JP2019214938A - Double-link piston crank mechanism of internal combustion engine - Google Patents

Abstract

To supply a sufficient quantity of a lubricant to a bearing portion of an upper pin.SOLUTION: An upper link 4 has: a rod part 21; an annular piston-pin pin boss part arranged at one end of the rod part 21; an annular upper-pin pin boss part 23 arranged at the other end of the rod part 21; and a salient part 24 salient from a side face of the rod part 21. The salient part 24 has a recess 27 which is opened at the piston-pin pin boss side of the upper link 4, and can receive and secure the lubrication (oil). The lubricant received in the recess 27 is supplied into a bearing hole 26 of the upper-pin pin boss part 23 via an oil hole 31.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a double-link piston crank mechanism for an internal combustion engine.

  An upper link having one end connected to the piston via a piston pin, a lower link connected to the other end of the upper link via the upper pin and connected to a crankpin of the crankshaft, and one end swinging toward the engine body. 2. Description of the Related Art A double-link type piston crank mechanism of an internal combustion engine including a control link movably supported and the other end connected to the lower link via a control pin has been widely known.

  In such a double-link type piston crank mechanism of an internal combustion engine, it is required to maintain a sufficient lubrication state in order to prevent abrasion and seizure of sliding parts.

  For example, the bearing portion of the upper pin cannot supply the lubricating oil directly from the internal passage of the crankshaft like the bearing portion of the crankpin.

  Therefore, for example, in Patent Literature 1, in order to lubricate the bearing portion of the upper pin, a concave groove extending along the longitudinal direction of the rod portion is formed on the side surface of the rod portion of the upper link, and the inner periphery of the pin boss portion of the upper link is formed. A radial oil passage radially penetrating the outer periphery and the outer periphery is connected to the concave groove.

  In Patent Literature 1, oil fog around the upper link is collected by the entire groove, and supplied to the bearing portion of the upper pin as lubricating oil via a radial oil passage.

JP 2010-116777 A

  However, the concave groove of the upper link is formed by recessing the side surface of the upper link, and there is a possibility that lubricating oil that is dripped along the side surface of the rod portion of the upper link cannot be collected efficiently. There is.

  In other words, the lubricating oil traveling along the upper link surface may be blown off due to the high speed movement of the upper link in the crankcase. There is room for further improvement in order to supply ample lubrication oil.

  A double-link type piston crank mechanism for an internal combustion engine according to the present invention includes a first link having one end connected to a piston via a piston pin and the other end connected to a second link via a first connection pin. I have.

  The first link includes a rod portion, a pin boss portion for a piston pin provided at one end of the rod portion, a pin boss portion for a first connection pin provided at the other end of the rod portion, and a side surface of the rod portion. And a projection projecting from

  The protruding portion has a concave portion that is open toward the pin boss portion for the piston pin of the first link and that can receive oil.

  The concave portion and the inner peripheral surface of the pin boss portion for the first connection pin communicate with each other by an oil hole formed through the first link.

  ADVANTAGE OF THE INVENTION According to this invention, supply of oil to the inner periphery of the pin boss part for 1st connection pins can be ensured stably by receiving oil in the recessed part of a protrusion part, and lubricating oil abundantly supplied to 1st connection pin Can supply well.

FIG. 1 is an explanatory diagram schematically showing a schematic configuration of a multiple link type piston crank mechanism of an internal combustion engine according to the present invention. The perspective view of a lower link. The front view of an upper link. The side view of an upper link. Sectional drawing of the principal part of an upper link. FIG. 4 is a cross-sectional view of a main part of the double-link type piston crank mechanism in a state where the piston is at the bottom dead center at the lowest compression ratio within a settable compression ratio. FIG. 4 is a characteristic diagram showing a change in amplitude of an unbalanced moment in the yaw direction of the internal combustion engine with respect to a crank angle.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is an explanatory view schematically showing a schematic configuration of a multi-link type piston crank mechanism 1 of an internal combustion engine to which the present invention is applied.

  The internal combustion engine having the multi-link type piston crank mechanism 1 is mounted on a vehicle such as an automobile, for example.

  The multi-link type piston crank mechanism 1 is generally constituted by a piston 2, an upper link 4 as a first link, a lower link 7 as a second link, and a control link 9 as a third link.

  The piston 2 is rotatably connected to one end of an upper link 4 via a piston pin 3.

  The other end of the upper link 4 is rotatably connected to one end of a lower link 7 via an upper pin 5 as a first connecting pin.

  The lower link 7 is rotatably connected to a crankpin 6 a of the crankshaft 6.

  The control link 9 has one end rotatably connected to the other end of the lower link 7 via a control pin 8 as a second connection pin.

  The other end of the control link 9 is rotatably connected to an eccentric shaft portion 10a of a control shaft 10 supported on the engine body side.

  The control shaft 10 is arranged in parallel with the crankshaft 6, and is rotatably supported by, for example, a cylinder block (not shown).

  That is, the other end of the control link 9 rotatably connected to the eccentric shaft portion 10a of the control shaft 10 is swingably supported by the engine body. The central axis of the eccentric shaft portion 10a is eccentric with respect to the rotation center of the control shaft 10 by a predetermined amount.

  The multiple link type piston / crank mechanism 1 includes a piston 2 and a crankpin 6a of a crankshaft 6 linked by a plurality of links.

  The multi-link type piston crank mechanism 1 can change the position of the piston 2 at the top dead center by changing the position of the eccentric shaft portion 10a by rotating the control shaft 10, thereby changing the mechanical compression ratio of the internal combustion engine. can do.

  The control shaft 10 regulates the degree of freedom of the lower link 7, and is rotationally driven by, for example, an actuator composed of an electric motor.

  It should be noted that the multi-link piston crank mechanism 1 may be configured so that the compression ratio is not variable by fixing the position of the eccentric shaft portion 10a. That is, the multi-link type piston crank mechanism 1 may be configured as a fixed compression ratio mechanism by rotatably connecting the other end of the control link 9 to a support pin supported on the engine body side instead of the control shaft 10. It is possible.

  FIG. 2 is a perspective view of the lower link 7. The lower link 7 has, at the center, a cylindrical crankpin bearing portion 11 fitted to the crankpin 6a. Further, the lower link 7 has a pair of upper pin bearing portions 12 and a pair of control pin bearing portions 13 at positions substantially opposite to each other by 180 ° with respect to the crank pin bearing portion 11. The upper pin bearing 12 corresponds to a first connection pin bearing. The control pin bearing 13 corresponds to a second connection pin bearing.

  The lower link 7 has a parallelogram shape close to a rhombus as a whole. The lower link 7 is divided into two parts, a lower link upper 7A including an upper pin bearing 12 and a lower link lower 7B including a control pin bearing 13, on a division surface 14 passing through the center of the crankpin bearing 11. Have been.

  The dividing surface 14 is inclined with respect to the lower link width direction along a straight line connecting the center of the upper pin bearing portion 12 and the center of the control pin bearing portion 13 when viewed in the crankshaft axial direction.

  In this embodiment, the upper pin bearing portion 12 side in the lower link width direction is defined as one end side of the lower link 7, and the control pin bearing portion 13 side in the lower link width direction is defined as the other end side of the lower link 7.

  The lower link upper 7A and the lower link lower 7B are fastened to each other by a pair of bolts (not shown) inserted in opposite directions after the crankpin bearing 11 is fitted into the crankpin 6a. In addition, the lower link upper 7A and the lower link lower 7B are fastened by two bolts arranged on both sides of the crankpin bearing 11. The lower link upper 7A and the lower link lower 7B may be fastened with two or more bolts.

  The upper pin bearing portion 12 is formed on both of a pair of one end side projecting pieces 16 which are separated from each other and opposed to each other. Between the pair of one end side projecting pieces 16, there is a groove 17 having a constant width that enables the upper link 4 to swing. The pair of one end side projecting pieces 16 are located at one end side of the lower link 7, and constitute a part of the lower link upper 7A. That is, one end side of the lower link 7 is formed in a forked shape so that the other end of the upper link 4 is sandwiched by the pair of one end side projecting pieces 16. The pair of one end-side projecting pieces 16 extend along the axial end surface of the lower link 7.

  Each of the upper pin bearing portions 12 is a through-hole having a circular cross section and arranged on the same axis. The upper pin 5 is press-fitted and held in the upper pin bearing portion 12.

  The control pin bearing portion 13 is formed on both of a pair of other end side projecting pieces 18 which are separated from each other and opposed to each other. A groove (not shown) having a fixed width is provided between the pair of other end-side projecting pieces 18 to allow the control link 9 to swing. The pair of other end side projecting pieces 18 are located on the other end side of the lower link 7 and constitute a part of the lower link lower 7B. That is, the other end of the lower link 7 is bifurcated so that one end of the control link 9 is sandwiched by the pair of other end projecting pieces 18. The pair of other end-side projecting pieces 18 extend along the axial end surface of the lower link 7.

  Each of the control pin bearings 13 is a through-hole having a circular cross section arranged on the same axis. The control pin 8 is press-fitted and held in the control pin bearing 13.

  3 and 4 show the upper link 4 connecting the piston 2 and the lower link 7. The upper link 4 is formed as a single component by forging or casting carbon steel, and has a rod portion 21 having a rod shape having a rectangular cross section that extends linearly, and a circle provided at one end of the rod portion 21. An annular pin boss 22 for the piston pin, an annular pin boss 23 for the upper pin provided at the other end of the rod 21, and a projection 24 projecting from the side surface of the rod 21 are provided.

  The pin boss portion 22 for the piston pin is rotatably fitted to the center of the piston pin 3 whose both ends are supported by the piston 2.

  The pin boss 23 for the upper pin corresponds to the pin boss for the first connection pin, and rotatably fits into the center of the upper pin 5 whose both ends are supported by the upper pin bearing 12 of the lower link 7. The pin boss 23 for the upper pin has a bearing hole 26 as an inner peripheral surface into which a bearing metal 25 in contact with the upper pin 5 is press-fitted.

  As shown in FIG. 5, the protruding portion 24 has a concave portion 27 which is open to the pin boss portion 22 for the piston pin of the upper link 4 and can receive and secure lubricating oil (oil). That is, the protruding portion 24 protrudes outside the rod portion 21 and scatters in the crankcase in which the upper pin 5 is accommodated, or lubricating oil dropped from the pin boss portion 22 side for the piston pin (for example, The oil reservoir is capable of receiving the lubricating oil dropped from the cooling channel).

  As shown in FIG. 1, the protruding portion 24 protrudes from the side surface of the rod portion 21 on the control link 9 side when viewed in the axial direction of the crankshaft. In addition, as shown in FIG. 4, the width of the protrusion 24 is formed to be the same as the width of the rod 21. That is, the projecting portion 24 is formed such that the width of the bearing hole 26 of the upper link 4 along the axial direction is the same as the width of the rod portion 21 of the bearing hole 26 of the upper link 4 along the axial direction. ing.

  Due to the formation of the protruding portion 24, the center of gravity of the upper link 4 is located closer to the control link 9 than the upper link center line C when viewed in the crankshaft axial direction. That is, the center of gravity of the upper link 4 is located on the right side of the upper link center line C in FIG.

  The upper link center line C is a straight line that passes through the center of the ring of the piston pin boss portion 22 and the center of the ring of the upper pin pin boss portion 23 and extends along the longitudinal direction of the rod portion 21.

  The protruding portion 24 is formed so as to be located closer to the upper pin pin boss portion 23 than the intermediate position in the longitudinal direction of the rod portion 21.

  The end surface 24a of the protruding portion 24 is formed along a plane orthogonal to the upper link center line C.

  As shown in FIG. 6, when the compression ratio of the multi-link type piston crank mechanism 1 is at the lowest compression ratio within a settable range and the piston 2 is at the bottom dead center as shown in FIG. It is formed not to be.

  As shown in FIG. 6, when the piston 2 is at the bottom dead center at the lowest compression ratio, the protrusion 24 in this embodiment enters between the pair of one-side protrusions 16 and the groove 17 of the lower link 7. Is set so as not to interfere with the bottom surface 17a of the. In other words, as shown in FIG. 6, the projecting portion 24 in the present embodiment is located at a position as close as possible to the pin boss portion 23 for the upper pin within a range not interfering with the lower link 7, that is, up to the interference limit with the lower link 7. The pin boss 23 is formed at a position close to the pin boss 23. That is, the projecting portion 24 in the present embodiment is set so as to approach the upper pin pin boss portion 23 as much as possible without interfering with the lower link 7.

  The recess 27 and the bearing hole 26 of the pin boss 23 for the upper pin communicate with each other through an oil hole 31 formed through the upper link 4 by machining such as a drill. That is, the lubricating oil received by the concave portion 27 is supplied to the bearing hole 26 of the pin boss portion 23 for the upper pin through the oil hole 31, and the bearing hole 26 (strictly, the inner peripheral surface of the bearing metal 25) and the upper pin 5 Lubricate the contact surface.

  One end of the oil hole 31 is open at the bottom of the recess 27, and the other end is open at the top of the circular bearing hole 26 of the pin boss 23 for the upper pin. The top of the bearing hole 26 is located on the upper link center line C. The top of the bearing hole 26 is located on the pin boss 22 side for the piston pin.

  Such an upper link 4 moves at high speed in a crankcase of an internal combustion engine together with a lower link 7 and a control link 9 as a component of a multi-link type piston crank mechanism. In FIG. 1, the upper link 4 reciprocates up and down substantially along the cylinder axis direction as the piston 2 moves up and down, and the lower link connected to the lower end of the upper link 4 in FIG. The link 7 swings up and down with the control pin 8 at the upper end of the control link 9 as a fulcrum. Then, the control link 9 swings left and right so as to allow displacement in the left and right directions due to the radius of rotation of the crank pin 6a. Therefore, the crankshaft 6 rotates with the vertical swing of the lower link 7.

  The upper link 4 moves at high speed in the crankcase. Therefore, the lubricating oil traveling on the upper link surface may be blown off by the high-speed movement of the upper link 4.

  However, even if the upper link 4 moves at high speed, the lubricating oil received in the recess 27 is not easily blown off from the recess 27.

  Also, by receiving the lubricating oil at the protruding portion 24 projecting from the rod portion 21, the lubricating oil dripping along the side surface of the rod portion of the upper link, the lubricating oil scattered in the crankcase, and the like are projected. It is easy to secure in the concave portion 27 of the portion 24.

  Therefore, in the double-link piston crank mechanism 1 of the present embodiment, it is possible to efficiently collect the oil fog around the upper link as lubricating oil to be supplied to the bearing hole 26 of the pin boss portion 23 for the upper pin in the recess 27. it can.

  That is, the upper link 4 can stably secure the lubricating oil to be supplied to the bearing hole 26 of the pin boss 23 for the upper pin in the concave portion 27, and can efficiently supply the lubricating oil to the upper pin 5 efficiently. .

  FIG. 7 is a characteristic diagram illustrating a change in the amplitude of the unbalanced moment in the yaw direction of the internal combustion engine with respect to the crank angle when the above-described double-link type piston crank mechanism 1 is employed in the three-cylinder internal combustion engine.

  A characteristic line C1 indicated by a solid line in FIG. 7 indicates an unbalanced moment in the yaw direction of the internal combustion engine having the multi-link type piston crank mechanism 1 using the upper link 4 of the above-described embodiment.

  A characteristic line C2 indicated by a broken line in FIG. 7 indicates an unbalanced moment in the yaw direction of the internal combustion engine having the multi-link type piston crank mechanism using the upper link having no protrusion.

  A characteristic line C3 indicated by a dashed line in FIG. 7 indicates a yaw of an internal combustion engine having a multi-link type piston crank mechanism using the upper link 4 in which the end surface 24a of the protruding portion 24 is located at an intermediate position in the longitudinal direction of the rod portion 21. The directional unbalance moment is shown.

  As shown in FIG. 7, a projecting portion 24 is provided on the rod portion 21 of the upper link 4, and the center of gravity of the upper link 4 is located on the control link 9 side with respect to the center line C of the upper link 4. It is possible to reduce the unbalanced moment in the yaw direction of the internal combustion engine that occurs in the internal combustion engine. Further, by reducing the unbalanced moment in the yaw direction of the internal combustion engine, the sound and vibration performance can be improved.

  The unbalance moment in the yaw direction of the internal combustion engine also changes depending on the position where the protrusion 24 is formed. That is, the unbalance moment in the yaw direction of the internal combustion engine can be improved as the protrusion 24 of the upper link 4 is closer to the pin boss portion 23 for the upper pin than the intermediate position in the longitudinal direction of the rod portion 21.

  Therefore, the unbalanced moment in the yaw direction of the internal combustion engine can be reduced more effectively by bringing the protruding portion 24 as close as possible to the pin boss portion 23 for the upper pin without interfering with the lower link 7. Further, the sound vibration performance can be further improved by bringing the protruding portion 24 as close as possible to the pin boss portion 23 for the upper pin within a range that does not interfere with the lower link 7.

  In order to reduce the unbalanced moment in the yaw direction of the internal combustion engine and improve the sound vibration performance, a projecting portion 24 is provided on the side of the rod portion 21 of the upper link 4 on the control link side, and the center of gravity of the upper link 4 is It is necessary to be eccentric to the control link 9 side from the link center line C. However, the effect of reducing the unbalanced moment in the yaw direction of the internal combustion engine becomes smaller as the protrusion 24 comes closer to the piston pin boss 22 of the rod 21.

  The oil hole 31 that connects the recess 27 of the protrusion 24 to the bearing hole 26 of the pin boss 23 for the upper pin becomes longer as the protrusion 24 approaches the pin boss 22 for the piston pin of the rod 21. The productivity of the upper link 4 becomes worse as the oil hole 31 is longer because the processing time of the oil hole 31 becomes longer as the oil hole 31 becomes longer.

  The lubricating performance of the bearing hole 26 of the pin boss portion 23 for the upper pin may be degraded as the oil hole 31 is longer because the longer the oil hole 31 is, the more difficult it is for the lubricating oil to flow.

  Therefore, when the projecting portion 24 is provided on the upper link 4, the effect of reducing the unbalanced moment in the yaw direction of the internal combustion engine, the productivity of the upper link 4, and the lubrication performance of the bearing hole 26 of the pin boss portion 23 for the upper pin are well balanced. It is important to balance them.

  Therefore, when providing the protruding portion 24 on the upper link 4, it is preferable that the protruding portion 24 is formed at an intermediate position along the longitudinal direction of the rod portion 21, or closer to the upper pin pin boss portion 23 than the intermediate position. More specifically, in providing the projecting portion 24 on the upper link 4, the end surface 24 a of the projecting portion 24 is formed at an intermediate position in the longitudinal direction of the rod portion 21 or closer to the pin boss portion 23 for the upper pin than the intermediate position. Is desirable.

  In order to make the center of gravity of the upper link 4 closer to the control link 9 than the center line C of the upper link, strictly speaking, the weight of the portion cut off when forming the oil hole 31 is taken into consideration. You need to set the weight.

  In addition, the above-described protruding portion 24 of the upper link 4 may be regarded as a weight portion for positioning the center of gravity of the upper link 4 on the control link 9 side of the upper link center line C in the crankshaft axial direction. It is possible. That is, the concave portion 27 can be regarded as provided in the weight portion that biases the center of gravity of the upper link 4 toward the control link 9.

  If an oil jet that can be jetted toward the projecting portion 24 is set, the lubricating oil can be more stably stored in the concave portion 27 of the projecting portion 24, and the lubricating oil can be stably lubricated by the bearing hole 26 of the pin boss portion 23 for the upper pin. Oil can be supplied.

1: Double-link type piston crank mechanism 4: Upper link (first link)
5 Upper pin (first connection pin)
6 ... crankshaft 6a ... crankpin 7 ... lower link (second link)
7A: Lower link upper 7B: Lower link lower 8: Control pin (second connecting pin)
9 Control link (third link)
10 Control shaft 10a Eccentric shaft 11 Crank pin bearing 12 Upper pin bearing (first connection pin bearing)
DESCRIPTION OF SYMBOLS 13 ... Control pin bearing part 14 ... Division surface 21 ... Rod part 22 ... Pin pin boss part 23 ... Pin pin boss part 24 ... Protrusion part 24a ... End surface 26 ... Bearing hole 27 ... Recess 31 ... Oil hole

Claims (4)

A first link having one end connected to the piston via a piston pin, a second link connected to the other end of the first link via a first connection pin, and being connected to a crankpin of a crankshaft; A third link having one end connected to the second link via a second connecting pin and the other end supported on the engine body side, a double-link type piston crank mechanism for an internal combustion engine,
The first link is a rod portion, an annular pin boss portion for the piston pin provided at one end of the rod portion and rotatably fitted with the piston pin, and provided at the other end of the rod portion. An annular first connection pin pin boss in which the first connection pin is rotatably fitted, and a protrusion protruding from a side surface of the rod portion;
The projecting portion has a concave portion that is open to the pin boss portion side for the piston pin of the first link and can receive oil.
A double-link type piston crank mechanism for an internal combustion engine, wherein the recess and the inner peripheral surface of the pin boss portion for the first connection pin communicate with each other through an oil hole formed through the first link. The projecting portion projects from a side surface of the rod portion on the third link side when viewed in a crankshaft axial direction,
The center of gravity of the first link is located closer to the third link than a straight line connecting the center of the pin boss for the piston pin and the center of the pin boss for the first connection pin when viewed in the axial direction of the crankshaft. The double-link type piston crank mechanism for an internal combustion engine according to claim 1.   The said protrusion part is formed in the intermediate | middle position along the longitudinal direction of the said rod part, or the pin boss part side for 1st connection pins with respect to the said intermediate position, The Claims 1 or 2 characterized by the above-mentioned. Double-link type piston crank mechanism for internal combustion engine. The second link has a first connection pin bearing for holding the first connection pin,
The first connection pin bearing is formed by a pair of projecting pieces facing each other,
The said projection part is formed so that it may enter between a pair of said projecting piece, and does not interfere with the said 2nd link, when the said piston is in a bottom dead center. A double-link type piston crank mechanism for an internal combustion engine according to any one of the above.

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