JP5251576B2 - Double link piston crank mechanism for internal combustion engine - Google Patents

Description

  The present invention relates to a multi-link type piston crank mechanism of an internal combustion engine, and more particularly to lubrication of a pin bearing portion of a connecting pin that rotatably connects an upper link, a control link, and a lower link.

  As a prior art in which a piston pin and a crank pin of a reciprocating internal combustion engine are connected by a multi-link type piston crank mechanism, Patent Document 1 previously proposed by the present applicant is known. This includes an upper link connected to the piston pin of the piston, a lower link connecting the upper link and the crank pin of the crankshaft, one end supported to be swingable to the engine body side, and the other end to the lower link. A control link coupled to the link. The upper link and the lower link are rotatably connected to each other via an upper pin, and the control link and the lower link are rotatably connected to each other via a control pin.

  The lower link in such a multi-link type piston crank mechanism is a kind of “lever” that receives the combustion pressure (combustion gas force) received by the piston from the upper pin via the upper link and uses the control pin as a fulcrum. The force is transmitted to the crankpin by movement

JP 2004-1224776 A

  In the lower link as described above, a large maximum combustion gas force received by the piston is input from the upper pin bearing portion via the piston pin, the upper link, and the upper pin. At the same time, a load is also generated in the crank pin bearing portion and the control pin bearing portion so as to balance this load. Accordingly, the surface pressure of each bearing portion is stricter than that of a general single link type reciprocating engine, and it is required to maintain a sufficient lubrication state in order to prevent wear and seizure.

  Here, for lubrication of the bearing portion of the crankpin, it is possible to supply a predetermined pressure of lubricating oil pressurized by an oil pump using an oil passage formed inside the crankshaft, and use hydraulic pressure. The forced lubrication can be performed relatively easily.

  However, during engine operation, the lower link revolves around the crankshaft together with the crankpin according to the rotation of the crankshaft, and is displaced in the rotational direction with respect to the crankpin. It is structurally difficult to forcibly supply the lubricating oil to the pin bearing portions of the upper link and the control link connected via the hydraulic pressure using hydraulic pressure. For this reason, in the above conventional configuration, so-called natural lubrication / atmosphere lubrication is performed in which the bearing portion of the upper pin and the bearing portion of the control pin are lubricated by the lubricating oil scattered in the internal combustion engine. In this case, the amount of lubrication is uncertain. It is difficult to obtain a sufficient lubrication state.

  The present invention relates to lubrication of a pin bearing portion of a connecting pin that rotatably connects an upper link, a control link, and a lower link in a multi-link type piston crank mechanism of an internal combustion engine. The multi-link type piston crank mechanism includes an upper link whose one end is connected to the piston via a piston pin, and is connected to the other end of the upper link via a first connection pin, and is connected to the crank pin of the crankshaft. A lower link that is rotatably mounted, and a control link that has one end pivotably supported on the engine body side and the other end coupled to the lower link via a second coupling pin. .

  Further, as an oil passage configuration, a crank pin oil passage formed on the crank pin and having one end opened to the outer peripheral surface of the crank pin, and at least one of the first connection pin and the second connection pin are rotatably fitted. The pin boss is formed in the pin boss portion of the upper link or the control link and passes through the inner peripheral surface and the outer peripheral surface of the pin boss portion, and the pin boss facing the outer surface of the pin boss portion formed in the lower link. A lower link oil passage penetrating the surface and the crankpin bearing surface.

  Then, when the crankpin oil passage and the lower link oil passage communicate with each other at a predetermined crank angle, the lubricant is jetted from the lower link oil passage to the pin boss oil passage, and a part thereof is supplied to the pin boss oil passage. Is set to Structurally, the crank pin oil passage and the lower link oil passage communicate with each other in a predetermined link arrangement, and the pin boss oil passage is located on an oil passage extension line of the lower link oil passage. It is said.

  Thereby, in a link arrangement at a predetermined crank angle where the crankpin oil passage and the lower link oil passage communicate with each other, lubricating oil having a predetermined pressure supplied to the crankpin oil passage is ejected from the lower link oil passage, A part thereof is forcibly supplied to the pin bearing portion between the connecting pin and the pin boss portion through the pin boss oil passage.

  According to the present invention, the lubricating oil is forcibly supplied to the pin bearing portion by the connecting pin of the lower link and the upper link or the control link, and the shortage of the lubricating oil amount of the pin bearing portion is suppressed or eliminated, A lubrication state can be realized.

The cross section which shows the link arrangement | positioning in the 1st crank angle of the piston top dead center vicinity in the multiple link type piston crank mechanism of the internal combustion engine which concerns on one Example of this invention in which a crankpin oil path and a lower link oil path connect. Correspondence diagram. FIG. 3 is a cross-sectional view along the oil passage extension line of the lower link oil passage in FIG. 1. FIG. 3 is a cross-sectional view showing a link arrangement at a second crank angle in the vicinity of a piston bottom dead center where a crankpin oil passage and a lower link oil passage communicate with each other in the multi-link piston crank mechanism of FIG. 1. Sectional drawing which shows the upper link to which the 2nd example of a pin boss oil path is applied. Sectional drawing (A) and side view (B) which show the upper link to which the 3rd example of a pin boss oil path is applied. The expansion perspective view which shows the pin boss | hub part of the upper link of FIG. (A) is a cross-sectional view showing the load acting on the upper pin from the lower link, (B) is a cross-sectional view showing exaggerated deformation of the upper pin due to this load. The cross-sectional view which shows the example which provided the lower link oil path of both the upper link side and the control link side in the lower link.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a configuration explanatory view showing a configuration example in which a multi-link piston crank mechanism is configured as a variable compression ratio mechanism. This mechanism includes a multi-link type piston crank mechanism mainly composed of a lower link 4, an upper link 5 and a control link 10. The crankshaft 1 includes a plurality of journal portions 2 and a crankpin 3, and the journal portion 2 is rotatably supported by a main bearing of the cylinder block 9. The crankpin 3 is eccentric from the journal portion 2 by a predetermined amount, and a lower link 4 is rotatably attached thereto.

  The lower link 4 is configured to be split into two members that are fastened by bolts or the like with the crank pin 3 interposed therebetween so that the crank link 3 can be assembled later. In the upper link 5, an upper pin boss portion 5 </ b> A on the lower end side is rotatably connected to a first lower side pin boss portion 4 </ b> A of the lower link 4 by an upper pin 6 as a first connecting pin, and an upper end side is connected to a piston by a piston pin 7. 8 is rotatably connected. The piston 8 receives the combustion pressure and reciprocates in the cylinder 9 </ b> A of the cylinder block 9.

  The control link 10 that restricts the movement of the lower link 4 is connected so that the control-side pin boss portion 10A on the upper end side can rotate to the second lower-side pin boss portion 4B of the lower link 4 by a control pin 11 as a second connection pin. The lower end side of the cylinder block 9 that is a part of the engine body is rotatably connected to the lower end side via the control shaft 12. Specifically, the control shaft 12 is rotatably supported by the engine body, and has an eccentric cam portion 12A that is eccentric from the center of rotation, and the lower end portion of the control link 10 is rotatable on the eccentric cam portion 12A. Is fitted. The rotation position of the control shaft 12 is controlled by a compression ratio control actuator (not shown) that operates based on a control signal from an engine control unit (not shown).

  In the variable compression ratio mechanism using such a multi-link type piston crank mechanism, when the control shaft 12 is rotated by the compression ratio control actuator, the center position of the eccentric cam portion 12A, particularly the relative position with respect to the engine body. Changes. Thereby, the rocking | fluctuation support position of the lower end of the control link 10 changes. When the swing support position of the control link 10 changes, the stroke of the piston 8 changes, and the position of the piston 8 at the piston top dead center (TDC) becomes higher or lower. This makes it possible to change the engine compression ratio. That is, the control shaft 12, the compression ratio control actuator, the engine control unit, and the like provided with the eccentric cam portion 12A constitute variable compression ratio means that makes the engine compression ratio variable.

  As shown in FIG. 2, the first lower pin boss portion 4A of the lower link 4 is configured to be bifurcated so as to sandwich the upper pin boss portion 5A, and the upper pin 6 can rotate the upper pin boss portion 5A. And is fixed to the first lower-side pin boss 4A that is bifurcated at both ends by press-fitting. Accordingly, the pin boss facing surface 4C provided between the bifurcated first lower side pin boss portion 4A of the lower link 4 faces the outer peripheral surface of the upper side pin boss portion 5A.

  Similarly, the second lower side pin boss part 4B of the lower link 4 is configured to be bifurcated so as to sandwich the control side pin boss part 10A, and the control pin 11 is fitted to the control side pin boss part 10A so as to be rotatable. Inserted and fixed to the second lower pin boss 4B that is bifurcated at both ends by press-fitting. Accordingly, the pin boss facing surface 4D provided between the bifurcated second lower side pin boss portion 4B of the lower link 4 faces the outer peripheral surface of the control side pin boss portion 10A.

  A crankpin oil passage 21 is formed in the crankpin 3. The crankpin oil passage 21 extends linearly in the radial direction, and both ends thereof open to the outer peripheral surface of the crankpin 3. The crankpin oil passage 21 is supplied with lubricating oil having a predetermined pressure pressurized by an oil pump (not shown) via an axial oil passage 20 extending in the axial direction of the crankshaft 1. The upper side pin boss portion 5A of the upper link 5 is formed with an upper side pin boss oil passage 23 that penetrates the inner peripheral surface and the outer peripheral surface including the bearing sleeve 13 fitted in the inner periphery. A lower link oil passage 22 is formed in the lower link 4. As shown in FIGS. 1 and 2, the lower link oil passage 22 includes the bearing metal 14 fitted in the bearing portion of the crank pin 3 and the pin boss facing surface 4C and the crank pin bearing surface, that is, the bearing metal. 14 through the inner peripheral surface.

  Next, characteristic configurations of the present invention will be listed with reference to the illustrated embodiments. However, the present invention is not limited to the configuration of the illustrated embodiment, and includes various modifications and changes without departing from the spirit of the present invention. For example, although an example in which the present invention is applied mainly to the pin connection portion between the lower link and the upper link is described here, the present invention can be similarly applied to the pin connection portion between the lower link and the control link. In FIG. 1, the crankpin oil passage 21 passes through the center of the crankshaft 1 in the diametrical direction. However, the crankpin oil passage 21 is not limited to such a penetration, and for example, the axial oil passage 20 and the crankpin The thing of the half length which ties an outer peripheral surface may be used.

  [1] FIG. 1 shows a link arrangement at a predetermined first crank angle near the piston compression top dead center at which the maximum combustion gas pressure F0 acts on the piston 8. As shown in the figure, in the link arrangement at the first crank angle, the crankpin oil passage 21 and the lower link oil passage 22 communicate with each other, and the lubricant jetted and splashed from the lower link oil passage 22 is provided. It is set so that most of the oil is supplied to the pin boss oil passage 23. Structurally, the pin boss oil passage 23 is located on the oil passage extension line 22 </ b> A along the passage center line of the lower link oil passage 22. That is, the opening portion of the pin boss oil passage 23 that opens to the outer peripheral surface of the pin boss portion 5A intersects the linear oil passage extension line 22A, and the pin boss oil passage 23 extends along the oil passage extension line 22A. It extends in a straight line. That is, the lower link oil passage 22 and the pin boss oil passage 23 are arranged on a straight line with a predetermined gap therebetween.

  With such a configuration, in the link arrangement at a predetermined crank angle, that is, the link arrangement in the vicinity of the piston top dead center where the maximum combustion gas pressure F0 acts, the crankpin oil passage 21 and the lower link oil passage 22 communicate with each other. Therefore, the lubricating oil having a predetermined pressure supplied from the oil pump to the crankpin oil passage 21 through the main gallery and the axial oil passage 20 on the cylinder block side is transferred from the crankpin oil passage 21 to the lower link oil passage. 22 flows into the pin boss facing surface 4C and is ejected and splashed from the opening. Here, since the pin boss oil passage 23 is located on the oil passage extension line 22A of the lower link oil passage 22 as described above, it is scattered from the opening portion opened to the pin boss facing surface 4C of the lower link oil passage 22. Most of the lubricating oil enters the pin boss oil passage 23 and is forcibly supplied to the bearing portion of the upper pin 6 through the pin boss oil passage 23.

  As described above, the hydraulic oil supplied to the crankpin oil passage 21 can be used to forcibly supply the lubricating oil to the pin bearing portion of the upper pin 6 via the lower link oil passage 22 and the pin boss oil passage 23. Compared to the natural oil supply method that relies on the lubricating oil in the atmosphere in the internal combustion engine described above, the lubricating oil can be stably and reliably supplied to the pin bearing portion of the upper pin (connection pin) 6 and the pin boss portion 5A. it can. Accordingly, the shortage of lubricating oil in the pin bearing portion can be suppressed / eliminated and a good lubricating state can be maintained.

  In the above-described embodiment, the pin boss oil passage 23 is disposed on the oil passage extension line 22A of the lower link oil passage 22, but the pin boss oil passage 23 is extended to the oil passage in consideration of a delay in the flow response of the lubricating oil. It may be arranged in the vicinity of the line 22A.

  [2] As shown in FIG. 1, the maximum combustion gas pressure F0 acts on the piston 8 in the vicinity of the compression top dead center, and due to the maximum combustion gas pressure F0, the lower link 4 is directed downward from the upper pin 6. An upper pin load F1, an upward crank pin load F2 from the crank pin 3, and a downward control pin load F3 from the control pin 11 act. Here, “up and down” means that the top dead center side of the piston is “up” and the bottom dead center side of the piston is “down”. The crankpin oil passage 21 is arranged so as to be substantially perpendicular to the direction of the maximum crankpin load F2 acting from the crankpin 3. Here, “substantially perpendicular” includes not only strictly 90 ° but also a range close to 90 ° (for example, a range of ± 5 °). That is, when the link is arranged at the crank angle near the compression top dead center where the maximum upward crankpin load F2 is applied, the crankpin oil passage 21 extending linearly in the radial direction is substantially in the thrust-anti-thrust direction. The crankpin oil passage 21 and the lower link oil passage 22 communicate with each other.

  If the crankpin oil passage 21 and the lower link oil passage 22 communicating with the crankpin oil passage 21 are located in the vicinity of the upper portion α2 where the maximum crankpin load F2 acts in the crankpin bearing portion, the lower link oil Since the lubricating oil is discharged through the path 22, it is difficult to ensure an appropriate oil film in the vicinity of the load acting site α2. On the other hand, in the link arrangement at the crank angle at which the maximum crankpin load F2 acts, as described above, the crankpin oil passage 21 is arranged substantially perpendicular to the maximum crankpin load F2, so that the crankpin The communicating portion between the oil passage 21 and the lower link oil passage 22 is kept away from the load acting portion α2, and the development of the oil film at the load acting portion α2 is not hindered, and a good lubricating state can be maintained.

  [3] In the link arrangement at the first crank angle, the maximum pin boss load F1 'acts on the pin boss portion 5A of the upper link 5 as a reaction of the upper pin load F1 due to the maximum in-cylinder pressure F0. The pin boss oil passage 23 is disposed at a position 90 ° or more away from the direction in which the pin boss load F1 'acts. That is, the angle formed by the linear pin boss oil passage 23 and the pin boss load F1 'is 90 ° or more. As a result, the pin boss oil passage 23 is positioned 90 ° or more away from the portion α1 where the maximum pin boss load F1 ′ acts, and does not hinder the development of the oil film at the load acting portion α1 as in the case of [2] above. It is possible to suppress / eliminate poor lubrication.

  [4] FIG. 3 shows a link arrangement at the second crank angle near the bottom dead center of the piston. During one rotation of the crankshaft 1, the lower link oil passage 22 communicates with the openings on both sides of the crankpin oil passage 21 that penetrates the crankpin 3 in the radial direction, so there are two crank angles at which both 21 and 22 communicate. Specifically, in addition to the first crank angle near the piston top dead center shown in FIG. 1, there is a second crank angle near the piston bottom dead center shown in FIG. Therefore, as a candidate for the above-described pin boss oil passage formation location, the location of the first pin boss oil passage 23 corresponding to the first crank angle shown in FIG. 1 and the second location corresponding to the second crank angle shown in FIG. There are two pin boss oil passages 23A.

  As a first example of the pin boss oil passage, of the two crank angles at which the crank pin oil passage 21 and the lower link oil passage 22 communicate with each other, the first crank that is far from the portion α1 where the maximum pin boss load F1 ′ acts. The pin boss oil passage 23 is formed only at one place corresponding to the corner (see FIG. 1).

  In this case, the strength / rigidity of the pin boss portion 5A is improved as compared with the case where the pin boss portions are provided at two locations, and the pin boss oil is provided on the side farther from the portion α1 where the maximum pin boss load F1 ′ acts. By providing the path 23, it is possible to suppress / avoid poor lubrication as in [3] above.

  [5] As a second example of the pin boss oil passage, as shown in FIG. 4, the first one is provided at two locations corresponding to two crank angles at which the crank pin oil passage 21 and the lower link oil passage 22 communicate with each other. A pin boss oil passage 23 and a second pin boss oil passage 23A are formed.

  In this case, the strength / rigidity of the pin boss portion 5A is lower than that in the first example, but the crankshaft 1 is ejected from the lower link oil passage 22 in a link arrangement of two crank angles during one rotation of the crankshaft 1. Lubricating oil can be forcibly supplied to the upper pin bearing portion via the respective pin boss oil passages 23, 23A, further increasing the amount of lubricating oil supplied to the pin bearing portion, and reducing the amount of lubricating oil. Further, it can be reliably suppressed and avoided.

  [6] As a third example of the pin boss oil passage, as shown in FIG. 5, the pin boss oil passage 23B corresponds to both of the two crank angles at which the crank pin oil passage 21 and the lower link oil passage 22 communicate with each other. It has one elliptical shape that is long in the circumferential direction. That is, in any of the crank angle link arrangements, the pin boss oil passage 23B is arranged on the oil passage extension 22A of the lower link oil passage 22, and most of the lubricating oil splashed from the lower link oil passage 22 is the pin boss oil passage. This pin boss oil passage 23B is a long hole in the circumferential direction so as to be supplied to 23B.

  In this way, the pin boss oil passage 23B is made into one large oil passage corresponding to both of the two crank angles where the crankpin oil passage 21 and the lower link oil passage 22 communicate with each other, and thus the same as in the second example. In addition to being able to forcibly supply the lubricating oil to the upper pin bearing portion with one crank angle link arrangement during one rotation of the crankshaft 1, there is a receiving port for the lubricating oil splashed from the lower link oil passage 22. Since it becomes large, lubricating oil can be reliably supplied from an upper pin bearing part.

  [7] As shown in FIGS. 2 and 6, an oil reservoir 24 that is recessed toward the opening of the pin boss oil passage 23 is recessed in the outer peripheral surface of the pin boss portion 5 </ b> A. The oil sump portion 24 has a constant width in the axial direction of the pin boss portion 5A, and has a bottom surface so that it gradually becomes deeper from the rod portion 5B of the upper link 5 toward the pin boss oil passage 23 of the pin boss portion 5A. Is curved in an arc.

  According to this configuration, most of the lubricating oil ejected from the lower link oil passage 22 is received by the oil reservoir 24 and led to the pin boss oil passage 23, and as shown by the arrow in FIG. Lubricating oil scattered in the block and lubricating oil flowing down the rod portion 5B of the upper link 5 can be received by the oil reservoir 24 and guided to the pin boss oil passage 23, and the amount of lubricating oil supplied to the upper pin bearing portion Can be further increased.

  [8] As shown in FIG. 6, a pair of ribs 25 projecting radially outward are provided on both sides in the axial direction of the pin boss portion 5 </ b> A, and the oil reservoir 24 is interposed between the pair of ribs 25. Is provided. Therefore, as shown in FIG. 7 (B), the pin boss portion 5A is partially thickened on both sides in the axial direction where the ribs 25 are provided, and the rigidity is locally increased, so that the inner peripheral surface serving as the bearing surface of the upper pin 6 Of these, there is concern about the occurrence of so-called edge contact in which the edge portions 26 at both ends in the axial direction are in strong local contact with the upper pin 6.

  With respect to this problem, a so-called press in which an upper pin 6 that is rotatably inserted through the pin boss portion 5A is fixed by press-fitting to a bifurcated lower link side pin boss portion 4A of the lower link 4 disposed on both sides of the pin boss portion 5A. By adopting the fit structure, as shown in FIG. 7A, the load F4 acting on the upper pin 6 from the lower link side pin boss portion 4A side is locally increased on both sides in the axial direction, and is exaggerated in FIG. 7B. Thus, the surface profile of the upper pin 6 becomes a so-called barrel shape in which the surface profile is thickened in the axial center. Therefore, the occurrence of the edge contact described above can be reduced / relieved. Moreover, the axial direction width | variety of the lower link 4 can be reduced by setting it as said press fit structure.

  [9] As described above, when the multi-link type piston crank mechanism is configured as a variable compression ratio mechanism, the link arrangement / attitude changes according to the setting of the engine compression ratio, that is, the rotational position of the control shaft 12. Therefore, when setting the compression ratio used for the maximum output point at which the combustion gas pressure F0 becomes maximum, specifically, when setting the low compression ratio used at the fully open output, the above-described link arrangement shown in FIGS. It is set to be obtained. That is, when the compression ratio used for the maximum output point is set, for example, at the first crank angle near the top dead center of the piston, the crankpin oil passage 21 and the lower link oil passage 22 communicate with each other, and the lower link oil The formation positions of these oil passages 21 to 23 are designed so that the lubricating oil ejected from the passage 22 is supplied to the pin boss oil passage 23. As a result, when the combustion gas pressure F1 is the highest and the setting condition of the low compression ratio used at the highest output point where the lubrication conditions are the strictest, the lubricating oil is forcibly applied to the bearing portion of the pin boss portion 5A through the pin boss oil passage 23. It is possible to supply and effectively suppress or eliminate the lubrication failure.

  [10] FIG. 8 shows an embodiment in which the oil passage structure of the present invention is applied to the control pin side as well as the upper link side. The lower link 4 includes a pin boss portion of the control link 10 in addition to the first lower link oil passage 22 penetrating the pin boss facing surface 4C facing the outer peripheral surface of the pin boss portion 5A of the upper link 5 and the crank pin bearing surface. A second lower link oil passage 22B penetrating the pin boss facing surface 4D facing the outer peripheral surface of 10A and the crank pin bearing surface is formed.

  The crank angle at which the first crankpin oil passage 21 and the lower link oil passage 22 communicate with each other and the crank angle at which the second lower link oil passage 22B and the crankpin oil passage 21 communicate with each other are different from each other. The formation positions of the lower link oil passages 22 and 22B are set so that Further, although not shown, the lubricating oil jetted from the second lower link oil passage 22B to the pin boss portion 10A of the control link 10 as well as the pin boss oil passage 23 formed in the pin boss portion 5A of the upper link 5 A pin boss oil passage is formed at an appropriate position.

  In this way, the timing at which the two lower link oil passages 22 and 22B communicate with the crankpin oil passage 21 is made different from each other, so that the lower link oil passages 22 and 22B communicate with the crankpin oil passage 21 at the same time. Thus, in order to ensure a high hydraulic pressure during communication, the momentum and amount of lubricating oil splashed from the lower link oil passages 22 and 22B increase, and the pin boss portion 5A of the upper link 5 passes through the lower link oil passages 22 and 22B. And the fall of the supply amount of the lubricating oil supplied to the pin boss | hub part 10A of the control link 10 can be suppressed.

DESCRIPTION OF SYMBOLS 1 ... Crankshaft 3 ... Crankpin 4 ... Lower link 5 ... Upper link 6 ... Upper pin (connection pin)
7 ... Piston pin 8 ... Piston 10 ... Control link 11 ... Control pin (connecting pin)
12 ... Control shaft (variable compression ratio means)
12A: Eccentric cam part (variable compression ratio means)
21 ... Crank pin oil passage 22 ... Lower link oil passage 23 ... Pin boss oil passage 24 ... Oil reservoir 25 ... Rib

Claims (10)

An upper link having one end connected to the piston via a piston pin, and a lower link connected to the other end of the upper link via a first connection pin and rotatably attached to the crankpin of the crankshaft A multi-link type piston crank mechanism for an internal combustion engine comprising: a control link having one end pivotably supported on the engine body side and the other end coupled to the lower link via a second coupling pin In
A crankpin oil passage formed on the crankpin, having one end opened on the outer peripheral surface of the crankpin, and supplied with lubricating oil of a predetermined pressure;
A pin boss oil passage formed in a pin boss portion of an upper link or a control link in which at least one of the first linking pin and the second linking pin is rotatably fitted, and penetrates an inner peripheral surface and an outer peripheral surface of the pin boss portion. When,
A lower link oil passage formed in the lower link and penetrating the pin boss facing surface facing the outer peripheral surface of the pin boss portion and the crank pin bearing surface;
The crankpin oil passage and the lower link oil passage communicate with each other at a predetermined crank angle, and a part of the lubricating oil ejected from the lower link oil passage is supplied to the pin boss oil passage. ,
The crank pin oil passage penetrates the crank pin in the radial direction;
Of the two crank angles at which the crank pin oil passage and the lower link oil passage communicate with each other during one rotation of the crankshaft, the pin boss oil passage is from a position where the maximum pin boss load acts from the connecting pin to the pin boss portion. A bearing structure in a multi-link piston crank mechanism of an internal combustion engine, wherein the bearing structure is formed only at a location corresponding to one of the far crank angles . An upper link having one end connected to the piston via a piston pin, and a lower link connected to the other end of the upper link via a first connection pin and rotatably attached to the crankpin of the crankshaft A multi-link type piston crank mechanism for an internal combustion engine comprising: a control link having one end pivotably supported on the engine body side and the other end coupled to the lower link via a second coupling pin In
A crankpin oil passage formed on the crankpin, having one end opened on the outer peripheral surface of the crankpin, and supplied with lubricating oil of a predetermined pressure;
A pin boss oil passage formed in a pin boss portion of an upper link or a control link in which at least one of the first linking pin and the second linking pin is rotatably fitted, and penetrates an inner peripheral surface and an outer peripheral surface of the pin boss portion. When,
A lower link oil passage formed in the lower link and penetrating the pin boss facing surface facing the outer peripheral surface of the pin boss portion and the crank pin bearing surface;
The crankpin oil passage and the lower link oil passage communicate with each other at a predetermined crank angle, and a part of the lubricating oil ejected from the lower link oil passage is supplied to the pin boss oil passage. ,
The crank pin oil passage penetrates the crank pin in the radial direction;
The pin boss oil passage is formed at two locations corresponding to two crank angles at which the crankpin oil passage and the lower link oil passage communicate with each other during one rotation of the crankshaft. Bearing structure in a multi-link piston crank mechanism of an engine. An upper link having one end connected to the piston via a piston pin, and a lower link connected to the other end of the upper link via a first connection pin and rotatably attached to the crankpin of the crankshaft A multi-link type piston crank mechanism for an internal combustion engine comprising: a control link having one end pivotably supported on the engine body side and the other end coupled to the lower link via a second coupling pin In
A crankpin oil passage formed on the crankpin, having one end opened on the outer peripheral surface of the crankpin, and supplied with lubricating oil of a predetermined pressure;
A pin boss oil passage formed in a pin boss portion of an upper link or a control link in which at least one of the first linking pin and the second linking pin is rotatably fitted, and penetrates an inner peripheral surface and an outer peripheral surface of the pin boss portion. When,
A lower link oil passage formed in the lower link and penetrating the pin boss facing surface facing the outer peripheral surface of the pin boss portion and the crank pin bearing surface;
The crankpin oil passage and the lower link oil passage communicate with each other at a predetermined crank angle, and a part of the lubricating oil ejected from the lower link oil passage is supplied to the pin boss oil passage. ,
The crank pin oil passage penetrates the crank pin in the radial direction;
The pin boss oil passage has an elliptical shape that is long in the circumferential direction corresponding to both of the two crank angles at which the crankpin oil passage and the lower link oil passage communicate with each other during one rotation of the crankshaft. A bearing structure in a multi-link type piston crank mechanism of an internal combustion engine characterized by the above. An upper link having one end connected to the piston via a piston pin, and a lower link connected to the other end of the upper link via a first connection pin and rotatably attached to the crankpin of the crankshaft A multi-link type piston crank mechanism for an internal combustion engine comprising: a control link having one end pivotably supported on the engine body side and the other end coupled to the lower link via a second coupling pin In
A crankpin oil passage formed on the crankpin, having one end opened on the outer peripheral surface of the crankpin, and supplied with lubricating oil of a predetermined pressure;
A pin boss oil passage formed in a pin boss portion of an upper link or a control link in which at least one of the first linking pin and the second linking pin is rotatably fitted, and penetrates an inner peripheral surface and an outer peripheral surface of the pin boss portion. When,
A lower link oil passage formed in the lower link and penetrating the pin boss facing surface facing the outer peripheral surface of the pin boss portion and the crank pin bearing surface;
The crankpin oil passage and the lower link oil passage communicate with each other at a predetermined crank angle, and a part of the lubricating oil ejected from the lower link oil passage is supplied to the pin boss oil passage. ,
A bearing structure in a multi-link type piston crank mechanism of an internal combustion engine , wherein an oil reservoir portion recessed toward an opening portion of the pin boss oil passage is provided on an outer peripheral surface of the pin boss portion . A pair of ribs projecting radially outward are provided on both sides in the axial direction of the pin boss part, and the oil sump part is provided between the pair of ribs,
Connecting pin rotatably inserted the pin boss portions, according to claim 4, characterized in that it is press-fitted to the bifurcated lower link-side pin boss portion arranged lower link on both sides of the pin boss portions A multi-link piston crank mechanism for internal combustion engines. An upper link having one end connected to the piston via a piston pin, and a lower link connected to the other end of the upper link via a first connection pin and rotatably attached to the crankpin of the crankshaft A multi-link type piston crank mechanism for an internal combustion engine comprising: a control link having one end pivotably supported on the engine body side and the other end coupled to the lower link via a second coupling pin In
A crankpin oil passage formed on the crankpin, having one end opened on the outer peripheral surface of the crankpin, and supplied with lubricating oil of a predetermined pressure;
A pin boss oil passage formed in a pin boss portion of an upper link or a control link in which at least one of the first linking pin and the second linking pin is rotatably fitted, and penetrates an inner peripheral surface and an outer peripheral surface of the pin boss portion. When,
A lower link oil passage formed in the lower link and penetrating the pin boss facing surface facing the outer peripheral surface of the pin boss portion and the crank pin bearing surface;
The crankpin oil passage and the lower link oil passage communicate with each other at a predetermined crank angle, and a part of the lubricating oil ejected from the lower link oil passage is supplied to the pin boss oil passage. ,
The lower link oil passage is formed on a first lower link oil passage penetrating the pin boss facing surface facing the outer peripheral surface of the pin boss portion of the upper link and the crank pin bearing surface, and on the outer peripheral surface of the pin boss portion of the control link. A second lower link oil passage penetrating the facing pin boss facing surface and the crank pin bearing surface,
An internal combustion engine characterized in that a crank angle at which the first crankpin oil passage and the lower link oil passage communicate with each other and a crank angle at which the second crankpin oil passage and the lower link oil passage communicate with each other are different. Double link type piston crank mechanism of the engine. An upper link having one end connected to the piston via a piston pin, and a lower link connected to the other end of the upper link via a first connection pin and rotatably attached to the crankpin of the crankshaft A multi-link type piston crank mechanism for an internal combustion engine comprising: a control link having one end pivotably supported on the engine body side and the other end coupled to the lower link via a second coupling pin In
A crankpin oil passage formed on the crankpin and having one end opening on the outer peripheral surface of the crankpin;
A pin boss oil passage formed in a pin boss portion of an upper link or a control link in which at least one of the first linking pin and the second linking pin is rotatably fitted, and penetrates an inner peripheral surface and an outer peripheral surface of the pin boss portion. When,
A lower link oil passage formed in the lower link and penetrating the pin boss facing surface facing the outer peripheral surface of the pin boss portion and the crank pin bearing surface;
The crank pin oil passage and the lower link oil passage communicate with each other at a predetermined link arrangement, and the pin boss oil passage is located on an oil passage extension line of the lower link oil passage. Double link type piston crank mechanism. The crank pin oil passage, according to any one of claims 1-7, characterized in that extending in a direction substantially perpendicular to the direction of maximum crankpin load acting on the lower link from the crankpin A multi-link piston crank mechanism for internal combustion engines. It said pin bosses oil passage, to the direction of maximum pin bosses load acting from the connecting pin to the pin boss portions, to one of the claims 1-8, characterized in that it is located at a distance more than 90 ° The bearing structure in the double link type piston crank mechanism of the internal combustion engine as described. Having variable compression ratio means for changing the engine compression ratio by changing the support position of the other end of the control link;
The crankpin oil passage communicates with the lower link oil passage at the predetermined crank angle in the setting of the compression ratio used for the maximum output point, and the lubricating oil flows from the lower link oil passage to the pin boss oil passage. The multi-link piston crank mechanism for an internal combustion engine according to any one of claims 1 to 9 , wherein the multi-link piston crank mechanism is set so as to be ejected.

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