JP2021001583A - Seal structure - Google Patents

Abstract

To improve sealability of a seal structure used in an internal combustion engine.SOLUTION: An apex seal 80 is held by a first wall surface member 24b to seal between the wall surface member 24b and a housing. An outer peripheral seal 190 seals between a second piston member 28 and the housing. The outer peripheral seal 190 has self-tensile force acting in a diameter expansion direction. The outer peripheral seal 190 is formed into the annular shape, and an abutment portion 191 is formed by parting a part of the annular shape. The outer peripheral seal 190 is constituted to be rotated integrally with the second piston member 28 while positioning the abutment portion 191 on a position not overlapping the apex seal 80 in the peripheral direction.SELECTED DRAWING: Figure 2

Description

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

Conventionally, a configuration has been proposed in which a rotor and a housing of a Wankel type rotary engine are sealed with an apex seal and a side seal (see, for example, Patent Documents 1 and 2). The side seals described in these documents are mounted in grooves formed on the side end faces of the rotor, and slide with respect to the housing as the rotor rotates.

Special Fair No. 5-7525 Japanese Unexamined Patent Publication No. 2016-109060

In a rotary piston type engine in which a plurality of piston members can rotate independently, the combustion chamber is composed of the plurality of piston members. A seal is provided on the outer circumference of the piston member to prevent gas leakage from the combustion chamber to the outside. This outer peripheral seal has a self-tension that acts radially outward. This self-tension presses the outer peripheral seal against the housing. In order to have this self-tension, the outer peripheral seal has a joint portion which is a break in the ring.

An apex seal for sealing between the piston member and the housing is attached to each rotating piston member. The apex seal rotates as the piston member rotates while being pressed against the outer peripheral seal. When the apex seal assembled to the first piston member is caught in the abutment portion of the outer peripheral seal provided on the outer periphery of the second piston member, the sealing pressure at both ends of the apex seal is reduced and the sealing property is lowered. There is a risk.

The present disclosure provides a sealing structure used in an internal combustion engine, which can improve the sealing property.

According to the present disclosure, a sealing structure used for an internal combustion engine is provided. The internal combustion engine is rotatably supported in a cylindrical housing, a first piston member rotatably supported in the housing about the center of rotation in one direction, and in the housing around the center of rotation. Includes a second piston member. The housing, the first piston member, and the second piston member form a combustion chamber for burning fuel. The first piston member has a wall surface member that forms a wall surface in the circumferential direction of the combustion chamber. The seal structure includes an apex seal that is held by the wall surface member and seals between the wall surface member and the housing, and an outer peripheral seal that seals between the second piston member and the housing. The outer peripheral seal has a self-tension acting in the diameter-expanding direction. The outer peripheral seal is formed in an annular shape, and a joint portion in which a part of the annular shape is divided is formed. The outer peripheral seal is configured so that the abutment portion is positioned at a position where it does not overlap with the apex seal in the circumferential direction and rotates integrally with the second piston member.

Since the abutment portion of the rotating outer peripheral seal is always outside the movable range of the apex seal, the apex seal is not caught in the apex seal portion. Therefore, the sealing property of the apex seal can be maintained.

In the above seal structure, the second piston member has a second wall surface member that forms a wall surface in the circumferential direction of the combustion chamber. The abutment portion is positioned within a range in which the second wall surface member exists in the circumferential direction. As a result, the abutment portion can be reliably positioned at a position that does not overlap with the apex seal in the circumferential direction.

In the above sealing structure, the sealing structure further includes a second apex seal that is held by the second wall surface member and seals between the second wall surface member and the housing. A part of the second apex seal is housed in the abutment. By positioning the outer peripheral seal using the second apex seal, the configuration of the internal combustion engine can be simplified.

In the above-mentioned seal structure, the second piston member has a protruding portion in which a part thereof protrudes. The protrusion is housed in the abutment. As a result, the abutment portion can be reliably positioned at a position that does not overlap with the apex seal in the circumferential direction.

According to the seal structure 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 figure for demonstrating an example of the operation of each component member at the time of burning fuel in a combustion chamber A. It is a figure for demonstrating an example of the operation of each component member at the time of burning fuel in a combustion chamber D. It is a schematic diagram which shows the shape of the outer peripheral seal. It is sectional drawing of the 1st piston member and the 2nd piston member. It is sectional drawing which shows the seal structure enlarged. It is a perspective view of the piston member which shows the seal structure of 2nd Embodiment. It is a perspective view of the 1st piston member in 3rd Embodiment. It is a schematic diagram of the seal structure in the third embodiment.

Hereinafter, embodiments of the present invention 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. 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 each have an annular shape. The first rotating body 24a and the second rotating body 28a have the same rotation center axis 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 axis 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. The first rotating body 24a and the second rotating body 28a are arranged adjacent to each other in the axial direction.

In the description of the present specification, the direction parallel to the rotation center axis AX is referred to as an axial direction, the direction along the circumference centered on the rotation center axis AX is referred to as a circumferential direction, and the direction orthogonal to the rotation center axis AX. Is referred to as the radial direction. In the radial direction, the side closer to the rotation center axis AX is referred to as the inner side, and the side away from the rotation center axis 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 central axis AX. The second rotating body 28a is formed so as to have a slope portion 28c in a cross section including the rotation central axis 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 slope portion 24c of the first rotating body 24a faces the second rotating body 28a. The slope portion 24c of the second rotating body 28a faces the first rotating body 24a.

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 axis 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 axis 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 has a first side 24b1 forming one side of the triangle, a second side 24b2 forming one side of the triangle, and a corner portion 24b3 where the first side 24b1 and the second side 24b2 intersect. It has a square shape. The first side 24b1 of the first wall surface member 24b faces the slope portion 28c of the second rotating body 28a. The second side 24b2 of the first wall surface member 24b faces the inner peripheral surface 4m (FIGS. 3 and 4 described later) of the housing 4. The first wall surface member 24b is fixed to the slope portion 24c of the first rotating body 24a on the other side of the triangle.

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

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 holds the apex seal 80. The second wall surface member 28b holds the apex seal 180. The second rotating body 28a holds an annular outer peripheral seal 90. The second rotating body 28a holds an annular outer peripheral seal 190. A mating surface seal 40 is provided between the first rotating body 24a and the second rotating body 28a. Details of these seals will be described later.

<Combustion chamber>
FIG. 3 is a diagram for explaining an example of the operation of each component member when fuel is burned in the combustion chamber A. FIG. 3 shows a cross section of the central portion of the housing 4 (for example, the contact portion between the first rotating body 24a and the second rotating body 28a) that is orthogonal to the rotation center axis AX.

As shown in FIG. 3, in the housing 4, four combustion chambers A to D for burning fuel by the inner peripheral surface 4 m of the housing 4, the first piston member 24, and the second piston member 28 are used. Is formed. 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.

The combustion chamber A and the combustion chamber C are defined by an inner peripheral surface 4 m of the housing 4, a front surface 24 m in the rotation direction of the first piston member 24, and a rear surface 28 n in the rotation direction of the second piston member 28. The combustion chamber B and the combustion chamber D are defined by an inner peripheral surface 4 m of the housing 4, a rear surface 24n in the rotation direction of the first piston member 24, and a front surface 28 m in the rotation direction of the second piston member 28.

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. The clockwise direction in FIG. 3 corresponds to one direction in the embodiment. The combustion chamber A, the combustion chamber B, the combustion chamber C, and the combustion chamber D are arranged in this order in this one direction.

In the combustion chamber A shown in FIG. 3, the air-fuel mixture of the compressed air and the fuel is ignited by self-ignition. 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 only the second piston member 28 can maintain the rotational position of the first piston member 24. Rotate clockwise in the figure in the direction of the broken arrow. In the combustion chamber A, the expansion stroke is such that the gas in the combustion chamber A expands and the volume of the combustion chamber A increases.

When the second piston member 28 rotates in the clockwise direction in the drawing in the direction of the broken line 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 B, the expanded exhaust gas is discharged to the exhaust pipe 8.

On the other hand, the combustion chamber D shown in FIG. 3 communicates with the intake pipe 6. Therefore, the air-fuel mixture is sucked into the combustion chamber D from the intake pipe 6. In the combustion chamber D, the intake stroke is such that the air-fuel mixture is sucked from the intake pipe 6.

The combustion chamber D becomes non-communication with the intake pipe 6 while the second piston member 28 is rotating in the clockwise direction in the drawing in the direction of the broken arrow due to the combustion of the fuel in the combustion chamber A. When the second piston member 28 further rotates, 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. In the combustion chamber D, the compression stroke is such that the air-fuel mixture sucked from the intake pipe 6 is compressed.

In the combustion chamber C shown in FIG. 3, when the second piston member 28 rotates clockwise in the drawing in the direction of the broken line arrow due to the combustion of fuel in the combustion chamber A, the rotation position of the first piston member 24 is changed. As it is maintained, the volume increases. The combustion chamber C communicates with the intake pipe 6 while the second piston member 28 is rotating. 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 C, the intake stroke is such that the air-fuel mixture is sucked from the intake pipe 6.

When a clockwise force acts on the first piston member 24 due to an increase in the pressure in the combustion chamber D, the first piston member 24 rotates, and the positional relationship between the first piston member 24 and the second piston member 28 changes. The positional relationship is shown in FIG.

FIG. 4 is a diagram for explaining an example of the operation of each component member when fuel is burned in the combustion chamber D. FIG. 4 shows a cross section orthogonal to the rotation center axis AX in the central portion of the housing 4, as in FIG. The configuration of the engine 2 shown in FIG. 4 has a positional relationship between the first piston member 24 and the second piston member 28 and the positions and volumes of the combustion chambers A to D as compared with the configuration of the engine 2 shown in FIG. The same is true except that

In the combustion chamber D shown in FIG. 4, the expansion stroke is performed after the compression stroke. That is, in the combustion chamber D, the air-fuel mixture of the compressed air and the fuel is ignited by self-ignition. When the fuel burns in the combustion chamber D, the counterclockwise movement of the second piston member 28 is suppressed by the one-way clutch 26, so that only the first piston member 24 can maintain the rotational position of the second piston member 28. It rotates clockwise and the volume of the combustion chamber D increases as the gas in the combustion chamber D expands.

In the combustion chamber A shown in FIG. 4, the exhaust stroke is performed after the expansion stroke. That is, when the first piston member 24 rotates clockwise due to the combustion of fuel in the combustion chamber D, the rotational position of the second piston member 28 is maintained, so that the volume of the combustion chamber A decreases. At this time, the combustion chamber A communicates with the exhaust pipe 8. Therefore, the exhaust gas in the combustion chamber A is discharged to the exhaust pipe 8 as the volume of the combustion chamber A decreases.

In the combustion chamber B shown in FIG. 4, the intake stroke is performed after the exhaust stroke. That is, when the first piston member 24 rotates clockwise due to the combustion of fuel in the combustion chamber D, the rotational position of the second piston member 28 is maintained, so that the volume of the combustion chamber B increases. At this time, the combustion chamber B communicates with the intake pipe 6 while the first piston member 24 is rotating. Therefore, as the volume of the combustion chamber B increases, the air-fuel mixture is sucked into the combustion chamber B from the intake pipe 6.

In the combustion chamber C shown in FIG. 4, the compression stroke is performed after the intake stroke. That is, when the first piston member 24 rotates clockwise due to the combustion of fuel in the combustion chamber D, the rotational position of the second piston member 28 is maintained, so that the volume of the combustion chamber C decreases. At this time, since the combustion chamber C does not communicate with either the intake pipe 6 or the exhaust pipe 8, the air-fuel mixture in the combustion chamber C is compressed by the decrease in the volume of the combustion chamber C.

Then, when a clockwise force acts on the second piston member 28 due to the increase in the pressure in the combustion chamber C, the second piston member 28 rotates, and the positions of the first piston member 24 and the second piston member 28 are located. The relationship is the positional relationship shown in FIG.

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. In the combustion chamber A, the combustion chamber B, the combustion chamber C, and the combustion chamber D, a cycle consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke is repeated.

<Seal structure>
Hereinafter, the seal structure for maintaining the airtightness in the combustion chambers A to D will be described. FIG. 5 is a schematic view showing the shape of the outer peripheral seal 90. As shown in FIG. 5, the planar shape of the outer peripheral seal 90 is formed into a substantially annular shape, and a joint portion 91 in which a part of the annular shape is divided is formed. Although not shown, the outer peripheral seal 190 is also formed in a substantially annular shape having a joint portion like the outer peripheral seal 90.

FIG. 6 is a cross-sectional view of the first piston member 24 and the second piston member 28. FIG. 6 shows a cross section of the first piston member 24 and the second piston member 28 that include the rotation center axis AX shown in FIG. 2 and passes through the first wall surface member 24b of the first piston member 24. In FIG. 6, the left-right direction in the figure is the axial direction.

The first piston member 24 and the second piston member 28 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 241 is formed in the first piston member 24. A lubricating oil passage 281 is formed in the second piston member 28. The lubricating oil passage 241 and the lubricating oil passage 281 communicate with each other.

As shown in FIGS. 2 and 6, the seal structures for airtightly sealing the combustion chambers A to D include the apex seal 50, the apex seals 80 and 180, the mating surface seal 40, and the corner seal 60. It is provided with outer peripheral seals 90 and 190.

The apex seal 50 is held by the first wall surface member 24b of the first piston member 24. A housing groove 245 is formed in the first wall surface member 24b, and the apex seal 50 is housed in the housing groove 245. The accommodating groove 245 is formed on the edge of the first wall surface member 24b facing the slope portion 28c of the second piston member 28, that is, on the first side 24b1 of the first wall surface member 24b shown in FIG. The apex seal 50 is held on the first side 24b1 of the first wall surface member 24b.

Although not shown, the second wall surface member 28b of the second piston member 28 is also formed with the same accommodating groove as the accommodating groove 245 described above. The second wall surface member 28b holds an apex seal similar to the apex seal 50 described above.

The apex seal 80 is provided as a separate member from the apex seal 50. The apex seal 80 is held by the first wall surface member 24b of the first piston member 24. A housing groove 248 is formed in the first wall surface member 24b, and the apex seal 80 is housed in the housing groove 248. The accommodating groove 248 is formed on the outer peripheral edge of the first wall surface member 24b facing the inner peripheral surface 4 m of the housing 4, that is, on the second side 24b2 of the first wall surface member 24b shown in FIG. The apex seal 80 is held on the second side 24b2 of the first wall surface member 24b.

The apex seal 180 is held by the second wall surface member 28b of the second piston member 28. The second wall surface member 28b is formed with an accommodating groove similar to the accommodating groove 248 described above, and the apex seal 180 is accommodated in the accommodating groove.

The mating surface seal 40 has an annular shape as shown in FIG. The mating surface seal 40 is arranged concentrically with the first piston member 24 and the second piston member 28. As shown in FIG. 6, the mating surface seal 40 is arranged inside the slope portion 28c of the second piston member 28 in the radial direction. The mating surface seal 40 is arranged inside the first wall surface member 24b 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 first piston member 24. An annular groove is formed on the facing surface of the first piston member 24 facing the second piston member 28. A part of the mating surface seal 40 is housed in the annular groove. The mating surface seal 40 has an outer groove portion that is arranged outside the annular groove and projects from the facing surface, and this outer groove portion is in close contact with the second piston member 28. The mating surface seal 40 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.

The corner seal 60 is arranged at the intersection of the mating surface seal 40 and the apex seal 50. The first piston member 24 is formed with a housing recess at the radial inner end of the first wall surface member 24b, and the corner seal 60 is housed in the housing recess. Therefore, the corner seal 60 is held by the first piston member 24 at the radial inner end of the first wall surface member 24b. A spring member 73 is provided on the bottom surface of the accommodating recess, and the spring member 73 urges the corner seal 60 toward the outside of the accommodating recess.

The corner seal 60 has a seal surface 61. The seal surface 61 is in contact with the second piston member 28. The seal surface 61 slides with respect to the second piston member as the first piston member 24 and the second piston member 28 rotate relative to each other. Since the spring member 73 urges the corner seal 60, the adhesion of the seal surface 61 to the second piston member 28 is ensured.

The corner seal 60 is formed with a recess in which a part of the seal surface 61 is recessed. A part of the mating surface seal 40 is arranged in the recess, and the mating surface seal 40 is engaged with the corner seal 60. A slit-shaped insertion portion is formed on the radial outer surface of the corner seal 60. The apex seal 50 is inserted into this insertion portion, and the apex seal 50 is engaged with the corner seal 60. The corner seal 60 connects the apex seal 50 and the mating surface seal 40 so as not to cause a break in the seal.

FIG. 7 is an enlarged cross-sectional view showing the seal structure. As shown in FIG. 7, the apex seal 50 is divided into a main piece 51 and a side piece 52 at its longitudinal end by an inclined surface that is inclined with respect to the longitudinal direction. The apex seal 50 has a longitudinally divided structure having a main piece 51 and a side piece 52.

The length of the side piece 52 in the longitudinal direction of the apex seal 50 is considerably shorter than the length of the main piece 51. In the radial direction (vertical direction in the drawing in FIG. 7), the main piece 51 is arranged on the outside and the side piece 52 is arranged on the inside. A main piece 51 is arranged on the corner portion 24b3 of the first wall surface member 24b instead of the side piece 52.

Bow-shaped spring portions 53 and 54 are installed on the bottom side of the accommodating groove 245 with respect to the main piece 51 and the side piece 52. The spring portions 53 and 54 urge the main piece 51 and the side piece 52 toward the outside of the accommodating groove 245, that is, toward the second piston member 28. As a result, the main piece 51 is in contact with the second piston member 28, more specifically, the slope portion 28c of the second rotating body 28a. The main piece 51 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. The spring portions 53 and 54 also urge the main piece 51 and the side pieces 52 toward both ends in the longitudinal direction thereof.

At its longitudinal end, the apex seal 80 is divided into a main piece 81 and a side piece 82 by an inclined surface that is inclined with respect to the longitudinal direction. The apex seal 80 has a longitudinally divided structure having a main piece 81 and a side piece 82.

The length of the side piece 82 in the longitudinal direction of the apex seal 80 is considerably shorter than the length of the main piece 81. In the axial direction (horizontal direction in the drawing in FIG. 7), the main piece 81 is arranged close to the second piston member 28, and the side piece 82 is arranged away from the second piston member 28. A main piece 81, not a side piece 82, is arranged at the corner portion 24b3 of the first wall surface member 24b.

Bow-shaped spring portions 83 and 84 are installed on the bottom side of the accommodating groove 248 with respect to the main piece 81 and the side piece 82. The spring portions 83 and 84 urge the main piece 81 and the side piece 82 toward the outside of the accommodating groove 248, that is, toward the housing 4. As a result, the main piece 81 and the side piece 82 are in contact with the inner peripheral surface 4 m of the housing 4. As the first piston member 24 rotates in the housing 4, the main piece 81 and the side piece 82 slide with respect to the housing 4. The spring portions 83 and 84 also urge the main piece 81 and the side pieces 82 toward both ends in the longitudinal direction thereof.

The main piece 81 has a sliding surface 81s1 in contact with the housing 4 and an opposite surface 81s2 on the opposite side of the sliding surface 81s1. The end of the main piece 51 on the side not facing the side piece 52 is in contact with the opposite surface 81s2 of the main piece 81. As a result, the corner portion 24b3 of the first wall surface member 24b is sealed by the main piece 51 and the main piece 81.

The orientation of the arrangement of the main piece and the side piece of the apex seal is not necessarily limited to the above contents. For example, the side piece may be arranged on the mating portion side of the apex seal 50 and the apex seal 80, that is, on the corner portion 24b3 side of the first wall surface member 24b.

As shown in FIG. 2, the outer peripheral seal 190 is formed in a substantially annular shape having a joint portion 191. As shown in FIGS. 6 and 7, the outer peripheral seal 190 is held by the second piston member 28.

The outer peripheral seal 190 has a self-tension acting in the diameter-expanding direction. The outer peripheral seal 190 has an outer diameter larger than the diameter of the inner peripheral surface 4 m of the housing 4 in a natural state in which no external force acts on the outer peripheral seal 190. The outer peripheral seal 190 is attached between the second piston member 28 and the housing 4 in a state in which the abutment portion 191 is deformed in the closing direction and the diameter is reduced. As a result, an urging force acts on the outer peripheral seal 190 in the radial direction. This urging force is applied to the outer peripheral seal 190 as a self-tension in the diameter expansion direction. Due to this self-tension, the outer peripheral seal 190 comes into airtight contact with the inner peripheral surface 4 m of the housing 4.

The end of the main piece 81 on the side not facing the side piece 82 is in contact with the outer peripheral seal 190. The urging force that the spring portion 84 acts on the main piece 81 acts so as to press the outer peripheral seal 190 against the second piston member 28. Due to this urging force, the main piece 81 of the apex seal 80 is in airtight contact with the outer peripheral seal 190, and the outer peripheral seal 190 is in airtight contact with the second piston member 28.

The outer peripheral seal 190 is in contact with the apex seal 80, the second piston member 28, and the inner peripheral surface 4 m of the housing 4. In this way, the outer peripheral seal 190 reliably seals the gap between the second piston member 28 and the housing 4.

The apex seals 50 and 80 and the outer peripheral seals 90 and 190 seal 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 the first piston member A seal is provided between the first wall surface member 24b of 24 and the housing 4. The apex seals 50 and 80 and the outer peripheral seals 90 and 190 seal between two combustion chambers adjacent to each other in the circumferential direction, and one of the combustion chambers A to D is adjacent to the one combustion chamber. It suppresses the leakage of gas into the combustion chamber.

As shown in FIG. 2, a part of the apex seal 80 is housed in the abutment portion 91 of the outer peripheral seal 90. One end of the apex seal 80 in the longitudinal direction is composed of a main piece 81, and the one end is in contact with the outer peripheral seal 190. The other end of the apex seal 80 in the longitudinal direction is formed by the side piece 82, and the other end is not in contact with the outer peripheral seal 90 but in contact with the first piston member 24. Therefore, in the cross section showing the entire apex seal 80 in the longitudinal direction shown in FIG. 7, the outer peripheral seal 90 is not shown. In the cross section shown in FIG. 7, the apex seal 180 housed in the abutment portion 91, more specifically, the side piece 82 is shown without being blocked by the outer peripheral seal 90.

The outer peripheral seal 90 and the outer peripheral seal 190 have the same structure. The outer peripheral seal 90 has a self-tension acting in the diameter-expanding direction. The apex seal 180 acts an urging force that presses the outer peripheral seal 90 against the first piston member 24. The outer peripheral seal 90 is in contact with the apex seal 180, the first piston member 24, and the inner peripheral surface 4 m of the housing 4. In this way, the outer peripheral seal 90 reliably seals the gap between the first piston member 24 and the housing 4.

The apex seal, the apex seal 180, and the outer peripheral seals 90 and 190 that come into contact with the slope portion of the first piston member 24 (not shown) are the second wall surface member 28b of the second piston member 28 and the slope portion of the first piston member 24. It seals between the 24c and the second wall surface member 28b of the second piston member 28 and the housing 4. The apex seal, the apex seal 180, and the outer peripheral seals 90 and 190, which are in contact with the slope portion of the first piston member 24 (not shown), seal between two combustion chambers adjacent to each other in the circumferential direction, and the combustion chambers A to A. The leakage of gas from the combustion chamber of one of D to the combustion chamber next to the combustion chamber of the one is suppressed.

As shown in FIG. 2, a part of the apex seal 180 is housed in the abutment portion 191 of the outer peripheral seal 190. One end of the apex seal 180 in the longitudinal direction contacts the outer peripheral seal 90, and the other end of the apex seal 80 in the longitudinal direction does not contact the outer peripheral seal 190 but contacts the second piston member 28. There is.

<Action and effect>
Next, the actions and effects of the above-described embodiments will be described.

The seal structure of the embodiment includes an apex seal 80 and an outer peripheral seal 190, as shown in FIG. As shown in FIGS. 6 and 7, the apex seal 80 is held by the first wall surface member 24b of the first piston member 24, and seals between the first wall surface member 24b and the housing 4. The outer peripheral seal 190 seals between the second piston member 28 and the housing 4. The outer peripheral seal 190 has a self-tension acting in the diameter-expanding direction. The outer peripheral seal 190 is formed in an annular shape, and a joint portion 191 in which a part of the annular shape is divided is formed. The outer peripheral seal 190 is configured so that the abutment portion 191 is positioned at a position where it does not overlap with the apex seal 80 in the circumferential direction and rotates integrally with the second piston member 28.

The outer peripheral seal 190 follows the rotation of the second piston member 28 and rotates integrally with the second piston member 28. The abutment portion 191 of the outer peripheral seal 190 is positioned outside the range R (FIG. 2) in which the apex seal 80 can move relative to the first piston member 24 in the circumferential direction. Since the apex seal 190's abutment portion 191 that rotates is always outside the movable range of the apex seal 80, the apex seal 80 does not get caught in the apex seal 191. By maintaining the sealability of the apex seal 80, the sealability of the engine 2 can be improved.

As shown in FIG. 2, the second piston member 28 has a second wall surface member 28b. The abutment portion 191 is positioned within a range in which the second wall surface member 28b exists in the circumferential direction. As a result, the abutment portion 191 can be reliably positioned at a position that does not overlap with the apex seal 80 in the circumferential direction. Since the abutment portion 191 does not exist at a position communicating with each of the combustion chambers A to D, gas leakage from the abutment portion 191 is suppressed, and therefore the combustion efficiency of the engine 2 can be improved.

As shown in FIG. 2, the seal structure further comprises an apex seal 180. The apex seal 180 is held by the second wall surface member 28b and seals between the second wall surface member 28b and the housing 4. A part of the apex seal 180 is housed in the abutment portion 191 of the outer peripheral seal 190. By positioning the outer peripheral seal 190 using the apex seal 180, the configuration of the engine 2 can be simplified.

[Second Embodiment]
FIG. 8 is a perspective view of the piston member showing the seal structure of the second embodiment. The seal structure for airtightly sealing the combustion chambers A to D in the second embodiment further includes a corner seal 96 and a corner seal 196.

The corner seal 96 is arranged in the abutment portion 91 of the outer peripheral seal 90. A groove is formed in the corner seal 96, and a part of the apex seal 80, typically a part of the side piece 82, is housed in the groove. One end of the apex seal 80 in the longitudinal direction is in contact with the outer peripheral seal 190, and the other end of the apex seal 80 in the longitudinal direction is in contact with the corner seal 96.

The corner seal 196 is arranged in the abutment portion 191 of the outer peripheral seal 190. A groove is formed in the corner seal 196, and a part of the apex seal 180, typically a part of the side piece, is housed in the groove. One end of the apex seal 180 in the longitudinal direction is in contact with the outer peripheral seal 90, and the other end of the apex seal 180 in the longitudinal direction is in contact with the corner seal 196.

In the seal structure of the second embodiment, the corner seal 196 is used to position the outer peripheral seal 190. Even with such a configuration, the abutment portion 191 can be positioned at a position that does not overlap with the apex seal 80 in the circumferential direction, and therefore the sealing property can be improved.

[Third Embodiment]
FIG. 9 is a perspective view of the first piston member 24 in the third embodiment. The first wall surface member 24b and the second wall surface member 28b are not limited to the triangular plate-like shape described in the first embodiment. The first wall surface member 24b and the second wall surface member 28b may have a quadrangular plate shape, for example, as shown in FIG. The first wall surface member 24b shown in FIG. 9 has a second side 24b2 facing the housing 4, a first side 24b1 facing the second rotating body 28a of the second piston member 28, and a third side 24b4. ing. The first wall surface member 24b has a corner portion 24b3 where the first side 24b1 and the second side 24b2 intersect, and a corner portion 24b5 where the first side 24b1 and the third side 24b4 intersect.

Alternatively, the first wall surface member 24b may have any square shape having a corner portion 24b3 where the first side 24b1 and the second side 24b2 intersect.

FIG. 10 is a schematic view of the seal structure according to the third embodiment. The seal structure shown in FIG. 10 is held by a pair of apex seals 50 held on the first side 24b1 of the first wall surface member 24b and in contact with the second piston member 28, and held on the second side 24b2 of the first wall surface member 24b. It includes a pair of apex seals 80 that come into contact with the housing 4. The pair of apex seals 50 are arranged side by side at intervals in the circumferential direction. The pair of apex seals 80 are arranged side by side at intervals in the circumferential direction. The first wall surface member 24b holds a plurality of apex seals 80 arranged in the circumferential direction.

The outer peripheral seal 90 has a joint portion 191 as in the first embodiment. The protrusion 98 is housed in the abutment 191. The protrusion 98 is formed by projecting a part of the second piston member 28 in the radial direction. The protrusion 98 constitutes a part of the second piston member 28, and when the second piston member 28 rotates, the protrusion 98 also rotates.

The protrusion 98 is provided within a range in which the first wall surface member 24b exists in the circumferential direction. The protrusion 98 is arranged between the pair of apex seals 80 in the circumferential direction. Typically, the protrusion 98 is arranged at an intermediate position with respect to both end faces of the first wall surface member 24b in the circumferential direction.

With the seal structure of the third embodiment having such a configuration, the abutment portion 191 is positioned at a position where it does not overlap with the apex seal 180 held by the second wall surface member 28b of the second piston member 28 in the circumferential direction. Therefore, the sealing property can be improved.

Compared with the configuration described in the first embodiment in which the first wall surface member 24b holds one apex seal 80, the first wall surface member 24b of the second embodiment holds a plurality of apex seals 80 arranged in the circumferential direction. Is formed wider. The first wall surface member 24b of the second embodiment has a larger size in the circumferential direction than that of the first embodiment. In the first wall surface member 24b of the second embodiment, the protrusion 98 is provided at a position corresponding to the central portion in the circumferential direction of the first wall surface member 24b, and is provided at the central portion in the circumferential direction of the first wall surface member 24b. The abutment portion 191 is positioned at a corresponding position. As a result, the abutment portion 191 can be arranged at a position farther from the combustion chamber, and gas leakage from the abutment portion 191 can be reduced more reliably, so that the combustion efficiency of the engine 2 can be further improved.

Although each embodiment has 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, 4m inner peripheral surface, 24 1st piston member, 24a 1st rotating body, 24b 1st wall surface member, 28 2nd piston member, 28a 2nd rotating body, 28b 2nd wall surface member, 40 mating surface Seal, 50, 80, 180 Apex seal, 51, 81 Main piece, 52, 82 Side piece, 53, 54, 83, 84 Spring part, 60, 96, 196 Corner seal, 61 Seal surface, 73 Spring member, 81s1 slide Moving surface, 81s2 opposite surface, 90,190 outer peripheral seal, 91,191 abutment, 98 protrusion, A, B, C, D combustion chamber, AX rotation center axis, R range.

Claims (4)

It is a seal structure used for internal combustion engines.
The internal combustion engine
Cylindrical housing and
A first piston member rotatably supported in one direction around the center of rotation in the housing.
The housing includes a second piston member rotatably supported in one direction around the center of rotation.
The housing, the first piston member, and the second piston member form a combustion chamber for burning fuel.
The first piston member has a wall surface member that forms a wall surface in the circumferential direction of the combustion chamber.
The seal structure is
An apex seal that is held by the wall surface member and seals between the wall surface member and the housing.
It is provided with an outer peripheral seal that seals between the second piston member and the housing.
The outer peripheral seal has a self-tension acting in the diameter-expanding direction.
The outer peripheral seal is formed in an annular shape, and a joint portion in which a part of the annular shape is divided is formed.
The outer peripheral seal has a seal structure in which the abutment portion is positioned at a position that does not overlap with the apex seal in the circumferential direction and rotates integrally with the second piston member. The second piston member has a second wall surface member that forms a wall surface in the circumferential direction of the combustion chamber.
The seal structure according to claim 1, wherein the abutment portion is positioned within a range in which the second wall surface member exists in the circumferential direction. The seal structure further comprises a second apex seal that is held by the second wall member and seals between the second wall member and the housing.
The seal structure according to claim 2, wherein a part of the second apex seal is housed in the abutment portion. The second piston member has a protrusion in which a part thereof protrudes.
The seal structure according to claim 1, wherein the protrusion is housed in the abutment.

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