JP2020159295A - Seal structure of internal combustion engine - Google Patents

Abstract

To improve a seal property of a seal structure using an internal combustion engine.SOLUTION: A seal structure is equipped with an annular fitting surface seal 40. The fitting surface seal 40 has self-tension acting in a diameter expanding direction. A second piston member 28 is formed with an annular groove 28G opening toward a first piston member 24. The fitting surface seal 40 is configured so as to be partially stored in the annular groove 28G and be contacted with a wall surface of the annular groove 28G by the self-tension . By the self-tension of the fitting surface seal 40, an outer inclined surface 40S5 of the fitting surface seal 40 and an outer inclined surface 28S2 of the annular groove 28G are contacted. The outer inclined surface 40S5 of the fitting surface seal 40 and the outer inclined surface 28S2 of the annular groove 28G incline and extend in axial directions of rotation of the first piston member 24 and the second piston member 28 so as to come close to the first piston member 24 toward the outer side in a diametrical direction.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to a seal structure of an internal combustion engine.

Conventionally, in a rotary engine, a ring-shaped sealing material that maintains airtightness between the bases of the first rotor and the second rotor, which are rotatably installed together with the rotating shaft, has been proposed (see, for example, Patent Document 1). ).

Japanese Unexamined Patent Publication No. 6-2559

The above document describes a configuration in which a ring-shaped sealing material is arranged on a mating surface between the first rotor and the second rotor. In order to suppress gas leakage from the annular cylinder chamber centered on the rotating shaft inward in the radial direction, it is necessary to ensure that the sealing material is in contact with both the first rotor and the second rotor. However, the above-mentioned document does not mention that the sealing material is surely brought into contact with both the first rotor and the second rotor, and it cannot be said that sufficient sealing property is always ensured.

The present disclosure provides a sealing structure for an internal combustion engine that can improve sealing performance.

According to the present disclosure, a sealing structure used for an internal combustion engine is provided. The internal combustion engine includes a housing, a first piston member rotatably supported within the housing, and a second piston member rotatably supported within the housing. The housing, the first piston member, and the second piston member form a combustion chamber for burning fuel. The second piston member has an annular facing surface facing the first piston member inside the combustion chamber in the radial direction. The seal structure includes an annular seal member arranged radially inside the combustion chamber. The sealing member has a self-tension that acts in either the diameter-expanding direction or the diameter-reducing direction. An annular groove that opens toward the first piston member is formed on the facing surface of the second piston member. A part of the sealing member is housed in the groove and is configured to come into contact with the wall surface of the groove by self-tension. At least one of the surface of the seal member that comes into contact with the wall surface of the groove due to the self-tension of the seal member and the wall surface of the groove that comes into contact with the seal member due to the self-tension of the seal member are of the first piston member and the second piston member. It has an inclined surface that is inclined with respect to the axial direction of rotation. The inclined surface extends closer to the first piston member toward the direction in which the self-tension of the sealing member acts. By receiving an axial force from the inclined surface, the seal member comes into contact with the first piston member.

According to this configuration, the sealing member can be reliably brought into close contact with both the first piston member and the second piston member, and the sealing property of the mating surface between the first piston member and the second piston member is improved. Can be done.

In the above-mentioned sealing structure, the inclined surface may be formed on the inner peripheral side surface of at least one of the surface of the sealing member and the wall surface of the groove.

In the above-mentioned sealing structure, the inclined surface may be formed on the outer peripheral side surface of at least one of the surface of the sealing member and the wall surface of the groove.

In the above sealing structure, both the surface of the sealing member and the wall surface of the groove may be inclined surfaces. The angle of inclination of the surface of the sealing member and the angle of inclination of the wall surface of the groove may be different.

In the above sealing structure, the first piston member may have an annular plane orthogonal to the axial direction, and the sealing member may be in contact with the annular plane.

According to the sealing structure of the internal combustion engine according to the present disclosure, the sealing property can be improved.

It is a perspective view which shows the structure of the internal combustion engine of an embodiment. It is a figure which shows an example of the structure of the piston member provided in the engine. It is a schematic diagram for demonstrating the operation of a combustion chamber and an engine. It is a perspective view of the 2nd piston member and a seal structure. It is sectional drawing which shows the mating surface seal of 1st Embodiment and its periphery in an enlarged manner. It is sectional drawing which enlarges and shows the mating surface seal of 2nd Embodiment and the periphery thereof. It is sectional drawing which enlarges and shows the mating surface seal of 3rd Embodiment and the periphery thereof. It is sectional drawing which enlarges and shows the mating surface seal of 4th Embodiment and the periphery thereof. It is sectional drawing which enlarges and shows the mating surface seal of 5th Embodiment and the periphery thereof.

Hereinafter, embodiments will be described with reference to the drawings. In the following description, the same parts are designated by the same reference numerals. Their names and functions are the same. Therefore, detailed explanations about them will not be repeated.

[First Embodiment]
<Outline configuration of engine 2>
FIG. 1 is a perspective view showing a configuration of an internal combustion engine according to an embodiment. The internal combustion engine of the embodiment is a rotary piston type engine 2. For example, gas, gasoline, light oil, or the like is used as the fuel for the engine 2. The engine 2 includes a housing 4, an intake pipe 6, an exhaust pipe 8, an injector 10, a throttle motor 14, a first output shaft 16, and a second output shaft 18.

One end of the intake pipe 6 is connected to an intake port (not shown) of the housing 4. For example, an air cleaner (not shown) is connected to the other end of the intake pipe 6. The air cleaner removes foreign matter from the air sucked from the outside of the engine 2. While the engine 2 is operating, the air sucked from the air cleaner flows through the intake pipe 6. The air flowing through the intake pipe 6 circulates in the intake port of the housing 4.

The intake pipe 6 is provided with a throttle valve that limits the flow rate of air flowing through the intake pipe 6. The throttle motor 14 adjusts the opening degree of the throttle valve.

The injector 10 is provided on the upstream side of the throttle valve of the intake pipe 6 and injects fuel (for example, gas) into the intake pipe 6. The injected fuel is mixed with air in the intake pipe 6 and flows to the intake port of the housing 4.

As shown in FIG. 1, the outer peripheral portion of the housing 4 is formed in a cylindrical shape, and the inner peripheral portion thereof is also formed in a cylindrical shape. The housing 4 houses a first piston member connected to the first output shaft 16 and a second piston member connected to the second output shaft 18 inside the housing 4.

One end of the exhaust pipe 8 is connected to an exhaust port (not shown) of the housing 4. An exhaust treatment device (not shown) is connected to the other end of the exhaust pipe 8, for example. During the operation of the engine 2, the exhaust generated by the combustion in the housing 4 flows from the exhaust port of the housing 4 to the exhaust pipe 8. The exhaust gas flowing through the exhaust pipe is purified by the exhaust treatment device and discharged to the outside of the engine 2.

Both the first output shaft 16 and the second output shaft 18 rotate due to the combustion of fuel in the housing 4. The first output shaft 16 and the second output shaft 18 are connected to, for example, a rotating shaft of a motor generator (not shown). This motor generator is, for example, a three-phase AC rotary electric machine.

<Internal structure of engine 2>
FIG. 2 is a diagram showing an example of the configuration of a piston member provided inside the engine 2. An example of the internal structure of the engine 2 will be described with reference to FIG.

As shown in FIG. 2, the first piston member 24 and the second piston member 28 are housed in the housing 4 in combination. The first piston member 24 includes a first rotating body 24a and a first wall surface member 24b. The second piston member 28 includes a second rotating body 28a and a second wall surface member 28b.

The first piston member 24 and the second piston member 28 are rotatably supported by the housing 4. The first rotating body 24a and the second rotating body 28a have the same rotation center AX shown by the alternate long and short dash line in FIG. The first rotating body 24a and the second rotating body 28a can rotate about the rotation center AX. The first rotating body 24a and the second rotating body 28a are provided so that one end surface of the first rotating body 24a and one end surface of the second rotating body 28a face each other in the axial direction.

In the description of the present specification, the direction parallel to the center of rotation AX is referred to as the axial direction, the direction along the circumference centered on the center of rotation AX is referred to as the circumferential direction, and the direction orthogonal to the center of rotation AX is the radial direction. It is called. In the radial direction, the side closer to the center of rotation AX is referred to as the inner side, and the side away from the center of rotation AX is referred to as the outer side.

The first rotating body 24a is formed so as to have a slope portion 24c in a cross section including the rotation center AX. The second rotating body 28a is formed so as to have a slope portion 28c in a cross section including the rotation center AX. As a result, in a state where the first rotating body 24a and the second rotating body 28a are combined, a recess having a V-shaped cross section is formed in the circumferential direction between the first rotating body 24a and the second rotating body 28a. Is formed in.

The first wall surface member 24b is provided so as to extend radially outward from the slope portion 24c of the first rotating body 24a and extend axially toward the slope portion 28c of the second rotating body 28a. Has been done. The first wall surface member 24b is composed of two triangular plate-shaped members. The two triangular plate-shaped members of the first wall surface member 24b are arranged at positions symmetrical with respect to the rotation center AX.

The second wall surface member 28b is provided so as to extend radially outward from the slope portion 28c of the second rotating body 28a and extend axially toward the slope portion 24c of the first rotating body 24a. Has been done. The second wall surface member 28b is composed of two triangular plate-shaped members having the same shape as the plate-shaped member constituting the first wall surface member 24b described above. The two triangular plate-shaped members of the second wall surface member 28b are arranged at positions symmetrical with respect to the rotation center AX. In FIG. 2, only one of the two plate-shaped members of the second wall surface member 28b is shown.

The triangular plate-shaped members of the first wall surface member 24b and the second wall surface member 28b are the first rotating body 24a and the first rotating body 24a in a state where the first piston member 24 and the second piston member 28 are housed in the housing 4. It is formed so as to match the triangular cross-sectional shape formed by the V-shaped recess between the two rotating bodies 28a and the inner peripheral surface of the housing 4.

The first wall surface member 24b is fixed to the slope portion 24c of the first rotating body 24a on one side of the triangle. One side of the triangle of the first wall surface member 24b faces the inner peripheral surface of the housing 4. One side of the triangle of the first wall surface member 24b faces the slope portion 28c of the second rotating body 28a.

The second wall surface member 28b is fixed to the slope portion 28c of the second rotating body 28a on one side of the triangle. One side of the triangle of the second wall surface member 28b faces the inner peripheral surface of the housing 4. One side of the triangle of the second wall surface member 28b faces the slope portion 24c of the first rotating body 24a.

The first output shaft 16 is connected to the first rotating body 24a so that the centers of rotation coincide with each other. A one-way clutch 22 is provided between the first rotating body 24a and the housing 4. The one-way clutch 22 allows rotation of the first rotating body 24a only in a predetermined rotation direction in the housing 4, and suppresses rotation in a direction opposite to the predetermined rotation direction.

The second output shaft 18 is connected to the second rotating body 28a so that the centers of rotation coincide with each other. A one-way clutch 26 is provided between the second rotating body 28a and the housing 4. The one-way clutch 26 allows rotation of the second rotating body 28a only in a predetermined rotation direction in the housing 4, and suppresses rotation in a direction opposite to the predetermined rotation direction.

The first wall surface member 24b and the second wall surface member 28b are not limited to the triangular plate shape, and may have any shape such as a disk shape.

<Combustion chamber>
FIG. 3 is a schematic diagram for explaining the operation of the combustion chambers A to D and the engine 2. FIG. 3 schematically shows a cross section orthogonal to the rotation center AX at the central portion of the housing 4 (for example, the contact portion between the first rotating body 24a and the second rotating body 28a). As shown in FIG. 3, four combustion chambers A to D for burning fuel are formed in the housing 4 by the housing 4, the first piston member 24, and the second piston member 28.

The combustion chambers A to D are the inner peripheral surface of the housing 4, the first wall surface member 24b and the slope portion 24c of the first piston member 24, and the second wall surface member 28b and the slope portion 28c of the second piston member 28, respectively. Is stipulated by. The first wall surface member 24b and the second wall surface member 28b form a wall surface in the circumferential direction of the combustion chambers A to D. The two combustion chambers adjacent to each other in the circumferential direction are separated by a first wall surface member 24b and a second wall surface member 28b.

In FIG. 3, the one-way clutches 22 and 26 shown in FIG. 2 suppress the counterclockwise rotation of the first piston member 24 and the second piston member 28, and allow the clockwise rotation.

In the combustion chamber A shown in FIG. 3, the air-fuel mixture of the compressed air and the fuel becomes an expansion stroke in which the air-fuel mixture is ignited by self-ignition. That is, when the fuel burns in the combustion chamber A, the counterclockwise movement of the first piston member 24 is suppressed by the one-way clutch 22, so that the rotational position of the first piston member 24 is maintained and the second piston member 28 Only rotates in the direction of the dashed arrow, and the volume of the combustion chamber A increases with the expansion of the gas in the combustion chamber A.

In the combustion chamber B shown in FIG. 3, the expanded exhaust gas is discharged from the exhaust pipe 8. That is, when the second piston member 28 rotates in the direction of the broken arrow arrow due to the combustion of fuel in the combustion chamber A, the rotational position of the first piston member 24 is maintained, so that the volume of the combustion chamber B decreases. At this time, the combustion chamber B communicates with the exhaust pipe 8. Therefore, the exhaust gas in the combustion chamber B is discharged to the exhaust pipe 8 as the volume of the combustion chamber B decreases.

In the combustion chamber C shown in FIG. 3, the intake stroke is such that the air-fuel mixture is sucked from the intake pipe 6. That is, when the second piston member 28 rotates in the direction of the broken arrow arrow due to the combustion of fuel in the combustion chamber A, the rotational position of the first piston member 24 is maintained, so that the volume of the combustion chamber C increases. At this time, the combustion chamber C communicates with the intake pipe 6 while the second piston member 28 is rotating in the direction of the broken line arrow. Therefore, as the volume of the combustion chamber C increases, the air-fuel mixture is sucked into the combustion chamber C from the intake pipe 6.

In the combustion chamber D shown in FIG. 3, the compression stroke is such that the air-fuel mixture sucked from the intake pipe 6 is compressed. That is, when the second piston member 28 rotates in the direction of the broken arrow arrow due to the combustion of fuel in the combustion chamber A, the rotational position of the first piston member 24 is maintained, so that the volume of the combustion chamber D decreases. At this time, since the combustion chamber D does not communicate with either the intake pipe 6 or the exhaust pipe 8, the air-fuel mixture in the combustion chamber D is compressed by the decrease in the volume of the combustion chamber D.

Then, when a clockwise force acts on the first piston member 24 due to the increase in the pressure in the combustion chamber D, the first piston member 24 rotates, and the positions of the first piston member 24 and the second piston member 28 are located. The relationships will be swapped.

In this way, each time combustion is performed in any of the combustion chambers A to D, the first piston member 24 and the second piston member 28 rotate alternately to operate the engine 2.

<Outline structure of seal structure>
Hereinafter, a seal structure for sealing between the facing surfaces of the first piston member 24 and the second piston member 28 will be described. The first piston member 24 has an annular facing surface facing the second piston member 28 inside the combustion chambers A to D in the radial direction. The second piston member 28 has an annular facing surface facing the first piston member 24 inside the combustion chambers A to D in the radial direction.

FIG. 4 is a perspective view of the second piston member 28 and the seal structure. The second piston member 28 and the first piston member 24 (not shown in FIG. 4) are arranged side by side in the axial direction. The first piston member 24 and the second piston member 28 are connected to each other via a bearing 100, and are configured to be rotatable relative to each other. A lubricating oil passage 281 is formed in the second piston member 28. The first piston member 24 is formed with a lubricating oil passage that communicates with the lubricating oil passage 281.

As shown in FIG. 4, the seal structures for maintaining the airtightness between the first piston member 24 and the second piston member 28 include the mating surface seal 40, the piston seals 50 and 150, and the corner seals 60 and 160. Includes.

The mating surface seal 40 has an annular shape having a joint portion at one position in the circumferential direction. The mating surface seal 40 is arranged concentrically with the first piston member 24 and the second piston member 28. The mating surface seal 40 is arranged inside the slope portion 28c in the radial direction. The mating surface seal 40 is arranged inside the second wall surface member 28b in the radial direction. Therefore, the mating surface seal 40 is arranged inside the combustion chambers A to D in the radial direction, and seals the inner peripheral portions of the combustion chambers A to D. The mating surface seal 40 is a gas seal that suppresses gas leakage from the combustion chambers A to D to the inner peripheral side.

The mating surface seal 40 is held by the second piston member 28. An annular groove 28G is formed on the facing surface of the second piston member 28 facing the first piston member 24. The annular groove 28G is open toward the first piston member 24. A part of the mating surface seal 40 is housed in the annular groove 28G. The mating surface seal 40 slides with respect to the first piston member 24 as the first piston member 24 and the second piston member 28 rotate relative to each other.

The piston seal 50 is held by the second wall surface member 28b of the second piston member 28. Accommodating grooves 285 and 288 are formed in the second wall surface member 28b, and the piston seal 50 is accommodated in the accommodating grooves 285 and 288. The accommodating groove 285 is formed at the edge of the second wall surface member 28b facing the slope portion 24c of the first piston member 24. The accommodating groove 288 is formed on the outer peripheral edge of the second wall surface member 28b facing the inner peripheral surface of the housing 4.

The piston seal 50 has a seal surface 51 that contacts the slope portion 24c of the first piston member 24. The seal surface 51 slides with respect to the first piston member 24 as the first piston member 24 and the second piston member 28 rotate relative to each other. The piston seal 50 has a seal surface 81 that contacts the inner peripheral surface of the housing 4. As the second piston member 28 rotates in the housing 4, the seal surface 81 slides with respect to the housing 4.

The piston seal 50 seals between the second wall surface member 28b of the second piston member 28 and the slope portion 24c of the first piston member 24, and also seals the second wall surface member 28b of the second piston member 28 and the housing. It seals between 4 and 4. The piston seal 50 seals between two combustion chambers adjacent to each other in the circumferential direction, and prevents gas from leaking from one of the combustion chambers A to D to the combustion chamber next to the one combustion chamber. It is suppressing.

The piston seal 150 has the same structure as the piston seal 50. The piston seal 150 is held by the first wall surface member 24b of the first piston member 24 (not shown in FIG. 4). The piston seal 150 has a seal surface that contacts the slope portion 28c of the second piston member 28 and a seal surface that contacts the housing. The piston seal 150 seals between the first wall surface member 24b of the first piston member 24 and the slope portion 28c of the second piston member 28, and between the first wall surface member 24b and the housing 4. The piston seal 150 seals between two combustion chambers adjacent to each other in the circumferential direction, and prevents gas from leaking from one of the combustion chambers A to D to the combustion chamber next to the one combustion chamber. It is suppressing.

The corner seal 60 is arranged at the intersection of the mating surface seal 40 and the piston seal 50. The corner seal 60 is held by the second piston member 28. A housing recess 286 is formed in the second piston member 28, and a corner seal 60 is housed in the housing recess 286. The accommodating recess 286 is formed at the radial inner end of the second wall surface member 28b. Therefore, the corner seal 60 is held by the second piston member 28 at the radial inner end of the second wall surface member 28b.

The corner seal 60 comes into contact with the first piston member 24. The corner seal 60 slides with respect to the first piston member 24 as the first piston member 24 and the second piston member 28 rotate relative to each other. A spring member 73 is provided on the bottom surface of the accommodating recess 286, and the spring member 73 urges the corner seal 60 toward the outside of the accommodating recess 286. As a result, the adhesion of the corner seal 60 to the first piston member 24 is ensured.

The corner seal 160 is arranged at the intersection of the mating surface seal 40 and the piston seal 150. The corner seal 160 is held by the first piston member 24. A housing recess is formed at the radial inner end of the first wall surface member 24b of the first piston member 24, and the corner seal 160 is housed in the housing recess. Therefore, the corner seal 160 is held by the first piston member 24 at the radial inner end of the first wall surface member 24b.

The corner seal 160 comes into contact with the second piston member 28. The corner seal 160 slides with respect to the second piston member 28 as the first piston member 24 and the second piston member 28 rotate relative to each other. A spring member 173 is provided on the corner seal 160, and the spring member 173 urges the corner seal 60 toward the second piston member 28. As a result, the adhesion of the corner seal 160 to the second piston member 28 is ensured.

A corner seal 90 is provided adjacent to the piston seal 50 in the axial direction. The spring member 93 urges the corner seal 90 outward in the radial direction, and the corner seal 90 is brought into close contact with the inner peripheral surface of the housing 4.

<Details of mating surface seal 40>
FIG. 5 is an enlarged cross-sectional view showing the mating surface seal 40 of the first embodiment and its periphery. FIG. 5 and subsequent cross-sectional views show cross sections (cross sections including the radial direction and the axial direction) orthogonal to the circumferential direction of the mating surface seal 40 and the first piston member 24 and the second piston member 28 around the mating surface seal 40. ing. The vertical direction in the figure is the radial direction. The upper side in the figure is the outer side in the radial direction, and the lower side in the figure is the inner side in the radial direction. The left-right direction in the figure is the axial direction.

The mating surface seal 40 has an unequal side hexagonal cross-sectional shape. The mating surface seal 40 has an outer peripheral surface 40S1, an inner peripheral surface 40S2, a facing surface 40S3, a sealing surface 40S4, an outer inclined surface 40S5, and an inner inclined surface 40S6. The outer peripheral surface 40S1, the inner peripheral surface 40S2, the facing surface 40S3, the sealing surface 40S4, the outer inclined surface 40S5, and the inner inclined surface 40S6 form the outer surface of the mating surface seal 40.

In the cross-sectional view shown in FIG. 4, the outer peripheral surface 40S1 and the inner peripheral surface 40S2 extend in the axial direction. The facing surface 40S3 and the sealing surface 40S4 extend in the radial direction. The outer peripheral surface 40S1 and the inner peripheral surface 40S2 extend in parallel with each other. The facing surface 40S3 and the sealing surface 40S4 extend in parallel with each other.

The outer inclined surface 40S5 and the inner inclined surface 40S6 are inclined and extend in the axial direction and the radial direction. The cross section of the mating surface seal 40 has a shape in which a rectangle is chamfered at both ends of one of the long sides. Two inclined surfaces arranged in the radial direction are formed on the surface of the mating surface seal 40, the outer inclined surface 40S5 is an inclined surface on the outer peripheral side, and the inner inclined surface 40S6 is an inclined surface on the inner peripheral side. The angle of inclination of the outer inclined surface 40S5 and the inner inclined surface 40S6 may be, for example, 30 ° or more and 60 ° or less, preferably 40 ° or more and 50 ° or less, preferably approximately 45 °.

The outer inclined surface 40S5 is a surface connecting the outer peripheral surface 40S1 and the facing surface 40S3, and is inclined in the axial direction and the radial direction so as to extend inward in the radial direction as the outer peripheral surface 40S1 approaches the facing surface 40S3. .. The outer inclined surface 40S5 extends so as to approach the first piston member 24 toward the outer side in the radial direction.

The inner inclined surface 40S6 is a surface connecting the inner peripheral surface 40S2 and the facing surface 40S3, and is inclined in the axial direction and the radial direction so as to extend radially outward as the inner peripheral surface 40S2 approaches the facing surface 40S3. ing. The inwardly inclined surface 40S6 extends so as to approach the first piston member 24 as it goes inward in the radial direction.

An annular groove 28G is formed in the second piston member 28, and a part of the mating surface seal 40 is housed in the annular groove 28G. As shown in FIG. 5, a portion of the mating surface seal 40 including the facing surface 40S3, the outer inclined surface 40S5, and the inner inclined surface 40S6 is arranged in the annular groove 28G. The portion of the mating surface seal 40 including the seal surface 40S4 is arranged outside the annular groove 28G.

The annular groove 28G includes an outer peripheral wall surface 28S1 forming a radial outer wall surface of the annular groove 28G wall surface, an inner peripheral wall surface 28S5 forming a radial inner wall surface of the annular groove 28G wall surface, and a bottom surface 28S3. Have. In the cross-sectional view shown in FIG. 4, the outer peripheral wall surface 28S1 and the inner peripheral wall surface 28S5 extend in the axial direction. The outer peripheral wall surface 28S1 and the inner peripheral wall surface 28S5 extend in parallel with each other. The bottom surface 28S3 extends in the radial direction.

The outer peripheral wall surface 28S1 faces the outer peripheral surface 40S1 of the mating surface seal 40, and a gap is formed between the outer peripheral wall surface 28S1 and the outer peripheral surface 40S1. The outer peripheral wall surface 28S1 of the annular groove 28G and the outer peripheral surface 40S1 of the mating surface seal 40 are not in contact with each other. The outer peripheral wall surface 28S1 and the outer peripheral surface 40S1 are arranged in parallel.

The inner peripheral wall surface 28S5 faces the inner peripheral wall surface 28S5 of the mating surface seal 40, and a gap is formed between the inner peripheral wall surface 28S5 and the inner peripheral surface 40S2. The inner peripheral wall surface 28S5 of the annular groove 28G and the inner peripheral surface 40S2 of the mating surface seal 40 are not in contact with each other. The inner peripheral wall surface 28S5 and the inner peripheral surface 40S2 are arranged in parallel.

The bottom surface 28S3 faces the facing surface 40S3 of the mating surface seal 40, and a gap is formed between the bottom surface 28S3 and the facing surface 40S3. The bottom surface 28S3 of the annular groove 28G and the facing surface 40S3 of the mating surface seal 40 are not in contact with each other. The bottom surface 28S3 and the facing surface 40S3 are arranged in parallel.

The annular groove 28G further has an outer inclined surface 28S2 and an inner inclined surface 28S4. The outer inclined surface 28S2 and the inner inclined surface 28S4 are inclined and extend in the axial direction and the radial direction. Two inclined surfaces arranged in the radial direction are formed on the wall surface of the annular groove 28G, the outer inclined surface 28S2 is an inclined surface on the outer peripheral side, and the inner inclined surface 28S4 is an inclined surface on the inner peripheral side. The inclination angle of the outer inclined surface 28S2 and the inner inclined surface 28S4 may be, for example, 30 ° or more and 60 ° or less, preferably 40 ° or more and 50 ° or less, preferably approximately 45 °.

The outer inclined surface 28S2 is a surface connecting the outer peripheral wall surface 28S1 and the bottom surface 28S3, and is inclined in the axial direction and the radial direction so as to extend radially inward as the outer peripheral wall surface 28S1 approaches the bottom surface 28S3. The outer inclined surface 28S2 extends toward the first piston member 24 as it goes outward in the radial direction.

The inner inclined surface 28S4 is a surface connecting the inner peripheral wall surface 28S5 and the bottom surface 28S3, and is inclined in the axial direction and the radial direction so as to extend radially outward as the inner peripheral wall surface 28S5 approaches the bottom surface 28S3. .. The inwardly inclined surface 28S4 extends toward the first piston member 24 as it goes inward in the radial direction.

The outer inclined surface 28S2 faces the outer inclined surface 40S5 of the mating surface seal 40. The outer inclined surface 28S2 of the annular groove 28G and the outer inclined surface 40S5 of the mating surface seal 40 are in surface contact with each other. No gap is formed between the outer inclined surface 28S2 and the outer inclined surface 40S5. The outer inclined surface 28S2 and the outer inclined surface 40S5 are arranged on the same surface.

The inner inclined surface 28S4 faces the inner inclined surface 40S6 of the mating surface seal 40, and a gap is formed between the inner inclined surface 28S4 and the inner inclined surface 40S6. The inner inclined surface 28S4 of the annular groove 28G and the inner inclined surface 40S6 of the mating surface seal 40 are not in contact with each other. The inner inclined surface 28S4 and the inner inclined surface 40S6 are arranged in parallel.

The seal surface 40S4 of the mating surface seal 40 faces the first piston member 24. The seal surface 40S4 is in surface contact with the first piston member 24. No gap is formed between the sealing surface 40S4 and the first piston member 24. The sealing surface 40S4 is arranged on the same plane as the surface of the first piston member 24. The surface of the first piston member 24 with which the seal surface 40S4 contacts has an annular planar shape orthogonal to the axial direction.

The mating surface seal 40 of the embodiment has a self-tension acting in the diameter-expanding direction. As described above, the mating surface seal 40 is formed in a substantially C shape having a joint portion at one position in the circumferential direction, and when the mating surface seal 40 is housed in the annular groove 28G, the mating surface seal 40 is closed and mated. The diameter of the surface seal 40 is reduced. As a result, a urging force acts on the mating surface seal 40 outward in the radial direction. This urging force is applied to the mating surface seal 40 as self-tension in the diameter expansion direction.

The mating surface seal 40 moves radially outward in the annular groove 28G by the action of self-tension in the diameter expansion direction, and the outer inclined surface 40S5 of the mating surface seal 40 comes into contact with the outer inclined surface 28S2 of the annular groove 28G. As a result, the adhesion of the outer inclined surface 40S5 to the second piston member 28 is ensured.

The urging force that the mating surface seal 40 tries to further increase the diameter acts from the outer inclined surface 40S5 of the mating surface seal 40 to the outer inclined surface 28S2 of the annular groove 28G. An axial force in the outward direction of the annular groove 28G acts on the mating surface seal 40 from the outer inclined surface 40S5. By receiving this axial force, the mating surface seal 40 moves toward the first piston member 24, and the sealing surface 40S4 of the mating surface seal 40 comes into contact with the annular plane of the first piston member 24. As a result, the adhesion of the sealing surface 40S4 to the first piston member 24 is ensured.

Therefore, it is possible to realize a configuration in which the mating surface seal 40 is surely brought into close contact with both the first piston member 24 and the second piston member 28, and the sealing property of the mating surface between the first piston member 24 and the second piston member 28 can be improved. Can be improved. The combustion efficiency of the engine 2 can be improved by reducing the amount of gas leaking from the combustion chambers A to D to the inner peripheral side.

With the mating surface seal 40 moving outward in the radial direction, the outer inclined surface 40S5 in contact with the outer inclined surface 28S2 of the annular groove 28G, and the sealing surface 40S4 in contact with the first piston member 24, the mating surface seal 40 A gap is secured between the outer peripheral surface 40S1 and the outer peripheral wall surface 28S1 of the annular groove 28G. The structure is such that the movement of the mating surface seal 40 along the outer inclined surface 28S2 is not hindered by the outer peripheral wall surface 28S1. Therefore, the mating surface seal 40 can be reliably moved in the axial direction until the mating surface seal 40 comes into contact with the first piston member 24.

In order to bring the mating surface seal 40 into contact with both the first piston member 24 and the second piston member 28 that move relative to each other, it is not necessary to add another member such as a spring. Since the mating surface seal 40 alone can realize two seals of the contact surface with the first piston member 24 and the contact surface with the second piston member 28, the number of parts can be reduced and the configuration can be simplified. Can be done. In addition, it is possible to prevent the hollow space secured for arranging the spring from becoming a gas leak path. Since only the minimum gap for absorbing the dimensional variation is formed between the mating surface seal 40 and the annular groove 28G, the volume of the hollow space that can be a gas leakage path is reduced, and therefore the volume of the hollow space is reduced. The amount of gas leakage can be reduced.

The mating surface seal 40 has an inner inclined surface 40S6 on the inner peripheral side surface, and the annular groove 28G has an inner inclined surface 28S4 on the inner peripheral side wall surface. As a result, even when the mating surface seal 40 moves inward in the radial direction due to the pressure of the gas in the combustion chambers A to D, the force acting on the inner inclined surface 40S6 to the inner inclined surface 28S4 causes the mating surface seal 40 to be the first piston. It is moved in a direction approaching the member 24. Therefore, the mating surface seal 40 can be reliably brought into close contact with both the first piston member 24 and the second piston member 28.

The mating surface seal 40 has an outer inclined surface 40S5 on the outer peripheral side surface, and the annular groove 28G has an outer inclined surface 28S2 on the outer peripheral side wall surface. As a result, when the mating surface seal 40 moves outward in the radial direction due to the centrifugal force generated by the rotation of the first piston member 24 and the second piston member 28, the force acting on the outer inclined surface 28S2 from the outer inclined surface 40S5 is applied. The mating surface seal 40 is moved in a direction approaching the first piston member 24. Therefore, the mating surface seal 40 can be reliably brought into close contact with both the first piston member 24 and the second piston member 28.

By making both the surface of the mating surface seal 40 and the wall surface of the annular groove 28G an inclined surface, the size of the gap formed around the mating surface seal 40 can be reduced, and the sealing property can be further improved.

If an inclined surface is formed on both the inner peripheral side and the outer peripheral side of the surface of the mating surface seal 40 and an inclined surface is formed on both the inner peripheral side and the outer peripheral side of the wall surface of the annular groove 28G, the mating surface is aligned. Regardless of whether the self-tension of the surface seal 40 and the pressure and centrifugal force of the gas acting on the mating surface seal 40 act to move the mating surface seal 40 in either the radial inside or the outside direction, the seal is sealed. The sex can be surely secured.

Since the surface of the first piston member 24 with which the mating surface seal 40 comes into contact is an annular flat surface, the size of the gap formed around the mating surface seal 40 can be reduced, and the sealing property can be further improved.

[Second Embodiment]
In the first embodiment shown in FIG. 5, the angle at which the inclined surface of the mating surface seal 40 is inclined with respect to the axial direction and the radial direction and the angle at which the inclined surface of the annular groove 28G is inclined with respect to the axial direction and the radial direction. An example in which is equal is described. Not limited to this example, the angle of inclination of the inclined surface of the mating surface seal 40 and the angle of inclination of the inclined surface of the annular groove 28G may be different from each other.

FIG. 6 is an enlarged cross-sectional view showing the mating surface seal 40 of the second embodiment and its periphery. In the second embodiment, the outer inclined surface 40S5 and the inner inclined surface 40S6 of the mating surface seal 40 are inclined at different angles from the outer inclined surface 28S2 and the inner inclined surface 28S4 of the annular groove 28G. In the mating surface seal 40, the outer inclined surface 40S5 does not come into surface contact with the outer inclined surface 28S2 of the annular groove 28G, but the first side 40E1 forming the boundary between the outer peripheral surface 40S1 and the outer inclined surface 40S5 is outside the annular groove 28G. It is configured to be in contact with the inclined surface 28S2.

In this way, the contact between the mating surface seal 40 and the second piston member 28 can be ensured on the first side 40E1, and the sealing surface 40S4 and the first piston member 24 of the mating surface seal 40 can be secured as in the first embodiment. Contact with can be secured. Therefore, it is possible to realize a configuration in which the mating surface seal 40 is brought into close contact with both the first piston member 24 and the second piston member 28. Since the position of the surface of the mating surface seal 40 that comes into contact with the second piston member 28 can be defined as the first side 40E1, quality control that ensures that the mating surface seal 40 is in contact with the second piston member 28 can be easily performed. it can.

[Third Embodiment]
FIG. 7 is an enlarged cross-sectional view showing the mating surface seal 40 of the third embodiment and its periphery. Also in the third embodiment, the outer inclined surface 40S5 and the inner inclined surface 40S6 of the mating surface seal 40 are inclined at different angles from the outer inclined surface 28S2 and the inner inclined surface 28S4 of the annular groove 28G. The mating surface seal 40 is configured so that the second side 40E2 forming the boundary between the outer inclined surface 40S5 and the facing surface 40S3 comes into contact with the outer inclined surface 28S2 of the annular groove 28G.

In this way, the contact between the mating surface seal 40 and the second piston member 28 can be ensured on the second side 40E2, and the sealing surface 40S4 and the first piston member 24 of the mating surface seal 40 can be secured as in the first embodiment. Contact with can be secured. Therefore, it is possible to realize a configuration in which the mating surface seal 40 is brought into close contact with both the first piston member 24 and the second piston member 28. Since the position of the surface of the mating surface seal 40 in contact with the second piston member 28 can be defined as the second side 40E2, quality control for ensuring that the mating surface seal 40 is in contact with the second piston member 28 can be easily performed. it can.

[Fourth Embodiment]
In the description of the embodiments so far, an example in which both the surface of the mating surface seal 40 and the wall surface of the annular groove 28G have an inclined surface has been described. Not limited to this example, only one of the surface of the mating surface seal 40 and the wall surface of the annular groove 28G may have an inclined surface.

FIG. 8 is an enlarged cross-sectional view showing the mating surface seal 40 of the fourth embodiment and its periphery. The mating surface seal 40 shown in FIG. 8 has a rectangular cross-sectional shape. The mating surface seal 40 has an outer peripheral surface 40S1, an inner peripheral surface 40S2, an opposing surface 40S3, and a sealing surface 40S4, but does not have an inclined surface. The wall surface of the annular groove 28G has the same shape as that of the first embodiment. The mating surface seal 40 is configured so that the first side 40E1 forming the boundary between the outer peripheral surface 40S1 and the facing surface 40S3 comes into contact with the outer inclined surface 28S2 of the annular groove 28G.

Even with such a configuration, the contact between the mating surface seal 40 and the second piston member 28 can be ensured on the first side 40E1, and the sealing surface 40S4 of the mating surface seal 40 and the first piston member as in the first embodiment. Contact with 24 can be secured. Therefore, it is possible to realize a configuration in which the mating surface seal 40 is brought into close contact with both the first piston member 24 and the second piston member 28.

The shape of the mating surface seal 40 can be simplified by providing an inclined surface in the annular groove 28G of the second piston member 28 and forming the mating surface seal 40 having a rectangular cross section. Therefore, the mating surface seal 40 of the fourth embodiment is easy to manufacture.

[Fifth Embodiment]
FIG. 9 is an enlarged cross-sectional view showing the mating surface seal 40 of the fifth embodiment and its periphery. The mating surface seal 40 shown in FIG. 9 has the same shape as that of the first embodiment. On the other hand, the wall surface of the annular groove 28G has a thrust surface 28S21 extending in the radial direction and a radial surface 28S22 extending in the axial direction in place of the outer inclined surface 28S2. Instead of the inner inclined surface 28S4, it has a thrust surface 28S41 extending in the radial direction and a radial surface 28S42 extending in the axial direction.

The outer inclined surface 40S5 of the mating surface seal 40 is in contact with the first side 28E1 forming the boundary between the thrust surface 28S21 and the radial surface 28S22. The inner inclined surface 40S6 of the mating surface seal 40 faces the second side 28E2 forming the boundary between the thrust surface 28S41 and the radial surface 28S42 with a gap.

Even with such a configuration, the contact between the mating surface seal 40 and the second piston member 28 can be ensured by the contact between the outer inclined surface 40S5 and the first side 28E1, and the mating surface seal 40 can be as in the first embodiment. Contact between the sealing surface 40S4 and the first piston member 24 can be ensured. Therefore, it is possible to realize a configuration in which the mating surface seal 40 is brought into close contact with both the first piston member 24 and the second piston member 28.

In the description so far, an example in which the mating surface seal 40 has a self-tension acting in the diameter-expanding direction has been described. Not limited to this example, the mating surface seal 40 may have a self-tension acting in the radial direction. When the mating surface seal 40 having the abutment portion is housed in the annular groove 28G, the abutment portion is widened to increase the diameter of the mating surface seal 40. As a result, an urging force inward in the radial direction acts on the mating surface seal 40. This urging force is applied to the mating surface seal 40 as self-tension in the diameter reduction direction.

The mating surface seal 40 moves inward in the radial direction in the annular groove 28G by the action of self-tension in the radial direction. In this case, one or both of the inner peripheral side surface of the mating surface seal 40 and the inner peripheral side wall surface of the annular groove 28G, which is the direction in which the self-tension acts, has an inclined surface. .. For example, as shown in FIG. 5, the mating surface seal 40 has an inner inclined surface 40S6 and the annular groove 28G has an inner inclined surface 28S4, and the inner inclined surface 40S6 of the mating surface seal 40 has an inner inclined surface of the annular groove 28G. Make contact with 28S4. By doing so, it is possible to realize a configuration in which the mating surface seal 40 is brought into close contact with both the first piston member 24 and the second piston member 28, as in the above-described embodiment.

Although the embodiments have been described above, it should be considered that the embodiments disclosed this time are exemplary in all respects and are not restrictive. The scope of the present invention is shown by the scope of claims rather than the above description, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

2 engine, 4 housing, 24 first piston member, 24a first rotating body, 24b first wall member, 24c, 28c slope part, 28 second piston member, 28E1, 40E1 first side, 28E2, 40E2 second side, 28G annular groove, 28S1 outer peripheral wall surface, 28S2, 40S5 outer inclined surface, 28S21, 28S41 thrust surface, 28S22, 28S42 radial surface, 28S3 bottom surface, 28S4, 40S6 inner inclined surface, 28S5 inner peripheral wall surface, 28a second rotating body, 28b second 2 wall member, 40 mating surface seal, 40S1 outer peripheral surface, 40S2 inner peripheral surface, 40S3 facing surface, 40S4 sealing surface, A, B, C, D combustion chamber.

Claims (6)

It is a seal structure used for internal combustion engines.
The internal combustion engine includes a housing, a first piston member rotatably supported in the housing, and a second piston member rotatably supported in the housing, the housing, the first piston. A combustion chamber for burning fuel is formed by the member and the second piston member, and the second piston member has an annular facing surface facing the first piston member inside the combustion chamber in the radial direction. And
The seal structure includes an annular seal member arranged radially inside the combustion chamber.
The sealing member has a self-tension that acts in either the diameter-expanding direction or the diameter-reducing direction.
An annular groove that opens toward the first piston member is formed on the facing surface.
The seal member is configured so that a part of the seal member is housed in the groove and comes into contact with the wall surface of the groove by self-tension.
At least one of the surface of the seal member that comes into contact with the wall surface of the groove due to the self-tension of the seal member and the wall surface of the groove that comes into contact with the seal member due to the self-tension of the seal member is the first piston. It has an inclined surface that is inclined with respect to the axial direction of rotation of the member and the second piston member.
The inclined surface extends toward the first piston member as the self-tension of the sealing member acts.
A seal structure for an internal combustion engine in which the seal member comes into contact with the first piston member by receiving a force in the axial direction from the inclined surface. The seal structure according to claim 1, wherein the inclined surface is formed on the inner peripheral side surface of at least one of the surface of the seal member and the wall surface of the groove. The seal structure according to claim 1, wherein the inclined surface is formed on the outer peripheral side surface of at least one of the surface of the seal member and the wall surface of the groove. The seal structure according to any one of claims 1 to 3, wherein both the surface of the seal member and the wall surface of the groove are inclined surfaces. The seal structure according to claim 4, wherein the angle of inclination of the surface of the seal member and the angle of inclination of the wall surface of the groove are different. The first piston member has an annular plane orthogonal to the axial direction.
The seal structure according to any one of claims 1 to 5, wherein the seal member contacts the annular plane.

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