JP2010185396A - Lubricating device for reciprocating type variable compression ratio engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply an oil jet 21 to a cylinder 6 inner wall surface by using lubricating oil supplied through a crankshaft 3 interior. <P>SOLUTION: A multilink type piston crank mechanism equipped with an upper link 11, a lower link 13, and a control link 15 is provided, and the lubricating oil is supplied through the crankshaft 3 interior. In a crankshaft 3 side, an oil supply hole with an opened tip is provided on a thrust bearing surface in an inner side of a crank web, and in a lower link 13 side, an oil guide groove 33 is recessed on an annular flange surface 32 of a crank pin periphery in correspondence to a thrust bearing surface of a crankshaft 3 side. In a predetermined attitude of the lower link 13, if the oil guide groove 33 is aligned with the oil supply hole, the oil jet 21 is supplied. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reciprocating variable compression ratio engine using a multi-link type piston-crank mechanism, and more particularly to a lubricating device for lubricating a cylinder inner wall surface and the like.

  The present applicant previously used a multi-link type piston-crank mechanism as a variable compression ratio mechanism of a reciprocating internal combustion engine, and changed the piston top dead center position by moving a part of the link configuration. Various mechanisms have been proposed (for example, Patent Documents 1 and 2). The upper link is connected to the piston via a piston pin, the lower link is connected to the upper link via the upper pin so as to be swingable, and is rotatably attached to the crank pin of the crankshaft. And a control link that is swingably connected to the lower link via a control pin, and an eccentric shaft that is rotatably provided to the cylinder block and supports the other end of the control link so as to be swingable. The control shaft is variably controlled by controlling the position of the eccentric shaft of the control shaft in accordance with the engine operating conditions.

  Further, Patent Document 3 proposes a lubricating device that guides lubricating oil from a control shaft to a control link and injects the oil as an oil jet from an end of the control link connected to a control pin.

JP 2000-73804 A JP 2002-215902 A JP 2004-116334 A

  In the configuration of Patent Document 3, when the control link and the upper pin are located along the same plane (one plane orthogonal to the crankshaft axis), the control link is extended from the end of the control link in the direction crossing the upper link. The supply of the oil jet is likely to be limited by interference between the upper link and the oil jet. In the case where the upper pin is located at a relatively lower portion, the spray distance necessary for the oil jet becomes longer.

  In addition, an oil passage for supplying lubricating oil to the main journal or the like is generally formed inside the crankshaft. However, in the above configuration, the lubricating oil from the inside of the crankshaft cannot be used effectively.

  Therefore, the present invention is a reciprocating variable compression ratio engine that uses a multi-link piston-crank mechanism so that the sliding portion of each part such as a cylinder can be reliably lubricated using lubricating oil flowing inside the crankshaft. The purpose is to do.

  The lubricating device according to the present invention includes an upper link connected to a piston via a piston pin, a lower link connected to the upper link via an upper pin so as to be swingable, and rotatably attached to a crank pin of a crankshaft. A link, a control link having one end portion pivotably connected to the lower link via a control pin, and a cylinder block rotatably provided, and rotatably supporting the other end portion of the control link And a reciprocating variable compression ratio engine that variably controls the engine compression ratio by controlling the position of the eccentric shaft of the control shaft according to engine operating conditions. The crankshaft has an oil supply hole formed at the tip thereof on the thrust bearing surface around the crankpin of the crankshaft, and the lower link side annular flange surface in sliding contact with the thrust bearing surface has a predetermined lower link. In this swinging posture, an oil guide groove that matches the opening of the tip of the oil supply hole is formed, and an oil jet is supplied along the oil guide groove.

  That is, the lower link reciprocally swings with the rotation of the crankshaft, but the oil guide groove of the lower link and the oil supply hole that opens on the thrust bearing surface around the piston pin match in a predetermined posture, High pressure lubricating oil supplied through the crankshaft is ejected as an oil jet. Thereby, lubrication of a desired part, for example, a cylinder inner wall surface, etc. can be performed.

  The oil guide groove is formed in an annular flange surface serving as an end portion in the axial direction of the lower link, and is offset from the position of the upper link or the position of the control link in the axial direction of the crankshaft. Therefore, the supply of the oil jet in the direction crossing these upper links and control links is not limited at all. Further, when lubricating the inner wall surface of the cylinder, since the oil jet is supplied from the lower link located relatively close to the cylinder, the necessary spray distance is short. In addition, the oil jet hole is not formed in the lower link that receives a large load, but a slight oil guide groove is formed in the annular flange surface. Jet supply can be easily handled by forming a plurality of guide grooves.

  According to the present invention, each part of the multi-link type piston-crank mechanism can be reliably lubricated using the lubricating oil supplied through the crankshaft.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing which shows one Example of this invention. The partially cutaway sectional view of the principal part of a crankshaft provided with an oil supply hole. The perspective view of the lower link provided with the oil guide groove. The expansion perspective view of the principal part. Structure explanatory drawing which shows an example of the directivity direction of an oil jet. Structure explanatory drawing which shows another example of the directivity direction of an oil jet.

  FIG. 1 shows an example of a basic configuration of a reciprocating variable compression ratio engine equipped with a lubricating device of the present invention. As shown in the drawing, a piston 1 is placed in a cylinder 6 formed in a cylinder block 5. The upper link 11 is connected to the piston 1 through a piston pin 2 so as to be swingable. The other end of the upper link 11 is rotatably connected to one end of the lower link 13 via an upper pin 12. The lower link 13 is swingably attached to the crankpin 4 of the crankshaft 3 at the center thereof. The lower link 13 is divided into upper and lower or left and right parts, and is integrated by a bolt (not shown). The crankshaft 3 rotates around the point O.

  One end of a control link 15 is rotatably connected to the other end of the lower link 13 via a control pin 14. The other end of the control link 15 is swingably supported by a part of the internal combustion engine body, and the position of the swing fulcrum can be displaced with respect to the internal combustion engine body in order to change the compression ratio. It has become. Specifically, a control shaft 18 extending in parallel with the crankshaft 3 is provided, and the other end of the control link 15 is rotatably fitted to an eccentric shaft 19 provided eccentric to the control shaft 18. The control shaft 18 is rotatably supported with respect to the cylinder block 5 and linked to an appropriate actuator mechanism (not shown).

  Therefore, when the control shaft 18 is rotationally driven by the actuator mechanism in order to change the compression ratio, the center position of the eccentric shaft 19 serving as the swing fulcrum of the control link 15 moves relative to the engine body. As a result, the motion restraint condition of the lower link 13 by the control link 15 changes, the stroke position of the piston 1 with respect to the crank angle changes, and consequently the engine compression ratio changes.

  Here, in this embodiment, the oil jet indicated by the arrow 21 is supplied from between the lower link 13 and the crankshaft 3 toward the inner wall surface of the cylinder 6, and lubrication and cooling of the inner wall surface of the cylinder 6 on which the piston 1 slides. Is done.

  FIG. 2 shows an oil supply hole 22 on the crankshaft 3 side that forms a part of the lubrication mechanism. The crankshaft 3 extends in a radial direction from the main journal 23, a crank web 24 that forms a pair connecting the main journal 23 and the crank pin 4, and the crank web 24 to the opposite side of the crank pin 4. And a counterweight portion 25. On the inner surfaces of the crank web 24 facing each other, a thrust bearing surface 26 surrounding the crankpin 4 in an annular shape is formed. In addition, as an oil passage, a first oil hole 27 is drilled so as to obliquely penetrate the crank pin 4 from the main journal 23, and a diameter is formed at the center of the crank pin 4 so as to intersect the first oil hole 27. A second oil hole 28 along the direction is drilled. The main journal 23 is further formed with a third oil hole 29 in the radial direction intersecting with the end of the first oil hole 27, and the end of the first oil hole 27 on the crank web 24 side is closed with a plug. Has been. Lubricating oil is introduced into these oil passages from the bearing portion of the main journal 23 on the cylinder block 5 side and flows from the third oil hole 29 to the second oil hole 28 via the first oil hole 27. Thus, the sliding portion between the crankpin 4 and the lower link 13 is lubricated. In addition, it can also comprise so that lubricating oil may be guided further from the lower link 13 to the upper pin 12 or the upper link 11 side as needed.

  A thin oil supply hole 22 reaching the first oil hole 27 is obliquely drilled in the crank web 24, and the tip of the oil supply hole 22 opens in the thrust bearing surface 26. In addition, the position of the oil supply hole 22 in the illustrated thrust bearing surface 26 is an example, and is not necessarily limited to this position. Further, the oil supply hole 22 is formed so as to be inclined with respect to the central axis of the crankpin 4 so as to follow the direction of the desired oil jet 21 as much as possible.

  As shown in FIGS. 3 and 4, the lower link 13 attached to the crank pin 4 has a peripheral edge of the crank pin fitting hole 31 protruding slightly in the axial direction in a cylindrical shape, and its end surface is an annular flange. Surface 32 is formed. The radial width of the annular flange surface 32 corresponds to the radial width of the thrust bearing surface 26 on the crankshaft 3 side, and is configured to be in sliding contact with each other through a very small predetermined gap. Yes. An oil guide groove 33 is recessed at a predetermined location on the annular flange surface 32 corresponding to the oil supply hole 22. The oil guide groove 33 may completely traverse the thrust bearing surface 26 in the radial direction, but desirably, the end on the inner diameter side is closed and the end on the outer diameter side is closed as shown in FIG. The part opens to the cylindrical surface on the outer peripheral side of the annular flange surface 32 protruding in a cylindrical shape. Therefore, in a state where the annular flange surface 32 is aligned with the thrust bearing surface 26 and the oil guide groove 33 is covered with the thrust bearing surface 26, the oil guide groove 33 becomes a narrow oil passage extending in the radial direction of the crank pin 4, and The tip is open toward the outer peripheral side. The oil guide groove 33 does not need to be along the exact radial direction of the crank pin 4, but in a direction appropriately inclined with respect to the radial line of the crank pin 4 in order to form the oil jet 21 in a desired direction. It is possible to form.

  In the configuration as described above, when the lower link 13 swings to a predetermined position as the crankshaft 3 rotates, the oil supply hole 22 on the crankshaft 3 side matches the oil guide groove 33 on the lower link 13 side, High-pressure lubricating oil is ejected along the oil guide groove 33 to form the oil jet 21. The directing direction of the oil jet 21 and the timing of the injection (that is, the crank angle position) can be appropriately set as necessary.

  In the example of FIG. 1, when the piston 1 is at the top dead center position or at a position in the vicinity thereof, the oil supply hole 22 and the oil guide groove 33 are aligned, and the inner wall surface of the cylinder 6 is positioned as close to the top as possible. The oil jet 21 is supplied in the direction.

  As shown in FIG. 1, the upper link 11 mainly swings in a configuration in which the center of the upper pin 12 is located on the left side of the drawing and the center of the control pin 14 is located on the right side of the drawing across the central axis of the cylinder 6. If the left side of the figure to be defined is defined as “anti-thrust side” and the right side of the figure as the opposite side is defined as “thrust side”, in this FIG. A jet 21 is supplied. In such a multi-link piston-crank mechanism, the thrust side is generally more severe in terms of surface pressure and wear. In the present invention, since the oil jet 21 is supplied from the position of the crank pin 4 that is relatively close to the cylinder 6, the required spray distance is short and reliable lubrication can be performed. Further, since the oil jet 21 is supplied through a wide space where the upper link 11 does not exist, the oil jet 21 can be directed to a position as high as possible in the cylinder 6.

  FIG. 5 shows an embodiment in which the oil jet 21 is directed to a region on the anti-thrust side of the inner wall surface of the cylinder 6 as an example. In this case, the oil jet 21 advances in a manner that crosses the upper link 11, but as the position in the axial direction of the crankpin 4, the position of the oil guide groove 33, that is, the oil jet 21, as is apparent from FIG. 3. The positions of the upper links 11 sandwiched between the thicknesses of the lower links 13 do not overlap with each other and are offset from each other, so that the oil jet 21 does not substantially interfere with the upper links 11. It can go to the inner wall surface of the cylinder 6. Therefore, regardless of the swinging posture of the upper link 11, the region on the anti-thrust side of the cylinder 6 can be reliably lubricated.

  In the present invention, a plurality of oil guide grooves 33 and oil supply holes 22 oriented in different directions as shown in FIGS. 1 and 5 can be provided in one cylinder. In particular, by using the end faces on both sides of the lower link 13, oil guide grooves 33 that are directed in different directions are provided, and two corresponding oil supply holes 22 are provided in each of the pair of crank webs 24. it can. In addition, the plurality of oil jets 21 by the plurality of oil guide grooves 33 can be easily configured to be supplied at different timings.

  In particular, in the present invention, the lower link 13 to which a very large load acts is not provided with a through hole, but only a few oil guide grooves 33 are provided, and the plurality of oil guide grooves 33 are arranged on both sides or one side. Even if formed, the strength reduction of the lower link 13 is minimized.

  In order to reduce the decrease in hydraulic pressure, it is desirable that the plurality of oil jets 21 have different timings. However, if necessary, the plurality of oil jets 21 may be supplied at the same time, or the same location. It is also possible to configure so that the oil jet 21 is supplied a plurality of times.

  Next, an embodiment in which the posture change of the lower link 13 accompanying the change of the compression ratio (that is, the change of the position of the control link 15) is used will be described with reference to FIG. FIG. 6 shows a state in which the compression ratio is controlled to a high compression ratio, and therefore the eccentric shaft 19 of the control shaft 18 is located relatively below. Then, at a predetermined crank angle position, the oil jet 21 is supplied so as to be directed toward the lower end portion of the inner wall surface of the cylinder 6 (on the opposite side of the thrust). The high compression ratio is controlled in this way in the low and medium load range of the engine, and the oil jet 21 lubricates the sliding portion between the piston 1 and the cylinder 6.

  On the other hand, in the high load region of the engine, the compression ratio is controlled to a low compression ratio, and the position of the eccentric shaft 19 of the control shaft 18 is a relatively upper position. Along with this, the posture of the lower link 13 slightly changes when the oil supply hole 22 and the oil guide groove 33 are matched, and the oil jet 21 is directed downward from the lower end of the cylinder 6. Therefore, the amount of lubricating oil adhering to the inner wall surface of the cylinder 6 is reduced. In the engine high load region, the consumption of the lubricating oil adhering to the inner wall surface of the cylinder 6 increases. Therefore, the reduction of the lubricating oil can be suppressed by changing the direction of the oil jet 21 as in this embodiment.

DESCRIPTION OF SYMBOLS 1 ... Piston 3 ... Crankshaft 11 ... Upper link 13 ... Lower link 15 ... Control link 18 ... Control shaft 19 ... Eccentric shaft 21 ... Oil jet 22 ... Oil supply hole 33 ... Oil guide groove

Claims (7)

An upper link connected to the piston via a piston pin, a lower link connected to the upper link via an upper pin so as to be swingable, and rotatably attached to a crank pin of the crankshaft, and one end portion of the upper link A control link that is swingably connected to the lower link via a control pin, and a control shaft that is rotatably provided to the cylinder block and includes an eccentric shaft that rotatably supports the other end of the control link. In a reciprocating variable compression ratio engine that variably controls the engine compression ratio by controlling the eccentric shaft position of the control shaft according to engine operating conditions,
An oil supply hole having a tip opening on the thrust bearing surface around the crankpin of the crankshaft is formed in the crankshaft, and a predetermined swing of the lower link is formed on the annular flange surface on the lower link side that is in sliding contact with the thrust bearing surface. A lubrication device for a reciprocating variable compression ratio engine, wherein an oil guide groove that coincides with the opening of the tip of the oil supply hole is formed in a moving posture, and an oil jet is supplied along the oil guide groove.   In the configuration in which the center of the upper pin is located on one side of the cylinder center axis and the center of the control pin is located on the other side, the oil jet crosses the upper link and is located on the upper pin side of the cylinder inner wall surface. 2. The lubrication apparatus for a reciprocating variable compression ratio engine according to claim 1, wherein the oil supply hole and the oil guide groove are arranged so as to be directed to the portion.   The oil supply hole and the oil guide groove are respectively provided on both sides in the axial direction of the lower link, and two oil jets formed by these are directed in different directions. Item 3. The lubricating device for a reciprocating variable compression ratio engine according to Item 1 or 2.   4. The reciprocating variable compression according to claim 3, wherein the oil supply hole and the oil guide groove on each side are matched with each other in different postures of the lower link, and each oil jet is supplied at different timings. Specific engine lubrication equipment.   5. The lubricating device for a reciprocating variable compression ratio engine according to claim 3, wherein an oil jet is supplied in each of two directions orthogonal to the piston pin on the inner wall surface of the cylinder.   6. The reciprocating variable compression ratio engine lubrication device according to claim 1, wherein an oil jet directed to the upper part of the cylinder is supplied near the top dead center of the piston.   Supply the oil so that the oil jet is directed to the lower end of the cylinder inner wall surface at the control pin position corresponding to the low compression ratio, and the oil jet is directed to the position below the cylinder lower end at the control pin position corresponding to the high compression ratio. The lubrication device for a reciprocating variable compression ratio engine according to any one of claims 1 to 6, wherein a hole and an oil guide groove are arranged.

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