JP4591079B2 - Crank mechanism of internal combustion engine - Google Patents

Description

  The present invention relates to a crank mechanism for an internal combustion engine.

A so-called multi-link type crank mechanism in which a crank pin of a crank shaft and a piston pin of a piston are linked via a plurality of links has been known. (For example, see Patent Document 1)
Japanese Patent Publication No. 2001-227367

  However, in the known multi-link type crank mechanism, attention is paid to the acceleration amplitude of the third component among the acceleration amplitudes of the respective order components based on the crank rotation speed (crank shaft rotation speed) of the piston acceleration. When the acceleration component of the third-order component has deteriorated (the acceleration amplitude is large) is applied to an in-line three-cylinder engine or a V-type six-cylinder engine, the sound vibration performance of the internal combustion engine is extremely deteriorated. There is a risk of it.

  Therefore, the present invention provides a multi-link crank mechanism in which the third component acceleration amplitude is the sixth or lower order component among the acceleration components of the respective order components based on the crank rotation speed of the piston acceleration. It is characterized by being set to be smaller than the acceleration amplitude.

  According to the present invention, since the amplitude of the tertiary vibration component of the piston acceleration can be actively reduced, it is possible to prevent the deterioration of the sound vibration performance of the internal combustion engine caused by the tertiary vibration component of the piston acceleration. it can.

  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 crank mechanism 1 of an internal combustion engine in a first embodiment of the present invention, and shows a state at the time of piston top dead center. FIG. 2 is a link diagram schematically showing the link arrangement at the time of piston top dead center of the crank mechanism 1 of the internal combustion engine in the first embodiment. The crank mechanism 1 is a so-called multi-link type composed of a plurality of links.

  The crankshaft 2 includes a plurality of crank journals 3 and a crank pin 4, and the crank journal 3 is rotatably supported by a main bearing (not shown) of a cylinder block (not shown). The crank pin 4 is eccentric from the crank journal 3 by a predetermined amount, and a lower link 5 is rotatably connected thereto.

  The upper link 6 has a lower end side rotatably connected to one end of the lower link 5 by an upper pin 7 and an upper end side rotatably connected to a piston 9 by a piston pin 8. The piston 9 receives the combustion pressure and reciprocates in the cylinder of the cylinder block.

  The control link 10 is pivotally connected to the other end of the lower link 5 at the upper end side by a control pin 11, and the lower end side is connected to a lower portion of a cylinder block (not shown) that becomes a part of the engine body via the control shaft 12. It is connected so as to be able to rotate, and the movement of the lower link 5 is constrained while performing a swinging motion around the control shaft 12. Further, the control shaft 12 in the first embodiment is stationary with respect to the internal combustion engine body.

  The control shaft 12 is located obliquely below the crankshaft 2. That is, it is offset from a straight line that passes through the crank journal axis Oa and is parallel to the reciprocating axis Lb of the piston pin axis Ob (the reciprocating axis of the piston pin 8). The control shaft 12 is disposed at a position (downward in FIGS. 1 and 2).

In FIG. 2, Lc is an upper pin movement locus that is the movement locus of the upper pin axis Oc, Ld is a crank pin movement locus that is the movement locus of the crankpin axis Od, and Le is a movement locus of the control pin axis Oe. It is a substantially arc-shaped control pin motion locus. Of is the axis of the control shaft 12. Here, the crank mechanism 1 according to the first embodiment is configured such that the control shaft 12, the crank journal axis Oa, and the reciprocating axis Lb of the piston pin axis Ob. Are located on the same side. In other words, the control shaft 12 and the crank journal axis Oa are located on the left side (left side in FIG. 2) of the reciprocating axis Lb of the piston pin 8.

  The crankpin axis Od revolves around the crank journal axis Oa. As shown in FIGS. 1 and 2, when the piston is at the top dead center, the crank journal axis Oa, the crankpin axis Od, the upper The pin shaft center Oc and the piston pin shaft center Ob are configured to be aligned on a substantially straight line.

  Further, the height of the arc-shaped control pin movement locus Le in the piston reciprocating direction (vertical direction in FIG. 2) of the counter crankshaft side end portion P1 (left side end portion in FIG. 2) is the crankshaft side end portion P2 ( 2 is higher than the height of the piston in the reciprocating direction and the position of the control pin shaft center 0e at the top dead center of the piston is in the reciprocating direction of the piston in the counter crankshaft side end P1 and the crankshaft side. It is comprised so that it may be located between the edge parts P2. In other words, the height of the control pin motion locus Le viewed in the piston reciprocating direction is set to be higher on the non-crankshaft side and lower on the crankshaft side.

  3 to 5 show a crank mechanism 80 of a general internal combustion engine as a comparative example. In addition, the same code | symbol is attached | subjected about the component same as the crank mechanism 1 of 1st Embodiment mentioned above, and the overlapping description is abbreviate | omitted.

  The crank mechanism 80 of this comparative example has substantially the same configuration as the crank mechanism 1 of the first embodiment described above. However, as shown in FIG. 3, at the piston top dead center, the crank journal axis Oa, The pin shaft center Od, the upper pin shaft center Oc, and the piston pin shaft center Ob are not configured so as to be aligned in a substantially straight line. Both end points of the control pin motion locus Le, that is, the counter crankshaft side end portion P1 (left end portion in FIG. 3) and the crankshaft side end portion P2 (right end portion in FIG. 3) are in the piston reciprocating direction (in FIG. 3). It is configured to have substantially the same height in the vertical direction).

  In the first embodiment of the present invention, the crank journal axis Oa, the crankpin axis Od, the upper pin axis Oc, and the piston pin axis Ob are arranged in a substantially straight line at the time of piston top dead center. Therefore, the upward stroke and the downward stroke of the piston 9 near the top dead center of the piston can be made similar.

  As shown in FIG. 4, the crank journal axis Oa, the crankpin axis Od, the upper pin axis Oc, and the piston pin axis Ob are arranged substantially in a straight line at the top dead center of the piston. If it becomes a broken line state, the distance between the crank journal axis Oa and the piston pin axis Ob, which determines the stroke of the piston 9, will fluctuate greatly only by a slight change in the direction of each link. Therefore, a large difference occurs between the piston ascending stroke and the piston descending stroke near the piston top dead center.

  However, as in the first embodiment of the present invention, at the top dead center of the piston, the crank journal axis Oa, the crankpin axis Od, the upper pin axis Oc, and the piston pin axis Ob are aligned in a substantially straight line. As shown in FIG. 6, each link end point can only swing left and right around the top of the arc when viewed in the direction of the crank journal axis Oa and the piston pin axis Ob determining the stroke of the piston 9. Therefore, even if the direction in which each link faces changes slightly, the change in the distance between the crank journal axis Oa and the piston pin axis Ob that determines the stroke of the piston 9 is much smaller than that in the comparative example described above. As a result, the difference between the upward stroke and the downward stroke of the piston 9 near the piston top dead center is reduced.

  Further, in the first embodiment of the present invention, when the two link arrangements shifted by 90 degrees from the piston top dead center are viewed, as shown in FIG. 7, the crankpin axis Od is oriented in the horizontal right direction ( The upper link 6 of the link arrangement shown by the dotted line on the right side of FIG. 7 is inclined more greatly than the state in which the crankpin axis Od is oriented in the horizontal left direction (link arrangement shown by the solid line on the left side of FIG. 7). The pin axis Oc is separated from the reciprocal axis Lb of the piston pin axis Ob. Since the length of the upper link 6 is not changed, the piston pin axis Ob should be pulled downward when the upper link 6 alone is considered, but the piston reciprocating direction of the control pin axis Oe The height of the lower link is lower in the state in which the crankpin axis Od is oriented in the horizontal right direction than in the state in which the crankpin axis Od is oriented in the horizontal left direction. 5 rotates counterclockwise about the crankpin axis Od. As a result, the upper pin axis Oc is lifted further upward, and the upper pin axis Oc is the reciprocating axis of the piston pin axis Ob. The downward movement of the piston pin axis Ob due to being away from the center is corrected. Accordingly, the height of the piston pin axis Ob in the two link arrangements shifted by 90 degrees from the piston top dead center, that is, the piston position, can be set to a close position, and the piston 9 with the piston top dead center as a boundary is set. It is possible to improve the symmetry of the ascending process and descending process. Therefore, in the present embodiment, the acceleration amplitude of the third order component among the acceleration amplitudes of the respective order components based on the crank rotation speed of the piston acceleration can be positively reduced. In other words, the amplitude of the tertiary vibration component with respect to the crankshaft rotation synchronization of the piston motion can be positively reduced. That is, since the acceleration amplitude of the third-order component of the piston acceleration is set to be smaller than other acceleration amplitudes of the sixth or lower order, the in-line three-cylinder engine or the V-type is not deteriorated without deteriorating the engine vibration performance. It becomes possible to apply to a 6-cylinder engine.

  Here, FIG. 8 is a characteristic diagram showing the piston acceleration waveform and its Fourier expansion waveform in the first embodiment of the present invention, and FIG. 9 is a characteristic diagram showing the piston acceleration waveform and its Fourier expansion waveform in the comparative example. is there.

  In the first embodiment of the present invention, the acceleration amplitude of the second-order component and the acceleration amplitude of the fourth-order component of the piston acceleration are rather increased compared to the comparative example (see FIGS. 8 and 9). In a cylinder engine or a V-type 6-cylinder engine, they cancel each other out due to the phase difference between the cylinders. In the comparative example, as shown in FIG. 5, the height of the control pin shaft center Oe viewed in the piston reciprocating direction is such that the crankpin shaft center Od faces the horizontal left direction (the solid line on the left side of FIG. 5). The link pin arrangement shown in FIG. 5 and the state in which the crankpin axis is oriented in the horizontal right direction (link arrangement shown by the dotted line on the right side of FIG. 5) are approximately the same, so the upper pin axis Oc is the piston pin axis. The decrease in the height of the piston pin axis Ob due to being away from the reciprocal axis of the center Ob is not corrected.

  As described above, the crank mechanism 1 according to the first embodiment of the present invention is configured such that each link is serialized at the top dead center of the piston, and the height of the control pin motion locus Le viewed in the piston reciprocating direction is high. Since the counter crankshaft side is relatively high and the crankshaft side is relatively low, the symmetry of the ascending stroke and the descending stroke of the piston 9 with respect to the piston top dead center is improved. And the amplitude of the tertiary vibration component of the piston acceleration can be positively reduced. Therefore, particularly when applied to an in-line 3-cylinder engine or a V-type 6-cylinder engine, the sound vibration performance of the internal combustion engine can be improved.

  Next, the crank mechanism 20 of the internal combustion engine in the second embodiment of the present invention will be described. In each embodiment described below, the same components as those in the first embodiment described above are denoted by the same reference numerals and description thereof is omitted.

  The crank mechanism 20 of the internal combustion engine in the second embodiment has substantially the same configuration as the crank mechanism 1 of the first embodiment described above, but as shown in FIGS. 10 and 11, the piston pin axis Ob reciprocates. The axis Lb is configured to pass through the crank journal axis Oa.

  In such a second embodiment, in addition to the operational effects of the first embodiment described above, it is possible to deal with multi-links of a normal engine having no crank offset.

  12 and 13 show the crank mechanism 30 of the internal combustion engine in the third embodiment of the present invention.

  The crank mechanism 30 of the internal combustion engine in the third embodiment has substantially the same configuration as the crank mechanism of the first embodiment described above, but the crank journal shaft center with respect to the reciprocating axis Lb of the piston pin shaft Ob. Oa is located on the opposite side of the control shaft 12 (control shaft axis Of). Even in such a link arrangement, the symmetry of the ascending stroke and the descending stroke of the piston 9 can be enhanced. In such a link arrangement, the lever ratio of the lower link 5 that serves as a lever when the crank pin 4 is considered as a fulcrum at the maximum combustion pressure timing immediately after the piston top dead center can be reduced. In addition to the operational effects of the configuration, the load on the crankpin 4 can be greatly reduced.

  FIG. 14 shows the crank mechanism of the internal combustion engine in the fourth embodiment of the present invention.

  The crank mechanism of the internal combustion engine in the fourth embodiment has substantially the same configuration as the crank mechanism of the first embodiment described above, but the main shaft portion in which the control shaft 12 is rotatably supported with respect to the main body of the internal combustion engine. 12a and an eccentric shaft portion 12b that is eccentric by a predetermined amount from the rotation center of the main shaft portion 12a. And the lower end side of the control link 10 is connected with the eccentric shaft part 12b of the control shaft 12 so that rotation is possible. Further, the rotational attitude of the main shaft portion 12a of the control shaft 12 with respect to the engine body can be changed according to the operating conditions of the internal combustion engine by an electric motor drive or hydraulic drive actuator (not shown). Furthermore, the compression ratio of the internal combustion engine is made possible by changing the rotational attitude of the main shaft portion 12a relative to the engine body by this actuator.

  In the fourth embodiment, the distance between the crank journal axis Oa and the piston pin axis Ob that determines the compression ratio of the internal combustion engine is the maximum, that is, the piston top dead center position is the highest. Since the shaft center Oa, the crankpin shaft center Od, the upper pin shaft center Oc, and the piston pin shaft center Ob are in a straight line, the crank journal shaft center Oa, crankpin shaft center Od, upper The rotational position of the control shaft 12 in which the pin axis Oc and the piston pin axis Ob are arranged substantially in a straight line is set to be the maximum compression ratio of the internal combustion engine.

  The technical idea of the present invention that can be grasped from the above embodiment will be listed together with the effects thereof.

  (1) An upper link whose one end is connected to the piston via a piston pin, and is connected to the other end of the upper link so as to be swingable via the upper pin and is rotatably connected to the crank pin of the crankshaft. A lower link, one end of which is swingably connected to the lower link via a control pin, and the other end of which is swingably supported by a control shaft supported by the internal combustion engine body, In the internal combustion engine crank mechanism, the acceleration amplitude of the third-order component among the acceleration amplitudes of the respective order components based on the crank rotation speed of the piston acceleration is higher than the acceleration amplitudes of the other order components of the sixth order or less. It is set to be smaller. As a result, the amplitude of the tertiary vibration component of the piston acceleration can be positively reduced, so that the sound vibration performance of the internal combustion engine caused by the tertiary vibration component of the piston acceleration can be prevented.

  (2) In the crank mechanism of the internal combustion engine described in (1) above, specifically, the distance between the upper pin axis and the control pin axis is the distance between the upper pin axis and the crank pin axis. And the distance between the control pin shaft center and the crank pin shaft center, and the end portion on the side opposite to the crankshaft of the substantially arc-shaped control pin motion trajectory of the control pin shaft accompanying the rotation of the crankshaft. Is located on the piston top dead center side in the piston reciprocating direction relative to the position of the crankshaft side end of this control pin motion locus, and the axial center position of the control pin at the piston top dead center is In the reciprocating direction, it is configured to be located between the opposite end of the control pin movement trajectory and the crankshaft side end. .

  (3) More specifically, the crank mechanism of the internal combustion engine according to the above (1) or (2) has a crank journal axis, a crank pin axis, and an upper pin axis at the top dead center of the piston. The piston pin shaft centers are arranged on a substantially straight line.

  (4) In the crank mechanism of the internal combustion engine described in (3) above, the crank journal axis and the control shaft are located on the same side with respect to the reciprocating axis of the piston pin.

  (5) In the crank mechanism of the internal combustion engine described in (3) above, the reciprocating axis of the piston pin passes through the crank journal axis.

  (6) In the crank mechanism of the internal combustion engine described in (3) above, the crankshaft journal axis is located on the opposite side of the control shaft with respect to the reciprocating axis of the piston pin.

  (7) In the crank mechanism for an internal combustion engine according to any one of (1) to (6), the control shaft is in an eccentric relationship with the main shaft portion that is rotatably supported by the internal combustion engine body and the shaft center of the main shaft portion. It is composed of an eccentric shaft part, and the other end of the control link is swingably supported by the eccentric shaft part, and the control shaft is fixed to the internal combustion engine body up to a predetermined rotational posture according to the operating conditions of the internal combustion engine. And an actuator that can be rotated and held.

  (8) In the crank mechanism of the internal combustion engine according to (7), the crank journal axis, the crank pin axis, the upper pin axis, and the piston pin axis of the crank shaft are substantially linear when the piston is at the top dead center. The maximum compression ratio of the internal combustion engine is when the control shafts are aligned.

The explanatory view showing typically the crank mechanism of the internal-combustion engine in a 1st embodiment of the present invention. The link figure which showed typically the link arrangement | positioning at the time of the piston top dead center of the crank mechanism of the internal combustion engine in 1st Embodiment of this invention. The link figure which showed typically the link arrangement | positioning at the time of the piston top dead center of the crank mechanism of the internal combustion engine of a comparative example. The link figure which showed typically the link arrangement | positioning at the time of the piston top dead center of the crank mechanism of the internal combustion engine of a comparative example. The link figure which showed typically the link arrangement | positioning in the timing which shifted | deviated about 90 degree | times by the crank angle from the piston top dead center of the crank mechanism of the internal combustion engine of a comparative example. The link figure which showed typically the link arrangement | positioning at the time of the piston top dead center of the crank mechanism of the internal combustion engine in 1st Embodiment of this invention. The link figure which showed typically the link arrangement | positioning in the timing which shifted | deviated about 90 degree | times by the crank angle from the piston top dead center of the crank mechanism of the internal combustion engine in 1st Embodiment of this invention. The characteristic line figure which shows the piston acceleration waveform and its Fourier expansion waveform in 1st Embodiment of this invention. The characteristic line figure which shows the piston acceleration waveform and its Fourier expansion waveform in a comparative example. The link figure which showed typically the link arrangement | positioning at the time of the piston top dead center of the crank mechanism of the internal combustion engine in 2nd Embodiment of this invention. The link figure which showed typically the link arrangement | positioning in the timing which shifted | deviated about 90 degree | times by the crank angle from the piston top dead center of the crank mechanism of the internal combustion engine in 2nd Embodiment of this invention. The link figure which showed typically the link arrangement | positioning at the time of the piston top dead center of the crank mechanism of the internal combustion engine in 3rd Embodiment of this invention. The link figure which showed typically the link arrangement | positioning in the timing which shifted | deviated about 90 degree | times by the crank angle from the piston top dead center of the crank mechanism of the internal combustion engine in 3rd Embodiment of this invention. Explanatory drawing which showed typically the crank mechanism of the internal combustion engine in 4th Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Crank mechanism 2 ... Crankshaft 3 ... Crank journal 4 ... Crank pin 5 ... Lower link 6 ... Upper link 7 ... Upper pin 8 ... Piston pin 10 ... Control link 11 ... Control pin 12 ... Control shaft

Claims (7)

An upper link having one end connected to the piston via a piston pin, and a lower link connected to the other end of the upper link so as to be swingable via the upper pin and rotatably connected to the crank pin of the crankshaft And a control link having one end pivotably connected to the lower link via a control pin and the other end pivotably supported by a control shaft supported with respect to the internal combustion engine body. In the crank mechanism of the engine,
The distance between the upper pin shaft center and the control pin shaft center is set to be larger than the distance between the upper pin shaft center and the crank pin shaft center and the distance between the control pin shaft center and the crank pin shaft center. And
The position of the end on the side of the crankshaft opposite the crankshaft side of the control pin motion locus of the substantially arc-shaped control pin axis along with the rotation of the crankshaft is the piston reciprocating direction relative to the position of the end of the crankshaft side Is located on the piston top dead center side, and the axial center position of the control pin at the piston top dead center is in the piston reciprocating direction, between the counter crankshaft side end of the control pin movement locus and the crankshaft side end. Configured to be located in
Among the acceleration amplitudes of the respective order components based on the crank rotation speed of the piston acceleration, the acceleration amplitude of the third order component is set to be smaller than the acceleration amplitudes of the other order components of the sixth order or less. A crank mechanism for an internal combustion engine. At top dead center the piston, crank journal axis of the crankshaft, the crank pin axis, according possible to claim 1, characterized in that the upper pin axis and the piston pin axis is formed so as to align in a substantially straight line A crank mechanism for an internal combustion engine. The crank mechanism for an internal combustion engine according to claim 2 , wherein the crank journal axis and the control shaft are located on the same side with respect to the reciprocating axis of the piston pin. The crank mechanism for an internal combustion engine according to claim 2 , wherein the reciprocating axis of the piston pin passes through the crank journal axis. The crank mechanism for an internal combustion engine according to claim 2 , wherein the crankshaft journal axis is located on the opposite side of the control shaft with respect to the reciprocating axis of the piston pin. The control shaft includes a main shaft portion that is rotatably supported by the internal combustion engine body, and an eccentric shaft portion that is eccentric with the shaft center of the main shaft portion, and the other end of the control link is swingably supported by the eccentric shaft portion. And
Depending on the operating condition of the internal combustion engine to rotate the control shaft relative to the internal combustion engine body to a predetermined rotational position, claim 1-5, characterized in that an actuator capable of retaining The crank mechanism of the internal combustion engine described in 1. The maximum compression ratio of the internal combustion engine is when the control shaft rotates with the crank journal axis, crank pin axis, upper pin axis, and piston pin axis aligned on a straight line at the top dead center of the piston. The crank mechanism for an internal combustion engine according to claim 6 .

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