JP2017172412A - Rib structure of piston inner wall - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the strike sound of a piston in an internal combustion engine.SOLUTION: A rib structure of a piston 1 inner wall has a plurality of SAN 31a-31c and 32a-32c formed on an inner wall 30x of a piston skirt 30; and recessed portions 30x1-30x8 which are surrounded by the SAN 31a-31c and 32a-32c, and have smaller thickness than the SAN 31a-31c and 32a-32c. The width of the whole or a part of the SAN 31a-31c and 32a-32c is decreased as it moves away from a center of the piston skirt 30, and/or the whole or a part of intervals of the SAN 31a-31c and 32a-32c is increased as it moves away from the center of the piston skirt.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a rib structure of an inner wall of a piston of an internal combustion engine mounted on a vehicle or the like.

  FIG. 3A is a front view showing a configuration of a conventional piston used in an internal combustion engine such as a gasoline engine, and FIG. 3B is a partial cross-sectional view taken along a line AA in FIG. is there. As shown in each figure, the piston 100 is a planar circular piston head 10 constituting a floor surface of a combustion chamber of the engine, a side wall 20 formed downward from the periphery of the piston head 10, and further formed below the side wall 20. The piston skirt 30 and the piston boss 40 are provided as main components.

  A piston ring groove 20 a into which a piston ring (not shown) is fitted is formed on the periphery of the side wall 20.

  The piston skirt 30 formed below the side wall 20 has a surface substantially flush with the side wall 20 and is disposed to face the central axis of the piston 100 that coincides with the AA line in the drawing. The piston boss 40 has a surface formed so as to recede toward the central axis of the piston 100 with respect to the side wall 20, and is disposed to face the central axis. Therefore, the piston skirt 30 and the piston boss 40 are alternately arranged along the circumferential direction of the piston 100.

  Further, inside the piston 100, a cavity is formed by the inner wall 30 x of the wall body 30 a of the piston skirt 30 and the back surface of the wall of the piston boss 40. Further, on the piston boss 40, a piston pin hole 40a into which the piston pin is inserted is opened.

  The piston 100 as described above reciprocates in the cylinder based on the combustion of fuel in the combustion chamber in the internal combustion engine. The reciprocating motion of the piston 100 is converted into a rotational motion via the connecting rod and the crankshaft, and is taken out as driving force of the internal combustion engine (see, for example, Patent Document 1).

Japanese Patent Laid-Open No. 3-15649

  However, the conventional piston 100 has the following problems. That is, as shown in FIGS. 4A to 4C, the piston 100 starts from the piston pin hole 40a (piston pin position) that is the connection center with the connecting rod 102 when the piston 100 reciprocates in the cylinder bore 101. It swings left and right, that is, in a direction perpendicular to the extending direction of the piston 100. In particular, in the displacement from FIG. 4 (a) to 4 (b), which is the compression stroke, the piston 100 collides with the cylinder bore 101 at the lower end E1 by rotating to the right to generate a hitting sound. Similarly, in the displacement from FIG. 4 (b) to 4 (c), which is the combustion stroke, the piston 100 rotates to the left and collides with the cylinder bore 101 at the upper end E2 to generate a hitting sound.

  As described above, the piston 100 collides with the cylinder bore 101 during the vertical movement in the cylinder bore 101 to generate a hitting sound, which adversely affects the emission sound of the engine. Although it is important to control the behavior of the piston in the compression stroke and the combustion stroke in order to improve the hitting sound, the control method is to reduce the striking force of the piston 100 based on the change of the position of the piston pin hole 40a and the like. A different approach was sought.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide a piston inner wall rib structure capable of improving piston hitting sound.

  In order to achieve the above object, a rib structure of the piston inner wall is formed on the inner wall of the piston skirt and has a plurality of crosspieces and a concave portion surrounded by the crosspiece and having a thickness smaller than that of the crosspiece. Thus, the width of all or part of the crosspieces decreases as the distance from the center of the piston skirt decreases, and / or the interval between all or part of the crosspieces increases as the distance from the center of the piston skirt increases. It is the rib structure of the piston inner wall.

  Furthermore, as another aspect of the present invention, the plurality of crosspieces are formed in parallel with the circumferential direction of the piston and arranged along the vertical direction, the first sub-crosspieces that do not intersect each other, and A second sub-bar portion that is formed along the vertical direction of the piston and is arranged along the circumferential direction and that does not intersect with each other, the first sub-bar portion and the second sub-bar portion, May be crossed.

  Further, according to another aspect of the present invention, each of the bars forming the first sub-bar has the same width, and each of the bars forming the second sub-bar is formed from the center of the piston. The width may be reduced as the distance increases.

  The present invention as described above has an effect that it is possible to improve the hitting sound of the piston.

(A) Front view showing the configuration of the piston according to the embodiment of the present invention (b) Partial sectional view taken along line AA in FIG. (A) Partial sectional view showing a configuration of a rib structure of a piston inner wall according to another embodiment of the present invention (b) Partial sectional view showing a configuration of a rib structure of a piston inner wall according to another embodiment of the present invention (A) Front view showing configuration of conventional piston (b) Partial cross-sectional view taken along line AA in FIG. 3 (a) (A) A diagram for explaining the behavior of a conventional piston in a cylinder bore (b) A diagram for explaining the behavior of a conventional piston in a cylinder bore (c) A diagram for explaining the behavior of a conventional piston in a cylinder bore Figure

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

  Fig.1 (a) is a front view which shows the structure of the piston 1 which concerns on embodiment of this invention, FIG.1 (b) is a fragmentary sectional view by the AA straight line of Fig.1 (a). However, the same or corresponding components as those in the conventional example shown in FIGS. 4 (a) and 4 (b) are denoted by the same reference numerals and detailed description thereof is omitted.

  Further, in the wall body 30a of the piston skirt 30 of the piston 1 of the present embodiment, a crosspiece described later is formed on the inner wall 30x, and the thickness of the portion of the wall body 30a where the crosspiece is not formed. Is reduced from the conventional example. Therefore, the average thickness of the wall body 30a of the piston skirt 30 of the piston 1 is smaller than the average thickness of the wall body 30a of the piston skirt 30 of the conventional piston 1.

  Next, the configuration of the inner wall 30x of the piston skirt 30 will be described with reference to FIG. However, in the following description, the X axis in the figure defines the circumferential direction of the piston 1, and the Y axis in the figure defines the vertical direction of the piston 1.

  In the inner wall 30x, a first sub-cross section constituted by a crosspiece 31a, a crosspiece 31b, and a crosspiece 31c that do not intersect with each other, and a second sub-crosspiece section constituted by a cross-piece 32a, a crosspiece 32b, and a crosspiece 32c that do not cross each other A web-like cross section is formed by crossing.

  The first sub bar portion is composed of a cross bar 31a, a cross bar 31b, and a cross bar 31c that are formed in parallel with each other in the circumferential direction of the piston 1. The crosspiece 31a is a part that extends in parallel with the X-axis and is formed at a position including the intersection of the X-axis and the Y-axis indicated by a black circle in the drawing, which is the center of the piston skirt 30. The crosspiece 31b is a part which is located above the crosspiece 31a and formed in parallel to the crosspiece 31a. The crosspiece 31c is a part located below the crosspiece 31a and formed in parallel to the crosspiece 31a.

  The crosspiece 31a is wider than the crosspiece 31b and the crosspiece 31c, and the crosspiece 31b and the crosspiece 31b have the same width. Further, the interval between the crosspiece 31a and the crosspiece 31b and the interval between the crosspiece 31a and the crosspiece 31c are the same.

  The second sub-bars are each formed of a bar 32a, a bar 32b, and a bar 32c that extend in the vertical direction of the piston 1 and are arranged along the circumferential direction and do not intersect with each other. The crosspiece 32a is a part that extends in parallel to the Y axis and is formed at a position including the intersection of the X axis and the Y axis, which is the center of the piston skirt 30. The crosspiece 32b is a part located on the left side of the crosspiece 32a. The crosspiece 32c is a part located on the right side of the crosspiece 32a.

  Moreover, the crosspiece 32a has a configuration in which the width is the largest at the center of the piston skirt 30 and the width becomes smaller as it extends in the vertical direction. The crosspieces 32b and the crosspieces 32c have equal widths at arbitrary locations in the vertical direction, and each has a mode of extending along the circumferential direction so as to curve away from the center as it goes up and down the piston skirt 30.

  Due to the crosspiece formed by intersecting the first sub crosspiece and the second sub crosspiece as described above, in the wall body 30a of the piston skirt 30, a concave portion having a thickness smaller than that of each of the crosspieces is formed. The Specifically, a recess 30x1 is formed by the bars 31a, 31b, 32a and 32c, a recess 30x2 is formed by the bars 31a, 31c, 32a and 32c, and a recess 30x3 is formed by the bars 31a, 31b and 32c. However, a recess 30x4 is formed by the crosspieces 31c, 32a, and 32c. Although reference numerals are omitted, concave portions 30x1, 30x2, 30x3, and 30x4 are formed between the crosspiece 32a and the crosspiece 32b, each having a symmetrical shape with respect to the Y axis.

  Furthermore, between the crosspiece 32b and the left end of the inner wall 30x, the crosspieces 31a, 31b, and 32b form a recess 30x5, the crosspieces 31a, 31c, and 32b form a recess 30x6, the crosspieces 31b and 32b form a recess 30x7, and the crosspieces 31c and 32b. Thus, the recesses 30x8 are formed. Although reference numerals are omitted, recesses having a symmetrical shape with respect to the Y axis are formed in the recesses 30x5, 30x6, 30x7, and 30x8 with respect to the Y axis, between the crosspiece 32c and the right end of the inner wall 30x.

  In the above configuration, the crosspiece formed by the first sub crosspiece and the second sub crosspiece corresponds to a plurality of crosspieces according to the present invention, and the concave portion including the concave portions 30x1 to 30x8 formed by the crosspiece is a book. These correspond to the concave portions of the invention, and these constitute the rib structure of the inner wall of the piston of the present invention.

  In the first embodiment of the present invention having such a configuration, the thickness of the piston skirt 30 is centered by the web-shaped beam portion formed by the intersection of the first sub-beam portion and the second sub-beam portion. It is characterized by changing to the standard.

  That is, as shown in FIG. 1B, the rib structure of the inner wall of the piston 1 is provided with the above-described configuration, so that the thickness of the piston skirt 30 is in the vicinity of the center where the crosspiece 31a and the crosspiece 32a intersect. The width of the crosspiece 32a changes smaller as it moves away from the center in the vertical direction, and the width of the crosspiece 31b and the crosspiece 31c is smaller than that of the crosspiece 31a. The area expands to 30x3, and the wall thickness changes thinly.

  Similarly, the thickness of the piston skirt 30 is changed from the concave portion corresponding to the concave portion 30x1 to the concave portion 30x5 as an example because the bars 32b and 32c are curved in a direction away from the center as they are separated from the center in the left-right direction. As the area expands, the wall thickness changes thinly.

  Thereby, the piston skirt 30 has a configuration in which the upper and lower ends are likely to thermally expand from the center. Therefore, when incorporated in an internal combustion engine such as a gasoline engine, the clearance from the cylinder bore can be made small even at a relatively low temperature at the time of startup, and the swing angle of the piston pin center is kept small in the reciprocating motion of the piston 1. be able to. Therefore, it is possible to reduce the impact of the collision with the cylinder bore, to suppress the occurrence of the hitting sound, and to improve this.

  Further, the web-shaped crosspiece is formed by adjusting the width and / or interval of each crosspiece, thereby making it easy to adjust the center of gravity of the piston 1. As a result, it is possible to stabilize the posture of the piston 1 during the reciprocating motion in the cylinder bore, particularly during the expansion stroke, and to suppress the occurrence of hitting sound.

  Furthermore, in the present embodiment, the average thickness of the wall body 30a of the piston skirt 30 of the piston 1 is smaller than the average thickness of the wall body 30a of the piston skirt 30 of the conventional piston 1, thereby reducing the weight. ing. Thereby, it becomes possible to improve the fuel consumption of the internal combustion engine.

  Furthermore, in the present embodiment, since the step based on the crosspiece portion is provided on the inner wall 30x of the piston skirt 30, oil easily adheres to the step. As a result, the oil holding force of the piston 1 is increased and the piston 1 is easily cooled, and the strength and reliability of the piston 1 can be improved particularly during high-temperature operation.

  Thus, according to the rib structure of the piston inner wall of the present embodiment, it is possible to improve the hitting sound of the piston.

  However, the present invention is not limited to the above embodiment. In the above description, the crosspiece of the present invention intersects the first sub crosspiece formed along the circumferential direction of the piston 1 and the second sub crosspiece formed extending in the vertical direction of the piston. However, the present invention may be configured by only the sub-bar portion formed along the circumferential direction of the piston 1 as shown in FIG.

  In the configuration example, the sub beam portion includes a beam 33a, a beam 33b, a beam 33c, a beam 33d, and a beam 33e that are formed in parallel with each other in the circumferential direction of the piston 1. The crosspiece 31a extends parallel to the X axis and is formed at a position including the intersection of the X axis and the Y axis indicated by the black circle in the figure, which is the center of the piston skirt 30, and the width decreases as it extends to the left and right. Formed to be. The crosspieces 33b and 33c are positioned above and below the crosspiece 33a, respectively, and are narrower than the crosspiece 33a, and are formed so that the width decreases as they extend to the left and right. Similarly, the bars 33d and 33e are positioned above and below the bars 33b and 33c, respectively, and are narrower than the bars 33b and 33c, and are formed to have a smaller width as they extend left and right. . Further, each of the bars 33b to 33e is formed by bending both ends so as to approach the center of the piston skirt 30 along the Y axis.

  Accordingly, the recesses 35x1 to 35x4 formed by the crosspieces 33a to 33e have a shape that increases in area as they move away from the center of the piston skirt 30, and as a result, the piston skirt 30 is moved up and down from the center in the same manner as the web-like aspect. The end can be easily thermally expanded, and the same effect as in the above embodiment can be obtained.

  Furthermore, as shown in FIG. 2B, the present invention may be configured only from sub-bar portions formed along the top and bottom of the piston 1.

  In the configuration example, the sub beam portion includes a beam 34a, a beam 34b, a beam 34c, a beam 34d, and a beam 34e that are arranged in the vertical direction of the piston 1 and do not intersect each other. The crosspiece 34a extends parallel to the Y axis and is formed at a position including the intersection of the X axis and the Y axis indicated by the black circle in the figure, which is the center of the piston skirt 30, and the width decreases as it extends vertically. Formed to be. The crosspieces 34b and 34c are respectively positioned on the left and right sides of the crosspiece 31a, are narrower than the crosspiece 34a, and are formed so that the width decreases as they extend vertically. Similarly, the crosspieces 34d and 34e are positioned on the left and right sides of the crosspieces 34b and 34c, respectively, and are narrower than the crosspieces 34b and 34c, and are formed so that the width decreases as they extend vertically. Furthermore, each of the crosspieces 34b to 34e is formed by bending both ends so as to approach the center of the piston skirt 30 along the X axis.

  Accordingly, the recesses 36x1 to 36x6 formed by the crosspieces 34a to 34e have a shape that increases in area as they move away from the center of the piston skirt 30, and as a result, the piston skirt 30 is moved up and down from the center in the same manner as the web-like aspect. The end can be easily thermally expanded, and the same effect as in the above embodiment can be obtained.

  Further, in each configuration example shown in FIGS. 2A and 2B, the crosspieces may be configured to cross each other, or the front portion or a part of the crosspieces may have the same width. Furthermore, each crosspiece may be curved, or may be in a form extending on a straight line.

  As described above, the present invention is a rib structure of the piston inner wall, and is formed on the inner wall of the piston skirt, and a plurality of crosspieces and a recess having a smaller wall thickness than the crosspieces. A rib structure of the inner wall of the piston, wherein the width of all or part of the crosspieces decreases with increasing distance from the center of the piston skirt, and / or the interval of all or part of the crosspieces, What is necessary is just the rib structure of the piston inner wall which becomes large as it distances from the center of a piston skirt, and is not limited by other specific purposes, uses, and structures.

  Therefore, the present invention may be implemented by adding various modifications to the above embodiment, including those described above, as long as they do not depart from the spirit of the present invention.

  The present invention as described above has an effect that it is possible to improve the hitting sound of the piston, and is useful in application to an internal combustion engine such as a gasoline engine.

DESCRIPTION OF SYMBOLS 1 Piston 30 Piston skirt 30a Wall body 30x Inner wall 30x1-30x8, 35x1-35x4, 36x1-36x6 Recessed part 31a-31c, 32a-32c, 33a-33e, 34a-34e Crosspiece 101 Cylinder bore

Claims (1)

A rib structure of the piston inner wall formed on the inner wall of the piston skirt and having a plurality of crosspieces and a concave portion surrounded by the crosspiece and having a thickness smaller than the crosspiece,
The width of all or part of the crosspieces decreases as the distance from the center of the piston skirt decreases, and / or the interval of all or part of the crosspieces increases as the distance from the center of the piston skirt increases. ,
Rib structure of piston inner wall.

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