JP2005207390A - Motion converting structure of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To increase a power take-out efficiency in a motion converting structure of a piston type internal combustion engine in which at least compression ratio is made variable among the compression ratio and displacement. <P>SOLUTION: A first crankshaft 24 can specify the position of a piston 13 at a dead center in association with the piston 13. A variable compression ratio mechanism 30 changes the position of the piston at the dead center to make variable at least the compression ratio among the compression ratio and the displacement. In this structure, the first crankshaft 24 is installed separately from an output shaft 15. A swing link member 18 is swung according to the reciprocating linear motion of the piston 13 and its swing is transmitted to the output shaft 15 through a one-way clutch 17. The one-way clutch 17 arrests the swing of the swing link mechanism 18 transmitted to the output shaft 15 in one direction. The first crankshaft 24 acts so as to return the piston 13 from a bottom dead center to a top dead center. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a motion conversion structure for extracting power by converting a reciprocating linear motion of a piston into a rotational motion of an output shaft in an internal combustion engine in which at least the compression ratio of the compression ratio and the displacement is variable.

  As such a motion conversion structure of an internal combustion engine, for example, those shown in Patent Document 1 and Patent Document 2 are known. In these motion conversion structures, the piston and the crankshaft are linked via a plurality of link members. The reciprocating linear motion of the piston is converted into rotational motion of the crankshaft through these link members, and this is taken out as rotational power.

  In the above structure, the crankshaft is used not only for taking out such power but also for restricting the movement trajectory of the link member described above. In other words, in this structure, the movement trajectory of the link member is restricted to that corresponding to the displacement of the crankpin accompanying the rotation of the crankshaft, thereby defining the position of the piston at the top dead center and the bottom dead center. The ratio and the exhaust amount are set to a predetermined size.

In the above structure, a link member other than the plurality of link members is connected to one of the plurality of link members that link the piston and the crankshaft, and the support position and posture of the other link member are connected. By changing the above, the movement trajectory restricted by the crankshaft can be changed. By changing the movement locus, the position of the piston at the top dead center or the bottom dead center is shifted, and at least the compression ratio of the compression ratio and the exhaust amount is changed.
Japanese Patent Laid-Open No. 2003-13764 Japanese Patent Laid-Open No. 2-19621

  However, in both the above-described structures, the crankshaft is used as a member (dead center defining member) for defining the position of the piston at the top dead center and the bottom dead center, and the crankshaft is further used to extract rotational power. It is also used as the only output shaft.

  When the rotational power is continuously extracted in the above structure, in many cases, it is necessary to continuously rotate the crankshaft by 360 degrees or more in one direction based on repeated reciprocating linear motion of the piston. . However, in this case, there may be a moment when the moment arm length for rotating the crankshaft becomes “0” in the vicinity of the top dead center. In such a structure, the efficiency for rotating the crankshaft near the top dead center is reduced. Especially when the crankshaft is used as the only output shaft as in the same configuration, the crankshaft is rotated. This is not convenient because a particularly large moving force is required in the piston.

  The present invention has been made in view of such circumstances, and an object thereof is to increase the power extraction efficiency in a motion conversion structure of a piston-type internal combustion engine in which at least the compression ratio of the compression ratio and the displacement is variable. is there.

In the following, means for achieving the above object and its effects are described.
First, the invention according to claim 1 is a motion conversion structure of an internal combustion engine that takes out power by converting a reciprocating linear motion of a piston in a cylinder formed in an engine body into a rotational motion of an output shaft, Linked with at least one of the plurality of link members, and a dead center defining member capable of defining the position of the piston at the dead point by coordinating with the piston via a link member and restricting the movement trajectory of these link members The internal combustion engine having a variable compression ratio mechanism that changes the position of the piston at the dead point by changing the movement trajectory in the link member and at least the compression ratio of the compression ratio and the displacement is variable. In the conversion structure, the dead center defining member and the output shaft are separately provided and rotated with respect to at least one of the plurality of link members and the piston. A swing link member that is connected to the output shaft and swings with the reciprocating linear motion of the piston, a swing transmission portion that transmits the swing of the swing link member to the output shaft, and the output by the swing transmission portion. A transmission direction restraint portion for restraining the swing of the swing link member transmitted to the shaft in one direction, and a piston return mechanism for returning the piston from the bottom dead center side to the top dead center side. The gist.

  In this configuration, the swing is transmitted to the output shaft using a swing link member that swings with the reciprocating linear motion of the piston. Since this oscillation transmitted to the output shaft by the oscillation transmission unit is restricted in only one direction by the transmission direction restriction unit, the reciprocating linear motion of the piston in one direction of the output shaft is caused by repetition of this oscillation transmission. It will be repeatedly converted into rotational motion. In such a motion conversion structure, the swing angle (width) of the swing link member per reciprocating piston can be less than 360 degrees. Therefore, in this case, for example, unlike the conventional mode in which the crankshaft is used as the output shaft and the crankshaft is rotated 360 degrees per reciprocating piston, the moment arm length for rotating the output shaft is, for example, near the top dead center. It becomes possible to easily avoid “0”.

  On the other hand, for example, when a crankshaft is used as a dead center defining member and the crankshaft is rotated 360 degrees per reciprocating piston, the moment arm length for rotating the crankshaft near the top dead center is It may be “0”.

  In this configuration, even if the crankshaft is used as the dead point defining member, the output shaft is provided separately from the dead point defining member. For example, the crankshaft used as the dead point defining member is Compared with the conventional mode that is also used as the only output shaft, the torque required to rotate the crankshaft is reduced. Accordingly, even if the moment arm length becomes “0” near the top dead center as described above, the reaction force that the piston receives from the crankshaft side is small because the torque required to rotate the crankshaft is small. Accordingly, it becomes easy to secure the power extracted from the output shaft.

  Therefore, according to this configuration, it is easy to set the moment arm length for rotating the output shaft to be larger than “0”, and the crankshaft is temporarily used as the dead center defining member and the crankshaft is rotated. Even if the moment arm length for causing the movement to become “0”, the reaction force acting on the piston can be suppressed, and the power can be efficiently extracted.

  According to a second aspect of the present invention, in the first aspect of the invention, the dead center defining member and the piston return mechanism use a crankshaft supported rotatably in the engine body. The gist.

  According to the above configuration, the position of the piston at the top dead center and the bottom dead center is defined by restricting the movement trajectory of the link member based on the displacement of the crank pin accompanying the rotation of the crankshaft. Further, the piston is returned from the bottom dead center side to the top dead center side based on the displacement of the crank pin. That is, both the definition of the position of the piston at the top dead center and the bottom dead center and the return to the top dead center side can be realized using the crankshaft. Therefore, for example, the number of parts can be reduced and the internal combustion engine can be reduced in size and weight as compared with a case where the dead point defining member and the piston return mechanism are configured separately without using a common member.

  As an aspect of the plurality of link members described above, for example, according to the invention described in claim 3, in the invention according to claim 1 or 2, the plurality of link members include a connecting rod connected to the piston, The variable compression ratio mechanism can be configured to include a control link member connected to a movable member provided so as to be displaceable and the swing link member. In this case, the connecting rod whose movement locus is restricted by the dead center defining member is changed based on the displacement of the movable member by changing the movement locus of the control link member connected to the movable member of the variable compression ratio mechanism. The position of the piston at the dead center is changed. As a result, at least the compression ratio of the compression ratio and the exhaust amount is changed.

  The invention according to claim 4 is the invention according to claim 3, wherein the connecting rod and the swing link member are connected via the control link member, and the dead center defining member is the swing link. The gist is that it defines the swing angle of the member.

  According to the above configuration, even if the movement trajectory of the control link member is changed by the variable compression ratio mechanism so as to change the position of the piston at the dead center, the swing angle (width) of the swing link member is changed regardless of the change. It will be kept constant. That is, since the swing angle is the same before and after the movement trajectory of the control link member is changed, even if the stroke amount of the piston is reduced by changing the movement trajectory, the swing link member Accordingly, the swing angle does not decrease.

  For example, when a one-way clutch is used as the swing transmission part and the transmission direction restraint part, thereby converting the swing of the swing link member into the rotational movement of the output shaft, the swing is performed in the direction of rotating the output shaft. The more the swinging link member swings more than the swinging angle of the play until the one-way clutch is locked (swing is transmitted to the output shaft) after the link member starts swinging, the piston The rotation angle of the output shaft per round trip increases. As a result, the torque fluctuation rate of the output shaft becomes suitable, and power can be extracted with high efficiency.

  That is, in the present invention, even if the stroke amount of the piston is changed in the decreasing direction, the swinging angle of the swinging link member does not decrease along with this, so the rotation angle of the output shaft per one piston reciprocation is reduced. As described above, it is possible to maintain a suitable torque fluctuation rate and to extract power with high efficiency. In other words, it is possible to expand the variable range of the exhaust amount to the side where the same exhaust amount is reduced while realizing such high-efficiency power extraction, and consequently, the exhaust amount can be set smaller in the engine low load state. As a result, the fuel efficiency improvement effect becomes exceptional.

  The invention according to claim 5 is the invention according to claim 3, wherein the connecting rod is connected to the swing link member without the control link member, and the dead center defining member is the control link member. The gist is that it is connected to the swing link member via

  According to the above configuration, since the control link member can be moved away from the portion that directly receives the combustion pressure acting on the piston in the vicinity of the top dead center, the size is increased to ensure mechanical strength such as impact resistance. And weight can be avoided.

  As a connection mode between the swing link member and the control link member, for example, according to the invention according to claim 6, in the invention according to claim 4 or 5, the swing link member and the control link member are provided. It is possible to adopt a configuration in which pins are directly connected to each other. Further, for example, as in the invention described in claim 7, in the invention described in claim 4 or 5, the swing link member and the control link member are connected via another link member. The configuration can be taken.

(First embodiment)
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, the engine body 11 of the internal combustion engine has a cylinder (cylinder) 12 in which a piston 13 is accommodated so as to be capable of reciprocating linearly in the vertical direction. In the cylinder 12, a combustion chamber 14 for burning a fuel / air mixture is provided above the piston 13. The piston 13 receives the pressure (combustion pressure) generated with combustion in the combustion chamber 14 and moves downward.

  An output shaft 15 is rotatably supported below the cylinder 12 in the engine body 11. The internal combustion engine is provided with a power take-out mechanism 16 that converts the reciprocating linear motion of the piston 13 into the rotational motion of the output shaft 15. That is, the swing link member 18 is supported on the output shaft 15 via the one-way clutch 17 so as to be rotatable relative to the output shaft 15. The swing link member 18 has an intermediate portion in the longitudinal direction (substantially left-right direction in the figure) supported by the output shaft 15, and one end portion of the swing member 18 is connected to the piston 13 via the control link member 19 and the connecting rod 20. It is connected so that it can be transmitted.

  The swing link member 18 and the control link member 19 are connected to each other via a connecting pin 21, and the control link member 19 and the connecting rod 20 are connected to each other via a connecting pin 22 so as to be relatively rotatable. Further, the piston 13 is connected to the end of the connecting rod 20 opposite to the side to which the control link member 19 is connected via a piston pin 23. With these connections, the swing link member 18 swings with the output shaft 15 as a fulcrum (specifically, with the rotation center axis CL1 of the output shaft 15 as a fulcrum) based on the reciprocating linear motion of the piston 13.

  The one-way clutch 17 is for transmitting the swing of the swing link member 18 to the output shaft 15 and restrains the swing of the swing link member 18 transmitted to the output shaft 15 in one direction. Is for. In other words, the one-way clutch 17 only swings in one direction of the swing link member 18, for example, the clockwise direction in the drawing, that is, swings downward (the swing in which the one end of the swing link member 18 is displaced downward). Is transmitted to the output shaft 15.

  As the type of the one-way clutch 17, for example, a general type called a sprag type, a roller type, or an engagement type can be used. In any type, the one-way clutch 17 includes an inner race, an outer race, and an engaging member. The inner race is fixed to the output shaft 15, and the outer race is fixed to the swing link member 18.

  The engaging member is disposed between the outer race and the inner race. The engaging member meshes with the inner race and the outer race only when the one end of the swing link member 18 swings downward and the rotational speed of the swing is equal to or higher than the rotational speed of the output shaft 15. The lock state is established, and the downward swing (clockwise rotation) is transmitted from the swing link member 18 to the output shaft 15. Further, when the swinging direction of the engaging member is different from that described above, for example, when the one end portion of the swinging link member 18 swings upward, the engaging member is not engaged with the inner race and the outer race, and is brought into the unlocked state. Oscillation transmission from the moving link member 18 to the output shaft 15 is blocked. That is, the one-way clutch 17 functions as a swing transmission unit and a transmission direction restraint unit.

  The output shaft 15 rotates by a predetermined angle (less than 180 degrees in this embodiment) in one direction (clockwise direction in the figure) while the piston 13 makes one reciprocation. The transmission of the swing from the swing link member 18 to the output shaft 15 is continuously continued by the reciprocating motion of the piston 13 a plurality of times, whereby the output shaft 15 is continuously moved in one direction in the internal combustion engine. It is rotated and taken out as power. That is, the reciprocating linear motion of the piston 13 is converted into the rotational motion of the output shaft 15, and this is taken out as power.

  A first crankshaft 24 is rotatably supported on the engine body 11. The first crankshaft 24 is provided with a crankpin 25 having a center axis CL3 that is eccentric with respect to the rotation center axis CL2 of the shaft 24. The crankpin 25 revolves around the rotation center axis CL <b> 2 as the first crankshaft 24 rotates. The first crankshaft 24 is connected to the other end (the end opposite to the one end) of the swing link member 18 via a link rod 26 so that power can be transmitted. That is, the link rod 26 is interposed between the crank pin 25 of the first crankshaft 24 and the connecting pin 27 provided at the other end of the swing link member 18 so as to connect them. .

  The first crankshaft 24 rotates as the piston 13 reciprocates linearly. That is, when the piston 13 moves downward due to the action of combustion pressure or the like, the swing link member 18 is rotated so that the one end is swung downward. As a result, the connecting pin 27 provided at the other end of the swing link member 18 is moved upward, and accordingly, the crank pin 25 is also moved upward via the link rod 26.

  As a result, the first crankshaft 24 is rotated about the rotation center axis CL2, and the rotation is continued by the inertial force even after the piston 13 reaches the vicinity of the bottom dead center. When the swing link member 18 is swung so that the connecting pin 27 is moved downward by the revolution of the crank pin 25 accompanying the rotation of the first crankshaft 24, the piston 13 is moved upward. Thus, the position of the top dead center and the bottom dead center of the piston 13 is defined by the revolution of the crank pin 25.

  That is, the first crankshaft 24 is linked to the piston 13 through a plurality of link members such as the link rod 26, the swing link member 18, the control link member 19, and the connecting rod 20, and restricts the movement trajectory of these link members. Thus, it functions as a dead point defining member capable of defining the position of the piston 13 at the top dead center and the bottom dead center. The first crankshaft 24 further constitutes a piston return mechanism that swings the one end of the swing link member 18 upward with the output shaft 15 as a fulcrum to return the piston 13 from the bottom dead center side to the top dead center side. doing.

  In this way, in this embodiment, since the rotational movement of the output shaft 15 is obtained by the swing of the swing link member 18 less than 360 degrees, the swing link member 18 is swung even near the top dead center. It becomes easy not to set the length of the moment arm to be moved to “0”, and the combustion pressure can be taken out well as the rotational force of the output shaft 15.

In the present embodiment, a variable compression ratio mechanism 30 that makes the compression ratio and the exhaust amount variable is provided.
The variable compression ratio mechanism 30 changes the movement trajectory of the connecting rod 20 by changing the movement trajectory of the control link member 19 among the movement trajectories of the plurality of link members constrained by the first crankshaft 24. The position of the piston 13 at the dead center and the bottom dead center is changed.

  That is, the second crankshaft 31 as a movable member constituting the variable compression ratio mechanism 30 is rotatably supported by the engine body 11. The second crankshaft 31 is supported such that its rotation center axis CL5 is immovable with respect to the engine main body 11, and the rotation of the second crankshaft 31 about the rotation center axis CL5 causes the shaft 31 to move. The provided crank pin 32 can be displaced. The second crankshaft 31 can be rotated around the rotation center axis CL5 by an actuator (not shown) provided in the engine body 11. The actuator adjusts the position of the crank pin 32 with respect to the engine body 11 through the rotation of the second crankshaft 31.

  The crank pin 32 of the second crankshaft 31 is connected to a connecting pin 34 provided on the control link member 19 via a link rod 33. When the crank pin 32 is displaced based on the rotation of the second crankshaft 31 by the actuator and the connection pin 34 of the control link member 19 is displaced due to this, for example, the control link member 19 is centered on the connection pin 21. It is rotated relative to the swing link member 18 about the axis CL6. Therefore, when the phase of the first crankshaft 24, that is, the phase of the swing link member 18 centering on the rotation center axis CL1 is compared, the relative position of the connecting pin 22 on the connecting rod 20 side with respect to the connecting pin 21 is It will be different before and after the rotation. As a result, the movement locus of the control link member 19 constrained by the first crankshaft 24 and the movement locus of the connecting rod 20 are changed based on the relative rotation, and the stroke amount, that is, the compression ratio and the exhaust amount of the piston 13 are changed. Is done.

Next, the operation of the variable compression ratio mechanism 30 will be described with reference to FIGS.
2 (a) and 2 (b) both show a state in which the crank pin 32 of the second crankshaft 31 is arranged so that the compression ratio and the displacement are minimized. FIG. 2 (a) Is a state where the piston 13 is at the top dead center position, and FIG. 2B is a state where the piston is at the bottom dead center position. As shown in these drawings, the swing angle (width) of the swing link member 18 is defined based on the rotation of the first crankshaft 24. For example, when the connecting pin 27 of the swing link member 18 is disposed at the lowest position within the displaceable range based on the rotation of the first crankshaft 24, the swing link member 18 is provided at the one end. The connected pin 21 is disposed at the uppermost position in the displaceable range (see FIG. 2A). Thereby, in the state where the crank pin 32 is disposed at the position of FIG. 2, the piston 13 is disposed at the uppermost position (top dead center).

  On the contrary, when the connecting pin 27 is disposed at the uppermost position in the displaceable range as shown in FIG. 2B, the connecting pin 21 is positioned at the lowermost position in the displaceable range. In the state where the crank pin 32 is disposed at the position of FIG. 2, the piston 13 is disposed at the lowest position (bottom dead center).

  In the present embodiment, the connecting pin 22 on the connecting rod 20 side is positioned higher than the connecting pin 21 on the swing link member 18 side regardless of the phase of the first crankshaft 24 or the second crankshaft 31. It is arranged. In the state of FIG. 2, the vertical distance between the connecting pin 21 and the connecting pin 22 at the bottom dead center is maximized, that is, the position of the connecting pin 22 at the bottom dead center is the highest. Thus, the position of the crank pin 32 of the second crank shaft 31 is set. Therefore, in this state, the position of the piston 13 at the bottom dead center is the uppermost position, the stroke amount of the piston 13 is minimized, and both the compression ratio and the exhaust amount are minimized.

  On the other hand, both FIG. 3A and FIG. 3B show a state in which the crank pin 32 of the second crankshaft 31 is arranged so that the compression ratio and the displacement are maximized. Specifically, the second crankshaft 31 is rotated from the state of FIG. 2 by a predetermined angle (less than 90 degrees in the present embodiment) in the clockwise direction of the figure by the above-described actuator, and the crank pin 32 is moved to the lower left along with this rotation. It is displaced in the (lower left direction in the figure). 3A shows a state where the piston 13 is at the top dead center position, and FIG. 3B shows a state where the piston 13 is at the bottom dead center position.

  In the present embodiment, the phases of the first crankshaft 24 at the top dead center and the bottom dead center are the same in the state of FIG. 3 and the state of FIG. 2 described above. That is, when the connecting pin 21 of the swing link member 18 is disposed at the uppermost position (see FIG. 3A), the crank pin 32 of the second crankshaft 31 is disposed at the position of FIG. The position of the piston 13 is the uppermost one (top dead center). Conversely, when the connecting pin 21 of the swing link member 18 is disposed at the lowest position (see FIG. 3B), the crank pin 32 of the second crankshaft 31 is disposed at the position of FIG. The position of the piston 13 at the bottom is the lowest (bottom dead center).

  In the present embodiment, the vertical distance between the connecting pin 21 on the swing link member 18 side and the connecting pin 22 on the connecting rod 20 side at the top dead center is the same in the state of FIG. 3 and the state of FIG. 2 described above. In other words, the positions of the crank pins 32 of the second crankshaft 31 are set so that the positions of the pistons 13 at the top dead center are equal. The position of the crank pin 32 in the state of FIG. 3 is further set so that the vertical distance between the connecting pin 21 and the connecting pin 22 at the bottom dead center is minimized. Therefore, in the state of FIG. 3, the position of the piston 13 at the bottom dead center is the lowest position, the stroke amount of the piston 13 is maximized, and both the compression ratio and the exhaust amount are maximized.

In the present embodiment, the following effects can be obtained.
(1) In this embodiment, the swing is transmitted to the output shaft 15 using the swing link member 18 that swings with the reciprocating linear motion of the piston 13. Since this swing transmitted to the output shaft 15 is restricted in only one direction by the one-way clutch 17, the reciprocating linear motion of the piston 13 becomes a rotational motion in one direction of the output shaft 15 by repeating this swing transmission. It will be converted repeatedly. In such a motion conversion structure, the swing angle (width) of the swing link member 18 per reciprocation of the piston 13 can be less than 360 degrees. Therefore, in this case, for example, unlike the conventional mode in which the crankshaft is used as the output shaft and the crankshaft is rotated 360 degrees per reciprocation of the piston, for example, the moment arm length for rotating the output shaft 15 near top dead center. Can be easily avoided from becoming "0".

  On the other hand, when the first crankshaft 24 is used as the dead center defining member as in this embodiment, the moment arm length for rotating the first crankshaft 24 near the top dead center is “0”. There is. In the present embodiment, since the output shaft 15 is provided separately from the first crankshaft 24, for example, compared to the conventional mode in which the crankshaft used as the dead center defining member is also used as the only output shaft, The torque required to rotate the first crankshaft 24 is reduced. Therefore, as described above, even if the moment arm length becomes “0” near the top dead center, the torque required to rotate the first crankshaft 24 is small, so the piston 13 is on the first crankshaft 24 side. The reaction force received from the motor is reduced, and it is easy to secure the power extracted from the output shaft 15 correspondingly.

  Therefore, according to the present embodiment, it is easy to set the moment arm length for rotating the output shaft 15 to be larger than “0”, and the moment arm length for temporarily rotating the first crankshaft 24. Even if the value becomes “0”, the reaction force acting on the piston 13 can be suppressed, and the power can be efficiently extracted.

  (2) In the present embodiment, the plurality of link members (link rod 26, swing link member 18, control link member 19, connecting rod 20) based on the displacement of the crankpin 25 accompanying the rotation of the first crankshaft 24. By restricting the movement trajectory, the position of the piston 13 at the top dead center and the bottom dead center can be defined. Further, the piston 13 is returned from the bottom dead center side to the top dead center side based on the displacement of the crank pin 25. That is, both the definition of the position of the piston 13 at the top dead center and the bottom dead center and the return to the top dead center side are realized by using the first crankshaft 24. Therefore, for example, the number of parts can be reduced and the internal combustion engine can be reduced in size and weight as compared with a case where the dead point defining member and the piston return mechanism are configured separately without using a common member.

  (3) The connecting rod 20 and the swing link member 18 are connected via the control link member 19. The first crankshaft 24 defines the swing angle of the swing link member 18. According to this, even if the movement locus of the control link member 19 is changed by the variable compression ratio mechanism 30 so as to change the position of the piston 13 at the dead point, the swing angle of the swing link member 18 ( Width) is kept constant. That is, since the swing angle is the same before and after the movement locus of the control link member 19 is changed, even if the stroke amount of the piston 13 is reduced due to the change of the movement locus, the swing link. Accordingly, the swing angle of the member 18 does not decrease.

  When the one-way clutch 17 is used to transmit the swing to the output shaft 15 as in the present embodiment, the swing link member 18 starts swinging in the direction in which the output shaft 15 rotates, and the clutch 17 In general, the rocking link member 18 needs to be swung by a certain angle before is locked (the rocking is transmitted to the output shaft 15). This angle is a so-called “play” in the one-way clutch 17. In this case, the rotation angle of the output shaft 15 per reciprocation of the piston 13 increases as the swing link member 18 swings larger than the swing angle corresponding to the “play” from the start of the swing. . As a result, the torque fluctuation rate of the output shaft 15 becomes favorable, and power can be extracted with high efficiency.

  That is, in this embodiment, even if the stroke amount of the piston 13 is changed in the decreasing direction, the swinging angle of the swinging link member 18 does not become smaller with this change. The rotation angle of 15 is not reduced, and a suitable torque fluctuation rate can be maintained and power can be extracted efficiently as described above. In other words, it is possible to expand the variable range of the exhaust amount to the side where the same exhaust amount is reduced while realizing such high-efficiency power extraction, and consequently, the exhaust amount can be set smaller in the engine low load state. As a result, the fuel efficiency improvement effect becomes exceptional.

(Second Embodiment)
This 2nd Embodiment changes the cooperation aspect of the said "plurality of link members" in the said 1st Embodiment, and has the structure similar to 1st Embodiment in another point. Accordingly, the same components as those in the first embodiment are denoted by the same reference numerals in the drawings, and redundant description is omitted.

  As shown in FIG. 4, in this embodiment, the connecting rod 20 is directly pin-connected to the swing link member 18 without using the control link member 19. That is, a connecting pin 40 is provided at one end of the swing link member 18, and the connecting rod 20 is rotatably connected to the connecting pin 40.

  On the other hand, the first crankshaft 24 is connected to the swing link member 18 via the control link member 19. The control link member 19 is rotatably connected to a connecting pin 41 provided at the other end of the swing link member 18 (the end opposite to the one end). The first crankshaft 24 is connected to the control link member 19 via a link rod 26. That is, the other end of the link rod 26 whose one end is connected to the crank pin 25 of the first crankshaft 24 is rotatably connected to a connecting pin 42 provided on the control link member 19.

  Also in the present embodiment, as described above, the position of the crank pin 32 relative to the engine body 11 is adjusted by rotating the second crank shaft 31 by the actuator, and the crank pin 32 is connected via the link rod 33. It is connected to the connecting pin 34 of the control link member 19.

  When the crank pin 32 is displaced by this position adjustment and the connecting pin 34 of the control link member 19 is displaced due to this displacement, for example, when the phases of the first crankshaft 24 are compared in the same state, the engine body 11 The arrangement angle of the control link member 19 with respect to is different before and after the displacement. Therefore, the distance between the crank pin 25 of the first crankshaft 24 and the connecting pin 41 of the swing link member 18 differs before and after the displacement. That is, the swing angle (width) of the swing link member 18 is changed by displacing the crank pin 32 of the second crankshaft 31, and as a result, the stroke amount of the piston 13, that is, the compression ratio and the exhaust amount. Is changed.

In the present embodiment, in addition to the same effects as the above (1) and (2), the following effects can be obtained.
(4) According to the present embodiment, since the control link member 19 can be moved away from the portion that directly receives the combustion pressure acting on the piston 13 in the vicinity of the top dead center, mechanical strength such as impact resistance is improved. Increase in size and weight for securing can be avoided.

(Third embodiment)
In the third embodiment, the swing link member 18 and the control link member 19 are rod-connected in the second embodiment, and the other configurations are substantially the same as those of the second embodiment. Accordingly, the same components as those in the second embodiment are denoted by the same reference numerals in the drawings, and redundant description is omitted.

  As shown in FIG. 5, in this embodiment, the swing link member 18 and the control link member 19 are connected via another link member 50 as described above. That is, one end of the link member 50 is rotatably connected to the connecting pin 51 provided at the other end of the swing link member 18, and the other end is rotated to the connecting pin 52 provided at the control link member 19. Connected as possible.

  In the present embodiment, the crank pin 25 of the first crankshaft 24 is connected to the control link member 19 directly and rotatably without the link rod 26 or the like.

  In the present embodiment, when the crank pin 32 is displaced by the position adjustment by the actuator and the connection pin 34 of the control link member 19 is displaced due to the displacement, for example, the phase of the first crank shaft 24 is the same. When compared, the arrangement angle of the control link member 19 with respect to the engine body 11 is different before and after the displacement. Accordingly, the distance between the crank pin 25 of the first crankshaft 24 and the connecting pin 51 of the swing link member 18 differs before and after the displacement. That is, the swing angle (width) of the swing link member 18 is changed by displacing the crank pin 32 of the second crankshaft 31, and as a result, the stroke amount of the piston 13, that is, the compression ratio and the exhaust amount. Is changed.

In the present embodiment, the same effects as the above (1), (2) and (4) can be obtained.
In addition, embodiment is not limited above, For example, it is good also as the following aspects.

  In the above embodiment, the control link member 19 is connected to the second crankshaft 31 as the movable member via the link rod 33 that is rotatably connected to the crankpin 32 provided on the coaxial 31. For example, as shown in FIG. 6, the control link member 19 and the movable member may be directly connected without using the link rod 33 or the like. That is, as shown in FIG. 6, the control link member 19 is rotatably connected to the connecting pin 21 provided at one end of the swing link member 18. The control link member 19 is provided with a connecting pin 60 at an intermediate portion in the longitudinal direction (substantially left-right direction in the figure), and the connecting rod 60 is rotatably connected to the connecting pin 60.

  In the control link member 19, an elongated hole 61 extending in the longitudinal direction is provided at the end of the swing link member 18 opposite to the end connected to the connection pin 21. A slide pin 62 as the movable member is inserted into the long hole 61. The slide pin 62 is provided so as to be slidable substantially in the left-right direction in the figure, and its position is adjusted by an actuator (not shown) provided in the engine body 11.

  6A shows a state where the piston 13 (not shown) is at the top dead center position, and FIG. 6B shows a state where the piston 13 is at the bottom dead center position. In both figures, the member indicated by a solid line indicates a state when the stroke amount of the piston 13 is minimized, and the member indicated by a two-dot chain line indicates a state when the stroke amount is maximum. In this configuration, as in the first embodiment, the swing angle (width) of the swing link member 18 is the same when the stroke amount is minimized and maximized.

  That is, in this configuration, when the stroke amount of the piston 13 is minimized, the position is adjusted so that the slide pin 62 is arranged at the position (position A) indicated by the solid line, and the stroke amount is maximized. At this time, the position is adjusted so that the slide pin 62 is arranged at the position (position B) indicated by the two-dot chain line. In this configuration, as shown in FIG. 6A, the position of the piston 13 at the top dead center is the same when the slide pin 62 is disposed at the position A and at the position B. It has become.

  On the other hand, as shown in FIG. 6B, at the bottom dead center, when the slide pin 62 is disposed at the position A, the piston 13 is located at a lower position when the slide pin 62 is disposed at the position B. Placed in position.

  When the slide pin 62 is displaced between the position A and the position B, the slide pin 62 may be displaced straight along a straight line connecting the position A and the position B, or may be displaced along a path deviating from the straight line. You may make it make it. For example, when displacing along the same straight line, the slide pin 62 is arranged at any position between the position A and the position B as long as the elongated hole 61 has a shape extending linearly in the longitudinal direction. Even if it is made, the position of the piston 13 at the top dead center can be made the same. In other words, even if the elongated hole 61 is not linearly extended, for example, the displacement path of the slide pin 62 according to the shape of the elongated hole 61 when the piston 13 is at the top dead center position. Is set, the position of the piston 13 at the top dead center can be made unchanged.

  In the above-described embodiment, the swing link member 18 is used as one of a plurality of link members that link the piston 13 and the first crankshaft 24. However, the present invention is not limited to this. That is, for example, as shown in FIG. 7, the connecting rod 20, the control link member 19, and the link rod 26 are employed as a plurality of link members that link the piston 13 and the first crankshaft 24, and the swing link member 18 is not connected. It may be adopted.

  In the configuration of FIG. 7, the crank pin 32 of the second crankshaft 31 is directly and rotatably connected to the control link member 19, and the first crankshaft 24 is connected via a link rod 26. . The connecting rod 20 is rotatably connected to a connecting pin 70 provided on the control link member 19. The connecting pin 70 is slidably inserted along the same hole 71 in an elongated hole 71 formed so as to extend in the radial direction of the output shaft 15 in the swing link member 18.

  Each position of the connecting pin 70 at the top dead center and the bottom dead center is defined by the first crankshaft 24 in a state where the crank pin 32 is held at a predetermined position (for example, the position in FIG. 7). The reciprocating motion of the connecting pin 70 between the above positions is converted into the swing of the swing link member 18. Of the swing of the swing link member 18, only swing in one direction is transmitted to the output shaft 15 via the one-way clutch 17. The movement trajectory of the connecting pin 70 in the reciprocating motion is changed by the displacement of the crank pin 32 based on the rotation of the second crankshaft 31 by the same actuator (not shown) as described above. As a result, at least the compression ratio of the compression ratio and the exhaust amount is changed.

  In the above embodiment, the dead center defining member and the piston return mechanism are configured using the first crankshaft 24. However, the present invention is not limited to this, and may be configured as shown in FIG. This configuration is, for example, instead of the first crankshaft 24 and the connecting pin 27 in the first embodiment. In other words, the other end of the swing link member 18 (the end opposite to the one end to which the control link member 19 is connected) slides in the vertical direction in the slider housing chamber 80 formed in the engine body 11. It is pressed downward via a slider 82 that is accommodated and urged downward by a compression spring 81. When the piston 13 moves downward, the other end of the swing link member 18 swings upward, so that the slider 82 is moved upward. The slider 82 is brought into contact with the upper wall surface of the slider accommodating chamber 80. When this happens, the position of the piston 13 at the bottom dead center is defined. Then, the other end portion of the swing link member 18 is pushed downward by the pressing force of the compression spring 81 so that the piston 13 is returned upward, and the other end portion of the swing link member 18 is moved to the slider accommodating chamber 80. The position of the piston 13 at the top dead center is defined by being in contact with the lower wall surface.

  In addition to taking out the power from the output shaft 15, the rotational power of the first crankshaft 24 may be taken out as an output. Even in this case, for example, the first crankshaft 24 whose moment arm length can be “0” as compared with the conventional mode in which power is taken out only from the crankshaft serving also as the dead center defining member and the output shaft. The reaction force from the piston toward the piston 13 can be reduced. Therefore, it is possible to take out power with high efficiency.

  -It is not necessary to make both the compression ratio and the exhaust amount variable. For example, only the compression ratio is made variable by shifting the reciprocating region of the piston 13 in the vertical direction while keeping the stroke amount of the piston 13 unchanged. You may set the dimension and arrangement | positioning location, such as each link member.

The schematic perspective view which shows the motion conversion structure of the internal combustion engine of 1st Embodiment. (A) And (b) is a perspective view for demonstrating effects | actions, such as a variable compression ratio mechanism. (A) And (b) is a perspective view for demonstrating effects | actions, such as a variable compression ratio mechanism. The schematic perspective view which shows the motion conversion structure of the internal combustion engine of 2nd Embodiment. The schematic perspective view which shows the motion conversion structure of the internal combustion engine of 3rd Embodiment. (A) And (b) is the elements on larger scale which show another Example. Schematic which shows another Example. The fragmentary sectional view which shows another Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Engine body, 12 ... Cylinder, 13 ... Piston, 15 ... Output shaft, 17 ... One-way clutch, 18 ... Swing link member, 19 ... Control link member, 20 ... Connecting rod, 24 ... First crankshaft, 30 ... Variable Compression ratio mechanism, 31 ... second crankshaft, 41 ... connecting pin, 50 ... another link member, 62 ... slide pin, 81 ... compression spring, 82 ... slider.

Claims (7)

A motion conversion structure for an internal combustion engine that extracts the power by converting the reciprocating linear motion of the piston in the cylinder formed in the engine body into the rotational motion of the output shaft,
At least one of the plurality of link members, a dead center defining member capable of defining the position of the piston at the dead center by restricting the movement trajectory of the link members in cooperation with the piston via a plurality of link members. And a variable compression ratio mechanism that changes the position of the piston at the dead point by changing the movement trajectory of the link member, and at least the compression ratio of the compression ratio and the displacement is variable. In the motion conversion structure of
The dead center defining member and the output shaft are provided separately, and are pivotally connected to at least one of the plurality of link members and the piston, and swinging with the reciprocating linear motion of the piston. A dynamic link member, a swing transmission portion that transmits the swing of the swing link member to the output shaft, and the swing of the swing link member that is transmitted to the output shaft by the swing transmission portion in one direction. A motion conversion structure for an internal combustion engine, comprising: a transmission direction restraint portion that restrains the piston from the bottom dead center side to a top dead center side. The motion conversion structure for an internal combustion engine according to claim 1, wherein a crankshaft that is rotatably supported in the engine body is used for the dead center defining member and the piston return mechanism. The plurality of link members include a connecting rod connected to the piston, a control link member connected to a movable member displaceably provided in the variable compression ratio mechanism, and the swing link member. Or the motion conversion structure of the internal combustion engine of 2. The internal combustion engine according to claim 3, wherein the connecting rod and the swing link member are connected via the control link member, and the dead point defining member defines a swing angle of the swing link member. Engine motion conversion structure. The said connecting rod is connected with the said rocking | fluctuation link member without passing through the said control link member, and the said dead center prescription | regulation member is connected with the said rocking | fluctuation link member via the said control link member. The internal combustion engine motion conversion structure. The motion conversion structure for an internal combustion engine according to claim 4 or 5, wherein the swing link member and the control link member are directly pin-connected. The motion conversion structure for an internal combustion engine according to claim 4, wherein the swing link member and the control link member are connected via another link member.

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