JP5327361B2 - Vibration reduction structure of multi-link engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration reducing structure of a multi-link engine, wherein the structure can reduce vibrations in a transverse direction with respect to a piston movement direction with a simple configuration. <P>SOLUTION: The vibration reducing structure for a multi-link engine 100 includes: an upper link 13 coupled to a piston 11 by way of a piston pin 16; a lower link 14 coupled to the upper link 13 by way of an upper pin 17 and rotatably coupled to a crank pin 12A; and a control link 15 coupled to the lower link 14 by way of a control pin 18 and rockably coupled to a rocking shaft 21. The upper link 13, the lower link 14 and the control link 15 are configured in such a manner that inertia forces of at least one prescribed order of second or higher order in terms of an engine rotational speed act on at least the upper link 13 and the control link 15 in a direction oriented transversely leftward and rightward with respect to a piston movement direction and that a sum of leftward and rightward inertia forces of the prescribed order of each link is balanced. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a vibration reduction structure for a multi-link engine.

  2. Description of the Related Art Conventionally, a multi-link engine that connects a piston and a crankshaft via a plurality of links is known.

  For example, Patent Document 1 discloses a multi-link engine in which a piston and a crankshaft are connected via an upper link and a lower link, and the compression ratio is variably controlled by controlling the posture of the lower link. . This multi-link engine has a control link with one end connected to the lower link and the other end connected to the eccentric shaft of the control shaft. By changing the rotation angle of the control shaft, the attitude of the lower link via the control link To control.

JP 2006-207634 A

  By the way, in a multi-link engine, due to the inertial force of each link, not only in the piston movement direction but also in the lateral direction with respect to the piston movement direction (left and right lateral to the piston movement direction when viewed from the crankshaft axis direction). (Direction) also vibrates. Among the lateral vibrations, for example, the secondary vibration component of the engine rotation is not a problem in the conventional piston-crank mechanism in which the piston and crankshaft are connected by a single connecting rod. belongs to.

  As for the order of the vibration component, the vibration component having the same cycle as the engine rotation cycle (cycle when the crankshaft makes one rotation) is the first order, and the vibration component of the half cycle is the second order, and how many minutes below. The order of the higher-order vibration component is specified depending on whether or not it is one period.

  The multi-link engine described in Patent Document 1 includes a secondary balancer device below the crankshaft, and rotates the first balancer shaft and the second balancer shaft of the secondary balancer device in the direction opposite to the crankshaft rotation direction. Thus, the secondary vibration in the direction inclined with respect to the piston moving direction is reduced.

  However, since the multi-link engine described in Patent Document 1 includes a secondary balancer device separately, there is a problem that not only the cost is increased, but also fuel efficiency is deteriorated due to an increase in friction when the secondary balancer device is driven. .

  Accordingly, the present invention has been made paying attention to such problems, and provides a vibration reduction structure for a multi-link engine that can reduce vibration in a lateral direction with respect to the piston movement direction with a simple configuration. For the purpose.

The present invention solves the above problems by the following means .

The present invention includes an upper link whose one end is connected to the piston via a piston pin, a lower link connected to the other end of the upper link via an upper pin, and rotatably connected to the crank pin of the crankshaft. A vibration reducing structure for a multi-link engine having one end connected to the lower link via a control pin and the other end connected to the swing shaft so as to be swingable. In addition, at least one of the predetermined orders of inertia force of the engine rotation second order or higher acts on the control link in the lateral direction with respect to the piston movement direction, and the left order inertial force of the predetermined order at the center of gravity of each link. and so that the sum of the inertial force in the right direction are balanced, child structure upper link, the lower link and the control link The features.

  According to the present invention, with a simple configuration, it is possible to reduce the secondary or higher order vibration in the lateral direction with respect to the direction of movement of the piston generated in the multi-link engine body, and to suppress the increase in cost and the deterioration of fuel consumption performance. be able to.

1 is a schematic configuration diagram of a multi-link engine of a first embodiment. It is a model figure of the multi-link type engine for calculating the sum total of the inertia force in the gravity center position of each link. It is a schematic block diagram of an upper link, a lower link, and a control link. It is a schematic block diagram of the multiple link type engine which is a comparative example. It is a figure which shows the secondary inertia force of the engine left-right direction in each link gravity center. It is a figure which shows the relationship between the lower link gravity center and the secondary excitation force of the engine left-right direction, and the relationship between the crankpin center and the secondary excitation force of the engine left-right direction. It is a schematic block diagram of the upper link of the multilink type engine of 2nd Embodiment, a lower link, and a control link. It is a schematic block diagram of the multilink type engine of 3rd Embodiment. It is a figure which shows the secondary inertia force of an engine left-right direction. It is a schematic block diagram of the multilink type engine of 4th Embodiment. It is a figure which shows the secondary inertia force of an engine left-right direction and an engine up-down direction.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram showing a multi-link engine of the present embodiment.

  The multi-link engine 100 is an in-line four-cylinder engine for a vehicle, and includes a variable compression ratio mechanism 10 that changes a compression ratio by changing a piston top dead center position. The variable compression ratio mechanism 10 connects the piston 11 and the crankshaft 12 by an upper link 13 and a lower link 14 and changes the compression ratio by controlling the posture of the lower link 14 by a control link 15.

  The upper link 13 is connected to the piston 11 via the piston pin 16 at the upper end. The upper link 13 is connected to one end of the lower link 14 via an upper pin 17 at the lower end. The other end of the lower link 14 is connected to the control link 15 via a control pin 18.

  The lower link 14 forms a connection hole 14A to which the crank pin 12A is connected so that the crank pin 12A is disposed between the center of the upper pin 17 and the center of the control pin 18. The lower link 14 can be divided from two members on the left and right in the figure, and has a connecting hole 14A in the approximate center. The lower link 14 inserts the crank pin 12A of the crank shaft 12 into the connecting hole 14A and swings about the crank pin 12A.

  The crankshaft 12 includes a crankpin 12A, a journal 12B, and a counterweight 12C. The center of the crankpin 12A is eccentric by a predetermined amount from the center of the journal 12B. The counterweight 12C is integrally formed with the crank arm and reduces the rotational primary vibration component of the piston motion.

  The upper end of the control link 15 is rotatably connected to the lower link 14 via a control pin 18. The lower end of the control link 15 is connected to an eccentric shaft (swing shaft) 21 of the control shaft 20. The control link 15 swings about the eccentric shaft 21.

  The control shaft 20 is disposed in parallel with the crankshaft 12 and is rotatably supported by the cylinder block. The eccentric shaft 21 of the control shaft 20 is formed at a position eccentric from the control shaft axis by a predetermined amount. The control shaft 20 is rotationally controlled by an actuator (not shown) and moves the eccentric shaft 21.

  When the control shaft 20 is rotated by the actuator and the eccentric shaft 21 is moved in a direction relatively lower than the central axis of the control shaft 20, the lower link 14 is relatively positioned at the upper pin 17 around the crank pin 12A. Tilt to ascend. Thereby, piston 11 raises and the compression ratio of multi-link type engine 100 becomes high. On the other hand, when the eccentric shaft 21 moves in a direction that is relatively higher than the central axis of the control shaft 20, the lower link 14 is in a direction in which the position of the upper pin 17 is relatively lowered with the crank pin 12A as a center. Tilt. As a result, the piston 11 is lowered, and the compression ratio of the multi-link engine 100 is lowered.

  In the multi-link engine 100, for example, in order to improve the output in the low and medium load operation region where the low compression ratio is set to prevent knocking in the high load operation region regardless of the engine rotation speed and the possibility of knocking is low. High compression ratio is set.

  By the way, in the multi-link type engine as described above, the sum of inertia forces generated in the links of the upper link, the lower link and the control link becomes an excitation force for exciting the engine body, and the engine body causes the piston to move to the piston. It vibrates not only in the direction of movement (engine up-down direction) but also in the direction transverse to the piston movement direction (engine left-right direction). Among the vibrations in the left-right direction of the engine, for example, the secondary vibration component of engine rotation is unique to the multi-link engine.

  Since the multi-link engine 100 is a four-cylinder engine, the influence of the primary vibration among the vibrations in the left-right direction of the engine is small, so the object is to reduce the secondary or higher vibration with respect to the engine rotation. In particular, it is necessary to reduce the secondary vibration in the left-right direction of the engine, which is a cause of a booming noise that is a vehicle interior noise. Therefore, in the multi-link engine 100, as the inertia force of at least one predetermined order of the engine rotation secondary or higher, the engine left-right secondary at the center of gravity of the links of the upper link 13, the lower link 14, and the control link 15 The mass of each link, the shape, and the like are configured so that the sum of the left inertial force and the sum of the rightward inertial force are balanced to reduce secondary vibrations in the left-right direction of the engine.

  FIG. 2 is a model diagram of the multi-link engine 100 for calculating the sum of the secondary and higher inertial forces in the left-right direction of the engine at the center of gravity of each link. FIG. 2 is a Cartesian coordinate system in which the rotation center of the crankshaft 12 is shown as a coordinate center (0, 0), where the x axis is provided in the engine left-right direction and the y axis is provided in the engine up-down direction.

As shown in FIG. 2, the center of the piston pin 16 is a position (x ₄ , y ₄ ), the center of the upper pin 17 is a position (x ₃ , y ₃ ), and the center of the crank pin 12A is a position (x ₁ , y ₃ ). ₁ ), the center of the control pin 18 is the position (x ₂ , y ₂ ), and the center of the eccentric shaft 21 of the control shaft 20 is the position (x _c , y _c ).

Upper link 13, the mass and m _u, the length between the centers of the upper pin 17 of the piston pin 16 and L _6. Upper link centroid G _u is located on a straight line or in the vicinity thereof through a piston pin center and the upper pin center, in terms of simplification also when located in a straight line near the interior division point of the piston pin center and the upper pin center Suppose that Then, the distance from the piston pin center to the upper link centroid _{G u} and _{x gu0.} The distance x _gu0 is positive on the upper pin side and negative on the opposite side with respect to the center of the piston pin.

Lower link 14, the mass and m _l, the length between the centers of the crank pin 12A of the upper pin 17 and L _4, the length between the center of the crank pin center and the control pin 18 L ₂ And The lower link 14 is configured to form a connection hole 14A to which the crank pin 12A is connected so that the crank pin 12A is disposed between the center of the upper pin 17 and the center of the control pin 18. , the center of the crankpin 12A to be inserted into the lower link centroid G _l and the connecting hole 14A are both located on a straight line or in the vicinity thereof through the upper pin center and the control center of the pin. In the case of being located in the vicinity of a straight line, it is assumed from the viewpoint of simplification that each is an internal dividing point between the upper pin center and the control pin center. Then, the distance from the crank pin center to the lower link centroid _{G l} and _{x GL0.} The distance x _gl0 is positive on the control pin side and negative on the upper pin side with respect to the center of the crank pin.

The control link 15 has a mass _mc, and a length between the center of the control pin 18 and the center of the eccentric shaft 21 is L ₃ . The control link center of gravity _Gc is located on or near a straight line passing through the control pin center and the eccentric shaft center, and even when located near the straight line, the control link center of gravity _Gc is within the control pin center and the eccentric shaft center. Assume that the minute point. Then, the distance from the eccentric shaft center to the control link centroid _{G c} and _{x GC0.} The distance x _gc0 is positive on the control pin side and negative on the opposite side with respect to the center of the eccentric shaft.

  The upper pin 17 and the control pin 18 are regarded as a part of one of the links, and it is assumed that the influence is incorporated when the mass and the center of gravity of each link are obtained.

Note that a line passing through the center of the rotation center of the crank pin 12A of a crankshaft 12, an angle between the x axis and the crank angle theta _A.

In the model setting as described above, when calculating the sum of the secondary and higher-order inertia forces in the left-right direction of the engine at the center of gravity position of each link, first, the engine left-right direction displacement x _{gl of} the lower link center of gravity G _l and the upper link center of gravity G _u are calculated. Engine left-right direction displacement x _gu and control link center-of-gravity G _c engine left-right direction displacement x _gc are respectively obtained.

The engine left-right direction displacements x _gl , x _gu , and x _gc of each link are expressed as in equations (1) to (3).

Here, the engine lateral direction displacement x ₂ of the control pin 18 can be separated (4) as shown in the expression in the primary displacement with respect to the engine rotational x _2L and second or higher displacement x _2H. The primary displacement x _2L and the secondary or higher displacement x _2H are calculated from constants A _n and B _n determined by each link shape and the crank angle θ _A , respectively.

On the other hand, the crank shaft 12 is the rotation variation is suppressed by the flywheel provided at the shaft end, the engine lateral direction displacement x ₁ of the crankpin 12A is expressed by only the primary displacement as (5) The second or higher order displacement x _1H is zero.

Further, since the piston 11 slides along the cylinder, the piston pin 16 is not displaced in the left-right direction of the engine. Therefore, the secondary or higher-order displacement x _4H of the piston pin 16 in the left-right direction of the engine becomes zero as shown in the equation (6).

The eccentric shaft 21 moves when the control shaft 20 rotates. However, the moving speed of the eccentric shaft 21 is smaller than the engine rotational speed, and the eccentric shaft 21 can be regarded as a fixed end. The displacement _xcH becomes zero as shown in equation (7).

(4) to (7) Rearranging equation as displacement (1) to (3) below the engine lateral direction of the second or higher using a lower link centroid _{G l} of second and higher order displacement _{x GLH,} upper link centroid secondary or displacement _{x Gch} secondary or displacement _{x GUH} and control link centroid _{G c} of G _u is (8) to (10) below.

Then, the total secondary or higher inertial force Fes in the left-right direction of the engine at each link gravity center position is expressed by the following equation (11) according to each link mass m ₁ , m _u , m _c and the above equations (8) to (10). It is expressed in In the equation (11), the first term on the right side represents the inertial force of the lower link 14, the second term on the right side represents the inertial force of the control link 15, and the third term on the right side represents the inertial force of the upper link 13.

  In the above equation (11), if the total sum Fes of the secondary and higher-order inertia forces in the left-right direction of the engine is zero, specifically, the equation (12) obtained by arranging the equations (11) is zero, that is, the engine of each link. If the sum of the left and right secondary inertia forces in the left and right direction is balanced with the sum of the right and left inertia forces, the secondary and higher excitation forces that excite the engine body in the left and right direction of the engine will disappear. Secondary vibrations are suppressed.

  Therefore, in the multi-link engine 100 of the present embodiment, the mass, shape, and the like of the upper link 13, the lower link 14, and the control link 15 are determined so as to satisfy the expression (12).

  FIG. 3 is a diagram showing each link designed to satisfy the expression (12). 3A shows the upper link 13, FIG. 3B shows the lower link 14, and FIG. 3C shows the control link 15.

As shown in FIG. 3 (A), the upper link 13, the mass is in m _u, the length between the centers of the upper pin 17 of the piston pin 16 is formed to be L _6. The upper link 13 is formed as a rod-like member, and has a symmetrical three-dimensional shape with a plane including the center line of the piston pin 16 and the center line of the upper pin 17 interposed therebetween. Upper link centroid G _u is set between the piston pin center and the upper pin center a line or in the vicinity thereof through a piston pin center and the upper pin center. Distance from the piston pin center to the upper link centroid _{G u} is _{x gu0.}

As shown in FIG. 3B, the lower link 14 has a mass of m ₁ , a length between the center of the upper pin 17 and the center of the crank pin 12A is L ₄ , and the center of the crank pin and the control pin 18 the length between the center is formed such that L _2. The lower link 14 is formed with a connecting hole 14A between the upper pin 17 and the control pin 18 so that the center of the crank pin is arranged on or near the line passing through the center of the upper pin and the center of the control pin. . By forming such coupling hole 14A, through the upper pin side and the control pin side is almost the structure of the lower link 14 which are symmetrical, the upper pin center and the control pin center also lower link centroid G _l across the coupling hole 14A Set on or near the line. Further, the lower link 14 is a line that the lower link centroid G _l passes through the upper pin center and the control center of the pin is configured to be disposed between the control pin center and the crank pin center. The distance from the crank pin center to the lower link centroid _{G l} is _{x GL0.}

As shown in FIG. 3 (C), the control link 15, the mass is at m _c, the length between the center and the center of the eccentric shaft 21 of the control pin 18 is formed to be L _3. The control link 15 is formed as a rod-like member, and has a symmetrical three-dimensional shape across a plane including the center line of the control pin 18 and the center line of the eccentric shaft 18. The control link gravity center _Gc is set on or near a line passing through the control pin center and the eccentric shaft center and between the control pin center and the eccentric shaft center. Distance from the eccentric shaft center to the control link centroid _{G c} is _{x GC0.}

  If each of the links is configured so that the position of the center of gravity represented by the mass, the length between the pins, and the distance from the center of the predetermined pin to the center of gravity is satisfied to satisfy the expression (12), the multi-link engine 100 has the engine left-right direction. The second and higher order vibrations are suppressed.

  The effect of the multi-link engine 100 will be described with reference to FIGS. FIG. 4 is a comparative example for the multi-link engine 100 and shows a multi-link engine 200 that does not satisfy the equation (12). FIG. 5 is a diagram showing the secondary inertial force in the engine left-right direction in the multi-link engine 100.

  The multi-link engine 200 shown in FIG. 4A has basically the same link arrangement as the multi-link engine 100, but the mass of the upper link 213 is lighter than that of the multi-link engine 100. The mass of the control link 215 is heavy, and the distance from the center of the crankpin to the center of gravity of the lower link is increased. The mass of the lower link 214 is set to be heavier than the masses of the upper link 213 and the control link 215. In such a case, out of the three terms on the left side of equation (12), the absolute values of the two positive terms (first term and second term) are the absolute values of one negative term (third term). It tends to be relatively larger than the value, making it difficult to satisfy the equation (12). In the multi-link engine 200 that does not satisfy the equation (12), as shown in FIG. 4B, the secondary inertia force in the left-right direction of the engine of each link is not balanced, and the sum of the secondary inertia forces is reduced. I can't. Therefore, in the multi-link engine 200, secondary vibration in the engine left-right direction occurs.

  On the other hand, in the multi-link engine 100, each link is configured to satisfy the expression (12). As shown in FIG. 5, the secondary inertia force of the lower link 14 (the left side of the expression (12) The secondary inertia force of the control link 15 (corresponding to the third term on the left side of the equation (12)) is the secondary inertia force of the upper link 13 (corresponding to the second term on the left side of the equation (12)). Therefore, the sum of the inertial forces in the direction of the secondary side of each link is balanced with the sum of the inertial forces in the opposite direction. Therefore, the total sum of the secondary inertial forces in the left-right direction of the engine at each link gravity center position is substantially zero. As a result, the secondary excitation force that vibrates the engine main body becomes substantially zero, and therefore, in the multi-link engine 100, generation of secondary vibration in the left-right direction of the engine is suppressed.

  As described above, the description has been made by paying attention to the secondary vibration of the engine rotation. However, the inertial force acting in the lateral direction with respect to the piston moving direction of at least one of the secondary rotations of the engine rotation is a predetermined order of each link. If the sum of the leftward inertial force and the rightward inertial force is balanced, this contributes to suppression of the muffled noise. In the multi-link engine 100 of the present embodiment, each link is configured so as to satisfy the expression (12), so that occurrence of higher-order vibrations higher than the secondary is also suppressed.

  As described above, in the multi-link engine 100 of the first embodiment, the following effects can be obtained.

  In the multi-link engine 100, specifically, the expression (12) is satisfied so that the sum of the secondary and higher inertial forces of the upper link 13, the lower link 14, and the control link 15 in the left-right direction of the engine is substantially zero. In addition, since the mass, shape, and the like of the upper link 13, the lower link 14, and the control link 15 are determined, it is possible to reduce secondary and higher order vibrations in the left-right direction of the engine with a simple configuration.

Incidentally, the (12) of this embodiment, it is desirable that the center of the crankpin 12A is inserted in the lower link 14 to a lower link centroid G _l and the connecting hole 14A is in the line passing through the upper pin center and the control pin central . However, from a variety of constraints, as shown in FIG. 6 (A), to be located in the vicinity thereof by shifting the center of the lower link centroid G _l and crankpin 12A from line passing through the upper pin center and the control center of the pin, the lower In some cases, the link 14 must be formed.

FIG. 6 (B) in the case of the lower link 14 is lower link centroid G _l offset from a line passing through the upper pin center and the control pin center, the lower link gravity center G _l shift amount and D, the engine left and right direction of each link The relationship with the secondary excitation force which is the sum total of a secondary inertia force is shown. Shift amount D of the lower link centroid G _l is a line passing through the upper pin center and the control pin center is expressed as the distance between the lower link centroid G _l.

In multi-link engine 100, as shown by a solid line A in FIG. 6 (B), the higher the lower link centroid G _l is shifted from a line passing through the upper pin center and the control center of the pin, the secondary excitation force of the engine lateral direction is larger made, but if the lower link centroid G _l range R ₁ deviation amount D is within ten mm from 0mm of multi-link engine that does not take into account the inertia of the engine left and right directions indicated by the broken line B (e.g., The secondary excitation force can be made smaller than that in the comparative example of FIG. 4 to suppress the booming noise that is the vehicle interior noise. In this way multi-link engine 100, if the small deviation of the lower link centroid G _l, (12) constitute the links so as to satisfy the equation, reducing the second and higher order vibrations of the engine left and right directions It is possible.

FIG. 6C shows the crank pin center shift amount correlation value θ _B when the connecting hole 14A of the lower link 14 is formed so that the center of the crank pin 12A is shifted from the line passing through the upper pin center and the control pin center. And the secondary excitation force that is the sum of the secondary inertia forces in the left-right direction of the engine of each link. The crankpin center shift amount correlation value θ _B is expressed as an angle formed by a line passing through the upper pin center and the crankpin center and a line passing through the control pin center and the crankpin center.

In the multi-link engine 100, when the crank pin center shift amount correlation value θ _B is smaller than 180 °, the secondary excitation force in the left-right direction of the engine increases as shown by the solid line C in FIG. If the crankpin center deviation amount correlation value θ _B is within a range R ₂ within 180 ° to tens of degrees, a multi-link engine that does not take into account the left-right inertial force of the engine indicated by the broken line B (for example, The secondary excitation force can be made smaller than that in the comparative example of FIG. 4 to suppress the booming noise that is the vehicle interior noise. In this way, in the multi-link engine 100, if there is a slight shift in the center of the crankpin, each link can be configured to satisfy the equation (12) to reduce secondary or higher order vibrations in the left-right direction of the engine. Is possible.

(Second Embodiment)
FIG. 7 is a diagram illustrating each link of the multi-link engine 100 according to the second embodiment. 7A to 7C show the lower link 14, the upper link 13, and the control link 15, respectively.

  The basic configuration of the multi-link engine 100 of the second embodiment is substantially the same as that of the first embodiment, but differs in the configuration of the lower link 14. Hereinafter, the difference will be mainly described.

As shown in FIG. 7 (A), the lower link 14 is on a line passing through the center of the upper pin 17 and the center of the control pin 18, and the center of the crank pin is disposed between the center of the upper pin and the center of the control pin. A connecting hole 14A is formed as described above. Further, the lower link 14 is formed so as to match the center of the crankpin 12A to the lower link centroid G _l is inserted into the coupling hole 14A.

With this form the lower link 14, the distance x _GL0 from the crank pin center to the lower link centroid G _l is zero. The coupling hole 14A across the upper pin side and the control pin side is almost the structure of the lower link 14 which are symmetrical, the length L from a length L ₄ and the crank pin center from the upper pin center to a crank pin center to control pin center ₂ becomes substantially equal.

When the distance x _gl0 becomes zero, the lower link term of the first term on the left side of the equation (12) becomes zero, and when the lengths L ₂ and L ₄ become substantially equal, the upper link term of the third term on the left side of the equation (12) becomes Since it can be arranged, equation (12) is transformed into equation (13).

  If the upper link 13 and the control link 15 are configured so that the position of the center of gravity represented by the mass, the length between the pins, and the distance from the center of the predetermined pin to the center of gravity is satisfied to satisfy the expression (13), a multi-link engine At 100, secondary and higher order vibrations in the left-right direction of the engine are suppressed.

That is, the lower link 14 has an upper pin center and a control pin center so as to suppress vibrations of at least one of the second and higher engine rotations acting on each link in a direction transverse to the piston movement direction. A connecting hole 14A to which the crank pin 12A is connected is formed so that the crank pin is disposed therebetween. Further, the upper link 13 and control link 15, the ratio of the distance x _Gu0 from piston pin center to the upper link centroid to the length L ₆ from the piston pin center the upper pin to the center, the product of the upper link mass m _u is, the ratio of the distance x _GC0 between the swing axis center to the control link centroid to the length L ₃ from the control pin center to the rocking axis center, and the product of the control link mass m _c, configured to balance.

Here, the upper link 13 and the control link 15 are rod-shaped members having two connecting portions 13A and 15A as shown in FIGS. 7B and 7C, and are formed in substantially the same shape. The Therefore, a value obtained by dividing the length L ₆ between the piston pin center and the upper pin center distance x _Gu0 from piston pin center to the upper link centroid G _u in the upper link 13, control link centroid from the eccentric shaft center G _c It becomes approximately equal to the value obtained by dividing the length L ₃ between the distance x _GC0 the control pin center and the eccentric axis center up. Therefore, if the mass m _u of the upper link 13 and the mass m _c of the control link 15 are set to be approximately equal, the equation (13) can be satisfied.

  In the present embodiment, the lower link 14 is connected to the center of the upper pin and the control pin so as to suppress vibration of at least one of the second and higher orders of the engine rotation that acts on each link in a direction transverse to the piston movement direction. A connecting hole 14A for connecting the crankpin 12A is formed so that the crankpin 12A is disposed between the center and the center, and the upper link 13 and the control link 15 are configured so that the upper link mass and the control link mass are equal. It is configured.

  As described above, in the multi-link engine 100 of the second embodiment, the following effects can be obtained.

In the multi-link engine 100, the lower link 14 is on a line passing through the upper pin center and the control pin center, and the connection hole 14A is formed so that the crank pin center is disposed between the upper pin center and the control pin center. In addition, the lower link center of gravity _Gl is configured to substantially coincide with the center of the crankpin, and the upper link 13 and the control link 15 are configured such that the upper link mass _mu and the control link mass _mc are substantially equal. Therefore, the expression (13) is satisfied, and it is possible to reduce secondary and higher order vibrations in the left-right direction of the engine as in the first embodiment.

(Third embodiment)
With reference to FIG.8 and FIG.9, the multilink type engine 100 of 3rd Embodiment is demonstrated. FIG. 8 is a schematic configuration diagram of the multi-link engine 100 of the third embodiment. FIG. 9 is a diagram illustrating the secondary inertial force in the engine left-right direction that acts on the center of gravity of each link.

  The multi-link engine 100 of the third embodiment is the same as the first embodiment in that each link is formed so as to satisfy the expression (12), but the configuration of the control link 15 is different. That is, the balance weight 15B is installed on the control link 15, and the difference will be mainly described below.

As shown in the equation (11), among the secondary and higher inertial forces in the left-right direction of the engine, the inertial forces acting on the lower link 14 and the control link 15 are in the same direction (indicated by a positive term). Only the inertial force acting on the control link 15 is in the reverse direction (indicated by a negative term). Therefore the lower link 14, in the case of satisfying the counteracts the inertia force of the upper link 13 the sum of the inertial force of the control link 15 (12), the upper link 13 and the like to increase the mass m _u of the upper link 13 It is necessary to considerably increase the inertial force.

  Therefore, in the multi-link engine 100 of the third embodiment, the balance weight 15B is provided in the control link 15, and the sum of the inertia forces of the lower link 14 and the control link 15 is made as small as possible, so that the inertia force of each link can be reduced. While facilitating the balance, the vibration of the second or higher order in the left-right direction of the engine is reduced.

As shown in FIG. 8, the control link 15 of the multi-link engine 100 includes a balance weight 15B at the end on the eccentric shaft side. Due to the balance weight 15B, the control link center of gravity _Gc is set on a line passing through the center of the control pin 18 and the center of the eccentric shaft 21 and on the opposite side of the control pin side with respect to the center of the eccentric shaft.

When the control link center of gravity _Gc is set in this way, the behavior of the control link center of gravity _{Gc in} the left-right direction of the engine is opposite to that in the first embodiment. Therefore, the orientation of the secondary inertial force of the engine lateral direction of the control link gravity G _c, as shown in FIG. 9, becomes inertial force in a direction opposite to the direction that acts on the lower link of gravity G _l, the upper link of gravity G _The direction is the same as the inertial force acting on _u . This is the distance _{x GC0} from the eccentric shaft center to the control link centroid _{G c} is a negative value, the (11) and (12) of the control link section ((12) of the left side first term) It means becoming negative.

  As described above, in the multi-link engine 100 of the third embodiment, the following effects can be obtained.

In multi-link engine 100, a counterweight 15B is provided on the eccentric shaft end of the control link 15, a line passing through the eccentric shaft center as the control pin about the control link centroid G _c, control pin side from the eccentric shaft center Set to the opposite side. The lower link 14 tends to be heavier than the control link 15 and tends to have a secondary or higher inertial force, but the direction of the secondary or higher inertial force acting on the control link center of gravity _Gc in the left-right direction of the engine is the first embodiment. Further, since the direction can be opposite to that of the second embodiment, the sum of the secondary and higher inertial forces of the lower link 14 and the control link 15 can be reduced. Thereby, the secondary or higher-order vibration in the left-right direction of the engine caused by the lower link 14 and the control link 15 can be reduced. Further, if the sum of the inertial forces of the lower link 14 and the control link 15 is reduced, it becomes easier to balance the secondary and higher inertial forces in the left-right direction of the engine by the upper link 13, and the balance of the inertial forces of the links is facilitated. be able to.

  In the multi-link type engine 100, the sum of the secondary and higher inertial forces in the left-right direction of the engine at the center of gravity of the upper link and the control link is set equal to the secondary and higher-order inertial forces in the left-right direction of the engine at the center of gravity of the lower link. Since the configuration is such that Expression (12) is satisfied, as shown in FIG. 9, the total sum of the secondary inertia forces in the left-right direction of the engine is also substantially zero. Thereby, the secondary excitation force that vibrates the engine body is reduced, and the occurrence of secondary vibration is suppressed.

  Although only the secondary vibration has been described with reference to FIG. 9, in the multi-link engine 100 of the third embodiment, the occurrence of higher-order vibration higher than the secondary is also suppressed as in the first embodiment.

In the third embodiment, the balance weight 15B is set so that the control link center of gravity _Gc is on a line passing through the center of the control pin and the center of the eccentric shaft and is set on the opposite side of the control pin side from the center of the eccentric shaft. Although it installed in the control link 15, it is not restricted to this. That is, even if the control link center of gravity _Gc is on a line passing through the center of the control pin and the center of the eccentric shaft and between the center of the eccentric shaft and the center of the control pin, the balance weight 15B is installed on the control link 15. Te, may be closer to the eccentric shaft around the control link centroid G _c. Then, from the eccentric shaft center shorter distance x _GC0 to control link centroid G _c, (12) Since the equation decreases the value of the control link section, the second or higher inertia forces of the lower link 14 and control link 15 The sum can be reduced, and the secondary and higher vibrations in the left-right direction of the engine can be reduced while facilitating the balance of the inertial force of each link.

(Fourth embodiment)
With reference to FIG.10 and FIG.11, the multilink type engine 100 of 4th Embodiment is demonstrated. FIG. 10A is a schematic configuration diagram of the multi-link engine 100 of the fourth embodiment, and FIG. 10B is a schematic configuration diagram of the control link 15. 11 (A) and 11 (B) show the secondary inertia force in the engine left-right direction and engine up-down direction (piston movement direction).

The configuration of the multi-link engine 100 of the fourth embodiment is substantially the same as that of the third embodiment, but differs in the position of the center of gravity of the control link 15. In other words, so as to shift from the line control link centroid G _c is passing through the eccentric shaft center as the control center of the pin, which has established a counterweight 15B on the control link 15, the difference will be mainly described below.

As shown in FIG. 10A, the control link 15 of the multi-link engine 100 includes a balance weight 15B at the end of the eccentric shaft. Counterweight 15B, when installed in the control link 15, the reverse side is the control link centroid G _c is the Kontorupin side from the center of the eccentric shaft 21, in the vicinity of the line passing through the eccentric shaft center and the center of the control pin 18 Therefore, it is configured to be slightly deviated from the line.

Therefore, as shown in FIG. 10B, the control link center of gravity _Gc is based on the center of gravity component P on the line X passing through the center of the control pin and the center of the eccentric shaft, and the line X. And a center-of-gravity component Q on a line Y that is orthogonal and passes through the center of the eccentric axis.

The center-of-gravity component P is on a line passing through the center of the control pin and the center of the eccentric shaft, and is on the side opposite to the control pin side from the center of the eccentric shaft, and as described in detail in the third embodiment, Contributes to direction inertia. In the control link 15, the orientation of the second or higher inertial force of the engine lateral direction acting on the center-of-gravity component P is, since the direction opposite to the second and higher order inertia forces acting on the lower link centroid G _l, a third embodiment Similarly, secondary and higher order vibrations in the left-right direction of the engine can be reduced as shown in FIG. 11A while facilitating the balance of the secondary and higher inertial forces of each link.

In contrast, the center-of-gravity component Q contributes to the inertia force of the control link 15 in the vertical direction of the engine because it swings in the vertical direction of the engine when the control link 15 swings around the eccentric shaft 21. Therefore, by adjusting the shape and mass of the balance weight 15B and adjusting the distance y _gc0 from the center of the eccentric shaft to the center of gravity component Q, as shown in FIG. The sum of the secondary inertia forces in the engine vertical direction acting on the engine can be made substantially zero, and the secondary vibration in the engine vertical direction can be reduced.

  As described above, in the multi-link engine 100 of the fourth embodiment, the following effects can be obtained.

In multi-link engine 100, a counterweight 15B is provided on the eccentric shaft end of the control link 15, the reverse side of the Kontorupin side from the eccentric shaft around the control link centroid G _c, an eccentric shaft center as the control center of the pin By setting so as to deviate from the passing line, it is possible to reduce vibrations in the vertical direction of the engine as well as in the horizontal direction of the engine.

  Note that the present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  In the first to fourth embodiments, the example in which the present invention is applied to a four-cylinder engine has been described. However, if the present invention is applied to a six-cylinder engine, the third-order vibration in the left-right direction of the engine that becomes a problem in the six-cylinder engine is described. Can be reduced.

100 Multi-link engine 11 Piston 12 Crankshaft 12A Crankpin 13 Upper link 14 Lower link 14A Connection hole 15 Control link 15B Balance weight 16 Piston pin 17 Upper pin 18 Control pin 20 Control shaft 21 Eccentric shaft (oscillating shaft)

Claims (4)

An upper link whose one end is connected to the piston via a piston pin, a lower link connected to the other end of the upper link via an upper pin and rotatably connected to the crank pin of the crankshaft, and one end A multi-link engine vibration reduction structure comprising a control link coupled to the lower link via a control pin and having the other end pivotably coupled to a pivot shaft,
An inertia force of at least one predetermined order of engine rotation secondary or higher is applied to at least the upper link and the control link in the lateral direction with respect to the piston movement direction, and the predetermined order at the center of gravity position of each link. The upper link, the lower link, and the control link are configured so that the sum of the leftward inertial force and the rightward inertial force is balanced.
A vibration reduction structure for a multi-link engine characterized by the above. An upper link whose one end is connected to the piston via a piston pin, a lower link connected to the other end of the upper link via an upper pin and rotatably connected to the crank pin of the crankshaft, and one end A multi-link engine vibration reduction structure comprising a control link coupled to the lower link via a control pin and having the other end pivotably coupled to a pivot shaft,
The upper link, the lower link, and the control link are subjected to an inertial force of a predetermined order of at least one of second and higher engine rotations in the lateral direction with respect to the piston movement direction, and the gravity center position of the upper link. The direction of the inertial force in the horizontal direction of the predetermined order in the direction is opposite to the direction of the inertial force in the horizontal direction of the predetermined order at the center of gravity of the other two links, and the predetermined order at the center of gravity of the upper link Left and right lateral inertial force of the two links is greater than the predetermined order of right and left lateral inertial force at the center of gravity of the other two links, and the predetermined order of right and left lateral inertial force at the center of gravity of the upper link, The upper link and the lower link are adjusted so that the sum of the inertial forces in the horizontal direction of the predetermined order at the center of gravity of the other two links is balanced. Constituting the link and the control link,
A vibration reduction structure for a multi-link engine characterized by the above . An upper link whose one end is connected to the piston via a piston pin, a lower link connected to the other end of the upper link via an upper pin and rotatably connected to the crank pin of the crankshaft, and one end A multi-link engine vibration reduction structure comprising a control link coupled to the lower link via a control pin and having the other end pivotably coupled to a pivot shaft,
Only the upper link and the control link have an inertia force of a predetermined order of at least one of the engine rotation secondary and higher acting in the lateral direction with respect to the piston moving direction, and the predetermined link at the center of gravity position of the upper link. The direction of the lateral inertial force of the order is opposite to the direction of the lateral inertial force of the predetermined order at the center of gravity position of the control link, and the predetermined order of the horizontal direction of the predetermined link at the center of gravity of the upper link The upper link, the lower link, and the control link are configured so that the inertial force and the inertial force in the lateral direction of the predetermined order at the center of gravity of the control link are balanced.
A vibration reduction structure for a multi-link engine characterized by the above . An upper link whose one end is connected to the piston via a piston pin, a lower link connected to the other end of the upper link via an upper pin and rotatably connected to the crank pin of the crankshaft, and one end A multi-link engine vibration reduction structure comprising a control link coupled to the lower link via a control pin and having the other end pivotably coupled to a pivot shaft,
The upper link, the lower link, and the control link have an inertial force of a predetermined order of at least one of the engine rotation secondary and higher acting in the lateral direction with respect to the piston moving direction, and the gravity center position of the lower link The direction of the inertial force in the lateral direction of the predetermined order in the direction is opposite to the direction of the inertial force in the lateral direction of the predetermined order at the center of gravity of the other two links, and the predetermined order at the center of gravity of the lower link Left and right lateral inertia force of the other two links at the center of gravity position of the other two links is larger than the predetermined degree of left and right lateral inertia force, The upper link and the lower link so that the sum of the inertial forces of the predetermined order at the center of gravity of the other two links is balanced. And forming the control link,
A vibration reduction structure for a multi-link engine characterized by the above .

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