JP4265227B2 - Exhaust manifold mounting structure for rotary piston engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure for mounting an exhaust manifold to an engine body of a rotary piston engine, and belongs to the technical field of an engine exhaust structure.
[0002]
[Prior art]
In recent years, in an exhaust system of a vehicle engine, when an exhaust manifold is attached to a cylinder head, a metal gasket may be used as a gasket interposed between the two, for example, as described in Patent Document 1 There is.
[0003]
According to this, a metal gasket having a structure in which two metal thin plates are laminated is interposed between one side surface of the cylinder head and a flange provided in the exhaust manifold, and corresponds to the exhaust port of the cylinder head. By the bead portion provided along the inner periphery of the opening, the exhaust gas flow on the mounting surface is well sealed.
[0004]
[Patent Document 1]
JP-A-8-28706 (FIG. 9)
[0005]
[Problems to be solved by the invention]
By the way, in a two-cylinder rotary piston engine, for example, a cross section of a main part in the case of two cylinders is extracted and as shown in FIG. 7, the engine body A has a structure in which a pair of rotor housings B and B and side housings C are overlapped. An intake manifold (not shown) and an exhaust manifold D are attached to a side surface A ′ of the engine body A parallel to the overlapping direction of the housings B, B, C. On the side of the exhaust manifold D that becomes hot during operation, a metal gasket E having a structure in which a plurality of thin metal plates as described above is laminated between the exhaust manifold D and the side surface A ′ of the engine body A is interposed. However, when the temperature of the engine main body A rises due to continuous operation at a high load for a long time, these housings B, B, etc. are formed along the mating surfaces due to the difference in thermal expansion coefficients of the housings B, B, C. A shift of C occurs, and a step is generated on the side surface A ′ of the engine body A. In particular, when the exhaust port C ′ is provided in the side housing C, the following problem occurs with respect to the metal gasket E due to this step.
[0006]
That is, as shown in FIG. 8A, an exhaust manifold D is attached to the side surface A ′ of the engine body A through which the mating surface of the rotor housing B and the side housing C is exposed via the metal gasket E. By tightening the manifold D, the bead portion E ′ of the metal gasket E is sandwiched between the side housing C and the exhaust manifold D and elastically deformed, and the bead portion E ′ that seals the periphery of the exhaust port C ′ becomes the side housing C. It is crimped to the periphery of the exhaust port C ′ on the side surface.
[0007]
When the tightening with the predetermined tightening force is completed, the metal gasket E is sandwiched between the side housing C and the exhaust manifold D as shown in FIG. Further crimping occurs around '.
[0008]
However, during continuous operation at a high load for a long time, for example, due to the difference in coefficient of thermal expansion between the rotor housing B and the side housing C, the rotor housing B protrudes from the side surface of the side housing C as shown in FIG. In the case where a step is generated between them, the outer edge portion E ″ of the bead portion E ′ is pushed by the rotor housing B, while the crimping force at the bead portion E ′ is reduced at the bead portion E ′.
[0009]
Therefore, the sealing performance around the exhaust port C ′ by the bead portion E ′ is lowered, or the sag of the metal gasket E is promoted by the repeated action of the pressing force on the outer edge portion E ″, and the sealing performance and durability are lowered. To come.
[0010]
In particular, when the exhaust port C ′ is provided in the side housing C, as shown in FIG. 8C, the distance between the exhaust port C ′ and the rotor housing B in the side housing C is short, and the bead portion in the metal gasket E Since E ′ and the outer edge E ″ receiving the pressing force from the rotor housing B are close to each other, the above phenomenon becomes remarkable.
[0011]
To solve this problem, it is considered that the side surface of the rotor housing B is retracted from the side surface of the side housing C so that the pressing force does not act on the metal gasket E even if the side surface of the rotor housing B protrudes. However, this is difficult to achieve for the following reasons.
[0012]
In other words, as shown in FIG. 9, in order to achieve an appropriate combustion stroke in the rotary piston engine, when mounting the mounting holes B1a and B1b for mounting a pair of upper and lower spark plugs on one side surface B1 of the rotor housing B, Since the hole shape changes along the machining direction or a strict setting of the tip position of the spark plug is required, high machining accuracy is required. For this reason, in this drilling process, the side surface B ′ opposite to the side surface B1 is usually used as the reference surface for processing. Therefore, it is necessary to make the side surface B ′ as flush as possible.
[0013]
On the other hand, when the intake manifold F is disposed on the upper side of the side surface B ′, the mounting flange provided on the intake manifold F is usually a flat plate, so that the rotor housing B and the side housing C are overlapped. The mating surfaces must be flush. Therefore, even at the lower part of the side surface B ′ to which the exhaust manifold D is to be attached, the mating surfaces of the rotor housing B and the side housing C must be flush with each other.
[0014]
In view of the above, the present invention has an object to provide a structure for attaching an exhaust manifold to a rotary piston engine that can maintain the sealing performance and durability of a metal gasket for a long period of time.
[0015]
[Means for Solving the Problems]
In order to solve the above problems, the present invention is configured as follows.
[0016]
First, according to the first aspect of the present invention, an exhaust manifold is attached to a rotary piston engine in which an exhaust manifold is attached via a metal gasket to an exhaust port opened on a side surface of an engine body having a structure in which a rotor housing and a side housing are overlapped. Regarding the structure, the metal gasket has a structure in which a plurality of thin metal plates are laminated, and at least a thin plate in contact with the engine main body is swelled so as to be elastically deformable toward the engine main body along the inner peripheral edge of the opening corresponding to the exhaust port. A bead portion is provided, and an outer edge portion of the thin plate extends so as to overlap a side surface of another housing adjacent to the housing provided with the exhaust port, and the other housing The part where the thin plate overlaps is recessed inside the engine body And wherein the Rukoto.
[0017]
According to this invention, since the metal gasket has a structure in which a plurality of thin metal plates are laminated, not only can the gap between the engine main body and the exhaust manifold be adjusted, but also a metal gasket made of a single thin plate. Therefore, the degree of freedom of elastic and plastic deformation is increased, and the exhaust manifold can be expanded and contracted, and the sag thereof can be satisfactorily followed.
[0018]
Then, a step is generated on the side of the engine body where the exhaust manifold is attached. For example, even if the other housing protrudes toward the exhaust manifold, a concave portion is provided at a predetermined portion of the housing. The housing does not interfere with the outer edge of the thin plate on the engine body side. That is, as a result of avoiding the pressing to the outer edge portion of the thin plate by the projecting portion, a decrease in the crimping force at the bead portion that seals the periphery of the exhaust port, that is, a decrease in the sealing performance, is prevented. Durability is maintained well.
[0019]
Next, the invention according to claim 2 is characterized in that, in the mounting structure according to claim 1, the cross-sectional shape of the bead portion is a half bead shape in which a tip bulges out.
[0020]
According to this invention, the invention described in claim 1 is further embodied in terms of the cross-sectional shape of the bead portion. In other words, because of the half bead shape, the bead portion follows the expansion / contraction deformation of the housing provided with the exhaust port and the exhaust manifold even better.
[0021]
According to a third aspect of the present invention, in the mounting structure according to the first or second aspect, the housing provided with the exhaust port is a side housing made of cast iron, and another housing adjacent to the housing. Is a rotor housing made of aluminum alloy.
[0022]
Since the difference in thermal expansion coefficient between the two materials is large, in the case of long-time high-load continuous operation, etc., the pressing of the outer edge of the thin plate on the engine body side due to the protrusion of the rotor housing having a large thermal expansion coefficient is remarkable. As a result, there is a possibility that the deterioration of the sealing performance will become more apparent. The present invention is particularly effective for the engine body having such a configuration.
[0023]
According to a fourth aspect of the present invention, in the mounting structure according to any one of the first to third aspects, the metal gasket includes a seal portion that seals the periphery of each exhaust port, and these seal portions. It is comprised by the connection part to connect.
[0024]
According to this invention, the invention according to any one of claims 1 to 3 is further embodied in terms of the configuration of the metal gasket. That is, the metal gasket is integrated while maintaining the weight reduction, and the workability of assembling the metal gasket to the engine body is improved.
[0025]
According to a fifth aspect of the present invention, in the mounting structure according to the fourth aspect, the connecting portion of the metal gasket is a thin plate excluding a thin plate on the engine body side among a plurality of thin plates constituting the gasket. It is configured.
[0026]
According to the present invention, since the number of thin plates constituting the connecting portion is reduced, the metal gasket can be further reduced in weight as compared with the invention according to claim 4. In addition, since the outer edge of the thin plate on the engine body side has few portions extending in the direction of the side surface of another adjacent housing, the recessed portion provided in the housing can be reduced, and the housing can be manufactured easily. There are benefits.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an exhaust manifold mounting structure for a rotary piston engine according to an embodiment of the present invention will be described.
[0028]
The present invention is applied to a two-cylinder (two-rotor type) rotary piston engine. As shown in FIGS. 1 and 2, an exhaust manifold 2 is attached to one side surface of the engine main body 1 via a metal gasket 3, and the exhaust gas discharged from the engine main body 1 is distributed. The gas is guided to the exhaust manifold 2 while being sealed by the metal gasket 3 and further discharged through the downstream exhaust pipe while being purified by a catalytic converter or the like interposed in the exhaust pipe.
[0029]
The engine body 1 has a structure in which a front side housing 11, a front rotor housing 12, an intermediate housing 13, a rear rotor housing 14, and a rear side housing 15 are stacked in order from the front side (right side in the illustrated example) of the vehicle. Yes. The first cylinder X1 is formed by the front side housing 11, the front rotor housing 12, and the intermediate housing 13, and the second cylinder X2 is formed by the intermediate housing 13, the rear rotor housing 14, and the rear side housing 15, respectively. Has been. In that case, the front side housing 11, the intermediate housing 13, and the rear side housing 15 are made of cast iron, and the front and rear rotor housings 12 and 14 are made of aluminum alloy, and these housings 11 to 15 are integrally formed. Bolts are fastened. The front and rear rotor housings 12 and 14 accommodate rotors (not shown).
[0030]
The front side housing 11, the intermediate housing 13, and the rear side housing 15 have first to third exhaust ports Y1 to Y3 that guide exhaust gas discharged from the front and rear rotor housings 12 and 14 to the exhaust manifold 2, respectively. Is provided. In this case, the exhaust gas flows from the first cylinder X1 to the first and second exhaust ports Y1 and Y2 as indicated by arrows a and b, and from the second cylinder X2 as indicated by arrows c and d. 2 and the third exhaust ports Y2 and Y3.
[0031]
The front side housing 11, the intermediate housing 13, and the rear side housing 15 are respectively provided with first to third port insert members 16 to 18, and correspond to the inner surfaces of these housings 11, 13, and 15, respectively. Secondary air passages P ... P through which secondary air supplied from an air supply source (not shown) passes are formed by the outer surfaces of the first to third port insert members 16-18. This secondary air is discharged to the exhaust manifold 2 together with the exhaust gas that passes through the first to third exhaust ports Y1 to Y3 as indicated by arrows a to d, and is agitated in the exhaust manifold 2 so as to remain in the exhaust gas. The combustion component will be reburned.
[0032]
Further, first to sixth intake ports Z1 to Z6 are provided in a relatively upper part of the engine body 1, and an intake manifold (not shown) is provided via a flat engine mounting flange 19 provided on the intake manifold. Bolt holes 11a, 11a, 12a, 13a, 14a, 15a, 15a are provided.
[0033]
An exhaust manifold 2 attached to a relatively lower portion of the engine body 1 includes first to third branch pipes 21 to 23 communicating with the first to third exhaust ports Y1 to Y3, respectively, and the first to third branch pipes. It has a collecting pipe (not shown) that collects the exhaust gas that has passed through 21 to 23 and covers these with a shell pipe 24.
[0034]
Further, the exhaust manifold 2 includes a flat engine mounting flange 25 for bolting the exhaust manifold 2 to the engine body 1. The engine mounting flange 25 is provided with a secondary air supply passage 25a that extends in the front-rear direction and introduces secondary air supplied from an air supply source (not shown) to the exhaust ports Y1 to Y3.
[0035]
The front side housing 11, the intermediate housing 13, and the rear side housing 15 are connected to the secondary air branch passages 11b and 13b that communicate the secondary air supply passage 25a with the first to third exhaust ports Y1 to Y3. , 15b are provided.
[0036]
Next, the metal gasket 3 that is interposed between the engine body 1 and the engine mounting flange 25 of the exhaust manifold 2 and that is a characteristic part of the present invention will be described.
[0037]
As shown in FIGS. 3 and 4, the metal gasket 3 includes three seal portions S... S that seal the periphery of the exhaust ports Y1 to Y3 and the front and rear directions that connect the seal portions S. It is composed of two elongated connecting portions J and J. And the metal gasket 3 has the opening part 3a ... 3a corresponding to exhaust port Y1-Y3 in seal part S ... S.
[0038]
Further, in the seal portion S ... S, secondary air corresponding to the bolt holes 3b ... 3b for fastening the engine main body 1 and the engine mounting flange 25 to the secondary air branch passages 11b, 13b, 15b. Passage holes 3c... 3c are provided (see also FIG. 2).
[0039]
And the metal gasket 3 is set as the structure integrated by laminating | stacking the stainless steel thin plates 31-36 which have six spring elasticity, and caulking a part suitably. Among these thin plates 31 to 36, the thin plate 31 on the engine body 1 side and the thin plate 36 on the engine mounting flange 25 side have the same shape, and on the other hand, four thin plates sandwiched between these thin plates 31 and 36. 32 to 35 have the same shape.
[0040]
That is, each thin plate 31 to 36 is provided with half-bead-shaped bead portions 31a ... 31a, ..., 36a ... 36a whose tips bulge along the inner peripheral edge of the openings 3a ... 3a (in FIG. 4). Only one bead portion is shown for each thin plate). In that case, in thin plates 31, 33, 35, bead portions 31a, 33a, 35a all bulge toward engine body 1, while in thin plates 32, 34, 36, bead portions 32a, 34a, 36a are provided. All are laminated so as to bulge to the engine mounting flange 25 side.
[0041]
And in the thin plates 31 and 36 on the engine main body 1 side and the engine mounting flange 25 side, the outer edge portions 31b and 36b of the seal portion S are extended by a predetermined dimension in the direction of the adjacent seal portion S. In the four thin plates 32 to 35 sandwiched between the thin plates 31 and 36, the outer edge portions 32b to 35b are further extended to connect the seal portions S and S to each other. That is, the thin plates 32 to 35 constitute the connecting portions J and J, while the remaining thin plates 31 and 36 are not related to the configuration of the connecting portions J and J.
[0042]
As described above, in the thin plates 31 and 36 on the engine body 1 side and the engine mounting flange 25 side, the outer edge portions 31b and 36b of the seal portion S are adjacent to the adjacent seal portion S, that is, as shown in FIG. It extends so as to overlap the front or side surfaces of the rear rotor housings 12 and 14 by a predetermined dimension in the direction of the rear rotor housings 12 and 14 (only the outer edge portion 31b is shown in FIG. 2). These extending portions 31b and 36b are basically provided as necessary structures in order to give the thin plates 32 and 36, and consequently the metal gasket 3, a predetermined rigidity or sealing property.
[0043]
Further, since it is necessary to satisfactorily seal the circulation of the secondary air around the secondary air passage holes 3c... 3c, the thin plates 31 to 36 correspond to the secondary air passage holes 3c. 4, bead portions 31 c... 31 c having substantially the same cross-sectional shape are provided (only the bead portion of the thin plate 31 is shown in FIG. 3).
[0044]
Next, in order to explain the side structure of the engine main body 1 which is a characteristic part of the present invention, as an example, a portion where the front rotor housing 12 and the intermediate housing 13 are adjacent to each other in FIG. .
[0045]
First, FIG. 5A shows a metal gasket 3 in which thin plates 31 to 36 are laminated between the engine body 1 and the engine mounting flange 25 of the exhaust manifold 2, and each bead portion 31 a to 36 a is an intermediate medium. The state interposed so that it may be located in the side surface of the eight housing 13 is shown. An outer edge portion 31b of the thin plate 31 on the engine body 1 side is extended so as to overlap the side surface of the front rotor housing 12 by a predetermined dimension, and a predetermined portion of the front rotor housing 12 that overlaps the extended portion 31b. A recessed portion 12b that is recessed by a predetermined dimension toward the inside of the engine body 1 is provided. As clearly shown in FIGS. 1 and 2, the front rotor housing 12 has two portions that overlap with the extending portions 31 b and 31 b extending from the first and second exhaust ports Y <b> 1 and Y <b> 2. The recesses 12b and 12b are also provided at two locations overlapping the extension portions 31b and 31b extending from the second and third exhaust ports Y2 and Y3 in the rear rotor housing 14 as well. Are provided. In this case, the depth D is 2 mm and the length L is 5 mm as a dimension of the recessed part 12b.
[0046]
5B, when the engine mounting flange 25 is fastened to the engine body 1, the front rotor housing 12 is provided with the outer edge of the thin plate 31 on the engine body 1 side by providing the recessed portion 12b. It does not interfere with the portion 31b, that is, the extended portion 31b. Moreover, even if the front rotor housing 12 protrudes as indicated by a two-dot chain line indicated by the symbol e due to thermal expansion, the interference with the extending portion 31b of the thin plate 31, that is, the pressing portion 31b is not pressed. The sealability is maintained well without being deteriorated. In this case, if the thickness T of the thin plate 31 is about 200 microns and the predicted protrusion amount ΔD of the front rotor housing 12 due to thermal expansion is about 170 microns, the front rotor housing 12 protrudes beyond the thickness T of the thin plate 31. Therefore, the front rotor housing 12 does not press the thin plate 32.
[0047]
Here, the operation of the present embodiment will be described. First, when attaching the exhaust manifold 2 to the engine body 1, a structure in which a plurality of (in this case, six) thin plates 31 to 36 are laminated. Therefore, not only the clearance between the engine body 1 and the exhaust manifold 2 can be adjusted, but also the degree of freedom of elasticity and plastic deformation is increased compared to a metal gasket made of a single plate, and the exhaust manifold 2 is provided. Further, the expansion / contraction deformation of the engine mounting flange 25 and the sag thereof can be satisfactorily followed.
[0048]
Also, when the engine body 1 and the exhaust manifold 2 are bolted together, the bead portions 31a ... 31a, ..., 36a ... 36a of the thin plates 31-36 are elastically deformed, resulting in these bead portions 31a ... 31a, ..., 36a. ... Appropriate pressure-bonding force is generated at 36a, and good sealing performance can be obtained against the flow of exhaust gas. Particularly, in this case, the bead portions 31a ... 31a, ..., 36a ... 36a have a half-bead shape in cross section, so that these bead portions 31a ... 31a, ..., 36a ... 36a are provided with the front side housing 11 provided with exhaust ports Y1 to Y3. The intermediate housing 13, the rear side housing 15, and the engine mounting flange 25 provided in the exhaust manifold 2 can follow the expansion / contraction deformation more satisfactorily.
[0049]
Then, a step is formed on the side surface of the engine body 1 to which the exhaust manifold 2 is attached. Even if the front or rear rotor housings 12 and 14 protrude toward the exhaust manifold 2, for example, a recess of a predetermined size is formed at a predetermined portion of the housings 12 and 14. Since the portions 12b, 12b, 14b, and 14b are provided, the housings 12 and 14 do not interfere with the extending portions 31b to 31b of the thin plate 31 on the engine body 1 side when the metal gasket 3 is sandwiched. That is, as a result of the pressing of the thin plate 31 against the extended portions 31b... 31b by the protruding portion being avoided, the pressure-bonding force generated at the bead portions 31a. Thus, the sealing performance and durability of the metal gasket 3 are maintained well.
[0050]
In particular, in the present embodiment, the front side housing 11, the intermediate housing 13, and the rear side housing 15 are made of cast iron, and the front and rear rotor housings 12 and 14 are made of aluminum alloy. Since the difference in thermal expansion coefficient is large, the extended portion 31b of the thin plate 31 on the engine body 1 side due to the protrusion of the front and rear rotor housings 12 and 14 having a large thermal expansion coefficient in the case of continuous operation at a high load for a long time. The pressing to 31b becomes remarkable, and there is a possibility that the deterioration of the sealing performance becomes more obvious. The present invention in which the recessed portions 12b, 12b, 14b, and 14b are provided at predetermined portions of the front and rear rotor housings 12 and 14 with respect to the engine body 1 having such a configuration is particularly effective.
[0051]
Further, the metal gasket 3 is composed of seal portions S ... S for sealing the periphery of the exhaust ports Y1 to Y3, and connecting portions J, J for connecting these seal portions S ... S. The metal gasket 3 is integrated while maintaining the above, and the workability of assembling the metal gasket 3 to the engine body 1 is improved.
[0052]
The connecting portions J and J of the metal gasket 3 include four thin plates 32 excluding the thin plates 31 and 36 on the engine main body 1 side and the exhaust manifold 2 side among the six thin plates 31 to 36 constituting the metal gasket 3. Since it is comprised by -35, further weight reduction is achieved. Further, since the extending portions 31b, 36b of the thin plates 31, 36 have few portions overlapping the side surfaces of the front and rear rotor housings 12, 14, the recessed portions 12b provided in the front and rear rotor housings 12, 14 are provided. The area of 12b, 14b, 14b is small, and there is an advantage that the manufacturing process of the housings 12, 14 is easy.
[0053]
In the above embodiment, the thin plate 31 on the engine main body 1 side of the metal gasket 3 defines the extending portion 31b to a predetermined size. However, as shown by a two-dot chain line in FIG. The portion 31b may be further extended to serve as an extended portion 31b ″ that connects the seal portions S and S in the same manner as the thin plates 32 to 35. In this case, the recessed portion 12b ″ provided in the front rotor housing 12 has, for example, two points. What is necessary is just to provide over the front-back width direction of the front rotor housing 12, as shown with a dashed line. Similarly, the thin plate 36 on the side of the engine mounting flange 25 of the exhaust manifold 2 may be an extended portion 36b ″ obtained by further extending the extended portion 36b so far.
[0054]
Further, the metal gasket 4 having a full bead shape shown in FIG. 6 may be used in place of the cross-sectional shape of the bead portion instead of the half bead shape. The full bead-shaped bead portions 41a to 46a provided on the thin plates 41 to 46 are suitable when further sealing properties and durability are required. Note that the full bead shape is not limited to that illustrated in FIG. 6, and a shape such as a mountain shape or a trapezoid shape can be applied depending on the application.
[0055]
In the above embodiment, the case where the front or rear rotor housings 12 and 14 protrude due to the difference in thermal expansion coefficient has been described. However, from the beginning, the front or rear rotor housings 12 and 14 are manufactured for reasons of manufacturing processing accuracy or assembly accuracy. Even if 14 protrudes, for example, the present invention is effective based on the description of FIG. 5B showing the characteristic laminated structure of the metal gasket 3, the side structure of the front rotor housing 12, and the like. It is easily understood that the deterioration of the sealing performance and durability of the metal gasket 3 is reduced as compared with the conventional case.
[0056]
【The invention's effect】
As described above, the present invention provides a structure for mounting an exhaust manifold to a rotary piston engine that can maintain the sealing performance and durability of a metal gasket for a long period of time. For example, even if it protrudes to the exhaust manifold side due to continuous high load or the like for a long time, the protruding portion does not interfere with the thin plate constituting the metal gasket. The present invention is widely suitable for the technical field of engine exhaust purification.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a main part showing a structure for mounting an exhaust manifold to an engine body according to an embodiment of the present invention.
FIG. 2 is a reduced arrow view taken along the line II-II in FIG.
FIG. 3 is a plan view of a metal gasket.
4 is an enlarged cross-sectional view taken along line III-III in FIG.
FIGS. 5A and 5B are enlarged cross-sectional views showing an interposed state of a metal gasket, where FIG. 5A shows a state before fastening, and FIG. 5B shows a state after fastening.
6 is a cross-sectional view corresponding to FIG. 4 of a metal gasket having a bead portion having another cross-sectional shape.
FIG. 7 is a cross-sectional view of a main part showing a conventional structure for mounting an exhaust manifold to an engine body.
FIG. 8 is a somewhat schematic enlarged cross-sectional view for explaining a problem in a conventional mounting structure, in which (a) is during tightening, (b) is after tightening, and (c) is after tightening. The state when a rotor housing protrudes is shown.
FIG. 9 is a schematic front view of a rotor housing.
[Explanation of symbols]
1 Engine body
2 Exhaust manifold
3,4 metal gasket
3a opening
11 Front side housing (side housing)
12 Front rotor housing (rotor housing)
12b, 12b ″, 14b recessed portion
13 Intermediate housing (side housing)
14 Rear rotor housing (rotor housing)
15 Rear side housing (side housing)
31-36, 41-46 Thin plate (metal thin plate)
31a-36a, 41a-46a Bead part
31b, 31b ″ extended portion (outer edge portion)
J connecting part
S Seal part
Y1 to Y3 1st to 3rd exhaust port

Claims (5)

An exhaust manifold mounting structure for a rotary piston engine in which an exhaust manifold is mounted via a metal gasket to an exhaust port that opens to the side of an engine body having a structure in which a rotor housing and a side housing are overlapped. In the structure in which a plurality of thin metal plates are laminated, at least a thin plate in contact with the engine body is provided with a bead portion that bulges elastically deformable toward the engine body along the inner peripheral edge of the opening corresponding to the exhaust port. The outer edge of the thin plate extends so as to overlap the side surface of another housing adjacent to the housing provided with the exhaust port, and the portion of the other housing where the thin plate overlaps is the engine A rotary piston that is recessed toward the inside of the body Exhaust manifold mounting structure of the engine. The exhaust manifold mounting structure for a rotary piston engine according to claim 1, wherein a cross-sectional shape of the bead portion is a half bead shape with a bulging tip. 3. The rotary piston according to claim 1, wherein the housing provided with the exhaust port is a side housing made of cast iron, and the other housing adjacent to the housing is a rotor housing made of aluminum alloy. Engine exhaust manifold mounting structure. 4. The rotary according to claim 1, wherein the metal gasket includes a seal portion that seals the periphery of each exhaust port and a connecting portion that connects these seal portions. Piston engine exhaust manifold mounting structure. 5. The exhaust manifold mounting of a rotary piston engine according to claim 4, wherein the connecting portion of the metal gasket is constituted by a thin plate excluding a thin plate on the engine body side among a plurality of thin plates constituting the gasket. Construction.

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