JP2019100332A - Double-link type piston crank mechanism - Google Patents

Abstract

To improve the sound vibration performance of an internal combustion engine.SOLUTION: A lower link 6 of a double-link type piston crank mechanism is formed into a shape made by adding, to a fundamental shape having a substantial parallelogram, an overlap part 10 which protrudes to the outside from the fundamental shape. The overlap part 10 protrudes to the outside in a radial direction of a crank pin bearing part 11 in a substantial fan shape from a substantially V-shape composed of a part of a first linear part 15, a part of a circular arc part 19, and a part of a second linear part 17 at a lower link lower 6B. A center of gravity G2 of the lower link 6 including the weight part 10 is located at a position displaced to a control pin fitting hole 23 side from a center of gravity G1 of the fundamental shape of the lower link 6 located in the vicinity of a center C1 of the crank pin bearing 11. By the lower link 6 which is constituted as above, a vibration component accompanied by a vertical motion of an upper link 3, and a yaw vibration and a pitch vibration of an internal combustion engine resulting from the vibration component are suppressed. Therefore, the sound vibration performance of the internal combustion engine is improved.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a piston crank mechanism of an internal combustion engine, and more particularly to a double link type piston crank mechanism.

  As an example of the double link type piston crank mechanism, one described in Patent Document 1 can be mentioned. This multi-link type piston crank mechanism has an upper link whose one end is connected to the piston via the piston pin, and a lower end connected to the other end of the upper link via the upper pin and connected to the crank pin of the crankshaft. A link and a control link that regulates the degree of freedom of the lower link are provided. The lower link has a parallelogram close to a rhombus, and upper pin fitting holes and control pin fitting holes are formed on both sides of a crank pin bearing portion provided at the center of the lower link. Such a lower link is configured such that the center of gravity of the lower link is located at the center in the crank pin bearing portion.

  In the double link type piston crank mechanism, the force from the upper link moving up and down by the combustion pressure from the piston is input to the lower link, and the lower link swings around the control pin.

JP 2017-53416 A

  In the multi-link type piston crank mechanism of Patent Document 1, a vibration component in the vertical direction is generated due to the vertical movement of the piston and the upper link. This vibration component remains uncancelled and still remains in an odd-cylinder internal combustion engine, for example a three-cylinder internal combustion engine. Then, yaw vibration and pitch vibration occur in the internal combustion engine due to the above-mentioned vibration component, and the sound vibration performance of the internal combustion engine may be deteriorated.

  Furthermore, there is a possibility that the noise and vibration performance of the internal combustion engine may be further deteriorated due to the long stroke of the double link type piston crank mechanism for the purpose of fuel efficiency improvement.

  In the present invention, a weight portion is provided on the control pin fitting hole side of the lower link, or a light weight portion made of a material having a relatively small specific gravity is provided on the upper pin fitting hole side.

  Therefore, the center of gravity of the lower link including the weight portion or the light weight portion is located closer to the control pin fitting hole. As a result, the generation of the vibration component accompanying the vertical movement of the upper link is suppressed.

  According to the present invention, yaw vibration and pitch vibration generated in the internal combustion engine are reduced, thereby improving the noise and vibration performance of the internal combustion engine.

It is structure explanatory drawing of the double link type | mold piston crank mechanism of 1st Example. It is a perspective view of the lower link of a 1st Example. It is a top view of the lower link of a 1st Example. It is a graph which shows the change of the amplitude of yaw oscillation in the case where the lower link which has basic shape was used, and the lower link of the 1st example, respectively. When the lower link having the basic shape is used, the magnitudes of the yaw vibration and the pitch vibration are shown when the lower link of the first embodiment and the lower link of the second embodiment are used. FIG. It is a top view of the lower link of 2nd Example. It is a top view of the lower link of 3rd Example. It is a perspective view of the lower link upper of a 3rd Example. It is a top view of the lower link of the 4th example.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a double-link type piston crank mechanism of a first embodiment applied to each cylinder of an odd number cylinder internal combustion engine, for example, an in-line three cylinder internal combustion engine. This double-link type piston crank mechanism is connected to the upper link 3 whose one end is connected to the piston 1 via the piston pin 2 and to the other end of the upper link 3 via the upper pin (connection pin) 4 The lower link 6 connected to the crankpin 5 of the shaft, and the control link 7 that regulates the degree of freedom of the lower link 6 are provided. One end of the control link 7 is swingably supported by a support pin 8 on the engine body side, and the other end is connected to the lower link 6 via a control pin (connection pin) 9. The multi-link piston crank mechanism can also be configured as a variable compression ratio mechanism by making the position of the support pin 8 variable.

  The lower link 6 has a basic shape configured to secure the rigidity necessary as a single unit of the lower link 6 and to minimize the weight of the lower link 6, and from this basic shape, the radial outer side of the crankpin bearing 11 is obtained. It is formed in the shape which added the weight part 10 which overhanged. The lower link 6 is formed of a metal material, for example, an SCR 420H. Here, the specific gravity of the SCR 420H is 7.8.

  The basic shape of the lower link 6 is, as shown in FIGS. 2 and 3, a parallelogram close to a rhombus surrounded by a solid line and a broken line. This basic shape is, as shown in FIG. 2 and FIG. 3, a pair of first straight portions 14 and 15 extending in parallel from two apexes 12 and 13 facing each other with the center crank pin bearing 11 interposed therebetween; A pair of second straight portions 16 and 17 extending in parallel from the apexes 12 and 13 so as to form a predetermined inclination angle α between the first linear portions 14 and 15, and the apexes 12 and 13 are opposite to each other On the side, it is comprised by two circular arc parts 18 and 19 which connect 1st linear part 14 and 2nd linear part 16 comrades and 1st linear part 15 and 2nd linear part 17 comrades. Then, a part of the first linear part 14, a part of the arc part 18 and a part of the second linear part 16 are a pair of upper pin pin bosses 20 a and 20 a facing each other on both axial end sides of the crankpin 5. Configured. On the other hand, a part of the first linear part 15, the arc part 19 and a part of the second linear part 17 are opposed to each other at both axial ends of the crankpin 5 in the pair of control pin pin bosses 21a and 21a. (Only one is shown in FIG. 2). The upper pin pin bosses 20 a and 20 a and the control pin pin bosses 21 a and 21 a are positioned approximately 180 ° opposite to each other with the crank pin bearing 11 positioned at the center of the lower link 6.

  The upper pin pin boss portion 20a is formed with a circular upper pin fitting hole 22 having a smaller diameter than the crank pin bearing portion 11 and into which the upper pin 4 is fitted. Here, the arc portion 18 is concentric with the upper pin fitting hole 22.

  On the other hand, in the control pin pin boss portion 21a, a circular control pin fitting hole 23 having a smaller diameter than the crank pin bearing portion 11 and in which the control pin 9 is fitted is formed. Here, the arc portion 19 is concentric with the control pin fitting hole 23.

  The center of gravity G1 of the basic shape of the lower link 6 configured in this way is located near the center C1 of the crank pin bearing portion 11.

  Further, as shown in FIG. 2 and FIG. 3, lower link 6 is for lower link upper 6A including upper pin pin bosses 20a and 20a and a control pin on divided surface 24 passing through center C1 of crank pin bearing 11. The lower link lower 6B including the pin boss portions 21a and 21a is divided into two parts.

  The lower link upper 6A and the lower link lower 6B are fastened to each other by two bolts 25 (see FIG. 3) after the crank pin bearing portion 11 is fitted into the crank pin 5. Thus, in a state where lower link upper 6A and lower link lower 6B are fastened to each other, lower link 6 has two end faces 27, 27 along a plane orthogonal to upper pin 4 and control pin 9 (see FIGS. 2 and 3). Only one is shown).

  A groove portion 28 recessed in the axial direction of the crankpin 5 is formed at a portion of the lower link upper 6A between the first linear portion 14 and the crankpin bearing portion 11 among the end faces 27 for weight reduction. ing. The groove portion 28 has a substantially rectangular shape when viewed in the axial direction of the crank pin 5 and is continuous from the vicinity of the upper pin fitting hole 22 to the vicinity of the vertex 12.

  Similarly, a groove 29 recessed in the axial direction of the crankpin 5 is formed at a portion of the lower link lower 6B opposite to the groove 28 across the crankpin bearing 11 among the end surfaces 27. There is. The groove 29 has a substantially rectangular shape when viewed in the axial direction of the crank pin 5 and is continuous from the vicinity of the control pin fitting hole 23 to the vicinity of the vertex 13.

  Further, in the portion of the lower link upper 6A between the second straight portion 16 and the crankpin bearing portion 11 in each end face 27, there is a groove 30 recessed in the axial direction of the crankpin 5 for weight reduction. It is formed. The groove 30 has a substantially square shape when viewed from the axial direction of the crankpin 5.

  Similarly, a groove 31 recessed in the axial direction of the crankpin 5 is formed for weight reduction at the portion of the lower link lower 6B opposite to the groove 30 with the crank pin bearing 11 interposed between the end faces 27. There is. The groove portion 31 has a substantially square shape when viewed from the axial direction of the crankpin 5.

  The weight portion 10 is integrally formed with the lower link lower 6B on the control pin fitting hole 23 side of the lower link lower 6B, and the lower link 6 has a center of gravity G1 of the basic shape located near the center C1 of the crankpin bearing 11. By shifting the center of gravity to the control pin fitting hole 23 side, the vibration component accompanying the vertical movement of the upper link 3 and the yaw vibration and pitch vibration of the internal combustion engine resulting from the vibration component are suppressed. The weight portion 10 is extended in a generally fan-like shape outward in the radial direction of the crank pin bearing portion 11 from the control pin pin boss portions 21a and 21a in the lower link lower 6B. That is, the weight portion 10 is directed from the substantially V-shape configured by a part of the first linear portion 15 to the arc pin 19 and a part of the second linear portion 17 radially outward of the crankpin bearing portion 11. And extends along the end face 27 of the lower link 6, on both sides of a line E passing through the center C1 of the crank pin bearing 11, the center C2 of the control pin fitting hole 23, and the center C3 of the upper pin fitting hole 22. Almost evenly distributed. The shape of the weight portion 10 thus configured is such that when the lower link 6 rotates, the weight portion 10 does not interfere with a cylinder block (not shown).

  The center of gravity G2 of the lower link 6 including the weight portion 10 is shifted from the center C1 of the crank pin bearing portion 11 to the control pin fitting hole 23 side. Furthermore, the center of gravity G2 is shifted from the center of gravity G1 of the basic shape of the lower link 6 to the control pin fitting hole 23 side on the line segment C1-C2.

  In such a multi-link type piston crank mechanism, the lower link 6 receives the combustion pressure received by the piston 1 via the upper link 3 by the upper pin 4 and swings the control pin 9 as a fulcrum to force the crank pin 5 introduce.

  FIG. 4 occurs in an in-line three-cylinder internal combustion engine when using a lower link having a substantially parallelogram basic shape, that is, a lower link without a weight portion and using the lower link 6 of the first embodiment. Changes in the amplitude of the yaw vibration are shown. In FIG. 4, the horizontal axis indicates time, while the vertical axis indicates the magnitude of yaw vibration. The broken line shows the change in the amplitude of the yaw vibration in the case of using the lower link without a weight portion, while the solid line shows the change in the amplitude of the yaw vibration in the case of using the lower link 6 of the first embodiment. Is shown.

  As shown in FIG. 4, the amplitude of the yaw vibration in the case of using the lower link 6 of the first embodiment is smaller than the amplitude of the yaw vibration in the case of using the lower link without a weight portion. Therefore, it is understood that the yaw vibration generated in the in-line three-cylinder internal combustion engine is reduced by adding the weight portion 10 to the lower link lower 6B.

  As described above, in the first embodiment, the weight portion 10 is cranked from a generally V-shaped configuration including a portion of the first straight portion 15, the arc portion 19 and a portion of the second straight portion 17. The pin bearing portion 11 projects radially outward. Therefore, the center of gravity G2 of the lower link 6 including the weight portion 10 corresponds to the control pin fitting hole with respect to the center of gravity G1 of the substantially parallelogram basic shape set to secure the minimum rigidity of the lower link 6. It is at a position shifted to the 23 side. As a result, the generation of the vibration component associated with the vertical movement of the upper link 3 is suppressed, and the yaw vibration and the pitch vibration generated in the in-line three-cylinder internal combustion engine are further reduced. That is, as shown in FIG. 5, in the case of using the lower link 6 (point B) of the first embodiment, the magnitudes of the yaw vibration and the pitch vibration are lower links having a basic shape of approximately parallelogram. It is smaller than the magnitudes of the yaw vibration and the pitch vibration in the case of using the lower link (point A) without a weight portion. Accordingly, the noise and vibration performance of the in-line three-cylinder internal combustion engine resulting from the yaw vibration and the pitch vibration is improved.

  In FIG. 5, the magnitude of pitch vibration on the horizontal axis indicates that the pitch vibration increases toward the right in FIG. 5, while the magnitude of yaw vibration on the vertical axis is on the upper side of FIG. It indicates that the yaw vibration increases as it approaches to.

  Further, there is a possibility that the noise and vibration performance of the in-line three-cylinder internal combustion engine may be further deteriorated when the double-link type piston crank mechanism is made to have a long stroke for the purpose of improving fuel consumption. The sixth embodiment can improve the noise and vibration performance also for the long-stroked multi-link type piston crank mechanism as described above.

  FIG. 6 shows the lower link 6 of the second embodiment.

  In the second embodiment, as shown in FIG. 5, the weight parts 26 of the lower link lower 6B are distributed more on the upper side than the line E passing through the center C1, the center C2 and the center C3.

  Accordingly, the center of gravity G3 of the lower link 6 including the weight portion 26 is located above the line E.

  The lower link 6 having the center of gravity G3 shifted to the upper side of the line E as in the second embodiment further suppresses the generation of the vibration component accompanying the vertical movement of the upper link 3 and occurs in the in-line three-cylinder internal combustion engine The yaw vibration is further reduced. That is, as shown in FIG. 5, when the lower link 6 (point C) of the second embodiment is used, the magnitude of the yaw vibration is the lower link 6 (point B) of the first embodiment. The magnitude of the yaw vibration in the case is smaller. Thereby, the noise and vibration performance of the in-line three-cylinder internal combustion engine is further improved.

  FIG. 7 shows the lower link 6 of the third embodiment.

  In the third embodiment, the lower link 6 is formed in the above-described parallelogram basic shape configured to ensure the rigidity necessary for a single lower link 6 and minimize the weight of the lower link 6. It is done. In the lower link 6, from the control pin fitting hole 23 side composed of the SCR 420H having a specific gravity of 7.8 on the upper pin fitting hole 22 side than the line F orthogonal to the line E passing through the centers C1, C2 and C3. A lightweight portion 32 made of a material having a small specific gravity is also provided. The light weight portion 32 has first to third small weight portions 32a, 32b and 32c shown by dots in FIGS. 7 and 8, and is made of a synthetic resin material such as Kobelite KM-9000. Here, the specific gravity of Kobelite KM-9000 is 1.32.

  Of the bottom portion 28a of the groove portion 28, a portion close to the upper pin fitting hole 22 and the crankpin bearing portion 11 is a portion smaller than the thickness of the upper pin pin boss portion 20a as shown in FIG. A generally circular first hole 33 is formed through the pin 5 in the axial direction. As shown in FIG. 7 and FIG. 8, the first small weight portion 32 a made of kobelite KM-9000 is filled in the first hole portion 33.

  Further, the central portion of the bottom 28a of the groove 28 in the direction along the first linear portion 14 is continuous from the bottom 28a of the groove 28 on the front side of FIG. 8 to the bottom of the unshown groove of FIG. A relatively circular second hole 34 penetrated in the axial direction of the crank pin 5 is formed through this part. The second small weight portion 32 b made of kobelite KM-9000 is filled in the second hole portion 34.

  Furthermore, about half of the bottom 30a of the groove 30 on the second straight part 16 side is a part smaller than the thickness of the upper pin pin boss 20a as shown in FIG. A third hole portion 35 penetrating in the axial direction of the pin 5 is formed to penetrate, and the third small weight portion 32 c made of koberite KM-9000 is filled in the third hole portion 35.

  The connection between the outer peripheral surface of the first small light portion 32a and the inner peripheral surface of the first hole 33, the connection between the outer peripheral surface of the second small light portion 32b and the inner peripheral surface of the second hole 34, And, the connection between the outer peripheral surface of the third small and light portion 32c and the inner peripheral surface of the third hole 35 is performed by a known different material bonding method.

  Note that the first to third holes 33, 34, 35 are provided in order to suppress the detachment of the first to third small light portions 32a, 32b, 32c from the first to third holes 33, 34, 35. Asperities may be provided on the inner circumferential surface.

  In the third embodiment, the V-shaped portion of the lower link upper 6A formed of a part of the first straight part 14, the arc part 18 and a part of the second straight part 16 A small and light weight portion is provided on an arc-shaped portion (a portion between the upper pin fitting hole 22 and the first and third small and light portions 32a and 32c) around the upper pin fitting hole 22 continuous with the portion. In addition, the metal portion consisting of the SCR 420H is continuous. Since the load resulting from the vertical movement of the piston and upper link is likely to act on the above-mentioned generally V-shaped portion or arc-shaped portion, in order to ensure rigidity to withstand this load, the metal portion is left as such. It is

  The center of gravity G4 of the lower link 6 including the first to third small and light portions 32a, 32b, and 32c is offset from the center C1 of the crankpin bearing 11 toward the control pin fitting hole 23. Furthermore, the center of gravity G4 is shifted from the center of gravity G1 of the basic shape of the lower link 6 to the control pin fitting hole 23 side on the line segment C1-C2.

  As described above, in the third embodiment, the first to third small-weight members made of a material having a smaller specific gravity than the line F of the lower link 6 on the upper pin fitting hole 22 side than on the control pin fitting hole 23 side. The parts 32a, 32b and 32c are provided. Therefore, the center of gravity G4 of the lower link 6 including the first to third small and light portions 32a, 32b and 32c is the center of gravity of the substantially parallelogram basic shape set to secure the minimum rigidity of the lower link 6. It is in the position which shifted to the control pin fitting hole 23 side to G1. As a result, the generation of the vibration component associated with the vertical movement of the upper link 3 is suppressed, and the yaw vibration and the pitch vibration generated in the in-line three-cylinder internal combustion engine are further reduced.

  FIG. 9 shows the lower link 6 of the fourth embodiment.

  The lower link 6 of the fourth embodiment is a weight portion 36 whose outer shape is smaller than the weight portion 10 of the first embodiment on the control pin fitting hole 23 side of the lower link lower 6B of the lower link 6 of the third embodiment. Is added. Therefore, the center of gravity G5 of the lower link 6 including the first to third small and light weight portions 32a, 32b and 32c and the weight portion 36 fits the control pin on the line segment C1-C2 more than the center of gravity G4 of the third embodiment. It is at a position shifted to the side of the joint hole 23.

  As in the fourth embodiment, also by the lower link 6 including the first to third small and light weight portions 32a, 32b and 32c and the small weight portion 36, the center of gravity G5 is shifted to the control pin fitting hole 23 side Is obtained. Therefore, the small weight portion 36 can reduce the yaw vibration and the pitch vibration generated in the in-line three-cylinder internal combustion engine while effectively suppressing the interference between the weight portion 36 and the cylinder block.

Reference Signs List 1 piston 3 upper link 6 lower link 6A lower link upper 6B lower link lower 7 control link 10 weight portion 11 crank pin bearing portion 14 , 15: first straight portion 16, 17: second straight portion 18, 19: arc portion 23: control pin fitting hole 26: weight portion C1, C2, C3, C3 · · · Centers G1, G2, G3, G4, G5 · · · Center of gravity 32 · · · Lightweight portion 32a, 32b, 32c · · · 1st to 3rd small light portion 33, 34, 35 · · · 1st to 3 hole 36 ・ ・ ・ Weight part

Claims (11)

An upper link whose one end is connected to the piston via a piston pin, a lower link which is connected to the other end of the upper link via an upper pin, and which is connected to a crankpin of a crankshaft A control link swingably connected and having a control link whose other end is connected to the lower link via a control pin,
The lower link is provided with an upper pin fitting hole for fitting the upper pin and a control pin fitting hole for fitting the control pin on both sides of a crank pin bearing portion to which the crank pin is fitted. Yes,
A double-link type piston crank mechanism characterized in that a weight portion is provided on the control pin fitting hole side of the lower link. The lower link has a pair of first straight portions facing each other across the crankpin bearing portion, and a pair of second straight portions facing each other at a predetermined angle with respect to the pair of first straight portions. To a basic shape of a substantially quadrilateral by the straight portion of the upper portion and the two arc portions connecting each first straight portion and each second straight portion on the upper pin fitting hole side and the control pin fitting hole side. Is formed,
The weight portion is located radially outward of the crank pin bearing portion from a control pin pin boss portion defined by the first linear portion, the arc portion and the second linear portion on the control pin fitting hole side. The double link piston crank mechanism according to claim 1, characterized in that it is overhanging.   The multiple link type according to claim 2, wherein the weight portion protrudes from the control pin pin boss portion along the end face of the control pin pin boss portion radially outward of the crank pin bearing portion. Piston crank mechanism.   The center of gravity of the lower link including the weight portion is located closer to the control pin fitting hole than the center of the crank pin bearing portion. Link type piston crank mechanism.   The weight parts are distributed more on the upper side than a line passing through the center of the crank pin bearing part and the center of the control pin fitting hole. Double link type piston crank mechanism.   The center of gravity of the lower link including the weight portion is located above a line passing through the center of the crank pin bearing portion and the center of the control pin fitting hole. Double-link type piston crank mechanism. An upper link whose one end is connected to the piston via a piston pin, a lower link which is connected to the other end of the upper link via an upper pin, and which is connected to a crankpin of a crankshaft A control link swingably connected and having a control link whose other end is connected to the lower link via a control pin,
The lower link is provided with an upper pin fitting hole for fitting the upper pin and a control pin fitting hole for fitting the control pin on both sides of a crank pin bearing portion to which the crank pin is fitted. Yes,
A double-link type piston crank mechanism characterized in that a light weight portion made of a material having a relatively small specific gravity is provided on the upper pin fitting hole side of the lower link.   The multi-link piston crank mechanism according to claim 7, wherein the light weight portion is formed of a synthetic resin material, and the portion of the lower link other than the light weight portion is formed of a metal material. .   9. The double link piston according to claim 7, wherein the center of gravity of the lower link including the light weight portion is positioned closer to the control pin fitting hole than the center of the crank pin bearing portion. Crank mechanism. The lower link has a pair of first straight portions facing each other across the crankpin bearing portion, and a pair of second straight portions facing each other at a predetermined angle with respect to the pair of first straight portions. To a basic shape of a substantially quadrilateral by the straight portion of the upper portion and the two arc portions connecting each first straight portion and each second straight portion on the upper pin fitting hole side and the control pin fitting hole side. Is formed,
It is continuous with the V-shaped portion and the V-shaped portion of the lower link formed by a part of the first linear portion, the arc portion and a part of the second linear portion on the upper pin fitting hole side. The multi-link piston crank mechanism according to any one of claims 7 to 9, wherein an arc-shaped portion around the upper pin fitting hole is formed of metal.   The multi-link piston crank mechanism according to any one of claims 1 to 10, wherein the lower link is used in an odd number cylinder internal combustion engine.

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