JP4357922B2 - Rotary valve seal structure - Google Patents

Description

  The present invention relates to a seal structure for a rotary valve, and more particularly, to a seal structure for a rotary valve provided in an intake manifold that is an intake path of an internal combustion engine.

  In an internal combustion engine such as an automobile engine, an intake manifold (intake pipe) is provided with an open / close switching type rotary valve, and equipped with a variable intake device that can obtain a suitable intake situation in both a low speed range and a high speed range. There is. In other words, the intake manifold's inertial supercharging effect is effective in both the low and high speed regions by switching the intake manifold path length in two stages according to the low and high rotation speed regions of the internal combustion engine by opening and closing the rotary valve. It is made available. As an example of such a variable intake device, the one disclosed in Patent Document 1 is known.

  This comprises a rotor in which a passage for fluid transfer is formed and a casing that rotatably accommodates the rotor, and a pair of ports formed in the casing by the rotational movement of the rotor is the passage. The rotary valve is configured to be switchable between an open state in which communication is performed and a closed state in which communication of the port is blocked. The rotary valve is disposed at an intermediate portion of the intake manifold.

  That is, if the rotary valve is closed, the intake pipe length is set to the length of the intake manifold shape, and if the rotary valve is opened, the intake manifold length is shortened by short-circuiting the intermediate portions of the intake manifold. , The structure. In this case, the casing that rotatably accommodates the rotor of the rotary valve is also configured as a structure (the one in Patent Document 1 is made of synthetic resin) that forms an intake manifold.

  In the rotary valve, the rotor is equipped with a seal member for sealing the gap with the casing and switching the open and closed states clearly. As shown in FIG. 12, the conventional rotor has a cylindrical rotor body 101 in which a plurality of intake passages 102 each having a square cross section are formed in a parallel state, and an opening portion of the intake passage 102 in the rotor body 101. It is comprised from the sealing member 103 equipped so that it may surround.

The seal member 103 is composed of a pair of ring portions 103a and a linear portion 103b along the rotational axis P direction of the rotor to connect the ring portions 103a, and fits into a groove formed in the rotor body 101. Each intake passage 102 is fitted. That is, in the case of a four-cylinder engine, four intake passages 102 and four seal members 103 are provided. Reference numeral 104 denotes a support body that rotatably supports the rotor body 101, and reference numeral 105 denotes a drive switching mechanism (such as a negative pressure diaphragm type) for driving and rotating the rotor body 101. 104 is integrally formed.
JP-A-7-253063

  In a rotary valve having a rotor with such a structure, in order to obtain a reliable sealing action, the sealing member is always in press contact with the cylindrical inner peripheral surface of the casing, and resists frictional resistance caused by the press contact. The rotor must be rotated. Therefore, a relatively large output is required as a drive source for the rotation operation, which is disadvantageous in cost and tends to be large in size.

  Since the contact member is always in contact, the seal member having high wear resistance is required to have excellent durability, and in that respect, the cost tends to be high. Further, in order to improve the sealing performance, it is preferable that the material of the sealing member is made of rubber.

  The purpose of the present invention is to reduce the cost of the drive system and reduce the size of the rotary valve, such as the above-described rotary valve seal structure, while maintaining good sealing performance, making the rotation operation light and requiring only a small drive device. It is in the point to be able to plan. In addition, another object is to improve the sealing performance by reviewing the material of the sealing member.

The configuration of claim 1 includes a rotor in which a passage for fluid transfer is formed and a casing that rotatably accommodates the rotor, and a pair of ports formed in the casing by the rotational movement of the rotor. In a seal structure of a rotary valve configured to be switchable between an open state in which communication is established in the passage and a closed state in which communication of the port is blocked,
The passage is formed to be orthogonal to the rotational axis of the rotor,
The rotor includes a rotating axis in a circular cross section, the contact surface portion for blocking the rotor body and is the same center of curvature, the communication of the port by repression contacting the peripheral portion of the port before Symbol casing A loop-shaped rubber seal member having
The casing is formed in a stepped hole combining two semicircular arcs whose respective centers are deviated from the rotational axis of the rotor,
The seal member is formed in an arc shape having a center different from the semicircular arc of the casing in a direction view along the rotation axis of the rotor, and an outer peripheral surface of the contact surface portion is formed in an opening direction of the rotor. as to become part upstream side in the inclined shape so as to approach the rotational axis of the rotor have characterized Rukoto of.

The structure of claim 2 is the structure of claim 1,
The rotor body is formed with an annular groove and a straight groove corresponding to the rectangular hole-shaped passage, and the seal member is a substantially square loop-shaped gasket fitted into the annular groove and the straight groove, The gasket includes a pair of arc seal portions fitted into the annular groove and a pair of linear seal portions fitted into the linear groove, and the arc seal portion and the linear seal portion have a cross-sectional shape in the width direction. It is characterized by being formed in a triangular shape that becomes higher at the center .

The structure of claim 3 is the structure of claim 2,
Undercut protrusions are integrally formed at substantially four corners of the gasket, and mounting holes into which the undercut protrusions can be press-fitted are formed in the linear grooves .

Configuration according to claim 4, Oite to any one of claims 1 to 3,
The pair of ports communicate with each other at two different locations in the middle portion of the intake manifold of the internal combustion engine. In the closed state, the middle portions at the two locations communicate with each other only through the intake manifold, and the opening In a state, it is characterized in that the middle part of the two places is configured to be short-circuited via the rotor .

The structure of claim 5 is the structure of claim 4,
The intake manifold is formed in a curved shape, and a structure for forming the curved manifold portion so that a pair of the ports are connected to the start end side and the terminal end side of the curved manifold portion, respectively. A casing is constituted .

  In the configuration of claim 1, the contact surface portion between the peripheral portion and the seal member, that is, the contact surface portion between the rotor or the casing and the seal member is closer to the outer side surface of the rotor in the opening direction of the contact surface portion. In the closed state, the rotor or the casing and the seal member are pressed and contacted by tilting the rotor closer to the rotational axis of the rotor, the gap between the rotor and the casing is sealed, and the closed state is changed to the open state. As the rotor moves in the opening direction, the contact between the rotor or casing and the seal member is released.

  Thus, in the closed state where the passage is blocked, the rotor and the casing are well sealed, and the rotor operation range is changed from the closed state to the open state to the open state. In most of the range, the rotor or casing and the seal member are not in contact with each other. Further, since the seal member is provided on the outer peripheral portion of the rotating rotor, the seal member can be easily and conveniently attached and detached from the outer diameter side of the rotor.

As a result, the frictional resistance due to the contact of the seal member hardly acts as compared with the conventional seal structure in which the seal member is always in contact while maintaining a good sealing performance in the closed state, and the rotational operation force of the rotor Can be greatly reduced, and the drive switching mechanism can be reduced in output and size. Moreover, since the seal member is made of rubber, the sealing function is clearly improved and the shutoff performance of the rotary valve can be improved as compared with the case of using a conventional synthetic resin material. That is, in the conventional always-contact structure, if the sealing member is made of rubber to improve the shut-off function, the frictional resistance increases and the rotational operation force of the rotor becomes heavier, and the durability of the rubber is not good. For this reason, there were problems with durability and reliability, which were difficult to realize. Nevertheless, as in the present invention, only the sealing member in a state near the closed have a configuration that pressure contact, is to solve the aforementioned problems such as poor Toka durability turning operation force becomes heavy As a result, an improved sealing structure is realized that only provides the advantage of excellent sealing properties with rubber.

Furthermore, since the shape of the contact surface portion in the direction along the rotation axis is set to an arc shape centered on another axis provided near the rotation axis, the seal member is pressed in the closed state. effective sealing features will leave be exhibited, while exhibit the previous SL effect, can be suppressed overhang amount of the outer diameter direction of the rotor rotation axis of the sealing member (or a part of the rotor) ( in comparison with the structure shown in FIG. 11 easy to understand), there is an advantage capable of promoting miniaturization of rotary valve.

In the configuration of the fourth aspect , the following effects can be obtained. That is, in order to obtain an intake inertia effect at both low speed and high speed in an intake manifold length in an internal combustion engine such as an automobile engine, in particular, in the low speed range where the intake path length is long, the intake air is slightly But because it is difficult to obtain effective when communicating short, high cutoff function for rotary valves are required.

Thus, as described above, in the Rotary valve according to the present invention, since the sealing member is out of contact in most rotational operation zone, in the closed state in such to press strongly than ever higher seal Therefore, it is possible to provide an optimum rotary valve seal structure for switching between the intake manifold and the short, which requires a high valve shut-off function in a low speed range.

In the structure of claim 5, by bending the intake manifold, because are then combined constitute the casing of Rotary valves, it is possible to reduce costs by reducing the component parts of Rotary valve in the intake manifold with Rotary Valve Miniaturization as a variable intake device is also possible.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic exploded perspective view of a variable intake device (intake manifold with a rotary valve) used in a four-cylinder engine of an automobile, and FIGS. 2 and 3 are cross-sectional views of main parts showing a closed state and an opened state of the rotary valve. 4 is a perspective view showing a part of the rotor, FIGS. 5 and 6 are schematic cross-sectional side views showing the operation of the rotary valve, and FIG. 7 is a cross-sectional side view showing the mounting structure of the seal member, FIG. , 9 are cross-sectional views showing the cross-sectional shape of a gasket as a seal member, and FIG. 12 is a perspective view showing a conventional rotor structure.

  The variable intake device A according to the present invention corresponds to a four-cylinder engine as shown in FIGS. 1 to 3, and includes four sets of intake manifolds 14 arranged in parallel and an intake passage forming a casing 4 of the rotary valve 1. The structure 11 and the rotor 3 and the like that are rotatably accommodated in the casing 4 are configured.

  The intake passage structure 11 is formed by welding a plurality of (three) joint members made of synthetic resin to each other, and includes a surge tank portion 13 that forms the intake chamber 12 and an intake passage that is connected to the intake chamber 12. Four mutually independent branch pipe parts 15 whose one ends are commonly connected to the surge tank part 13 and engines connected in common to the other ends of the respective branch pipe parts 15 so as to form the manifolds 14 ( And a mounting flange 16 and the like.

  An air inlet 17 is provided at one end of the surge tank 13 along the arrangement direction of the branch pipes 15. An air cleaner is connected to the air inlet 17 via a throttle body (not shown). An amount of air corresponding to the throttle opening in the body is introduced into the intake chamber 12. Each branch pipe part 15 whose one end is connected to the lower part of the surge tank part 13 is formed so as to bend in a substantially C shape and is arranged in parallel in the horizontal direction, and is connected to the other end of each branch pipe part 15. The provided mounting flange 16 is positioned above the surge tank portion 13.

  The intake passage structure 11 is provided with a bypass passage 18 having one end opened to the intake chamber 12 and the other end opened to an intermediate portion of the intake manifold 14, and the bypass passage 18 and the intake manifold 14 from the intake chamber 12 are provided. The intake path length from the end portion to the engine is set shorter than the intake path length from the intake chamber 12 through the intake manifold 14 to the engine.

  This is because the intake path length in the intake passage structure 11 is switched between long and short by switching the communication / blocking of each bypass passage 18 according to the engine speed, and the rotary that switches the communication / blocking of each bypass passage 18. The valve 1 is formed integrally with the intake passage structure 11.

That is, as shown in FIGS. 2 and 5, when switched to the closed state Rotary valve 1 with rotation operation in the closing direction of the rotor 3, the middle portion of the two portions of the intake manifold 14, only intake manifold 14 It is set to a long intake path length communicated via Then, 3 and 6, if the open state of the Rotary valve 1 with rotation operation in the opening direction of the rotor 3, the middle portion of the two portions of the intake manifold 14, passage of the rotor 3 2 Is set to a short intake path length that is short-circuited in the bypass passage 18. In the open state of the Rotary valve 1, not only the bypass passage 18, but communicates with even the intake manifold 14 which is curved, the air that has been sucked from passing through the shortest path, through all substantially the bypass passage 18 It will be.

  As shown in FIGS. 1 to 7, the rotary valve 1 includes a rotor 3 in which a passage 2 for transferring atmospheric air (an example of a fluid) is formed, and a casing 4 that rotatably accommodates the rotor 3. As the rotor 3 rotates, the pair of ports 5 and 6 formed in the casing 4 communicate with each other in the passage 2 (see FIG. 3), and the port 5 and 6 communicate with each other in a closed state (see FIG. 3). 2). The casing 4 is formed integrally with a part of the intake passage structure 11 described above, and the rotor 3 is rotatably accommodated in the cylindrical valve hole 21.

  The rotor 3 is composed of a substantially cylindrical rotor body 7 through which four passages 2 are formed, and a total of eight gaskets (an example of a seal member) 8 attached to the rotor body 7. A drive rotation mechanism 9 for rotating the rotor 3 is provided on the side. As shown in FIG. 4 (see also FIG. 10), the rotor body 7 has a pair of left and right annular grooves 7a and four linear grooves 7b formed in a direction along the rotation axis P, and are square holes. It is formed corresponding to the channel 2. That is, the rotor body 7 is formed to have a disc portion 7A having an annular groove 7a and a hole wall 7B having linear grooves 7b at both ends, and the rotational force of the drive rotation mechanism 9 is formed at one end thereof. The receiving crank arm 10 is attached via a rotating shaft 19, and only the rotating shaft 19 is provided at the other end.

  As shown in FIGS. 4 to 7, the gasket 8 can seal between the peripheral portion between the pair of openings of the passage 2 in the rotor body 7 and the peripheral portions of the ports 5 and 6 in the casing 4. It has a substantially square loop shape, and has a pair of arc seal portions 8a fitted into the annular groove 7a and a pair of straight seal portions 8b fitted into the straight grooves 7b. That is, the structure has a pair of gaskets 8 per intake manifold, and a total of eight gaskets 8 are provided in the rotor body 7 in the case of four cylinders. Although not shown, the pair of gaskets 8 may be configured as a single ring-shaped gasket by integrating the arc seal portions 8a in a ring shape. The bond strength with the main body 7 can be made stronger.

The gasket 8 is made of rubber, and the top portions of the seal portions 8a and 8b are formed in a triangular shape that becomes higher toward the center in the width direction as shown in FIGS. It is like that. Moreover, the bottom part of each seal part 8a, 8b is made high in the center part in the width direction, and the cavity part k is formed in a groove bottom. As a result, the spring constant of the gasket 8 when pressed against the casing 4 is lowered compared to the case where there is no hollow portion k, and a sufficient tightening margin can be secured even with a low reaction force, thereby realizing a good sealing performance. As a structure that can contribute. Material rubber, oil resistance, but are as NBR in consideration of the operating temperature (the upper limit 100 ° C.), have good other than it.

  As shown in FIGS. 7 and 9, the gasket 8 is fixed to the rotor body 7 by integrally forming undercut protrusions 8 c at substantially four corners of the gasket 8, and in the corresponding linear grooves 7 b of the rotor body 7. A structure for forming the mounting hole 7c is conceivable. The arc seal portion 8a and the straight seal portion 8b have substantially the same width as the groove widths of the grooves 7a and 7b. That is, the undercut protrusion 8c is forcibly inserted into the mounting hole 7c so that the undercut protrusion 8c is attached to the rotor body 7 in a state of being prevented from coming off. In FIG. 4, only one of the pair of gaskets 8 is depicted.

  The fixing means may be means for holding the gasket 8 on the rotor body 7 by setting the annular groove 7a and the linear groove 7b to be slightly narrow and forcibly inserting the seal portions 8a and 8b. Further, as indicated by phantom lines in FIG. 8, a recessed portion 7d that is partially recessed is formed on the side wall of each groove 7a, 7b, and a lateral protruding portion 8d that fits into the recessed portion 7d is formed as a gasket. It is also possible to have a means for holding the protrusion 8d in a state where it is prevented from coming off by forcibly inserting the lateral protrusion 8d into the recess 7d.

Next, the relationship between the gasket 8 and the casing 4 will be described. As shown in FIGS. 5 to 7, in the closed state Rotary valve 1, and the peripheral portion 20 and the gasket 8 for each port 5,6 of the casing 4 is in pressure contact, the rotor 3 (the rotor body 7) around Between the portion 20, that is, the hole wall 7 </ b> B and the casing 4 are sealed, and the casing 4 and the gasket 8 are moved along with the rotational movement of the rotor 3 in the opening direction so as to shift from the closed state to the open state. The contact surface portion sm between the peripheral portion 20 and the gasket 8 is moved toward the outer surface of the rotor 3 with respect to the outer surface of the rotor 3 in the opening direction of the contact surface portion sm (see arrow A in FIG. 6). The rotor 3 is tilted so as to approach the rotation axis P of the rotor 3.

  Specifically, as shown in FIG. 5, FIG. 6, etc., the outer diameter R <b> 8 of the gasket 8 is made somewhat larger than the outer diameter R <b> 7 of the rotor body 7, and its first center position (an example of another axis) ) X is set in the vicinity of the rotation axis P and on the first straight line S1 inclined 45 degrees with the longitudinal direction of the passage 2 in FIG. 6 (the direction connecting the ports 5 and 6 with straight lines). It is. The valve hole 21 of the casing 4 is inclined at 45 degrees with respect to the longitudinal direction of the passage 2 and on the second straight line S2 inclined at 90 degrees with the first straight line S1 and near the rotation axis P. A second center position (an example of another axis) set at 2 is formed in a stepped hole having two semicircular arc surfaces 21a having an inner diameter R4 having the same dimension as the outer diameter R8 of the gasket 8.

That is, the contact surface portion sm is formed by the outer peripheral surface centering on the first axis X of the gasket 8 and the peripheral portions 20 of the ports 5 and 6 on the inlet side and outlet side of the casing 4. The inner diameter R4 may be set slightly smaller than the outer diameter R8 in anticipation of the amount of elastic displacement caused by the pressing of the gasket 8. Figures 5 and 6 are views for explaining each state of the Rotary valve 1, also includes part due how to draw not in accordance with the drawing method.

Thus, in the state Rotary valve 1 is closed, as shown in FIG. 5, each gasket 8 presses in contact with each half arcuate surface 21a of the casing 4, good sealing properties, i.e. the bypass passage 18 of the precision A good shut-off state is obtained. Then, from its closed state, in order to state Open Rotary valve 1, when the rotating operation in the direction (arrow b direction in FIG. 6) open the rotor 3, a first center X is an outer diameter center of the gasket 8 Due to the eccentric structure in which the second center Y, which is the center of the inner diameter of the semicircular arc surface 21a, is displaced by 90 degrees, the gasket 8 gradually moves away from the semicircular arc surface 21a.

  As a result, when the valve 8 is slightly moved in the direction of arrow A from the closed state shown in FIG. 5, the contact between the gasket 8 and the semicircular arc surface 21a is released, and in the opened state rotated about 90 degrees as shown in FIG. The gasket 8 and the semicircular arc surface 21a are in a positional relationship farthest in the radial direction. That is, the gasket 8 and the valve hole 21 are maintained in a non-contact state in the most angular range from the open state to the closed state, out of all the rotational movement angles from the open state to the closed state. Even if the gasket 8 is made of rubber having excellent sealing performance, its high frictional resistance hardly acts, so that the rotary valve 1 can be operated lightly, but it has succeeded in obtaining high sealing performance in the closed state. Yes.

The second axis Y, which is the center of each semicircular arc surface 21 a of the valve hole 21, is a fixed axis with respect to the casing 4, but the first axis X, which is the center of the outer peripheral surface of the gasket 8, is the rotor body. 7 is a movable axis that moves as the rotor body 7 rotates. Thus, as in the present embodiment, in the opened state and a closed state is switched by rotating operation of 90 degrees of the rotor 3 structure, in the closed state Rotary valve 1 shown in FIG. 5, the first axis X is It matches the second axis Y, in the opened state of the rotary valve 1 shown in FIG. 6, the first axis X relative to the pivot axis P is located at a position moved by 90 degrees from the second axis Y ing.

  Accordingly, the drive rotation mechanism 9 can be made to have a smaller output and a smaller size than before, and the cost can be reduced and the space can be saved. The material of the gasket 8 is changed from resin to rubber. The sealability can be improved, and the pressing contact status is limited to the closed state and the rotation position in the vicinity thereof, so the frictional resistance due to contact can be greatly reduced, and while it is a rubber gasket, it is made of synthetic resin. There is also an advantage that durability superior to the one can be obtained.

  As a sealing structure of the rotary valve 1, as shown in FIG. That is, since the sealing performance of the gasket 8 is improved, sufficient path blocking performance in the closed state can be obtained even with this single seal structure. If the material of the gasket 8 is made of rubber, the sealing performance is improved, which is more preferable. In this single seal structure, the number of gaskets 8 can be halved from eight to four, so that further cost reduction and a lighter rotating operation state are possible.

Figure 11 is an exemplary embodiment of the present invention, the sealing structure of the rotary valve 1 is in the closed Ji state, she seals the outer surface 8e of the gasket 8, tangent to pivot axis P of the thin ends of their most radially thickness In the opening direction of the rotor body 7 (arrow A direction), the upper side is set to be an obtuse angle (90 + α degrees) approaching the rotation axis P, or a right angle, and is linear in the direction of the rotation axis. It is supposed to be .
Even in this configuration, when the rotor 3 is further rotated from the closed state to the direction opposite to the direction of the arrow A, the gasket 8 is more pressed against the valve hole 21 of the casing 4.

  Then, if the rotor 3 is rotated in the direction of the arrow B from the closed state, the gasket 8 is separated from the peripheral portion of the port 6 of the casing 4 immediately after that, so that the rotation by friction between the gasket 8 made of rubber and the casing 4 is performed. There is no dynamic resistance. As a result, a reliable sealing performance is obtained while the rotor 3 is easily rotated, and the sealing structure is durable and reliable.

In the above example, when the intake path length of the intake manifold 14 is long, but a structure with an emphasis on the first seal of Rotary valve (path-blocking property), for example, if the intake path length of the intake manifold 14 is short , i.e., in the case or the like which require sealing property in the state of opening of the rotary valve 1 (see FIG. 6), equipped with a gasket 8 around the portion of the opening of the passage 2, the gasket 8 when the open state is It is also possible to adopt a structure in which the casing 4 is in press contact with the peripheral portions 20 of the ports 5 and 6.

Partially exploded perspective view of variable intake device Side view of the intake manifold showing a closed state Rotary Valve Side view of the intake manifold showing a state opened Rotary Valve Exploded perspective view showing the structure of the rotor end Principle view showing a sealing structure in the closed state Rotary valve (Example 1) Principle view showing a sealing structure of a state opening Rotary valve (Example 1) Sectional view of the rotary valve shown a mounting state of the gasket Sectional drawing of the principal part which shows the fitting structure to the rotor groove | channel of a gasket Sectional view of the main part showing the mounting structure of the gasket to the rotor Principle view showing a sealing structure of Rotary valves (Example 2) Principle view showing a reference example of a seal structure for Rotary valves (Example 3) A perspective view showing a conventional rotor body and a seal member

Explanation of symbols

1 Rotary valve 2 passage 3 rotor 4 casing 5 and 6 ports
7 Rotor body 8 Seal member 11 Structure 14 Intake manifold 20 Surrounding portion sm Contact surface portion P Rotating axis X, Y Separate axis

Claims (5)

The rotor is formed with a fluid transfer passage and a casing that rotatably accommodates the rotor, and a pair of ports formed in the casing are communicated with each other by the rotation of the rotor. A rotary valve seal structure configured to be switchable between an open state and a closed state in which communication of the port is blocked,
The passage is formed to be orthogonal to the rotational axis of the rotor,
The rotor includes a rotating axis in a circular cross section, the contact surface portion for blocking the rotor body and is the same center of curvature, the communication of the port by repression contacting the peripheral portion of the port before Symbol casing A loop-shaped rubber seal member having
The casing is formed in a stepped hole combining two semicircular arcs whose respective centers are deviated from the rotational axis of the rotor,
The seal member is formed in an arc shape having a center different from the semicircular arc of the casing in a direction view along the rotation axis of the rotor, and an outer peripheral surface of the contact surface portion is formed in an opening direction of the rotor. The seal structure of the rotary valve which makes it the shape inclined so that the part which becomes the nearer side may approach the said rotation axis of the said rotor . In claim 1,
The rotor body is formed with an annular groove and a straight groove corresponding to the rectangular hole-shaped passage, and the seal member is a substantially square loop-shaped gasket fitted into the annular groove and the straight groove, The gasket includes a pair of arc seal portions fitted into the annular groove and a pair of linear seal portions fitted into the linear groove, and the arc seal portion and the linear seal portion have a cross-sectional shape in the width direction. The rotary valve seal structure is formed in a triangular shape that becomes higher at the center. In claim 2,
A seal structure for a rotary valve in which undercut protrusions are integrally formed at substantially four corners of the gasket, and mounting holes into which the undercut protrusions can be press-fitted into the linear grooves. In any one of Claims 1-3,
The pair of ports communicate with each other at two different locations in the middle portion of the intake manifold of the internal combustion engine. In the closed state, the middle portions at the two locations communicate with each other only through the intake manifold, and the opening In the state, a seal structure of the rotary valve configured so that the intermediate part of the two places is short-circuited via the rotor. In claim 4,
The intake manifold is formed in a curved shape, and a structure for forming the curved manifold portion so that a pair of the ports are connected to the start end side and the terminal end side of the curved manifold portion, respectively. Rotary valve seal structure with casing.

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