermal damage such as characteristic changes or thermal degradation, and loss of quietness in the passenger compartment or increase in external noise level.

  Further, according to the present embodiment, the connecting piece 31 is configured by extending the outer peripheral portion of the metal plate constituting the exhaust manifold 26 toward the heat insulator 28 side. Therefore, regarding the configuration of the thermal protection device 21, it is not necessary to prepare the connecting piece 31 as a separate part other than the heat insulator 28 and the exhaust manifold 26, and the configuration of the thermal protection device 21 can be simplified. Further, it is not necessary to attach the connecting piece 31 to the exhaust manifold 26, which is assumed when the connecting piece 31 is the separate part. In this respect, the number of manufacturing steps can be reduced.

  In this embodiment, since the exhaust manifold gasket 26 and the heat insulator 28 are integrated, the exhaust manifold gasket 26 included in the present embodiment is sandwiched between the engine 22 and the exhaust manifold 27 and fixed. 28 is partially fixed. Thereby, the manufacturing process required for the attachment of the heat insulator 28 to the exhaust manifold 27 can be simplified, and this can also reduce the cost.

  The heat insulator 28 has a configuration in which it is attached to the attachment member 29 of the exhaust manifold 27 by a bolt 37 at one fastening portion 39 in the vicinity of the connection position with the connection piece 31. The installation location of the fastening part 39 can be reduced, and the simplification of the configuration and the reduction of the number of manufacturing steps can be realized.

  The fastening portion 39 is a portion where the bolt 37 is inserted and is sandwiched between the bolt head and the mounting member 29 of the exhaust manifold 37, so that processing as a bolt seat surface is necessary, and the number of installation locations increases. Then, the configuration of the thermal protection device 21 becomes complicated, and the number of manufacturing steps increases.

  Further, according to the present embodiment, the flanges 35 a and 36 a are formed on the heat insulator 28, and these are fastened together by the hook member 32. Therefore, when the heat insulator 28 vibrates, the flanges 35a and 36a can realize the function of ribs, and the vibration amplitude of the heat insulator 28 can be reduced, thereby suppressing the occurrence of cracks in the heat insulator 21. it can.

  Further, since the lower member 35 and the upper member 36 are fastened to each other by the hook member 32, the lower member 35 and the upper member 36 are compared with the case where the lower member 35 and the upper member 36 are connected by rivets, spot welding, or the like. No special processing process is required, the connecting process is simplified, and the manufacturing process can be simplified and the number of man-hours can be reduced.

  FIG. 3 is an exploded perspective view of the thermal protection apparatus 21a according to the second embodiment of the present invention. Hereinafter, the present embodiment will be described with reference to FIG. Also, FIG. 2 is referred to as necessary for the convenience of explanation of the present embodiment. The thermal protection device 21a of the present embodiment is similar to the thermal protection device 21 of the above-described embodiment, and corresponding portions are denoted by the same reference numerals. The main feature of this embodiment is that the connecting piece 31a for connecting the exhaust manifold 26 and the heat insulator 28 is the same as in the above embodiment, and the metal plate constituting the exhaust manifold 26 is disposed on the heat insulator 28 side at the outer periphery. A mode in which the shape and size of the connecting piece 31a is formed by being stretched, and substantially prevents heat from the exhaust manifold 27 from being transmitted between the heat insulator 28 and the engine 22 above the engine 22. It is to be formed.

  Specifically, when the engine 22 is in operation, heat from the exhaust manifold 27 is transmitted to the upper side of the engine 22 from the gap 41 between the heat insulator 28 and the engine 22. Accordingly, the gap 41 becomes a heat transfer path. In the connecting piece 31a of the present embodiment, as an example, the width L2 in the left-right direction in FIG. 3 is selected to be approximately equal to or larger than the width L3 in the same direction of the exhaust manifold 27.

  The above selection method of the width L2 is an example of this embodiment, and the present invention is not limited to this example. In this embodiment, the connecting piece 31a prevents the heat from the exhaust manifold 27 from being transmitted through the gap 41 to the cylinder head cover 40, the rubber seal 40a, various harnesses, etc. above the engine 22 and causing heat damage. Therefore, the shape and size are appropriately selected. As an example of such an option, the width L2 is selected to be approximately the same as the width L3 or larger than the width L3.

  In this way, in the present embodiment, the connecting piece 31 a substantially has a movement path formed by the gap 41 between the heat insulator 28 and the engine 22 by the heat from the exhaust manifold 27 based on the shape and size thereof. It has a structure to dampen.

  Thereby, in this embodiment, in addition to the operational effects described in the above embodiment, the situation where the heat from the exhaust manifold 27 causes thermal damage to components such as the cylinder head cover 40 and the rubber seal 40a above the engine 22 is prevented. It is possible to realize a unique action and effect that the reliability of the engine 22 to which the thermal protection device 21a is mounted is remarkably improved.

  In each of the above embodiments, the lower member 35 and the upper member 36 are cited as the constituent members that constitute the insulator 28, but the present invention is not limited to such embodiments. As another example of the constituent member, when a clamp for holding harnesses is attached to the insulator 28, the clamp is a constituent member of the present invention, and the connection between the clamp and the insulator 28 is realized by the hook member 32. Moreover, when plates, such as a nameplate, are separately attached to the insulator 28 as an example, these plates are a structural member of this invention, and the connection of plates and the insulator 28 is implement | achieved by the hook member 32. FIG.

  The scope of the present invention is not limited to the examples disclosed in the above embodiments, and includes a wide range of modifications without departing from the spirit of the present invention.

  In a thermal protection device for an internal combustion engine including a gasket and a light metal heat insulator, the gasket and the heat insulator can be easily fastened to each other using a hook member, thereby simplifying the configuration and reducing the number of manufacturing steps. Can do.

It is a disassembled perspective view of the thermal protection apparatus 21 of 1st Example of this invention. 2 is a cross-sectional view of a thermal protection device 21. FIG. It is a disassembled perspective view of the thermal protection apparatus 21a of 2nd Example of this invention. It is sectional drawing of the engine 1 of a prior art. It is a perspective view of the insulator 6a of the 2nd prior art.

Explanation of symbols

21, 21a Thermal protection device 22 Engine 23 Cylinder head 24 Cylinder block 25 Exhaust port hole 26 Exhaust manifold gasket 27 Exhaust manifold 28 Heat insulator 29 Mounting member 31, 31a Connecting piece 32 Hook member 33 Male part 34 Female part 35 Lower member 35a, 36a Flange part 36 Upper member 37 Bolt 39 Fastening part 40 Cylinder head cover 40a Rubber seal 41 Gap

Claims (5)

A gasket that is interposed between the exhaust port of the internal combustion engine and the exhaust manifold, and is formed from a metal plate having elasticity and spring properties;
A heat insulator comprising a light metal plate provided at least partially surrounding the exhaust manifold;
A connecting piece for connecting the gasket and the heat insulator together,
At least the connecting piece and the vicinity of the gasket side end of the heat insulator are connected to each other via a hook member,
The heat protection device for an internal combustion engine, characterized in that the vicinity of the end of the heat insulator opposite to the gasket is fastened to the exhaust manifold via a metal fastener. 2. The thermal protection device for an internal combustion engine according to claim 1, wherein the connecting piece is configured by extending the metal plate toward the heat insulator at an outer peripheral portion of the gasket. 2. The internal combustion engine according to claim 1, wherein the shape and the size of the connecting piece are determined in such a manner that a movement path in which heat from the exhaust manifold moves upward between the heat insulator and the internal combustion engine is substantially blocked. Engine thermal protection device. The heat insulator includes a plurality of constituent members including a plurality of panel members configured by laminating a plurality of light metal plates,
The thermal protection device for an internal combustion engine according to claim 1, wherein the plurality of components to be connected to each other are connected to each other via the hook member. The plurality of panel members are arranged so as to surround the exhaust manifold almost entirely. In the flange portion provided on the outer periphery of each panel member, the plurality of panel members are mutually connected using the plurality of hook members. The thermal protection device for an internal combustion engine according to claim 4, wherein the thermal protection device is connected.

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