JP7325370B2 - Insulator for cylinder bore wall - Google Patents

Description

The present invention relates to a cylinder bore wall heat insulator having a heat retaining portion in contact with the cylinder bore wall, which is arranged in a groove-like cooling water flow path formed in a cylinder block of an internal combustion engine so as to surround the outer periphery of the cylinder bore wall.

In an internal combustion engine, fuel explodes near the top dead center of the piston in the bore, and the explosion pushes the piston down. Therefore, the upper side of the cylinder bore wall has a higher temperature, and the lower side of the cylinder bore wall has a lower temperature than the upper side. As a result, a difference occurs in the amount of thermal deformation between the upper side and the lower side of the cylinder bore wall. That is, the upper side of the cylinder bore wall expands greatly, and the lower side of the cylinder bore wall expands less than the upper side.

A difference in the amount of thermal deformation between the upper side and the lower side of the cylinder bore wall increases the frictional resistance between the piston and the cylinder bore wall. This frictional resistance is a factor in reducing fuel consumption. Therefore, it is required to equalize the amount of thermal deformation between the upper side and the lower side of the cylinder bore wall, that is, to equalize the temperature between the upper side and the lower side of the cylinder bore wall.

In Patent Document 1, a heat insulator having an expansive expansion member is installed in a groove-shaped cooling water flow path of a water jacket of an internal combustion engine in order to make the temperature of the cylinder bore wall uniform. The heat retaining tool is provided so as to keep warm the middle portion and the lower portion of the cylinder bore wall in the vertical direction.

JP 2015-203314 A

When the internal combustion engine is running, cooling water is circulated through the grooved cooling water passages. At that time, there is a risk that the inflatable member may be broken and torn off due to the flow of the cooling water, or may fall off from the base.
SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a heat retaining device for a cylinder bore wall that can prevent tearing and falling off due to breakage of an expansion member.

The above problems are solved by the following. That is, the cylinder bore wall heat retaining device of the present invention (1) includes a base facing the cylinder bore wall of a groove-shaped cooling water flow path through which cooling water flows, and a substantially rectangular opening provided in the center of the base. a frame member having
a base member provided on the side opposite to the surface of the frame member facing the cylinder bore wall;
an expansion member having a sheet shape sandwiched and held between the base member and the frame member and capable of protruding from the opening and abutting against the wall of the cylinder bore by expansion;
a half bead continuously provided on the frame member so as to cover the expansion member at a position adjacent to at least one side of the opening, the half bead protruding from the base portion and capable of coming into contact with the cylinder bore wall; ,
One or more elastic members provided on the base member and capable of coming into contact with opposing walls of the groove-like cooling water flow path, and biasing the frame member and the expansion member toward the cylinder bore wall, one or more elastic members that bring the half bead into contact with the cylinder bore wall;
Prepare.

Further, the cylinder bore wall heat retaining device according to the present invention (2) is the cylinder bore wall heat retaining device according to (1), wherein the frame member protrudes toward the expansion member at the boundary between the half bead and the base portion. It has an arc part that becomes

Further, the cylinder bore wall heat retaining device of the present invention (3) is the cylinder bore wall heat retaining device according to (1) or (2), wherein the half bead comprises a half bead main body corresponding to the at least one side; a wraparound portion extending from the half bead main body and adjacent to the other side adjacent to the at least one side, and the half bead main body and the wraparound portion cover the corners of the expansion member.

Further, the cylinder bore wall heat retaining device of the present invention (4) is the cylinder bore wall heat retaining device described in (1) or (2), wherein the half beads are substantially adjacent to two adjacent sides of the opening. It is provided in an L shape.

Further, the cylinder bore wall heat retaining device of the present invention (5) is the cylinder bore wall heat retaining device described in (1) or (2), wherein the half beads are substantially adjacent to two opposite sides of the opening. provided in parallel.

Further, the cylinder bore wall heat retaining device of the present invention (6) is the cylinder bore wall heat retaining device described in (1), wherein the half beads are formed in a substantially C shape adjacent to three adjacent sides of the opening. be provided.

Further, the cylinder bore wall heat retaining device of the present invention (7) is the cylinder bore wall heat retaining device described in (1), wherein the half beads are provided in a frame shape adjacent to four sides of the opening.

Further, the cylinder bore wall heat retaining device of the present invention (8) is the cylinder bore wall heat retaining device described in (1), wherein the half bead is disposed upstream in the flow direction of the cooling water flowing through the grooved cooling water flow path. It is provided at a position adjacent to the at least one side where it is located.

According to the present invention, it is possible to provide a heat retaining device for a cylinder bore wall that can prevent tearing and falling off due to breakage of an expansion member.

FIG. 3 is a schematic perspective view showing a form example of a cylinder block on which the heat insulator for the cylinder bore wall of the first embodiment is installed; FIG. 2 is a schematic plan view of the cylinder block of FIG. 1; FIG. 3 is a perspective view of the cylinder block taken along line F3-F3 shown in FIG. 2; FIG. 2 is a perspective view showing the cylinder block shown in FIG. 1 and heat insulators for first to fourth cylinder bore walls installed therein; FIG. 5 is a front view of the heat insulator for the first cylinder bore wall shown in FIG. 4; FIG. 6 is a rear view of the heat insulator for the first cylinder bore wall shown in FIG. 5; FIG. 6 is a cross-sectional view along line F7-F7 of the heat retaining device for the first cylinder bore wall shown in FIG. 5; Fig. 8 is a cross-sectional view showing an enlarged portion A of the heat retaining device of the first cylinder bore wall shown in Fig. 7; FIG. 6 is an exploded perspective view showing an exploded heat retaining device of the first cylinder bore wall shown in FIG. 5 ; FIG. 5 is a front view of a heat insulator for the second and third cylinder bore walls shown in FIG. 4; FIG. 5 is a front view of the heat insulator for the fourth cylinder bore wall shown in FIG. 4; FIG. 2 is a perspective view schematically showing a flow direction of cooling water flowing through a grooved cooling water flow path of the cylinder block shown in FIG. 1; FIG. 11 is a perspective view schematically showing a flow direction of cooling water flowing through a groove-shaped cooling water flow path while showing a cylinder block in which a heat insulator for a first cylinder bore wall of a second embodiment is installed; FIG. 14 is a front view showing a heat insulator for the first cylinder bore wall shown in FIG. 13; FIG. 11 is a perspective view schematically showing a flow direction of cooling water flowing through a groove-shaped cooling water flow path while showing a cylinder block in which heat retaining devices for first and fourth cylinder bore walls of a third embodiment are installed; FIG. 16 is a front view showing a heat insulator for the fourth cylinder bore wall shown in FIG. 15; FIG. 11 is a front view showing a heat retaining tool for the first cylinder bore wall of the fourth embodiment; FIG. 11 is a front view showing a heat retaining tool for the third cylinder bore wall of the fifth embodiment; FIG. 11 is a front view showing a heat retaining tool for the first cylinder bore wall of the sixth embodiment; FIG. 12 is a front view showing a heat retaining tool for the second cylinder bore wall of the seventh embodiment; FIG. 20 is a front view showing a heat retaining tool for the second cylinder bore wall of the eighth embodiment; FIG. 21 is a front view showing a heat retaining tool for the second cylinder bore wall of the ninth embodiment; FIG. 21 is a front view showing a heat retaining tool for the second cylinder bore wall of the tenth embodiment; FIG. 21 is a front view showing a heat insulator for the second cylinder bore wall of the eleventh embodiment; FIG. 20 is a front view showing a heat retaining tool for the first cylinder bore wall of the twelfth embodiment; FIG. 20 is a front view showing a heat retaining device for the fourth cylinder bore wall of the thirteenth embodiment;

A heat insulator for a cylinder bore wall of an embodiment includes: a frame member having a base facing the cylinder bore wall of the grooved cooling water flow path; A base member provided on the side opposite to the surface facing the cylinder bore wall, and a sheet-like member sandwiched and held between the base member and the frame member. an expansion member abuttable against the cylinder bore wall; and a half bead continuously provided on the frame member to cover the expansion member at a position adjacent to at least one side of the opening, the half bead projecting from the base. and one or more elastic members provided on the base member and capable of contacting opposite walls of the groove-like cooling water flow path, wherein the frame member and the expansion member are connected to each other. and one or more elastic members that bias the cylinder bore wall toward the cylinder bore wall and bring the half bead into contact with the cylinder bore wall.

The expansion member may be in the form of a square flat plate, and may be curved in an arc shape along the shape of the bore wall. The inflatable member may have, for example, the shape shown in FIG. 9 and the like. The shape and thickness of the inflatable member are not particularly limited and can be selected as appropriate. The inflatable member is made of an inflatable material (elastic body). Examples of expansive materials include heat-sensitive expansible rubber, water-swellable rubber, cellulose-based sponge, and the like.

The thermal expansion rubber is rubber that expands when heated in the groove-like cooling water flow path. Thermally expandable rubber is a composite made by impregnating a base foam material with a thermoplastic material having a lower melting point than that of the base foam material and compressing it. In addition, it is a material in which a cured thermoplastic material is softened by heating to release a compressed state. Examples of thermally expandable rubbers include thermally expandable rubbers described in JP-A-2004-143262. When the material of the rubber member is thermally expandable rubber, the heat-retaining member of the cylinder bore wall of the present invention is installed in the groove-like cooling water flow path, and heat is applied to the thermally expandable rubber, thereby expanding the thermally expandable rubber to a predetermined temperature. expands and deforms into the shape of

Base foam materials for heat-sensitive expansion rubbers include various polymer materials such as rubbers, elastomers, thermoplastic resins, and thermosetting resins. Specific examples include natural rubber, chloropropylene rubber, styrene-butadiene rubber, and nitrile. Various synthetic rubbers such as butadiene rubber, ethylene propylene diene terpolymer, silicone rubber, fluororubber, and acrylic rubber, various elastomers such as soft urethane, and various thermosetting resins such as hard urethane, phenolic resin, and melamine resin. be done.

As the thermoplastic material related to the thermally expandable rubber, one having a glass transition point, melting point or softening temperature of less than 120°C is preferable. Thermoplastic substances related to heat-sensitive expansion rubber include polyethylene, polypropylene, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyvinyl acetate, polyacrylate, styrene-butadiene copolymer, chlorinated polyethylene, polyvinylidene fluoride, ethylene acetate. Vinyl copolymer, ethylene vinyl acetate vinyl chloride acrylate copolymer, ethylene vinyl acetate acrylate copolymer, ethylene vinyl acetate vinyl chloride copolymer, nylon, acrylonitrile butadiene copolymer, polyacrylonitrile, polyvinyl chloride , polychloroprene, polybutadiene, thermoplastic polyimide, polyacetal, polyphenylene sulfide, polycarbonate, thermoplastic resin such as thermoplastic polyurethane, low-melting glass frit, starch, solder, wax and other thermoplastic compounds.

As the water-swellable rubber, the water-swellable rubber is a rubber material to which a water-absorbing substance is added, and is a rubber material that swells by absorbing water and retains its expanded shape. Examples of water-swellable rubbers include rubber materials in which water-absorbing substances such as cross-linked polyacrylic acid neutralized products, starch-acrylic acid graft copolymer cross-linked products, cross-linked carboxymethyl cellulose salts, and polyvinyl alcohol are added to rubber. mentioned. Examples of water-swellable rubbers include water-swellable rubbers containing ketiminated polyamide resins, glycidyl etherates, water-absorbing resins and rubbers described in JP-A-9-208752. When the material of the rubber member is water-swellable rubber, the heat insulator of the cylinder bore wall of the present invention is installed in the groove-shaped cooling water flow path, the cooling water is flowed, and the water-swellable rubber absorbs the water. The swelling rubber expands and expands and deforms into a predetermined shape.

Cellulose-based sponge absorbs water, swells, and has shape-retaining properties to retain the expanded shape.

The base member has a base member main body, an elastic member integrally formed with the base member main body, and a second elastic member integrally formed with the base member main body. The base member main body has a back plate provided on the back side of the expansion member, and a back frame provided on the back side of the back plate.

The rear plate may be in the shape of a square flat plate, or may be curved in an arc shape along the shape of the bore wall. The back plate may be made of a metal material such as a stainless steel plate. The back plate may have the shape shown in FIG. 9 or the like, for example. The back plate may be formed integrally with the back frame.

The back frame body may be in the form of a square flat plate and a frame having a through hole in the center. The back frame may be made of a metal material such as a stainless steel plate. The back frame may have, for example, the shape shown in FIG. 9 and the like. The back frame may be curved in an arc along the shape of the bore wall.

The back frame may have a frame portion having a frame shape. The back frame may be curved in an arc along the shape of the bore wall. The back frame may be formed in an arc shape by connecting a plurality of plates. The back frame may have one or more legs projecting downward from the frame. The back surface frame may have one or more stopper portions that protrude upward from the frame portion and are provided to prevent lifting.

The elastic member and the second elastic member may be made of a metal material such as a stainless steel plate. The elastic member and the second elastic member are composed of leaf springs.

The frame member may be a rectangular frame-shaped flat plate, and may be curved in an arc shape along the shape of the bore wall. The frame member may be made of a metal material such as a stainless steel plate. The frame member may have a shape such as that shown in FIG. 9, for example. The frame member has a base, an opening provided in the center of the base, and a half bead provided adjacent to the opening.

The half bead protrudes toward the cylinder bore wall from the base toward the opening. The half bead is arranged upstream of the expansion member in the flow direction of the cooling water. Therefore, the half bead can cover a portion of the expansion member to protect the expansion member from the cooling water flow.
The details of the heat insulator for the wall of the cylinder bore will be described below with reference to the drawings.
[First embodiment]

A heat retaining device 11 for a cylinder bore wall according to a first embodiment will be described with reference to FIGS. 1 to 12. FIG. As shown in FIGS. 1 to 3, the cylinder bore wall heat insulator 11 is installed, for example, in a water jacket (grooved cooling water flow path 12) of an internal combustion engine of an automobile. Generally, an internal combustion engine has a cylinder block 13 and a cylinder head (not shown) covering the upper side of the cylinder block.

The cylinder block 13 has a plurality of bores 14 through which the pistons move up and down, and groove-shaped cooling water flow paths 12 (water jackets) provided adjacent to the bores 14 through which cooling water flows. The groove-shaped cooling water flow path 12 has a cylinder bore wall 15 adjacent to the bore 14, a counter wall 17 facing the cylinder bore wall 15, and a bottom portion 18 defining a bottom surface. A cylinder bore wall 15 partitions between the bore 14 and the grooved cooling water flow path 12 . A plurality of bores 14 are arranged in a line to form a bore row.

The cylinder block 13 has a cooling water supply port 21 for supplying cooling water to the grooved cooling water flow paths 12 and a cooling water discharge port 22 for discharging the cooling water from the grooved cooling water flow paths 12 . As shown in FIG. 2, the cooling water supply port 21 is provided at a position facing the bore 14 located at one end of the bore row. A cooling water outlet 22 is provided in the bore 14 located at the other end opposite to the one end of the row of bores. Any number of bores 14 may be included in the cylinder block 13 . The cylinder block 13 has a first bore 14A, a second bore 14B, a third bore 14C, and a fourth bore 14D from the side closer to the cooling water supply port 21 .

The grooved cooling water flow path 12 has an intake side flow path 12A provided on the intake flow path side of the bore 14 and an exhaust side flow path 12B provided on the exhaust flow path side of the bore 14 . Cooling water flows through the grooved cooling water flow path 12 from a cooling water supply port 21 toward a cooling water discharge port 22 . The cooling water is composed of general engine cooling water such as LLC. The flow rate of the cooling water can be appropriately increased or decreased by a known method according to the temperature of the internal combustion engine.

As shown in FIGS. 2 and 4, in this embodiment, for example, four cylinder bore wall heat insulators 11 are installed in, for example, an intake side passage 12A in a grooved cooling water passage 12. As shown in FIG. The heat retaining tool 11A for the first cylinder bore wall is provided at positions corresponding to the intermediate portion and the lower portion in the depth direction of the cylinder bore wall (first cylinder bore wall 15A) of the first bore 14A. The heat insulators 11B for the second cylinder bore wall are provided at positions corresponding to the intermediate portion and the lower portion in the depth direction of the cylinder bore wall (second cylinder bore wall 15B) of the second bore 14B. The heat retaining device 11C for the third cylinder bore wall is provided at a position corresponding to the intermediate portion and the lower portion in the depth direction of the cylinder bore wall (third cylinder bore wall 15C) of the third bore 14C. The heat insulators 11D for the fourth cylinder bore wall are provided at positions corresponding to the intermediate portion and the lower portion in the depth direction of the cylinder bore wall (fourth cylinder bore wall 15D) of the fourth bore 14D.

Details of the heat insulators 11A to 11D for the first to fourth cylinder bore walls will be described. First, the heat insulator 11A for the first cylinder bore wall will be described, and then the heat insulators 11C to 11D for the second to fourth cylinder bore walls will be described in order. Only the heat retaining devices 11C to 11D for the second to fourth cylinder bore walls differ from the heat retaining device 11A for the first cylinder bore wall.

As shown in FIGS. 5 and 6, the heat insulator 11A for the first cylinder bore wall includes a base member 23, an expansion member 24 provided at a position closer to the cylinder bore wall 15 than the base member 23, and a A frame member 25 provided near the wall 15, one or more first fixing members 26 and one or more second fixing members provided on the base member 23 for integrally fixing the base member 23, expansion member 24, and frame member 25. a member 27; The base member 23, the expansion member 24, and the frame member 25 are stacked in order to form a flat plate as a whole.

As shown in FIG. 4 , the base member 23 is formed in a flat plate shape curved in an arc shape so as to follow the arc surface of the cylinder bore wall 15 . The base member 23 is provided on the side opposite to the surface of the frame member 25 facing the cylinder bore wall 15 . As shown in FIG. 6, the base member 23 includes a base member main body 31, an elastic member 32 integrally formed with the base member main body 31, and a second elastic member 33 integrally formed with the base member main body 31. and have As shown in FIG. 9, the base member main body 31 includes a rear frame 34 having a flat plate shape curved in an arc, and a flat plate curved in an arc provided at a position closer to the cylinder bore wall 15 than the rear frame 34. a shaped back plate 35; The back frame 34 is formed in a frame shape, has a through hole 36 provided in the center, and one or more legs 37 (see FIG. 5) that can come into contact with the bottom 18 of the groove-shaped cooling water flow path 12 . and have The through hole 36 penetrates the back frame 34 in its thickness direction.

The elastic member 32 is composed of a leaf spring. As shown in FIGS. 6 and 7, the elastic member 32 is integrally formed with the back frame 34. As shown in FIGS. The elastic member 32 abuts against the opposing wall 17 with a predetermined pressure, and can press the expansion member 24 against the cylinder bore wall 15 by its reaction force.

As shown in FIGS. 6 and 7, the elastic member 32 includes a connection portion 32A connected to the back frame 34 and a first contact portion extending from the connection portion 32A toward the opposing wall 17 and bent in a mountain shape. and a second contact portion 32C extending from the first contact portion 32B toward the rear plate 35 and in contact with the rear plate 35 . The first contact portion 32B can contact the opposing wall 17 . The second contact portion 32</b>C can slide with respect to the back plate 35 . The elastic member 32 is a cantilever leaf spring supported by the connection portion 32A, and the second contact portion 32C is in contact with the rear plate 35. As shown in FIG. For this reason, the elastic member 32 can exhibit a large repulsive force as a leaf spring that is supported substantially by the connecting portion 32A and the second contact portion 32C. The elastic member 32 is formed, for example, by bending using a press machine or the like.

The second elastic member 33 is composed of a leaf spring. The second elastic member 33 includes a second connection portion 33A connected to the back frame 34, and a third contact portion 33B extending from the second connection portion 33A toward the opposing wall 17 and bent in a mountain shape. have. The third contact portion 33B can contact the opposing wall 17 . The second elastic member 33 is a cantilever leaf spring supported by the second connecting portion 33A. Therefore, the repulsive force of the second elastic member 33 is smaller than the repulsive force of the elastic member 32 . The second elastic member 33 is formed, for example, by bending using a press machine or the like. The pressure with which the expansion member 24 is pressed against the cylinder bore wall 15 by the elastic member 32 and the second elastic member 33 is greater than the expansion pressure of the expansion member 24 .

As shown in FIGS. 5 and 7 , one or more first fixing members 26 and one or more second fixing members 27 are integrally formed with the back frame 34 . Each of the one or more first fixing members 26 is arranged so as to overlap the upper side portion 25A or the lower side portion 25D of the frame member 25 . The first fixing member 26 is formed in the shape of a small piece, and is bent to have a "U" cross section so as to sandwich the rear plate 35, the expansion member 24, and the frame member 25 with the rear frame 34. ing. The first fixing member 26 is formed, for example, by caulking (bending) using a press machine or the like.

Each of the one or more second fixing members 27 is arranged so as to overlap the right side portion 25B and the left side portion 25C of the frame member 25 . The second fixing member 27 may have a notch 27A in the middle. The second fixing member 27 extends along the right side portion 25B or the left side portion 25C of the frame member 25, and sandwiches the rear plate 35, the expansion member 24, and the frame member 25 with the rear frame member 34. It is bent into a "U" cross section. The second fixing member 27 is formed, for example, by caulking (bending) using a press machine or the like. The first fixing member 26 and the second fixing member 27 are not limited to the bending of the sheet metal described above, and may be formed by screws, rivets, eyelets, welding, brazing, burring, or the like.

The expansion member 24 is formed in a flat plate shape from a material that absorbs the cooling water in the groove-shaped cooling water flow paths 12 and exerts expansion properties or a material that has thermal expansion properties. In the present embodiment, the expansive member 24 is formed in a flat plate shape from, for example, heat-sensitive expansible rubber. The inflatable member 24 has a sheet shape sandwiched and held between the base member 23 and the frame member 25 . The expansion member 24 can protrude from the opening 42 of the frame member 25 and come into contact with the cylinder bore wall 15 by being expanded.

As shown in FIGS. 5, 7, and 8, the frame member 25 has a plate-like frame-like base portion 41 facing the cylinder bore wall 15, and a substantially square opening 42 provided in the central portion of the base portion 41. , a half bead 43 provided mainly at a position adjacent to one side of the opening 42 , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 . As shown in FIG. 8, the arc portion 44 has an arcuate cross section so as to be convex toward the inflatable member.

As shown in FIG. 7, the half bead 43 can protrude from the base 41 and abut the cylinder bore wall 15 . The half beads 43 are formed on the frame member 25 by plastic working using, for example, a press machine. As shown in FIG. 5, in the heat insulator 11A of the first cylinder bore wall, the half beads 43 are continuously formed on one side of the opening 42, i.e., at a position adjacent to the upper side 42A of the opening 42 so as to cover the expansion member 24. It is provided on the frame member 25 . The half bead 43 includes a half bead main body 43A extending linearly corresponding to the upper side 42A of the opening 42, and a pair of right side 42C and left side 42D extending from the half bead main body 43A and adjacent to the upper side 42A of the opening 42. and a wraparound portion 43B. The winding portions 43B extend downward from both ends of the half bead main body 43A and are formed continuously with the half bead main body 43A. The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 10, heat retaining tools 11B and 11C for the second and third cylinder bore walls corresponding to the second and third cylinder bore walls 15B and 15C will be described. The heat insulators 11B and 11C of the second and third cylinder bore walls have the same shape. Therefore, only the heat insulator 11B for the second cylinder bore wall will be described below.

As shown in FIG. 10, the heat insulator 11B for the second cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a flat and frame-shaped base 41, a substantially square opening 42 provided in the center of the base 41, and half beads 43 mainly provided adjacent to two sides of the opening 42. , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

As shown in FIG. 10 , half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the heat insulator 11B of the second cylinder bore wall, the half beads 43 are continuously attached to the frame member 25 so as to cover the expansion member 24 at positions adjacent to the two sides of the opening 42, that is, the lower side 42B and the right side 42C of the opening 42. is provided. The half bead 43 includes a half bead main body 43A extending linearly and in an L-shape corresponding to the lower side 42B and the right side 42C of the opening 42, and other sides extending from the half bead main body 43A and adjacent to the lower side 42B and the right side 42C of the opening 42. and a pair of wraparound portions 43B adjacent to a given upper side 42A and left side 42D. One of the winding portions 43B extends upward from the left end of the half bead main body 43A and is formed continuously with the half bead main body 43A. The other side of the winding portion 43B extends leftward from the upper end portion of the half bead main body 43A and is formed continuously with the half bead main body 43A. The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 11, the heat insulator 11D for the fourth cylinder bore wall corresponding to the fourth cylinder bore wall 15D will be described.

As shown in FIG. 11, the heat insulator 11D for the fourth cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a plate-like and frame-shaped base portion 41, a substantially rectangular opening 42 provided in the central portion of the base portion 41, and a half bead 43 mainly provided adjacent to one side of the opening 42. , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

As shown in FIG. 11 , half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the fourth cylinder bore wall heat retaining device 11D, the half bead 43 is continuously provided on the frame member 25 so as to cover the expansion member 24 at one side of the opening 42, that is, at a position adjacent to the right side 42C of the opening 42. there is The half bead 43 includes a half bead main body 43A that extends linearly corresponding to the right side 42C of the opening 42, and a pair that extends from the half bead main body 43A and is adjacent to the upper side 42A and the lower side 42B that are the other sides adjacent to the right side 42C of the opening 42. and a wraparound portion 43B. Each of the pair of winding portions 43B extends leftward from both ends of the half bead main body 43A and is formed continuously with the half bead main body 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 12, the action of the heat insulators 11A to 11D for the walls of the first to fourth cylinder bores of the present embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . The cooling water supplied from the cooling water supply port 21 is supplied to the intake side channel 12A and the exhaust side channel 12B of the grooved cooling water channel 12 . The cooling water immediately after being supplied to the intake side passage 12A is in a turbulent state, and as shown in FIG. It flows toward the upper portion (cylinder head side) in the depth direction of the passage 12 or toward the bottom portion 18 of the groove-shaped cooling water passage 12 . A part of the cooling water flowing toward the bottom portion 18 of the grooved cooling water flow path 12 rises near the third bore 14C toward a water hole (not shown) on the cylinder head side.

Since the heat insulator 11A of the first cylinder bore wall exists directly below the cooling water supply port 21, cooling water is mainly supplied from above to the heat insulator 11A of the first cylinder bore wall. A half bead 43 (half bead main body 43A) is provided on the heat insulator 11A of the first cylinder bore wall at a position on the upstream side in the flow direction of the cooling water, that is, at a position adjacent to the upper side of the opening 42 . Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow. A wraparound portion 43B of the half bead 43 is formed above the right side 42C and the left side 42D adjacent to the upper side 42A of the opening 42 . Therefore, the half bead main body 43A and wraparound portion 43B can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary between the upper side 42A and the right side 42C and the corners of the boundary between the upper side 42A and the left side 42D.

In this embodiment, since the arc portion 44 is provided at the boundary between the half bead 43 and the base portion 41, the frame member 25 does not have a corner at the boundary position. Therefore, even when pressure fluctuations due to the flow of cooling water are applied vibratingly at a certain frequency, stress concentration does not occur in the expansion member 24 at the boundary position. As a result, the expansion member 24 is prevented from being torn at the boundary between the half bead 43 and the base portion 41 due to breakage.

Cooling water is supplied from below and from the side to the heat insulators 11B and 11C of the second and third cylinder bore walls. The heat insulators 11B and 11C of the second and third cylinder bore walls are positioned upstream in the cooling water flow direction, that is, adjacent to the lower side 42B and the right side 42C of the opening 42 (the left side when viewed from the angle in FIG. 12). A half bead 43 (half bead main body 43A) is provided in an L shape at the position. Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow. A wraparound portion 43B of the half bead 43 is formed on the upper side 42A adjacent to the right side 42C of the opening 42 and the left side 42D adjacent to the lower side 42B of the opening 42. As shown in FIG. Therefore, the half bead main body 43A and wrap-around portion 43B form a boundary corner between the upper side 42A and the right side 42C (the left side when viewed from the angle in FIG. 12) and the lower side 42B and the left side 42D (the left side when viewed from the angle in FIG. 12). right side) can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary. The action of the arc portion 44 of the heat insulators 11B and 11C of the second and third cylinder bore walls is the same as the action of the arc portion 44 of the heat insulator 11A of the first cylinder bore wall.

Cooling water is supplied from the side to the heat insulator 11D on the wall of the fourth cylinder bore. The heat retaining device 11D of the fourth cylinder bore wall is provided with a half bead 43 (half bead main body 43A) at a position on the upstream side in the flow direction of the coolant, that is, at a position adjacent to the right side 42C of the opening 42 (the left side when viewed from the angle in FIG. 12). ) is provided. Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow. A wraparound portion 43B of the half bead 43 is formed on the upper side 42A and the lower side 42B of the opening 42 adjacent to the right side 42C. For this reason, the half bead body 43A and wrap-around portion 43B form a boundary corner between the upper side 42A and the right side 42C (the left side when viewed from the angle in FIG. 12) and the lower side 42B and the right side 42C (the left side when viewed from the angle in FIG. 12). left side) can receive pressure fluctuation due to the water flow of the cooling water at the corner of the boundary. The action of the arc portion 44 in the heat insulator 11D of the fourth cylinder bore wall is the same as the action of the arc portion 44 of the heat insulator 11A of the first cylinder bore wall. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to this embodiment, the following can be said. The cylinder bore wall heat insulator 11 is a frame member having a base portion 41 facing the cylinder bore wall 15 of the groove-shaped cooling water flow path 12 through which the cooling water flows, and an opening 42 provided in a substantially square shape in the central portion of the base portion 41. 25, a base member 23 provided on the side opposite to the surface of the frame member 25 facing the cylinder bore wall 15, and a sheet-like shape sandwiched and held between the base member 23 and the frame member 25, and expands. As a result, the expansion member 24 protruding from the opening 42 and capable of coming into contact with the cylinder bore wall 15 is continuously provided on the frame member 25 so as to cover the expansion member 24 at a position adjacent to at least one side of the opening 42 . A half bead 43 protruding from the base portion 41 and capable of coming into contact with the cylinder bore wall 15 , and one or more elastic members provided on the base member 23 and capable of coming into contact with the opposite wall 17 of the groove-like cooling water flow path 12 . The member 32 includes one or more elastic members 32 that bias the frame member 25 and the expansion member 24 toward the cylinder bore wall 15 and bring the half beads 43 into contact with the cylinder bore wall 15 .

According to this configuration, since the cylinder bore wall 15 can be kept warm by the heat insulator 11 of the cylinder bore wall, overcooling of the cylinder bore wall 15 by the cooling water can be prevented. As a result, the temperature of the cylinder bore wall 15 can be made uniform, and the fuel consumption of the internal combustion engine in which the cylinder bore wall heat insulator 11 is installed can be improved. Also, the half bead 43 in contact with the cylinder bore wall 15 can receive pressure fluctuations due to the flow of cooling water. Therefore, it is possible to prevent the expansion member 24 from tearing or falling off due to breakage due to pressure fluctuations caused by the cooling water flowing through the grooved cooling water flow passage 12 .

The frame member 25 has an arc portion 44 that protrudes toward the expansion member 24 at the boundary between the half bead 43 and the base portion 41 . In the groove-shaped cooling water flow passage 12, the flow of the cooling water may cause vibrational pressure fluctuations, and the expansion member 24 may be broken or torn due to the breakage. According to this configuration, the circular arc portion 44 can prevent an angular portion from being formed at the position of the boundary between the half bead 43 and the base portion 41 . As a result, even when the expansion member 24 is subjected to vibrational pressure fluctuations due to the flow of the cooling water, no edge is generated at the position of the boundary, and stress concentration at the boundary can be prevented. As a result, it is possible to prevent the expansion member 24 from being broken or torn due to breakage.

The half bead 43 has a half bead main body 43A corresponding to the at least one side, and a wrap portion 43B extending from the half bead main body 43A and adjacent to the other side adjacent to the at least one side. The corners of the inflatable member 24 are covered with the wraparound portion 43B. According to this configuration, the half bead main body 43A and the wraparound portion 43B can protect the corners of the expansion member 24 from pressure fluctuations due to the flow of cooling water. As a result, the corners of the expansive member 24, which are particularly susceptible to tearing or falling off due to breakage, can be protected by the half bead main body 43A and wraparound portion 43B, thereby preventing the breakage or fallout of the expansive member 24 originating from the corners. can be prevented.

The half beads 43 are provided in a substantially L shape adjacent to two sides of the opening 42 adjacent to each other. With this configuration, the two adjacent sides of the expansion member 24 and the corners between the two sides can be protected by the half beads 43 . As a result, the expansion member 24 can be protected by the half beads 43 from breakage and dropout even at a position where the flow direction of the cooling water is not limited to one direction.

The half bead 43 is provided at a position adjacent to the at least one side located upstream in the flow direction of the cooling water flowing through the grooved cooling water flow path 12 . According to this configuration, since the half bead 43 is provided on the upstream side in the flow direction, which is greatly affected by the pressure fluctuation of the cooling water, the portion of the expansion member 24 located on the upstream side in the flow direction is prevented from breaking or falling off. can be effectively prevented.

In the following embodiment, portions different from the first embodiment will be mainly described, and illustration and description of portions common to the first embodiment will be omitted.
[Second embodiment]

A heat insulator 11 for the cylinder bore wall according to the second embodiment will be described with reference to FIGS. 13 and 14. FIG. In this embodiment, the configurations of the grooved cooling water flow path 12, the cylinder block 13, and the cylinder head are the same as in the first embodiment. In this embodiment, only the heat insulator 11A of the first cylinder bore wall is installed so as to correspond to the first cylinder bore wall 15A of the intake side flow path 12A of the grooved cooling water flow path 12, and the second to fourth cylinder bore walls are provided. The heat insulators 11B-11D are not installed.

As shown in FIG. 14, the heat insulator 11A of the first cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a plate-like and frame-shaped base 41, a substantially square opening 42 provided in the center of the base 41, and positions adjacent to four sides (that is, the entire circumference) of the opening 42. It has a half bead 43 provided and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

Half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the heat insulator 11A of the first cylinder bore wall, the half beads 43 are arranged adjacent to the four sides of the opening 42, that is, the upper side 42A, the lower side 42B, the right side 42C, and the left side 42D so as to cover the expansion member 24. It is continuously provided on the frame member 25 . The half bead 43 has a half bead main body 43</b>A extending linearly and in a frame shape corresponding to the four sides of the opening 42 . The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 .

Next, with reference to FIGS. 13 and 14, the action of the heat insulator 11A for the first cylinder bore wall of the present embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . The cooling water supplied from the cooling water supply port 21 is supplied to the intake side channel 12A and the exhaust side channel 12B of the grooved cooling water channel 12 . The cooling water immediately after being supplied to the intake side passage 12A is in a turbulent state as shown in FIG. 13, and the cooling water flows in any direction.

The cooling water immediately after being supplied to the intake side passage 12A is in a turbulent state. Therefore, cooling water is supplied from an arbitrary direction to the heat insulator 11A on the wall of the first cylinder bore. The heat insulator 11A on the first cylinder bore wall is provided with half beads 43 at positions on the upstream side in the flow direction of the cooling water, that is, at positions adjacent to all sides (four sides) of the opening 42 . Therefore, the half bead 43 can receive pressure fluctuations caused by the cooling water flow.

In this embodiment, since the arc portion 44 is provided at the boundary between the half bead 43 and the base portion 41, the frame member 25 does not have a corner at the boundary position. Therefore, even when pressure fluctuations due to the flow of cooling water are applied vibratingly at a certain frequency, stress concentration does not occur in the expansion member 24 at the boundary position. As a result, the expansion member 24 is prevented from being torn at the boundary between the half bead 43 and the base portion 41 due to breakage. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to this embodiment, the following can be said. The half beads 43 are provided in a frame shape adjacent to four sides of the opening 42 . According to this configuration, for example, the heat insulator 11 on the cylinder bore wall is installed near the cooling water supply port 21, and even if the cooling water is in a turbulent state at that position, the pressure of the cooling water flowing from all directions is reduced. Fluctuations can be accommodated by half beads 43 . As a result, it is possible to reliably prevent breakage and falling off of the expansion member 24 by using the heat insulator 11 for the cylinder bore wall in this form at a location where it is difficult or difficult to analyze the flow of the cooling water.
[Third embodiment]

A heat insulator 11 for the cylinder bore wall according to the third embodiment will be described with reference to FIGS. 15 and 16. FIG. In this embodiment, a heat insulator 11A for the first cylinder bore wall is installed so as to correspond to the first cylinder bore wall 15A of the grooved cooling water flow path 12, and a heat insulator 11A for the fourth cylinder bore wall is installed so as to correspond to the fourth cylinder bore wall 15D. Tool 11D is installed. In this embodiment, the heat insulator 11B for the second cylinder bore wall and the heat insulator 11C for the third cylinder bore wall are not provided.

The cylinder block 13 has a cooling water supply port 21 for supplying cooling water to the grooved cooling water flow paths 12 and a cooling water discharge port 22 for discharging the cooling water from the grooved cooling water flow paths 12 . As shown in FIG. 15, the cooling water supply port 21 is provided at a position facing the first cylinder bore wall 15A of the first bore 14A located at one end of the bore row. The cooling water discharge port 22 is provided at a position facing the fourth cylinder bore wall 15D of the fourth bore 14D located at the other end of the bore row.

The heat insulator 11A on the wall of the first cylinder bore is installed at the boundary between the intake side passage 12A and the exhaust side passage 12B of the grooved cooling water passage 12 in the vicinity of the first bore 14A. The heat insulator 11A for the first cylinder bore wall is provided near the cooling water supply port 21 . The heat insulator 11D on the wall of the fourth cylinder bore is installed at the boundary between the intake side passage 12A and the exhaust side passage 12B of the grooved cooling water passage 12 near the fourth bore 14D. A heat insulator 11</b>D for the fourth cylinder bore wall is provided in the vicinity of the cooling water discharge port 22 .

The heat insulator 11A for the first cylinder bore wall has the same shape as the heat insulator 11A for the first cylinder bore wall of the first embodiment shown in FIG.

As shown in FIG. 16, the heat insulator 11D for the fourth cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a flat and frame-shaped base portion 41, a substantially rectangular opening 42 provided in the center of the base portion 41, and a pair of half beads provided mainly at positions adjacent to two sides of the opening 42. 43 and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

A pair of half beads 43 are formed to protrude from the base portion 41 toward the cylinder bore wall 15 . In the fourth cylinder bore wall heat retaining device 11D, the pair of half beads 43 are continuously formed on the two sides of the opening 42, i.e., adjacent to the right side 42C and the left side 42D of the opening 42, so as to cover the expansion member 24 continuously. 25. Each of the pair of half beads 43 includes a half bead body 43A extending linearly corresponding to the right side 42C and the left side 42D of the opening 42, and another side extending from the half bead body 43A and adjacent to the right side 42C and the left side 42D of the opening 42. and a pair of wraparound portions 43B adjacent to certain upper side 42A and lower side 42B. A pair of wraparound portions 43B located on the right side of the heat retaining device 11D on the fourth cylinder bore wall extend leftward from both ends of the half bead main body 43A and are formed continuously with the half bead main body 43A. The other side of the turn-around portion 43B located on the left side of the heat retaining device 11D of the fourth cylinder bore wall extends rightward from both ends of the half bead main body 43A and is formed continuously with the half bead main body 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIGS. 15 and 16, the action of the heat retaining device 11D for the walls of the first and fourth cylinder bores of the present embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . The cooling water supplied from the cooling water supply port 21 is supplied to the intake side channel 12A and the exhaust side channel 12B of the grooved cooling water channel 12 . The cooling water immediately after being supplied to the intake side passage 12A is in a turbulent state.

Since the heat insulator 11A of the first cylinder bore wall exists directly below the cooling water supply port 21, as shown in FIG. supplied. Since the shape of the heat insulator 11A of the first cylinder bore wall is the same as that of the first embodiment, it can exhibit the same effect as the first embodiment.

The cooling water supplied to the grooved cooling water flow path 12 is sent to the cooling water discharge port 22 through the intake side flow path 12A and the exhaust side flow path 12B. Therefore, in the vicinity of the cooling water discharge port 22, the cooling water split into two flows joins. In this embodiment, the heat insulator 11D of the fourth cylinder bore wall is provided with half beads 43 on the upstream side in the flow direction of the cooling water, that is, on the right side 42C and the left side 42D of the opening 42. As shown in FIG. Therefore, the pair of half beads 43 can receive pressure fluctuations caused by the cooling water flow.

In this embodiment, since the arc portion 44 is provided at the boundary between the half bead 43 and the base portion 41 in the heat retaining device 11D of the fourth cylinder bore wall, the frame member 25 does not have a corner at the boundary position. . Therefore, even when pressure fluctuations due to the flow of cooling water are applied vibratingly at a certain frequency, stress concentration does not occur in the expansion member 24 at the boundary position. As a result, the expansion member 24 is prevented from being torn at the boundary between the half bead 43 and the base portion 41 due to breakage. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to this embodiment, the following can be said. The half beads 43 are provided substantially parallel adjacent to two opposing sides of the opening 42 . According to this configuration, even in an arrangement in which cooling water flows from both sides of the cylinder bore wall sandwiching the heat insulator 11, the half beads 43 can receive pressure fluctuations caused by the cooling water flowing from both directions. Therefore, it is possible to prevent the expansion member 24 from tearing or falling off due to breakage due to pressure fluctuations caused by the cooling water flowing through the grooved cooling water flow passage 12 .
[Fourth embodiment]

With reference to FIG. 17, the heat insulator 11 for the cylinder bore wall of the fourth embodiment will be described. In this embodiment, the heat insulator 11A for the first cylinder bore wall is installed so as to correspond to the first cylinder bore wall 15A of the exhaust side passage 12B of the grooved cooling water passage 12 . In this embodiment, the heat insulators 11D for the second to fourth cylinder bore walls are not provided.

The heat insulator 11A for the first cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a plate-like and frame-shaped base portion 41, a substantially rectangular opening 42 provided in the central portion of the base portion 41, and a half bead 43 mainly provided adjacent to one side of the opening 42. , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

As shown in FIG. 17 , half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the heat insulator 11A for the first cylinder bore wall, the half bead 43 is continuously provided on the frame member 25 so as to cover the expansion member 24 at one side of the opening 42, that is, at a position adjacent to the left side 42D of the opening 42. there is The half bead 43 includes a half bead main body 43A that extends linearly corresponding to the left side 42D of the opening 42, and a pair that extends from the half bead main body 43A and is adjacent to the upper side 42A and the lower side 42B that are the other sides adjacent to the left side 42D of the opening 42. and a wraparound portion 43B. Each of the pair of winding portions 43B extends rightward from both ends of the half bead main body 43A and is formed continuously with the half bead main body 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 17, the action of the heat insulator 11A for the first cylinder bore wall of the present embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . The cooling water supplied from the cooling water supply port 21 is supplied to the intake side channel 12A and the exhaust side channel 12B of the grooved cooling water channel 12 .

Cooling water is supplied from the side to the heat insulator 11A of the first cylinder bore wall. The heat insulator 11A on the first cylinder bore wall has a half bead 43 (half bead main body 43A) at a position on the upstream side in the cooling water flow direction, that is, at a position adjacent to the left side 42D of the opening 42. As shown in FIG. Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow.

A wraparound portion 43B of the half bead 43 is formed on the upper side 42A and the lower side 42B of the opening 42 adjacent to the left side 42D. Therefore, the half bead main body 43A and wraparound portion 43B can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary between the upper side 42A and the left side 42D and the corners of the boundary between the lower side 42B and the left side 42D. The action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall is the same as the action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall of the first embodiment. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to this embodiment, the first cylinder bore wall 15A of the exhaust side passage 12B of the groove-shaped cooling water passage 12 is suitable for heat retention, and the first cylinder bore wall heat insulator can prevent the expansion member 24 from being torn off or falling off due to breakage. 11A can be provided.
[Fifth embodiment]

With reference to FIG. 18, the heat insulator 11 for the cylinder bore wall of the fifth embodiment will be described. In this embodiment, the configurations of the grooved cooling water flow path 12, the cylinder block 13, and the cylinder head are the same as in the first embodiment. In this embodiment, a heat insulator 11C for the third cylinder bore wall is installed so as to correspond to the third cylinder bore wall 15C of the intake side flow path 12A of the grooved cooling water flow path 12 . In this embodiment, the heat insulators 11A, 11B, 11D of the first, second and fourth cylinder bore walls are not provided.

The heat insulator 11C for the third cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a plate-like and frame-shaped base portion 41, a substantially rectangular opening 42 provided in the central portion of the base portion 41, and a half bead 43 mainly provided adjacent to one side of the opening 42. , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

As shown in FIG. 18 , half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the heat insulator 11C for the third cylinder bore wall, the half bead 43 is continuously provided on the frame member 25 so as to cover the expansion member 24 at one side of the opening 42, that is, at a position adjacent to the lower side 42B of the opening 42. there is The half bead 43 includes a half bead main body 43A extending linearly corresponding to the lower side 42B of the opening 42, and a pair of left side 42D and right side 42C extending from the half bead main body 43A and adjacent to the lower side 42B of the opening 42. and a wraparound portion 43B. Each of the pair of winding portions 43B extends upward from both ends of the half bead main body 43A and is formed continuously with the half bead main body 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 18, the action of the heat insulator 11C for the third cylinder bore wall of this embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . The cooling water supplied from the cooling water supply port 21 is supplied to the intake side channel 12A and the exhaust side channel 12B of the grooved cooling water channel 12 .

As shown in FIG. 12, cooling water is supplied from below to the heat insulator 11C of the third cylinder bore wall. The heat insulator 11C of the third cylinder bore wall is provided with a half bead 43 (half bead main body 43A) at a position on the upstream side in the cooling water flow direction, that is, at a position adjacent to the lower side 42B of the opening 42. As shown in FIG. Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow.

A wraparound portion 43B of the half bead 43 is formed on the right side 42C and the left side 42D adjacent to the lower side 42B of the opening 42 . Therefore, the half bead main body 43A and wraparound portion 43B can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary between the lower side 42B and the right side 42C and the corners of the boundary between the lower side 42B and the left side 42D. The action of the arc portion 44 of the heat insulator 11C for the third cylinder bore wall is the same as the action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall of the first embodiment. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to the present embodiment, the third cylinder bore wall 15C of the intake side passage 12A of the grooved cooling water passage 12 is suitable for heat retention, and a heat insulator for the third cylinder bore wall that can prevent tearing and falling off due to breakage of the expansion member 24. 11C can be provided.
[Sixth embodiment]

With reference to FIG. 19, the heat insulator 11 for the cylinder bore wall of the sixth embodiment will be described. In this embodiment, the configurations of the grooved cooling water flow path 12, the cylinder block 13, and the cylinder head are the same as in the first embodiment. In this embodiment, the heat insulator 11A for the first cylinder bore wall is installed so as to correspond to the first cylinder bore wall 15A of the intake side passage 12A of the grooved cooling water passage 12 . In this embodiment, the heat retaining devices 11B-11D for the walls of the second to fourth cylinder bores are not provided.

As shown in FIG. 19, the heat insulator 11A of the first cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a flat and frame-shaped base portion 41, a substantially rectangular opening 42 provided in the center of the base portion 41, and a pair of half beads provided mainly at positions adjacent to two sides of the opening 42. 43 and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

Each of the pair of half beads 43 is formed to protrude from the base portion 41 toward the cylinder bore wall 15 . In the heat retaining device 11A of the first cylinder bore wall, a pair of half beads 43 are provided on two sides of the opening 42, that is, at positions adjacent to the upper side 42A and the lower side 42B of the opening 42, so as to cover the expansion member 24 continuously. 25. The pair of half beads 43 includes a half bead main body 43A extending linearly corresponding to the upper side 42A and the lower side 42B of the opening 42, and a right side extending from the half bead main body 43A and being the other side adjacent to the upper side 42A and the lower side 42B of the opening 42. 42C and a pair of wraparound portions 43B adjacent to the left side 42D. A pair of wraparound portions 43B positioned above the heat retaining device 11A of the first cylinder bore wall extend downward from both ends of the pair of half bead bodies 43A and are formed continuously with the half bead bodies 43A. The other side of the wrap-around portion 43B positioned below the heat insulator 11D of the fourth cylinder bore wall extends upward from both ends of the pair of half bead bodies 43A and is formed continuously with the half bead bodies 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 19, the action of the heat insulator 11A for the first cylinder bore wall of this embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . The cooling water supplied from the cooling water supply port 21 is supplied to the intake side channel 12A and the exhaust side channel 12B of the grooved cooling water channel 12 . The cooling water immediately after being supplied to the intake side passage 12A is in a turbulent state.

Since the heat insulator 11A of the first cylinder bore wall exists directly below the cooling water supply port 21, as shown in FIG. supplied. Further, since the cooling water immediately after being supplied to the intake side passage 12A is in a turbulent state, the cooling water is also supplied from below to the heat insulator 11A of the first cylinder bore wall.

In this embodiment, the heat insulator 11A of the first cylinder bore wall is provided with half beads 43 on the upper side 42A and the lower side 42B of the opening 42 at the upstream position in the flow direction of the cooling water. Therefore, the pair of half beads 43 can receive pressure fluctuations caused by the cooling water flow.

In this embodiment, since the arc portion 44 is provided at the boundary between the half bead 43 and the base portion 41 in the heat retaining device 11A of the first cylinder bore wall, the frame member 25 does not have a corner at the boundary position. . Therefore, even when pressure fluctuations due to the flow of cooling water are applied vibratingly at a certain frequency, stress concentration does not occur in the expansion member 24 at the boundary position. As a result, the expansion member 24 is prevented from being torn at the boundary between the half bead 43 and the base portion 41 due to breakage. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to the present embodiment, the first cylinder bore wall 15A of the intake side passage 12A of the grooved cooling water passage 12 is suitable for heat retention, and the first cylinder bore wall heat insulator can prevent the expansion member 24 from being torn off or falling off due to breakage. 11A can be provided.
[Seventh embodiment]

With reference to FIG. 20, the heat insulator 11 for the cylinder bore wall of the seventh embodiment will be described. In this embodiment, the configurations of the grooved cooling water flow path 12, the cylinder block 13, and the cylinder head are the same as in the first embodiment. In this embodiment, the second cylinder bore wall heat insulator 11B is installed so as to correspond to the second cylinder bore wall 15B of the exhaust side passage 12B of the grooved cooling water passage 12 . In this embodiment, the heat insulators 11A, 11C and 11D for the first, third and fourth cylinder bore walls are not provided.

As shown in FIG. 20, the heat insulator 11B for the second cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a flat and frame-shaped base 41, a substantially square opening 42 provided in the center of the base 41, and half beads 43 mainly provided adjacent to two sides of the opening 42. , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

As shown in FIG. 20 , half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the heat insulator 11A of the first cylinder bore wall, the half beads 43 are continuously attached to the frame member 25 so as to cover the expansion member 24 at positions adjacent to the two sides of the opening 42, that is, the lower side 42B and the left side 42D of the opening 42. is provided. The half bead 43 includes a half bead main body 43A extending linearly and in an L-shape corresponding to the lower side 42B and the left side 42D of the opening 42, and other sides extending from the half bead main body 43A and adjacent to the lower side 42B and the left side 42D of the opening 42. and a pair of wraparound portions 43B adjacent to certain upper side 42A and right side 42C. One of the winding portions 43B extends upward from the right end of the half bead main body 43A and is formed continuously with the half bead main body 43A. The other side of the winding portion 43B extends rightward from the upper end portion of the half bead main body 43A and is formed continuously with the half bead main body 43A. The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 20, the action of the heat insulator 11B for the second cylinder bore wall of this embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . Cooling water is supplied from below and from the side to the heat insulator 11B on the second cylinder bore wall located in the exhaust side passage 12B. The heat retaining device 11B of the second cylinder bore wall is provided with an L-shaped half bead 43 (half bead main body 43A) at a position on the upstream side in the flow direction of the cooling water, that is, at a position adjacent to the lower side 42B and the left side 42D of the opening 42. there is Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow.

A wraparound portion 43B of the half bead 43 is formed on the upper side 42A adjacent to the left side 42D of the opening 42 and the right side 42C adjacent to the lower side 42B of the opening 42. As shown in FIG. Therefore, the half bead main body 43A and wraparound portion 43B can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary between the upper side 42A and the left side 42D and the corners of the boundary between the lower side 42B and the right side 42C. The action of the arc portion 44 of the heat insulator 11B for the second cylinder bore wall is the same as the action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall of the first embodiment. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to the present embodiment, the second cylinder bore wall heat retaining device is suitable for heat insulation of the second cylinder bore wall 15B of the exhaust side flow path 12B of the grooved cooling water flow path 12, and can prevent tearing and falling off due to breakage of the expansion member 24. 11B can be provided.
[Eighth embodiment]

With reference to FIG. 21, the heat insulator 11 for the cylinder bore wall of the eighth embodiment will be described. In this embodiment, the configurations of the grooved cooling water flow path 12, the cylinder block 13, and the cylinder head are the same as in the first embodiment. In the present embodiment, a second cylinder bore wall heat insulator 11B is installed so as to correspond to the second cylinder bore wall 15B of the intake side passage 12A of the grooved cooling water passage 12 . In this embodiment, the heat insulators 11A, 11C and 11D for the first, third and fourth cylinder bore walls are not provided.

As shown in FIG. 21, the heat insulator 11B for the second cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a flat and frame-shaped base 41, a substantially square opening 42 provided in the center of the base 41, and half beads 43 mainly provided adjacent to two sides of the opening 42. , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

Half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the heat insulator 11B of the second cylinder bore wall, the half beads 43 are continuously attached to the frame member 25 so as to cover the expansion member 24 at positions adjacent to the two sides of the opening 42, that is, the upper side 42A and the right side 42C of the opening 42. is provided. The half bead 43 includes a half bead main body 43A extending linearly and in an L-shape corresponding to the upper side 42A and the right side 42C of the opening 42, and other sides extending from the half bead main body 43A and adjacent to the upper side 42A and the right side 42C of the opening 42. and a pair of wraparound portions 43B adjacent to a left side 42D and a lower side 42B. One of the winding portions 43B extends downward from the left end of the half bead main body 43A and is formed continuously with the half bead main body 43A. The other side of the winding portion 43B extends leftward from the lower end portion of the half bead main body 43A and is formed continuously with the half bead main body 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 21, the action of the heat insulator 11B for the second cylinder bore wall of this embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . Depending on the arrangement of the cooling water supply port 21, the cooling water may be supplied mainly from above and from the side to the heat insulator 11B on the second cylinder bore wall positioned in the intake side passage 12A. The heat retaining device 11B of the second cylinder bore wall is provided with an L-shaped half bead 43 (half bead main body 43A) at a position on the upstream side in the flow direction of the cooling water, that is, at a position adjacent to the upper side 42A and the right side 42C of the opening 42. there is Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow.

A lower side 42B adjacent to the right side 42C of the opening 42 and a left side 42D adjacent to the upper side 42A of the opening 42 are formed with wraparound portions 43B of the half beads 43. As shown in FIG. Therefore, the half bead main body 43A and wraparound portion 43B can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary between the upper side 42A and the left side 42D and the corners of the boundary between the right side 42C and the lower side 42B. The action of the arc portion 44 of the heat insulator 11B for the second cylinder bore wall is the same as the action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall of the first embodiment. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to the present embodiment, the second cylinder bore wall heat retaining device is suitable for heat insulation of the second cylinder bore wall 15B of the intake side flow path 12A of the grooved cooling water flow path 12, and can prevent the expansion member 24 from tearing or falling off due to breakage. 11B can be provided.
[Ninth Embodiment]

With reference to FIG. 22, the heat insulator 11 for the cylinder bore wall of the ninth embodiment will be described. In this embodiment, the configurations of the grooved cooling water flow path 12, the cylinder block 13, and the cylinder head are the same as in the first embodiment. In this embodiment, the second cylinder bore wall heat insulator 11B is installed so as to correspond to the second cylinder bore wall 15B of the exhaust side passage 12B of the grooved cooling water passage 12 . In this embodiment, the heat insulators 11A, 11C and 11D for the first, third and fourth cylinder bore walls are not provided.

As shown in FIG. 22, the heat insulator 11B for the second cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a flat and frame-shaped base 41, a substantially square opening 42 provided in the center of the base 41, and half beads 43 mainly provided adjacent to two sides of the opening 42. , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

Half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the heat insulator 11B of the second cylinder bore wall, the half beads 43 are continuously attached to the frame member 25 so as to cover the expansion member 24 at positions adjacent to the two sides of the opening 42, that is, the upper side 42A and the left side 42D of the opening 42. is provided. The half bead 43 includes a half bead main body 43A extending linearly and in an L-shape corresponding to the upper side 42A and the left side 42D of the opening 42, and other sides extending from the half bead main body 43A and adjacent to the upper side 42A and the left side 42D of the opening 42. and a pair of wraparound portions 43B adjacent to a right side 42C and a lower side 42B. One of the winding portions 43B extends downward from the right end of the half bead main body 43A and is formed continuously with the half bead main body 43A. The other side of the winding portion 43B extends rightward from the lower end portion of the half bead main body 43A and is formed continuously with the half bead main body 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 22, the action of the heat insulator 11B for the second cylinder bore wall of this embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . Depending on the arrangement of the cooling water supply port 21, the cooling water may be supplied mainly from above and from the side to the heat insulator 11B on the second cylinder bore wall located in the exhaust side passage 12B. The heat retaining device 11B of the second cylinder bore wall is provided with an L-shaped half bead 43 (half bead main body 43A) at a position on the upstream side in the flow direction of the cooling water, that is, at a position adjacent to the upper side 42A and the left side 42D of the opening 42. there is Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow.

A wraparound portion 43B of the half bead 43 is formed on a lower side 42B adjacent to the left side 42D of the opening 42 and a right side 42C adjacent to the upper side 42A of the opening 42 . Therefore, the half bead main body 43A and wraparound portion 43B can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary between the left side 42D and the lower side 42B and the corners of the boundary between the upper side 42A and the right side 42C. The action of the arc portion 44 of the heat insulator 11B for the second cylinder bore wall is the same as the action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall of the first embodiment. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to the present embodiment, the second cylinder bore wall heat retaining device is suitable for heat insulation of the second cylinder bore wall 15B of the exhaust side flow path 12B of the grooved cooling water flow path 12, and can prevent tearing and falling off due to breakage of the expansion member 24. 11B can be provided.
[Tenth embodiment]

With reference to FIG. 23, the heat insulator 11 for the cylinder bore wall of the tenth embodiment will be described. In this embodiment, the configurations of the grooved cooling water flow path 12, the cylinder block 13, and the cylinder head are the same as in the first embodiment. In the present embodiment, a second cylinder bore wall heat insulator 11B is installed so as to correspond to the second cylinder bore wall 15B of the intake side passage 12A of the grooved cooling water passage 12 . In this embodiment, the heat insulators 11A, 11C and 11D for the first, third and fourth cylinder bore walls are not provided.

As shown in FIG. 23, the heat insulator 11B for the second cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a plate-shaped and frame-shaped base 41 , a substantially square opening 42 provided in the center of the base 41 , and half beads 43 provided mainly at positions adjacent to three sides of the opening 42 . , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

Half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the second cylinder bore wall heat insulator 11B, the half beads 43 are continuously framed to cover the expansion member 24 at positions adjacent to the three sides of the opening 42, ie, the upper side 42A, the lower side 42B and the right side 42C of the opening 42. It is provided on the member 25 . The half bead 43 includes a half bead main body 43A extending linearly and in a C shape corresponding to the upper side 42A, the lower side 42B and the right side 42C of the opening 42, and a half bead main body 43A extending from the half bead main body 43A and adjacent to the upper side 42A and the lower side 42B of the opening 42. and a pair of wraparound portions 43B adjacent to the left side 42D, which is the side of . One of the winding portions 43B extends downward from the upper left end portion of the half bead main body 43A and is formed continuously with the half bead main body 43A. The other side of the winding portion 43B extends upward from the lower left end portion of the half bead main body 43A and is formed continuously with the half bead main body 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 23, the action of the heat insulator 11B for the second cylinder bore wall of this embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . Depending on the arrangement of the cooling water supply port 21, cooling water may be supplied mainly from above, sideways, or below to the heat insulator 11B on the second cylinder bore wall positioned in the intake side passage 12A. The heat insulator 11B on the second cylinder bore wall has a C-shaped half bead 43 (half bead main body 43A) at a position on the upstream side in the flow direction of the cooling water, that is, at a position adjacent to the upper side 42A, the lower side 42B, and the right side 42C of the opening 42. is provided in Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow.

A wraparound portion 43B of the half bead 43 is formed on the left side 42D adjacent to the upper side 42A and the lower side 42B of the opening 42. As shown in FIG. Therefore, the half bead main body 43A and wraparound portion 43B can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary between the left side 42D and the upper side 42A and the corners of the boundary between the left side 42D and the lower side 42B. The action of the arc portion 44 of the heat insulator 11B for the second cylinder bore wall is the same as the action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall of the first embodiment. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to this embodiment, the following can be said. The half beads 43 are provided in a substantially C-shape adjacent to three adjacent sides of the opening 42 . According to this configuration, even in an arrangement in which cooling water flows from three directions around the heat insulator 11 of the cylinder bore wall, the half beads 43 can receive pressure fluctuations caused by the cooling water flowing from three directions. Therefore, it is possible to prevent the expansion member 24 from tearing or falling off due to breakage due to pressure fluctuations caused by the cooling water flowing through the grooved cooling water flow passage 12 .
[Eleventh embodiment]

With reference to FIG. 24, the heat insulator 11 for the cylinder bore wall of the eleventh embodiment will be described. In this embodiment, the configurations of the grooved cooling water flow path 12, the cylinder block 13, and the cylinder head are the same as in the first embodiment. In this embodiment, the second cylinder bore wall heat insulator 11B is installed so as to correspond to the second cylinder bore wall 15B of the exhaust side passage 12B of the grooved cooling water passage 12 . In this embodiment, the heat insulators 11A, 11C and 11D for the first, third and fourth cylinder bore walls are not provided.

As shown in FIG. 24, the heat insulator 11B for the second cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a plate-shaped and frame-shaped base 41 , a substantially square opening 42 provided in the center of the base 41 , and half beads 43 provided mainly at positions adjacent to three sides of the opening 42 . , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

Half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the heat insulator 11B of the second cylinder bore wall, the half beads 43 are continuously framed so as to cover the expansion member 24 at positions adjacent to the three sides of the opening 42, that is, the upper side 42A, the lower side 42B and the left side 42D of the opening 42. It is provided on the member 25 . The half bead 43 includes a half bead main body 43A extending linearly and in a C shape corresponding to the upper side 42A, the lower side 42B and the left side 42D of the opening 42, and a half bead main body 43A extending from the half bead main body 43A and adjacent to the upper side 42A and the lower side 42B of the opening 42. and a pair of wraparound portions 43B adjacent to the right side 42C, which is the side of . One of the winding portions 43B extends downward from the upper right end portion of the half bead main body 43A and is formed continuously with the half bead main body 43A. The other side of the winding portion 43B extends upward from the lower right end portion of the half bead main body 43A and is formed continuously with the half bead main body 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 24, the action of the heat insulator 11B for the second cylinder bore wall of this embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . Depending on the arrangement of the cooling water supply port 21, cooling water may be supplied mainly from above, sideways, or below to the heat insulator 11B on the second cylinder bore wall positioned in the intake side passage 12A. The heat insulator 11B on the second cylinder bore wall has a C-shaped half bead 43 (half bead main body 43A) at a position on the upstream side in the flow direction of the cooling water, that is, at a position adjacent to the upper side 42A, the lower side 42B, and the left side 42D of the opening 42. is provided in Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow.

A wraparound portion 43B of the half bead 43 is formed on the right side 42C adjacent to the upper side 42A and the lower side 42B of the opening 42. As shown in FIG. Therefore, the half bead main body 43A and wraparound portion 43B can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary between the right side 42C and the upper side 42A and the corners of the boundary between the right side 42C and the lower side 42B. The action of the arc portion 44 of the heat insulator 11B for the second cylinder bore wall is the same as the action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall of the first embodiment. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to the present embodiment, the second cylinder bore wall heat retaining device is suitable for heat insulation of the second cylinder bore wall 15B of the exhaust side flow path 12B of the grooved cooling water flow path 12, and can prevent tearing and falling off due to breakage of the expansion member 24. 11B can be provided.
[Twelfth embodiment]

With reference to FIG. 25, the heat insulator 11 for the cylinder bore wall of the twelfth embodiment will be described. In this embodiment, the configurations of the grooved cooling water flow path 12, the cylinder block 13, and the cylinder head are the same as in the first embodiment. In this embodiment, the heat insulator 11A for the first cylinder bore wall is installed so as to correspond to the first cylinder bore wall 15A of the intake side passage 12A of the grooved cooling water passage 12 . In this embodiment, the heat insulators 11D for the walls of the second to fourth cylinder bores are not provided.

As shown in FIG. 25, the heat insulator 11A of the first cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a plate-shaped and frame-shaped base 41 , a substantially square opening 42 provided in the center of the base 41 , and half beads 43 provided mainly at positions adjacent to three sides of the opening 42 . , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

Half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the second cylinder bore wall heat insulator 11B, the half beads 43 are continuously framed to cover the expansion member 24 at positions adjacent to the three sides of the opening 42, ie, the upper side 42A, the right side 42C and the left side 42D. It is provided on the member 25 . The half bead 43 includes a half bead main body 43A extending linearly and in a C shape corresponding to the upper side 42A, right side 42C and left side 42D of the opening 42, and a half bead main body 43A extending from the half bead main body 43A and adjacent to the right side 42C and left side 42D of the opening 42. and a pair of wraparound portions 43B adjacent to the lower side 42B, which is the side of the . One of the winding portions 43B extends leftward from the lower end portion on the right side of the half bead main body 43A and is formed continuously with the half bead main body 43A. The other side of the winding portion 43B extends rightward from the lower end portion on the left side of the half bead main body 43A and is formed continuously with the half bead main body 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 25, the action of the heat insulator 11B for the second cylinder bore wall of this embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . Depending on the arrangement of the cooling water supply port 21, the cooling water may be supplied mainly from above and from the side to the heat insulator 11A on the first cylinder bore wall located in the intake side passage 12A. The heat insulator 11A of the first cylinder bore wall has a C-shaped half bead 43 (half bead main body 43A) at a position on the upstream side in the flow direction of the cooling water, that is, at a position adjacent to the upper side 42A, right side 42C, and left side 42D of the opening 42. is provided in Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow.

A wraparound portion 43B of the half bead 43 is formed in the lower side 42B adjacent to the right side 42C and the left side 42D of the opening 42. As shown in FIG. Therefore, the half bead main body 43A and wraparound portion 43B can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary between the right side 42C and the lower side 42B and the corners of the boundary between the left side 42D and the lower side 42B. The action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall is the same as the action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall of the first embodiment. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to the present embodiment, the first cylinder bore wall heat retaining device is suitable for heat insulation of the first cylinder bore wall 15A of the intake side passage 12A of the grooved cooling water passage 12, and can prevent tearing and falling off due to breakage of the expansion member 24. 11A can be provided.
[Thirteenth embodiment]

With reference to FIG. 26, the heat insulator 11 for the cylinder bore wall of the thirteenth embodiment will be described. In this embodiment, the configurations of the grooved cooling water flow path 12, the cylinder block 13 and the cylinder head are the same as in the third embodiment. In this embodiment, the heat insulator 11D for the fourth cylinder bore wall is installed so as to correspond to the fourth cylinder bore wall 15D for the exhaust side passage 12B of the grooved cooling water passage 12 . The arrangement of the heat insulator 11D on the fourth cylinder bore wall is the same as the heat insulator 11D on the fourth cylinder bore wall of the third embodiment. In this embodiment, the heat retaining member 11C for the walls of the first to third cylinder bores is not provided.

As shown in FIG. 26, the heat insulator 11D for the fourth cylinder bore wall has a frame member 25. As shown in FIG. The frame member 25 includes a plate-shaped and frame-shaped base 41 , a substantially square opening 42 provided in the center of the base 41 , and half beads 43 provided mainly at positions adjacent to three sides of the opening 42 . , and an arc portion 44 provided at the boundary between the half bead 43 and the base portion 41 .

Half bead 43 is formed to protrude from base 41 toward cylinder bore wall 15 . In the fourth cylinder bore wall heat insulator 11D, the half beads 43 are continuously framed to cover the expansion member 24 at positions adjacent to the three sides of the opening 42, namely the lower side 42B, the right side 42C and the left side 42D. It is provided on the member 25 . The half bead 43 includes a half bead main body 43A extending linearly and in a C-shape corresponding to the lower side 42B, right side 42C and left side 42D of the opening 42, and a half bead main body 43A extending from the half bead main body 43A and adjacent to the right side 42C and left side 42D of the opening 42. and a pair of wraparound portions 43B adjacent to the upper side 42A, which is the side of the . One of the winding portions 43B extends leftward from the upper end portion on the right side of the half bead main body 43A and is formed continuously with the half bead main body 43A. The other side of the winding portion 43B extends rightward from the left upper end portion of the half bead main body 43A and is formed continuously with the half bead main body 43A.

The half bead main body 43A and the pair of wraparound portions 43B of the half bead 43 are brought into contact with the cylinder bore wall 15 by the repulsive force of the elastic member 32 and the second elastic member 33 when installed in the grooved cooling water flow path 12.

The half bead main body 43</b>A can cover the expansion member 24 positioned inside thereof to protect the expansion member 24 from the cooling water flowing through the groove-shaped cooling water flow path 12 . The half bead main body 43A and wraparound portion 43B can cover the corners of the expansive member 24, and can prevent the expansive member 24 from tearing or falling off due to breakage at the corners.

Next, with reference to FIG. 26, the operation of the heat insulator 11D for the wall of the fourth cylinder bore of the present embodiment will be described.

When the internal combustion engine is in an operating state, cooling water is supplied from the cooling water supply port 21 into the grooved cooling water flow path 12 . Depending on the flow rate of the cooling water, cooling water may be supplied mainly from the side and below to the heat insulator 11D on the fourth cylinder bore wall located at the boundary between the intake side passage 12A and the exhaust side passage 12B. be. The heat insulator 11D of the fourth cylinder bore wall has a C-shaped half bead 43 (half bead main body 43A) at a position on the upstream side in the flow direction of the cooling water, that is, at a position adjacent to the lower side 42B, the right side 42C, and the left side 42D of the opening 42. is provided in Therefore, the half bead 43 (half bead main body 43A) can receive pressure fluctuations due to the cooling water flow.

A wraparound portion 43B of the half bead 43 is formed on the upper side 42A adjacent to the right side 42C and the left side 42D of the opening 42. As shown in FIG. Therefore, the half bead main body 43A and wraparound portion 43B can receive pressure fluctuations due to the flow of cooling water at the corners of the boundary between the right side 42C and the upper side 42A and the corners of the boundary between the left side 42D and the upper side 42A. The action of the arc portion 44 of the heat insulator 11D for the fourth cylinder bore wall is the same as the action of the arc portion 44 of the heat insulator 11A for the first cylinder bore wall of the first embodiment. The cooling water passing through the groove-shaped cooling water flow paths 12 is discharged to the outside of the groove-shaped cooling water flow paths 12 from the cooling water discharge port 22 .

According to this embodiment, the fourth cylinder bore wall 15D located at the boundary between the intake side flow path 12A and the exhaust side flow path 12B of the grooved cooling water flow path 12 is suitable for heat retention, and the expansion member 24 is torn off or dropped off due to breakage. It is possible to provide the heat insulator 11D for the fourth cylinder bore wall that can prevent the

The above-described embodiments can be implemented with various replacements and modifications. Further, it is of course possible to implement the invention by appropriately combining the above-described embodiments.

11 Cylinder bore wall heat insulator 11A First cylinder bore wall heat insulator 11B Second cylinder bore wall heat insulator 11C Third cylinder bore wall heat insulator 11D Fourth cylinder bore wall heat insulator 12 Grooved cooling water flow path 15 Cylinder bore wall 15A First Cylinder bore wall 15B Second cylinder bore wall 15C Third cylinder bore wall 15D Fourth cylinder bore wall 17 Opposing wall 18 Bottom 23 Base member 24 Expansion member 25 Frame member 32 Elastic member 33 Second elastic member 34 Rear frame 35 Rear plate 41 Base 42 Opening 42A Upper side 42B Lower side 42C Right side 42D Left side 43 Half bead 43A Half bead main body 43B Wrapping part 44 Arc part

Claims (8)

a frame member having a base facing a cylinder bore wall of a groove-shaped cooling water flow path through which cooling water flows, and a substantially rectangular opening provided in the center of the base;
a base member provided on the side opposite to the surface of the frame member facing the cylinder bore wall;
an expansion member having a sheet shape sandwiched and held between the base member and the frame member and capable of protruding from the opening and abutting against the wall of the cylinder bore by expansion;
a half bead continuously provided on the frame member so as to cover the expansion member at a position adjacent to at least one side of the opening, the half bead protruding from the base portion and capable of coming into contact with the cylinder bore wall; ,
One or more elastic members provided on the base member and capable of coming into contact with opposing walls of the groove-like cooling water flow path, and biasing the frame member and the expansion member toward the cylinder bore wall, one or more elastic members that bring the half bead into contact with the cylinder bore wall;
Cylinder bore wall insulation. 2. The heat retaining device for a cylinder bore wall according to claim 1, wherein said frame member has an arc portion projecting toward said expansion member at a boundary between said half bead and said base portion. The half bead has a half bead body corresponding to the at least one side, and a wrap portion extending from the half bead body and adjacent to another side adjacent to the at least one side, and the half bead body and the wrap 3. The heat retaining device for the cylinder bore wall according to claim 1, wherein the corners of the expansion member are covered with a portion. 2. The heat retaining device for a cylinder bore wall according to claim 1, wherein said half beads are provided in a substantially L shape adjacent to two adjacent sides of said opening. 2. The heat retaining device for a cylinder bore wall according to claim 1, wherein said half beads are provided substantially parallel adjacent to two opposite sides of said opening. 2. The heat retaining device for a cylinder bore wall according to claim 1, wherein said half beads are provided in a substantially C-shape adjacent to three adjacent sides of said opening. 2. The heat retaining device for a cylinder bore wall according to claim 1, wherein said half beads are provided in a frame shape adjacent to four sides of said opening. 2. The heat retaining device for a cylinder bore wall according to claim 1, wherein the half bead is provided at a position adjacent to the at least one side located upstream in the flow direction of the cooling water flowing through the grooved cooling water passage.

Images