JP5353467B2 - Variable compression ratio internal combustion engine - Google Patents

Description

  The present invention relates to a variable compression ratio internal combustion engine.

  Patent Document 1 discloses a variable compression ratio internal combustion engine that can change a mechanical compression ratio in a combustion chamber by moving a cylinder block and a cylinder head relative to a crankcase. By the way, this internal combustion engine has a mechanism (hereinafter referred to as “valve mechanism”) that drives an intake valve and an exhaust valve to open and close. Normally, this valve operating mechanism is supplied with lubricating oil in order to make the operation of the valve operating mechanism good. In general, an oil pan for storing lubricating oil is disposed in a lower portion of the crankcase, and a valve mechanism is disposed in a cylinder head. Therefore, in order to supply the lubricating oil to the valve operating mechanism, the lubricating oil must be transported from the oil pan disposed in the lower part of the crankcase to the cylinder head. Therefore, in order to supply the lubricating oil to the valve operating mechanism, it is necessary to form a lubricating oil passage extending from the crankcase to the cylinder head in the crankcase, the cylinder block, and the cylinder head.

Japanese Patent Application Laid-Open No. 2005-069181 Japanese Patent Laid-Open No. 11-182645 Japanese Patent Laid-Open No. 10-264836 Japanese Patent Laid-Open No. 06-080804 JP 2002-327881 A JP 2007-187153 A Japanese Patent Laid-Open No. 04-030392

  As described above, the internal combustion engine of Patent Document 1 is a variable compression ratio internal combustion engine that changes the mechanical compression ratio in the combustion chamber by moving the cylinder block and the cylinder head relative to the crankcase. Therefore, a mechanism for moving the cylinder block relative to the crankcase is disposed between the cylinder block and the crankcase. As a matter of course, there is a portion that slides between the cylinder block and the crankcase. For this reason, when an attempt is made to form a lubricating oil passage extending from the crankcase to the cylinder head in the crankcase, the cylinder block, and the cylinder head in order to supply the lubricating oil to the valve operating mechanism, there is a gap between the cylinder block and the crankcase. In this region, the configuration of the lubricating oil path may be complicated. However, in order to transport the lubricating oil well, it is preferable that the lubricating oil has a simple configuration.

  Accordingly, an object of the present invention is to provide a lubricating oil passage having a simple configuration in a variable compression ratio internal combustion engine capable of changing the mechanical compression ratio in the combustion chamber by moving the cylinder block and the cylinder head relative to the crankcase. Is to provide. Also, this object of the present invention is broadly composed of at least two block parts movably connected to each other, and by moving one block part relative to the other block part, the combustion chamber It is an object of the present invention to provide a lubricating oil passage having a simple configuration in a variable compression ratio internal combustion engine capable of changing the mechanical compression ratio.

  In the first invention, the mechanical compression ratio in the combustion chamber is changed by moving at least two block parts connected to each other so as to be movable relative to each other and moving one block part relative to the other block part. A variable compression ratio internal combustion engine capable of opening and closing an intake valve or an exhaust valve is provided with a camshaft disposed in the one block portion and a crankshaft is disposed in the other block portion. The variable compression ratio internal combustion engine includes a rotation transmission shaft that transmits the rotation of the crankshaft to the camshaft, and a lubricating oil passage that circulates the lubricating oil between one block portion and the other block portion. It is formed in the rotation transmission shaft.

  According to a second invention, in the first invention, the rotation transmission shaft is composed of at least two shaft parts connected so as to be slidable with respect to each other, and are in contact with each other in a nesting manner. The lubricating oil passage of the rotation transmission shaft is configured so that the lubricating oil is circulated between the shaft portion contact portions when the shaft portion portions are referred to as shaft portion contact portions.

  According to a third aspect, in the second aspect, a seal made of an elastic body is disposed between the shaft portions so as to seal between the shaft portion contact portions, and the seal is arranged with respect to the axis of the shaft portion. They are arranged between the shaft contact portions in a state where they are crushed by a length longer than the width of the gap between the shaft contact portions when measured in the lateral direction.

According to a fourth aspect, in the second or third aspect, at least one of the shaft portions is arranged in parallel to a direction in which one block portion moves relative to the other block portion, One shaft portion has a wall surface perpendicular to its axis as a hydraulic wall surface, and the hydraulic pressure is applied to the hydraulic wall surface in a direction in which the one shaft portion slides away from the other shaft portion in the axial direction. Thus, the lubricating oil is supplied to the hydraulic wall surface, and the lubricating oil passage of the hydraulic wall surface and the rotation transmission shaft is circulated between the hydraulic wall surface and the lubricating oil passage of the rotation transmission shaft. The lubricating oil path between the two is configured.

According to a fifth aspect, in the fourth aspect, the one shaft portion is supported on the block portion by a support member, and the one shaft portion has a protruding portion that protrudes laterally with respect to the axis. The one shaft portion is supported on the block portion by the support member so that the protruding portion is disposed in the support member, and the wall surface of the protruding portion is relative to the axis of the shaft portion. A wall surface that is a vertical wall surface and is disposed in the support member constitutes the hydraulic wall surface.

  According to a sixth aspect, in the fifth aspect, a lubricating oil passage for flowing lubricating oil between the lubricating oil passage of the rotation transmission shaft and the lubricating oil passage formed in the block portion is provided in the support member. Is formed.

According to a seventh aspect, in the first aspect, the rotation transmission shaft is supported by the block portion by a support member, and the lubricating oil passage formed in the lubricating oil passage and the block portion of the rotation transmission shaft. A lubricating oil passage for allowing the lubricating oil to flow there between is formed in the support member.

  In an eighth invention according to any one of the fifth to seventh inventions, the support member has a portion that rotatably supports the rotation transmission shaft as a rotation transmission shaft support portion, and the rotation transmission shaft support portion. The lubricating oil passage of the support member is configured so that the lubricating oil flows between the two.

  According to the first aspect of the invention, a lubricating oil passage is formed in the rotation transmission shaft extending from one block portion to the other block portion, and this lubricating oil passage is lubricated between the one block portion and the other block portion. Used to distribute oil. That is, the inner region of the rotation transmission shaft is used as a region for forming a lubricating oil passage for flowing lubricating oil between one block portion and the other block portion. Therefore, it is not necessary to form a lubricating oil passage for allowing the lubricating oil to flow between one block portion and the other block portion in the inner region of the block portion. For this reason, the structure of the lubricating oil path which distribute | circulates lubricating oil between one block part and the other block part is simple.

  According to the second aspect of the invention, the lubricating oil is supplied from the lubricating oil passage of the rotation transmission shaft to the shaft partial contact portion, or the lubricating oil is discharged from the shaft partial contact portion to the lubricating oil passage of the rotation transmission shaft. That is, the lubricating oil passage of the rotation transmission shaft is used for the circulation of the lubricating oil between the shaft partial contact portions. For this reason, the structure of the lubricating oil which distribute | circulates lubricating oil between shaft part contact parts is simple.

  According to the third invention, the seal is disposed between the shaft partial contact portions in a state where the seal is crushed by a length longer than the length of the width of the gap between the shaft partial contact portions. If the seal is crushed only by a length shorter than the length of the width of the gap between the shaft portion contact portions, the shaft portion contact portions are not sufficiently sealed. However, according to the present invention, if the seal is crushed by a length longer than the length of the width of the gap between the shaft portion contact portions, the portion between the shaft portion contact portions is sufficiently sealed.

  According to the fourth aspect of the invention, at least one shaft portion is biased by the lubricating oil in a sliding direction so as to move away from the other shaft portion in the axial direction thereof. Here, in order to sufficiently transmit the rotation of the rotation transmission shaft to the camshaft when the one block portion is moved away from the other block portion, the shaft portion arranged on the one block portion side. Must be slid away from the other shaft part arranged on the other block part side following the movement of the one block part, or one block part can be In order to sufficiently transmit the rotation of the crankshaft to the rotation transmission shaft when moved away from the block portion, the shaft portion disposed on the other block portion side must be connected to the other block portion. Follow the movement and move away from the other shaft part arranged on the one block part side. It must be allowed to sea urchin sliding. According to the present invention, at least one shaft portion is urged by the lubricating oil in a direction that slides away from the other shaft portion in the axial direction thereof. Therefore, even when one block part is moved away from the other block part, the shaft part is slid by the lubricating oil pressure so as to follow the movement of the block part and move away from each other. The rotation of the shaft is sufficiently transmitted to the camshaft or the rotation of the crankshaft is sufficiently transmitted to the rotation transmission shaft. Furthermore, according to the present invention, the lubricating oil passage of the rotation transmission shaft is used for the circulation of the lubricating oil that urges at least one shaft portion to slide away from the other shaft portion in the axial direction. . For this reason, the configuration of the lubricating oil passage through which the lubricating oil flows is simple.

  According to the fifth aspect, the pressure of the lubricating oil is applied to the hydraulic wall surface in the support member. For this reason, since a hydraulic wall having a relatively large area can be used, sufficient transmission of rotation from the rotation transmission shaft to the camshaft or sufficient transmission of rotation from the crankshaft to the rotation transmission shaft is more reliably ensured. The

  According to the sixth and seventh aspects of the invention, the inside of the support member that supports the rotation transmission shaft is used as a lubricating oil passage for flowing lubricating oil between the lubricating oil passage of the rotation transmission shaft and the lubricating oil passage of the block portion. Is done. That is, the support member fulfills two functions: a function of supporting the rotation transmission shaft, and a function of circulating the lubricating oil between the lubricating oil passage of the rotation transmission shaft and the lubricating oil passage of the block portion. According to this, it is not necessary to prepare a configuration different from the support member only for flowing the lubricating oil between the lubricating oil passage of the rotation transmission shaft and the lubricating oil passage of the block portion.

  According to the eighth aspect of the invention, the lubricating oil is supplied from the lubricating oil passage of the rotation transmission shaft to the rotation transmission shaft support portion of the support member or the lubricating oil from the rotation transmission shaft support portion of the support member to the lubricating oil passage of the rotation transmission shaft. Is discharged. That is, the lubricating oil passage of the rotation transmission shaft is used for the circulation of the lubricating oil between the supporting member and the rotation transmission shaft supporting portion. For this reason, the structure of the lubricating oil path which distribute | circulates lubricating oil between the rotation transmission shaft support parts of a supporting member is simple.

1 is an overall view of a variable compression ratio internal combustion engine according to a first embodiment of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an overall view of a variable compression ratio internal combustion engine of a first embodiment, (A) is a view showing a variable compression ratio internal combustion engine when a cylinder block and a cylinder head are located closest to a crankcase; ) Is a view showing the variable compression ratio internal combustion engine when the cylinder block and the cylinder head are located farthest from the crankcase. It is the fragmentary sectional view which showed the structure of the rotation transmission shaft of 1st Embodiment in detail, and is the figure which showed the state of the rotation transmission shaft when a cylinder block and a cylinder head exist in the position closest to the crankcase. is there. It is the fragmentary sectional front view which showed the structure of the rotation transmission shaft of 1st Embodiment in detail, and is the figure which showed the rotation transmission shaft when a cylinder block and a cylinder head exist in the position furthest away with respect to the crankcase. . (A) is the partial cross section side view which showed the structure of the rotation transmission shaft of 1st Embodiment in detail, (B) is sectional drawing along line BB of (A). It is the fragmentary sectional view which showed the structure of the crankshaft side gearwheel of 1st Embodiment, and its periphery. It is a whole view of the variable compression ratio internal combustion engine of 2nd Embodiment of this invention. FIG. 10 is a diagram illustrating a configuration of a support member that supports a rotation transmission shaft at a position close to a camshaft side gear and a periphery thereof in the second embodiment, and when a cylinder block and a cylinder head are closest to a crankcase. It is the figure which showed the structure of a supporting member and its periphery, (A) is a fragmentary sectional front view, (B) is a fragmentary longitudinal cross-sectional view along line BB of (A), (C) [FIG. 4] It is a partial cross-sectional view along line CC of (B). FIG. 10 is a diagram showing a configuration of a support member that supports a rotation transmission shaft at a position close to a camshaft side gear and a periphery thereof in the second embodiment, and when a cylinder block and a cylinder head are at a position farthest from a crankcase. It is the figure which showed the structure of a supporting member and its periphery, (A) is a fragmentary sectional front view, (B) is the fragmentary longitudinal cross-sectional view along line BB of (A). (A) is the fragmentary sectional front view which showed the structure of the support member which supports a rotation transmission shaft in the position close | similar to the crankshaft side gearwheel in 2nd Embodiment, and its periphery, (B) is the line of (A). It is a partial longitudinal cross-sectional view along BB, (C) is a partial cross-sectional view along line CC of (B).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows one embodiment of a variable compression ratio internal combustion engine of the present invention (hereinafter referred to as “first embodiment”). In FIG. 1, reference numeral 1 denotes a variable compression ratio internal combustion engine (hereinafter simply referred to as “internal combustion engine”) of the first embodiment. The internal combustion engine 1 includes a cylinder block 2, a crankcase 22, a cylinder head 3, a crankshaft 4, a rotation transmission shaft 5, an intake valve camshaft 6, and an exhaust valve camshaft 7.

  The cylinder head 3 is fixed to the upper part of the cylinder block 2. The crankcase 22 is attached to the lower part of the cylinder block 2. The cylinder block 2 is attached to the crankcase 22 so as to be movable relative to the crankcase 22 in a reciprocating direction A of a piston (not shown) that reciprocates in a combustion chamber (not shown).

  Further, an eccentric shaft 23 is disposed between the cylinder block 2 and the crankcase 22. The eccentric shaft 23 is rotatable with respect to the main shaft 24, a cylindrical cam 25 attached to the main shaft 24 so as not to rotate with respect to the main shaft 24, a sub shaft 26, and the sub shaft 26. And a cylindrical cam 27 attached to the sub shaft 26. The cam 25 is attached to the main shaft 24 such that its center axis coincides with the center axis of the main shaft 24. On the other hand, the cam 27 is attached to the sub-shaft 26 such that the center axis thereof is deviated from the center axis of the sub-shaft 26. Further, the center axis of the main shaft 24 and the center axis of the sub shaft 26 are shifted from each other. Further, the central axes of the cams 25 and 27 are also shifted from each other. The sub-shaft 26 is rotatably fitted to the main shaft 24 in a cylindrical cavity formed in the main shaft 24. A cam 25 attached to the main shaft 24 is fitted into a cylindrical cavity formed in the cylinder block 2 so as to be rotatable with respect to the cylinder block 2. On the other hand, a cam 27 attached to the subshaft 26 is rotatably inserted into the crankcase 22 in a cylindrical cavity formed in the crankcase 22.

  As shown in FIG. 2A, when the main shaft 24 is rotated in the direction indicated by the solid arrow in FIG. 2A, the cam 25 attached to the main shaft 24 is the same. It can be rotated in the direction. At this time, as the main shaft 24 rotates, the sub shaft 26 moves in the main shaft 24 so as to approach the main body of the crankcase 22. At this time, as the subshaft 26 moves, the cam 27 attached to the subshaft 26 is rotated in the direction indicated by the chain line arrow in FIG. As a result, the cylinder block 2 and the cylinder head 3 attached to the upper portion of the cylinder block 2 reciprocate in the piston in which the cylinder block 3 reciprocates in the combustion chamber, that is, in the direction indicated by the arrow Au in FIG. It is moved away from the crankcase 22. Thus, the state in which the cylinder block 2 and the cylinder head 3 are moved away from the crankcase 22 is shown in FIG.

  Conversely, as shown in FIG. 2B, when the main shaft 24 is rotated in the direction indicated by the solid arrow in FIG. 2B, the cam 25 attached to the main shaft 24 also becomes. It can be rotated in the same direction. At this time, as the main shaft 24 rotates, the sub shaft 26 moves away from the main body of the crankcase 22 in the main shaft 24. At this time, as the subshaft 26 moves, the cam 27 attached to the subshaft 26 is rotated in the direction indicated by the chain line arrow in FIG. As a result, the cylinder block 2 and the cylinder head 3 attached to the upper portion of the cylinder block 2 reciprocate in the piston in which the cylinder head 3 reciprocates in the combustion chamber, that is, in the direction indicated by the arrow Ad in FIG. It is moved so as to approach the crankcase 22. Thus, FIG. 2A shows a state where the cylinder block 2 and the cylinder head 3 are moved so as to be closest to the crankcase 22. Therefore, when the cylinder block 2 and the cylinder head 3 are moved from the nearest position to the farthest position with respect to the crankcase 22 as shown in FIG. And move by distance D. When the cylinder block 2 and the cylinder head 3 are moved so as to approach the crankcase 22 in the direction indicated by the arrow Ad, the stroke length of the piston in the combustion chamber is shortened. At this time, the engine compression ratio in the combustion chamber is reduced. growing. On the other hand, when the cylinder block 2 and the cylinder head 3 are moved away from the cylinder block 2 in the direction indicated by the arrow Au, the stroke length of the piston in the combustion chamber becomes longer. At this time, the mechanical compression ratio in the combustion chamber is increased. Becomes smaller.

  The intake valve camshaft 6 includes a cam (not shown) that drives an intake valve (not shown) to open and close the valve, and is arranged on the cylinder head 3 so as to be rotatable about its axis. When the intake valve camshaft 6 is rotated, the intake valve is driven to open and close by a cam provided there. Further, a disc-shaped spur gear (hereinafter referred to as “intake valve camshaft gear”) 12 having teeth on the peripheral surface at one end of the intake valve camshaft 6 has a central axis coincident with the axis of the intake valve camshaft 6. It is attached as follows.

  On the other hand, the exhaust valve camshaft 7 includes a cam (not shown) that drives an exhaust valve (not shown) to open and close the valve, and is arranged on the cylinder head 3 so as to be rotatable about its axis. When the exhaust valve camshaft 7 is rotated, the exhaust valve is driven to open and close by a cam provided there. In addition, a disc-shaped spur gear (hereinafter referred to as “exhaust valve camshaft gear”) 13 having teeth on the peripheral surface at one end of the exhaust valve camshaft 7 has a central axis coincident with the axis of the exhaust valve camshaft 7. It is attached as follows.

  Further, a disk-shaped face gear (hereinafter referred to as “intermediate gear”) 11 is attached to the cylinder head 3 so as to be rotatable around its central axis. On the peripheral surface of the intermediate gear 11, teeth on which a chain belt 14 (to be described later) is wound are provided.

  A chain belt 14 is wound around the intermediate gear 11, the intake valve camshaft gear 12, and the exhaust valve camshaft gear 13. Therefore, when the intermediate gear 11 is rotated, the intake valve camshaft gear 12 and the exhaust valve camshaft gear 13 are rotated via the chain belt 14, and as a result, the intake valve camshaft 6 and the exhaust valve camshaft 7 are rotated. It is done.

  The crankshaft 4 is disposed in the crankcase 22 so as to be rotated around its axis by reciprocation of the piston in the combustion chamber. A disc-shaped face gear (hereinafter referred to as “crankshaft gear”) 8 is attached to one end of the crankshaft 4 so that the center axis thereof coincides with the axis of the crankshaft 4. Therefore, the crankshaft gear 8 rotates around its central axis when the crankshaft 4 rotates.

  The rotation transmission shaft 5 is a shaft that transmits the rotation of the crankshaft 4 to the intake valve camshaft 6 and the exhaust valve camshaft 7. A frustoconical bevel gear (hereinafter referred to as “crankshaft side gear”) 9 having teeth on the peripheral surface is attached to the end of the rotation transmission shaft 5 closer to the crankshaft 4. The gear 9 is attached to one end of the rotation transmission shaft 5 so that the center axis thereof coincides with the axis of the rotation transmission shaft 5. The gear 9 is meshed with the crankshaft gear 8. Therefore, the gear 9 is rotated around its central axis when the crankshaft gear 8 rotates.

  On the other hand, a frustoconical bevel gear (hereinafter referred to as “camshaft side gear”) having teeth on the peripheral surface at the end of the rotation transmission shaft 5 closer to the intake valve camshaft 6 and the exhaust valve camshaft 7. 10 is attached. The gear 10 is also attached to the rotation transmission shaft 5 so that the center axis thereof coincides with the axis of the rotation transmission shaft 5. The gear 10 is meshed with the intermediate gear 11. Accordingly, the intermediate gear 11 is rotated around its central axis when the rotation transmission shaft 5 rotates.

  Incidentally, the rotation transmission shaft 5 is a straight shaft composed of two straight shaft portions 5A and 5B, and the direction in which the cylinder block 2 and the cylinder head 3 are moved relative to the crankcase 22. That is, the internal combustion engine 1 is disposed so as to extend in the reciprocating direction A of the piston in the combustion chamber. Further, the camshaft side gear 10 is attached to the end of the shaft portion 5A, and the shaft portion 5A is hereinafter also referred to as “camshaft side shaft portion”. On the other hand, a crankshaft side gear 9 is attached to an end portion of the shaft portion 5B, and this shaft portion 5B is hereinafter also referred to as a “crankshaft side shaft portion”.

  As shown in FIG. 3, the shaft portions 5A and 5B are connected to each other so as to be slidable with respect to each other and in a nested manner. Specifically, a cavity 22 is formed in the crankshaft side shaft portion 5B. The cavity 22 extends in the axial direction from the end of the shaft portion 5B opposite to the side on which the crankshaft side gear 9 is attached toward the crankshaft side gear 9. A plurality of teeth 23B extending in the axial direction are formed on the inner circumferential wall surface of the cavity 22 at predetermined intervals in the circumferential direction. On the other hand, a plurality of grooves 23A extending in the axial direction are formed on the outer peripheral wall surface of the camshaft side shaft portion 5A at predetermined intervals in the circumferential direction. The shaft portion 5A is inserted into the cavity 22 of the shaft portion 5B so that the groove 23A of the shaft portion 5A fits into the teeth 23B of the shaft portion 5B. Thus, the spline 23 is formed by the groove 23A of the shaft portion 5A and the teeth 23B of the shaft portion 5B. The spline 23 allows the shaft portions 5A and 5B to slide with respect to each other and not to rotate with respect to each other. It is connected. The part constituting the groove 23A of the shaft part 5A forming the spline 23 and the part constituting the teeth 23B of the shaft part 5B can be said to be contact parts where the shaft parts 5A and 5B come into contact with each other.

  The camshaft side shaft portion 5 </ b> A is supported by the cylinder head 3 by a support member (hereinafter also referred to as “camshaft side support member”) 16 at a position close to the camshaft side gear 10. As can be seen from FIG. 3, the support member 16 supports the shaft portion 5A by a ball bearing 17A so as to be rotatable about its axis. Therefore, it can be said that the ball bearing 17A is a support portion of a support member that rotatably supports the rotation transmission shaft 5. On the other hand, the crankshaft side shaft portion 5 </ b> B is supported by the crankcase 22 by a support member (hereinafter also referred to as “crankshaft side support member”) 15 at a position close to the crankshaft side gear 8. As can be seen from FIG. 6, the support member 15 also supports the shaft portion 5A so as to be rotatable around its axis by a ball bearing 17B. Therefore, it can be said that the ball bearing 17B is a support portion of a support member that rotatably supports the rotation transmission shaft 5.

  When the cylinder block 2 and the cylinder head 3 are located closest to the crankcase 22, the shaft portions 5A and 5B of the rotation transmission shaft 5 are in the state shown in FIG. On the other hand, when the cylinder block 2 and the cylinder head 3 are located farthest from the crankcase 22, the shaft portions 5A and 5B of the rotation transmission shaft 5 are in the state shown in FIG. That is, when the cylinder block 2 and the cylinder head 3 are moved away from the crankcase 22, the camshaft side support member 16 moves away from the crankcase 22 following the movement of the cylinder head 3. For this reason, the shaft portion 5A supported by the support member 16 also slides relative to the shaft portion 5B so as to move away from the shaft portion 5B. Thus, even when the cylinder block 2 and the cylinder head 3 are moved away from the crankcase 22, the meshing between the camshaft side gear 10 and the intermediate gear 11 is maintained. On the other hand, when the cylinder block 2 and the cylinder head 3 are moved so as to approach the crankcase 22, the support member 16 moves so as to approach the crankcase 22 following the movement of the cylinder head 3. For this reason, the shaft portion 5A supported by the support member 16 also slides relative to the shaft portion 5B so as to approach the shaft portion 5B. Thus, even when the cylinder block 2 and the cylinder head 3 are moved so as to approach the crankcase 22, the engagement between the camshaft side gear 10 and the intermediate gear 11 is maintained.

  In the first embodiment, the axial length of the region where the shaft portions 5A and 5B are slidably connected to each other is such that the cylinder block 2 and the cylinder head 3 are moved to the farthest position from the crankcase 22. Even at times, the shaft portions 5A and 5B are set to such a length that the connection between them is not removed.

  Incidentally, as shown in FIG. 3, in the first embodiment, a lubricating oil passage 30A extending in the axial direction is formed in the camshaft side shaft portion 5A. On the other hand, a lubricating oil passage 30B extending in the axial direction is formed in the crankshaft side shaft portion 5B. The lubricating oil passages 30A and 30B are connected to each other in a region where the shaft portions 5A and 5B are slidably connected to each other. Therefore, in the first embodiment, it can also be expressed that the lubricating oil passages 30 </ b> A and 30 </ b> B are formed inside the rotation transmission shaft 5. The lubricating oil passage 30A in the shaft portion 5A is at least the end opposite to the end portion of the shaft portion 5A to which the camshaft side gear 10 is attached from the region of the shaft portion 5A supported by the camshaft side support member 16. Extending to the end and opening at the end. On the other hand, the lubricating oil passage 30B in the shaft portion 5B extends from the region of the shaft portion 5B supported by at least the crankshaft side support member 15 to the cavity 22. In the first embodiment, the lubricating oil passage 30 </ b> A, the lubricating oil passage 30 </ b> B, and the cavity 22 constitute a lubricating oil passage in the rotation transmission shaft 5. That is, in the first embodiment, the cavity 22 functions not only to accommodate the shaft portion 5A but also to function as a lubricating oil passage.

  As shown in FIGS. 3 to 5, a lubricating oil passage 32 </ b> A is formed in the camshaft side support member 16 so as to surround the rotation transmission shaft 5 and extend in an annular shape. The lubricating oil passage 32A and the lubricating oil passage 30A in the camshaft side shaft portion 5A are communicated with each other via a lubricating oil passage 31A formed in the shaft portion 5A. Further, the lubricating oil passage 32A is communicated with a lubricating oil passage (not shown) in the cylinder head 3 via a lubricating oil passage 36A formed in the support member 16. On the other hand, as shown in FIG. 6, a lubricating oil passage 32 </ b> B is formed in the crankshaft side support member 15 so as to surround the rotation transmission shaft 5 and extend annularly. The lubricating oil passage 32B and the lubricating oil passage 30B in the crankshaft side shaft portion 5B are communicated with each other via a lubricating oil passage 31B formed in the shaft portion 5B. Further, the lubricating oil passage 32 </ b> B communicates with a lubricating oil passage (not shown) in the crankcase 22 via a lubricating oil passage 36 </ b> B formed in the support member 15.

In the first embodiment, an oil pan (not shown) for storing lubricating oil is attached to the lower portion of the crankcase 22, and the lubricating oil stored in the oil pan is disposed in the crankcase 22. The oil is pumped up by an oil pump (not shown) and supplied to the lubricating oil passage 32 </ b> B in the crankshaft side support member 15 through the lubricating oil passage in the crankcase 22. The lubricating oil supplied to the lubricating oil passage 32B flows into the lubricating oil passage 30B in the shaft portion 5B via the lubricating oil passage 31B in the crankshaft side shaft portion 5B. The lubricating oil that has flowed into the lubricating oil passage 30B flows into the lubricating oil passage 30A in the camshaft side shaft portion 5A through the cavity 22 of the shaft portion 5B. The lubricating oil flowing into the lubricating oil passage 30A flows into the lubricating oil passage 32A in the camshaft side support member 16 via the lubricating oil passage 31A in the shaft portion 5A. The lubricating oil flowing into the lubricating oil passage 32A is supplied to the lubricating oil passage in the cylinder head 3.

  3 and 4, the shaft portions 5A and 5B are connected to each other and are elastic between the shaft portion 5B and the shaft portion 5A in a region close to the end of the shaft portion 5B. A ring-shaped seal 40 made of a body is arranged. The seal 40 seals the lubricating oil passage in the region where the shaft portions 5A and 5B are connected to each other. Here, in the first embodiment, since the seal 40 is disposed in a region close to the end of the shaft portion 5B, the lubricating oil is also supplied to the spline 23.

  3 to 5, the lubricating oil passage 32A in the camshaft side supporting member 16 extends to the lubricating oil chamber 33 formed in the supporting member 16 via the ball bearing 17A. Accordingly, the lubricating oil flowing into the lubricating oil passage 32A is supplied to the ball bearing 17A. Further, the camshaft side shaft portion 5A is formed with a protruding portion 34 that protrudes in a disc shape laterally from the outer peripheral wall surface in the axial direction. The protruding portion 34 is slidably accommodated in a recess 35 formed in the support member 16, and defines the lubricating oil chamber 33 together with the support member 16. Accordingly, the lubricating oil in the lubricating oil chamber 33 applies pressure to the wall surface 34 </ b> W of the protruding portion 34, and biases the protruding portion 34 toward the intermediate gear 11. According to this, the meshing between the camshaft side gear 10 and the intermediate gear 11 is sufficiently maintained. Since the wall surface 34W of the protruding portion 34 is applied with lubricating oil pressure, the wall surface 34W can be said to be a hydraulic wall surface.

  In the region where the camshaft side shaft portion 5A is supported by the camshaft side support member 16, a ring-shaped seal made of an elastic body is provided between the outer peripheral surface of the protruding portion 34 and the inner peripheral surface of the concave portion 35 of the support portion 16. 41 is arranged. The seal 41 seals the lubricating oil chamber 33 in the support member 16. On the other hand, an elastic body is provided between the outer peripheral surface of the shaft portion 5A and the support member 16 in a region where the shaft portion 5A is supported by the support member 16 and in a region opposite to the side where the seal 41 is disposed. The ring-shaped seal | sticker 42 which consists of is arrange | positioned. The support member 42 seals the lubricating oil passage 32 </ b> A in the support member 16.

  As can be seen from FIG. 6, the lubricating oil passage 32B in the crankshaft side support member 15 extends to the ball bearing 17B. Accordingly, the lubricating oil flowing into the lubricating oil passage 32B is supplied to the ball bearing 17B.

  The crankshaft side shaft portion 5B is supported by the crankshaft side support member 15 and is formed between the outer peripheral surface of the shaft portion 5B and the support member 15 in the region on both axial sides of the shaft portion 5B. The ring-shaped seals 43 and 44 are arranged. These seals 43 and 44 seal the lubricating oil passage 32 </ b> B in the support member 15.

  Also, the seal 40 disposed in the region where the shaft portions 5A and 5B are slidably connected to each other can be separated from the gap between the shaft portions 5A and 5B when the seal portion 40 is disposed between the shaft portions 5A and 5B. In other words, the spline 23 has a dimension that is crushed by a length longer than the width in the lateral direction with respect to the axial direction of the play. That is, when the seal 40 is disposed between the shaft portions 5A and 5B, the width of the cross section of the seal 40 is shorter than the original width by a length longer than the length of the gap width between the shaft portions 5A and 5B. The shaft portion 5A and the shaft portion 5B are crushed so as to be. According to this, the seal between the shaft portions 5A5B is sufficiently maintained.

  In the first embodiment, the camshaft side shaft portion is formed with a protruding portion disposed in the camshaft side support member, and a lateral direction with respect to the axis of the camshaft side shaft portion of the wall surface of the protruding portion is formed. The pressure of the lubricating oil is applied to the wall surface of the crankshaft side shaft portion so as to slide the shaft portions away from each other in the axial direction. However, the following configuration may be employed instead of or in addition to the protruding portion disposed in the support member described above in the first embodiment. That is, in the region where the shaft portions are slidably connected to each other in the axial direction, a protruding portion is formed on the camshaft side shaft portion so as to project laterally with respect to the axial line, and the shaft portions are axially aligned. In the first embodiment, a configuration in which the pressure of the lubricating oil is applied to the wall surface of the protruding portion in the direction of sliding away from each other may be employed.

  Of course, if the shaft portions can be slid away from each other in the axial direction, the camshaft side shaft portion where the protruding portion described above is formed is a portion or shaft portion disposed in the region within the support member. It does not have to be a portion that is arranged in a region where the members are slidably connected to each other in the axial direction. Considering this, broadly, in the first embodiment, the camshaft side shaft portion is formed with a wall surface extending in a direction transverse to its axis as a hydraulic wall surface, and the shaft portions are separated from each other in the axial direction. It can also be said that a configuration in which the pressure of the lubricating oil is applied to the hydraulic wall surface so as to slide is adopted.

  When the cylinder block and the cylinder head are moved away from the crankcase, it is necessary to slide the crankshaft side shaft portion away from the camshaft side shaft portion. What is necessary is just to form in a side shaft part. Considering this, more broadly, in the first embodiment, at least one shaft portion is formed with a wall surface extending laterally with respect to its axis as a hydraulic wall surface, and the shaft portions are separated from each other in the axial direction. It can also be said that a configuration in which the pressure of the lubricating oil is applied to the hydraulic wall surface so as to be slid on the surface is adopted.

  In the first embodiment, the camshaft side shaft portion is supported on the cylinder head by the camshaft side support member. However, instead of or in addition to this, the camshaft side shaft portion may be supported by the cylinder block by the support member. In the first embodiment, the crankshaft side shaft portion is supported by the crankcase by the crankshaft side support member. However, instead of this, or in addition to this, the crankshaft side shaft portion may be supported by the cylinder block by the support member.

  In the first embodiment, the rotation transmission shaft is composed of two shaft portions. However, instead of this, the rotation transmission shaft may be composed of one shaft. Next, an embodiment (hereinafter also referred to as “second embodiment”) to which the present invention is applied when the rotation transmission shaft is composed of one shaft will be described with reference to the drawings.

  In FIG. 7, reference numeral 201 denotes a variable compression ratio internal combustion engine (hereinafter also simply referred to as “internal combustion engine”) of the second embodiment. The internal combustion engine 201 includes a cylinder block 201, a crankcase 222, a cylinder head 203, a crankshaft 204, a rotation transmission shaft 205, an intake valve camshaft 206, and an exhaust valve camshaft 207. Here, except for the rotation transmission shaft 205, the configurations of the cylinder block 201, the crankcase 222, the cylinder head 203, the crankshaft 204, the intake valve camshaft 206, and the exhaust valve camshaft 207 are the same as those in the first embodiment. Therefore, detailed description will be omitted as appropriate. Further, since the configuration of the eccentric shaft 223, the main shaft 224, the cam 225, the sub shaft 26, and the cam 27 is the same as that of the first embodiment, detailed description thereof will be omitted as appropriate.

  An intake valve camshaft gear 212 is attached to one end of the intake valve camshaft 206. On the other hand, an exhaust valve camshaft gear 213 is attached to one end of the exhaust valve camshaft 207. Since the configurations of the intake valve camshaft gear 212 and the exhaust valve camshaft gear 213 are the same as those in the first embodiment, detailed description thereof will be omitted as appropriate.

  Further, a disk-shaped face gear (hereinafter referred to as “intermediate gear”) 211 is attached to the cylinder head 203 so as to be rotatable around its central axis. On the peripheral surface of the intermediate gear 11, teeth on which a chain belt 214 described later is wound are provided.

  A chain belt 214 is wound around the intermediate gear 211, the intake valve camshaft gear 212, and the exhaust valve camshaft gear 213. Therefore, when the intermediate gear 211 is rotated, the intake valve camshaft gear 212 and the exhaust valve camshaft gear 213 are rotated via the chain belt 214. As a result, the intake valve camshaft 206 and the exhaust valve camshaft 207 are rotated. It is done.

  The crankshaft 204 is disposed in the crankcase 222. A disc-shaped face gear (hereinafter referred to as “crankshaft gear”) 208 is attached to one end of the crankshaft 204 so that the center axis thereof coincides with the axis of the crankshaft 204. Accordingly, the crankshaft gear 208 rotates about its central axis when the crankshaft 204 rotates.

  The rotation transmission shaft 205 is a shaft that transmits the rotation of the crankshaft 204 to the intake valve camshaft 206 and the exhaust valve camshaft 207. A cylindrical spur gear (hereinafter referred to as “crankshaft side gear”) 209 having teeth on the peripheral surface is attached to the end of the rotation transmission shaft 205 closer to the crankshaft 204. The gear 209 is attached to the rotation transmission shaft 205 so that its center axis coincides with the axis of the rotation transmission shaft 205. The gear 209 is rotated around its central axis when the crankshaft gear 208 rotates.

  On the other hand, a cylindrical spur gear (hereinafter referred to as “camshaft side gear”) 210 having teeth on the peripheral surface at the end of the rotation transmission shaft 205 closer to the intake valve camshaft 206 and the exhaust valve camshaft 207. Is attached. The gear 210 is attached to the rotation transmission shaft 205 so that the center axis thereof coincides with the axis of the rotation transmission shaft 205. The gear 210 is meshed with the intermediate gear 211. Accordingly, the intermediate gear 211 is rotated around its central axis when the rotation transmission shaft 205 rotates.

  The rotation transmission shaft 205 is a straight shaft, and is arranged so as to extend in the direction in which the cylinder block 202 and the cylinder head 203 move relative to the crankcase 222, that is, in the reciprocating direction of the piston in the combustion chamber. Has been. The rotation transmission shaft 205 is supported by the crankcase 222 so as to be rotatable about its axis by a support member (hereinafter also referred to as “crankshaft side support member”) 215 at a position close to the crankshaft side gear 209. On the other hand, the rotation transmission shaft 205 is supported by the cylinder head 203 so as to be rotatable about its axis by a support member (hereinafter also referred to as “camshaft side support member”) 216 at a position close to the camshaft side gear 210. As shown in FIG. 8, the camshaft side support member 216 supports the rotation transmission shaft 205 by a ball bearing 217A so as to be rotatable about its axis. Therefore, it can be said that the ball bearing 217A is a support portion of the support member 215 that supports the rotation transmission shaft 205 so as to be rotatable about its axis. On the other hand, as shown in FIG. 10, the crankshaft side support member 215 supports the rotation transmission shaft 205 by a ball bearing 217B so as to be rotatable around its axis. Therefore, it can be said that the ball bearing 217B is a support portion of the support member 216 that supports the rotation transmission shaft 205 so as to be rotatable about its axis.

  When the cylinder block 202 and the cylinder head 203 are moved relative to the crankcase 222, the intermediate gear 211 slides relative to the camshaft side gear 210. Thus, even if the intermediate gear 211 slides relative to the camshaft side gear 210, the intermediate gear 211 and the camshaft side gear 210 are configured so that the meshing between the intermediate gear 211 and the camshaft side gear 210 is maintained. Has been.

  8 to 10, a lubricating oil passage 230 extending from the crankshaft side support member 215 to the camshaft side support member 216 is formed in the axial direction in the rotation transmission shaft 205 of the second embodiment. ing.

  As shown in FIG. 8, lubricating oil 232 </ b> A is formed in the camshaft side support member 216 so as to surround the rotation transmission shaft 205 and extend in an annular shape. The lubricating oil path 232A and the lubricating oil path 230 of the rotation transmission shaft 205 are communicated with each other via a lubricating oil path 231A formed in the rotation transmission shaft 205. Further, the lubricating oil path 232A communicates with a lubricating oil path (not shown) in the cylinder head 203 via a lubricating oil path 236A formed in the support member 216. Therefore, the lubricating oil in the lubricating oil path 230 of the rotation transmission shaft 205 flows into the lubricating oil path 232A of the support member 216 via the lubricating oil path 231A. The lubricating oil that has flowed into the lubricating oil path 232A flows into the lubricating oil path of the cylinder head 203 via the lubricating oil path 236A. Further, the lubricating oil path 232A extends to the ball bearing 217A.

  Note that the lubricating oil path 232A of the camshaft side support member 216 is sealed by ring-shaped seals 241 and 242 made of an elastic body in regions on both sides in the axial direction of the rotation transmission shaft 205. FIG. 8 shows the configuration of the support member 216 and its surroundings when the cylinder block 202 and the cylinder head 203 are located closest to the crankcase 222. On the other hand, FIG. 9 shows a configuration of the support member 216 and its periphery when the cylinder block 202 and the cylinder head 203 are located farthest from the crankcase 222. As can be seen from FIG. 9, in the second embodiment, the lubricating oil passage 231 </ b> A of the rotation transmission shaft 205 lubricates the support member 216 even when the cylinder block 202 and the cylinder head 203 are farthest from the crankcase 222. It communicates with the oil passage 232A.

  On the other hand, as shown in FIG. 10, a lubricating oil passage 232 </ b> B is formed in the crankshaft side support member 215 so as to surround the rotation transmission shaft 205 and extend in an annular shape. The lubricating oil passage 232B and the lubricating oil passage 230 of the rotation transmission shaft 205 are communicated with each other via a lubricating oil passage 231B formed in the rotation transmission shaft 205. Further, the lubricating oil passage 232B communicates with a lubricating oil passage (not shown) in the crankcase 222 via a lubricating oil passage 236B formed in the support member 215. Therefore, the lubricating oil that has flowed into the lubricating oil path 236B from the lubricating oil path of the crankcase 222 flows into the lubricating oil path 232B. The lubricating oil that has flowed into the lubricating oil path 232B flows into the lubricating oil path 230 via the lubricating oil path 231B. Further, the lubricating oil passage 232B extends to the ball bearing 217B.

  The lubricating oil path 232B of the crankshaft side support member 215 is sealed by ring-shaped seals 243 and 244 made of an elastic body in regions on both sides in the axial direction of the rotation transmission shaft 205.

  In the above-described embodiment, the cylinder block and the cylinder head are movable relative to the crankcase, and the cylinder block and the cylinder head are moved relative to the crankcase to thereby reduce the engine compression ratio in the combustion chamber. The present invention is applied to a variable compression ratio internal combustion engine that can be changed. However, the present invention is composed of at least two block parts that are movably connected to each other, and the mechanical compression ratio in the combustion chamber is changed by moving one block part relative to the other block part. The present invention is also applicable to a variable compression ratio internal combustion engine that can be used.

  DESCRIPTION OF SYMBOLS 1,210 ... Variable compression ratio internal combustion engine, 2, 202 ... Cylinder block, 3, 203 ... Cylinder head, 4 ... Crank shaft, 5, 205 ... Rotation transmission shaft, 5A, 5B ... Shaft part, 6, 206 ... Intake valve Camshaft, 7, 207 ... Exhaust valve camshaft, 15, 16, 215, 216 ... Support member, 17A, 17B, 217A, 217B ... Ball bearing, 22, 222 ... Crankcase, 23 ... Spline, 30A, 30B, 31A 31B, 32A, 32B ... Lubricating oil passage, 34 ... Projection, 34 ... Hydraulic wall surface, 40 ... Seal

Claims (8)

  A variable compression ratio that is composed of at least two block parts that are movably connected to each other and that can change the mechanical compression ratio in the combustion chamber by moving one block part relative to the other block part. A variable compression ratio internal combustion engine, wherein a camshaft having a cam for opening and closing an intake valve or an exhaust valve is disposed in the one block portion and a crankshaft is disposed in the other block portion. In the engine, a rotation transmission shaft for transmitting rotation of the crankshaft to the camshaft is provided, and a lubricating oil passage for flowing lubricating oil between one block portion and the other block portion is provided in the rotation transmission shaft. A variable compression ratio internal combustion engine characterized by being formed.   The rotation transmission shaft is composed of at least two shaft parts that are connected to each other so as to be slidable with respect to each other, and the parts of the shaft parts that are in contact with each other in a nested manner are referred to as shaft part contact parts, respectively. 2. The variable compression ratio internal combustion engine according to claim 1, wherein the lubricating oil passage of the rotation transmission shaft is configured so that the lubricating oil is circulated between the shaft partial contact portions when the two are connected.   A seal made of an elastic body is disposed between the shaft portions so as to seal between the shaft portion contact portions, and the shaft contact portions when the seal is measured in a direction transverse to the axis of the shaft portion. 3. The variable compression ratio internal combustion engine according to claim 2, wherein the internal combustion engine is disposed between the shaft contact portions in a state of being crushed by a length longer than the width of the gap. At least one of the shaft portions is arranged in parallel to a direction in which one block portion moves relative to the other block portion, and the one shaft portion has a wall surface perpendicular to the axis thereof. A hydraulic oil wall is provided, and the hydraulic oil is supplied to the hydraulic wall so that the oil pressure is applied to the hydraulic wall in a direction that slides the one shaft part away from the other shaft part in the axial direction, The lubricating oil path between the hydraulic wall surface and the lubricating oil path of the rotation transmission shaft is configured so that the lubricating oil flows between the hydraulic wall surface and the lubricating oil path of the rotation transmission shaft. The variable compression ratio internal combustion engine according to claim 2 or 3, characterized in that
The one shaft portion is supported by the block portion by a support member, and the one shaft portion has a projecting portion projecting laterally with respect to the axis thereof, and the projecting portion is disposed in the support member. As described above, the one shaft portion is supported by the support member on the block portion, and is a wall surface perpendicular to the axis of the shaft portion of the wall surface of the protruding portion, and is disposed in the support member. The variable compression ratio internal combustion engine according to claim 4, wherein a wall surface that constitutes the hydraulic wall surface.
  The lubricating oil path for allowing the lubricating oil to flow between the lubricating oil path of the rotation transmission shaft and the lubricating oil path formed in the block portion is formed in the support member. 5. The variable compression ratio internal combustion engine according to 5. The rotation transmission shaft is supported by the block portion by a support member, and a lubricating oil passage for flowing lubricating oil between the lubricating oil passage of the rotation transmission shaft and the lubricating oil passage formed in the block portion. The variable compression ratio internal combustion engine according to claim 1, wherein is formed in the support member.
  The lubricating oil passage of the support member has a portion where the support member rotatably supports the rotation transmission shaft as a rotation transmission shaft support portion, and the lubricating oil flows between the rotation transmission shaft support portion and the rotation transmission shaft support portion. The variable compression ratio internal combustion engine according to any one of claims 5 to 7, wherein

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