JP2013113323A - Crankshaft structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crankshaft structure capable of achieving both the weight reduction of a crankshaft and securing of rigidity of crank pins.SOLUTION: The crankshaft structure of an engine 1 includes: crank journals 11; the crank pins 12: crank webs 13, each of which connects the crank journal 11 with the crank pin 12; and oil passages 15 each extended from the crank journal 11 to the crank pin 12. Each of the crank webs 13 has a pair of thinned parts 16, 16 provided in a recessed state toward the crank pin 12 at portions located at both sides in the crank axial direction of the crank pin 12. The pair of the thinned parts 16, 16 are provided at the crank webs 13 side from the interface m of the crank pins 12 and the crank webs 13.

Description

  The present invention relates to a crankshaft structure in which a hollow portion is provided in a recess in a crank web.

  2. Description of the Related Art Conventionally, in order to reduce the weight of a crankshaft, a lightening portion (a lightening hole) has been provided in the crankshaft. For example, Patent Documents 1 and 2 disclose a crankshaft in which a lightening portion is formed so as to penetrate the crankpin from one end side of the crankpin.

  Further, Patent Document 3 discloses a crank journal, a crankpin, a crank web that connects the crank journal and the crankpin, and a pair of holes formed on the sides of the crank web and on both sides of the crank pin. Part) and an oil passage formed inside the crankpin. One surface of the hole that is closest to the oil flow path extends substantially parallel to the oil flow path.

Japanese Utility Model Publication No. 02-069116 Japanese Utility Model Publication No. 03-000110 JP 2010-230027 gazette

  However, the crank pin is provided with an oil passage for lubricating the sliding portion between the crank pin and the connecting rod. Therefore, if the thinned portion is formed so as to penetrate the crank pin, the thinned portion and the oil passage interfere with each other. (Duplicate). Therefore, in the crankshaft structure described in Patent Documents 1 and 2, it is necessary to perform a process of closing the opening of the lightening part with a mech plug or plug so that the lubricating oil supplied from the oil passage does not leak from the lightening part. This has resulted in an increase in the number of parts and a complicated manufacturing process.

  Further, in the crankshaft described in Patent Document 3, one surface of the hole portion that is closest to the oil flow path extends substantially parallel to the oil flow path, so that interference between the oil flow path and the lightening portion is caused. However, since both the lightening part and the oil flow path are formed inside the crankpin, there is a concern that the rigidity of the crankpin is lowered.

  The present invention has been made in view of these problems, and an object of the present invention is to provide a crankshaft structure capable of achieving both reduction in weight of the crankshaft and securing of rigidity of the crankpin.

  A crankshaft structure according to the present invention includes a plurality of crank journals, a crank pin disposed between adjacent crank journals, a plurality of crank webs connecting the crank journals and the crank pins, and the crank journals. A crankshaft structure of an internal combustion engine having an oil passage leading to the crankpin, wherein the crank web is recessed toward the crankpin at portions located on both sides in the crankshaft direction of the crankpin A pair of lightening portions are provided, and the pair of lightening portions are provided on the crank web side with respect to a boundary surface between the crank pin and the crank web.

According to this, since the pair of thinned portions are provided on the crank web side with respect to the boundary surface between the crankpin and the crank web, the thinned portions are not formed inside the crankpin. Therefore, the weight of the crankshaft can be reduced without reducing the rigidity of the crankpin.
In addition, since the pair of thinned portions are recessed in the crank web at positions located on both sides in the crankshaft direction of the crankpin, the oil passage formed in the crankpin and the thinned portion may interfere with each other. Absent. Therefore, since the lubricating oil does not flow into the lightening portion, the member that closes the opening of the lightening portion and its mounting process can be omitted, and the number of parts can be reduced and the manufacturing process can be simplified. it can.
In addition, since the pair of lightening portions are recessed on both sides of the crankpin, the weight balance of the crankshaft can be improved.

  The oil passage communicates with one crank journal and two crank pins arranged on both sides of the one crank journal, and extends from the center side in the crankshaft direction toward the end portion in the crankshaft direction. The bottom of the oil passage is formed of a crank pin on the end side in the crankshaft direction of the two crank pins and a crank web provided further on the end side of the crank pin on the end side. It is preferable to have a configuration provided on the center side in the crankshaft direction with respect to the boundary surface.

  According to this, the bottom portion of the oil passage is formed by the crank pin on the end portion side in the crank shaft direction of the two crank pins and the crank web provided on the further end portion side of the crank pin on the end portion side. Since it is provided closer to the center in the crankshaft direction than the boundary surface, no oil passage is formed inside the crank web on the end side. For this reason, it is possible to reduce the weight of the crank web by enlarging the thinned portion as long as it does not interfere with the boundary surface. Further, since the weight of the counterweight can be reduced by the weight of the crank web, the entire crankshaft can be significantly reduced in weight.

  Moreover, it is preferable that the thickness reduction part formed in the crank web of the said edge part side is larger than the thickness reduction part of the other crank web provided in the center side of the crankshaft direction.

  According to this, since the end side of the crankshaft is lighter than the center side, the resonance frequency of the crankshaft is increased, which is advantageous in terms of vibration and rigidity.

  ADVANTAGE OF THE INVENTION According to this invention, the crankshaft structure which can aim at coexistence of weight reduction of a crankshaft and ensuring rigidity of a crankpin can be provided.

It is a side view of an internal combustion engine provided with the crankshaft structure concerning this embodiment. It is sectional drawing of a crankshaft. (A) is AA arrow sectional drawing of FIG. 2, (b) is BB arrow sectional drawing of FIG. FIG. 3 is an enlarged cross-sectional view of the vicinity of a crankpin shown in part C of FIG. It is an expanded sectional view of the crankpin vicinity shown in the D section of FIG.

Embodiments of the present invention will be described in detail with reference to the drawings. In the description, the same elements are denoted by the same reference numerals, and redundant description is omitted.
In the present embodiment, a crankshaft of an in-line four-cylinder engine installed horizontally in an automobile will be described as an example, but the present invention is not limited to this. In the following description, when describing directions, the direction along the cylinder axis is referred to as “vertical direction”, and the direction along the rotation axis of the crankshaft is referred to as “left-right direction”. In the description, “the end side in the crankshaft direction” means a direction approaching the crank journal 11a or the crank journal 11e provided at both ends of the crankshaft 10, and “the center side in the crankshaft direction”. Means a direction approaching a crank journal 11 c provided in the center of the crankshaft 10.

FIG. 1 is a side view of an engine, and FIG. 2 is a cross-sectional view of a crankshaft.
As shown in FIG. 1, the engine 1 is an in-line four-cylinder engine, and is configured by sequentially laminating an oil pan 2, a cylinder block 3, a cylinder head 4, and a head cover 5 from below. A chain case 6 is mounted from the oil pan 2 to the head cover 5 at the left end of the engine 1. Inside the cylinder block 3, a crankshaft 10 is rotatably supported, and a connecting rod 7, a piston 8, a cylinder 9 (see FIG. 2) and the like are provided. An exhaust manifold 41 and the like are connected to the cylinder head 4.

  An oil pump P that is driven by rotation of the crankshaft 10 is connected to the left end side of the crankshaft 10. The lubricating oil sucked up by the oil pump P passes through an oil filter F and then passes through an oil passage formed inside the engine 1 to slide parts such as a crankshaft 10 and a camshaft (not shown). Have been supplied.

  As shown in FIG. 2, the crankshaft 10 includes five crank journals 11 that constitute the main rotation axis CL of the crankshaft, four crank pins 12 on which the lower ends of the connecting rods are attached, and each crank journal 11. A crank web 13 that connects the crank pins 12 and a counterweight 14 that is formed continuously with the crank web 13 are provided. The crankshaft 10 also has an oil passage 15 from the crank journal 11 through the crank web 13 to the crankpin 12. Further, the crankshaft 10 has a lightening portion 16 in the crank web 13. The crankshaft 10 is manufactured, for example, by forging (hot forging).

  The crank journal 11 is a cylindrical portion that constitutes the main rotation axis CL of the crankshaft 10. The crank journal 11 is divided into crank journals 11b, 11d provided with an oil passage 15 to be described later, and crank journals 11a, 11c, 11e provided with no oil passage 15. Each crank journal 11 is rotatably supported by a support portion 32 such as a bearing cap provided in the cylinder block 3 (more specifically, by a metal bearing installed at the tip of the support portion 32). The support portion 32 has an oil passage 32a. Lubricating oil is supplied from the oil passage 32a to the oil passage 15 (journal oil passages 15c and 15f) of the crankshaft 10, and the metal bearing is lubricated. It is done. The oil passage 15 of the crankshaft 10 will be described later.

Although not shown, an orifice (throttle) for adjusting the supply amount of the lubricating oil is provided at an appropriate position of the oil passage 32a of the support portion 32 that supports the crank journals 11a, 11c, and 11e where the oil passage 15 is not provided. Is provided. Thereby, the supply amount of the lubricating oil supplied to the crank journals 11b, 11d provided with the oil passage 15 is changed to the supply amount of the lubricating oil supplied to the crank journals 11a, 11c, 11e where the oil passage 15 is not provided. Can be less. Therefore, oil leakage in the crank journals 11a, 11c, 11e in which the oil passage 15 is not provided can be suppressed, so that the distribution of the lubricating oil can be optimized and the oil pump can be downsized.
Such a crankshaft oiling structure is disclosed in Japanese Patent Laid-Open No. 2008-196396.

  The crankpin 12 is a cylindrical portion that pivotally supports the lower end portion of the connecting rod 7 so as to be slidable. The crank pin 12 is supported by the crank journal 11 via a pair of crank webs 13 and 13 provided on both sides thereof. In the present embodiment, four crank pins 12 (hereinafter, sometimes referred to as “crank pins 12a, 12b, 12c, 12d” in order from the left side) have five crank journals 11 (hereinafter, “crank journals 11a in order from the left side”). , 11b, 11c, 11d, and 11e ").

  Here, the two crank pins 12a and 12d at both ends are arranged so as to be shifted to one side in the radial direction (for example, upward in FIG. 2) with respect to the crank journal 11, and the two crank pins 12b, 12c is displaced with respect to the crank journal 11 in a direction 180 ° opposite to the two crank pins 12a and 12d at both ends (for example, the downward direction in FIG. 2). That is, the axial position of the crank journal 11 and the axial position of the crank pin 12 are arranged on the same plane, and constitute a so-called single plane crankshaft. Therefore, when the piston 8 connected to the two crankpins 12a and 12d at both ends via the connecting rod 7 is located at the top dead center, the two crankpins 12b and 12c at the intermediate portion are connected via the connecting rod 7 to each other. The connected piston 8 is located at the bottom dead center.

  The crank web 13 is a wall-shaped part that connects the crank journal 11 and the crank pin 12. The crank web 13 is provided on both sides of the crank pin 12 in the crank shaft direction. On the side surface of each crank web 13 opposite to the crankpin 12, a thinned portion 16 is recessed toward the crankpin 12. In other words, the crank web 13 has a pair of lightening portions 16 and 16 that are recessed toward the crankpin 12 at portions located on both sides of the crankpin 12 in the crankshaft direction. The meat removal portion 16 will be described later.

  The counterweight 14 is a part for balancing the weight between the crankpin 12 and the crank web 13, and extends from the crank web 13 in the opposite direction to the crankpin 12.

  The oil passage 15 is an oil passage for supplying the lubricating oil supplied to the crank journal 11 to the crankpin 12. The oil passage 15 of this embodiment employs an aggregate oil passage structure that supplies lubricating oil from one crank journal 11 to a plurality of (two in this embodiment) crankpins 12. The oil passage 15 includes a first oil passage 15 a and a second oil passage 15 b that are inclined in opposite directions (in a C shape in a side view) with respect to the main rotation axis CL of the crankshaft 10.

The first oil passage 15a is formed in a substantially linear shape so as to connect the second crank journal 11b from the left and the crank pins 12a and 12b on both sides thereof. The second oil passage 15b is formed in a substantially straight line so as to connect the fourth crank journal 11d from the left and the crank pins 12c, 12d on both sides thereof.
In order to drill the first oil passage 15a and the second oil passage 15b, the opening formed in the crank web 13 adjacent to the crank journal 11c on the center side in the crankshaft direction press-fits the metal ball p. It is blocked by that. 2 and 5 (particularly FIG. 5), the first oil passage 15a and the second oil passage 15b reach the crank webs 13 and 13 disposed at the left and right ends of the crankshaft 10, respectively. Not.

  As shown in FIGS. 2 and 3, the first oil passage 15a intersects with a journal oil passage 15c that penetrates the central portion in the axial direction of the crank journal 11b in the radial direction. Further, the first oil passage 15a intersects pin oil passages 15d and 15e penetrating the axial center portions of the crank pins 12a and 12b in the radial direction. Similarly, the second oil passage 15b intersects a journal oil passage 15f that penetrates the axial center of the crank journal 11d in the radial direction. Further, the second oil passage 15b intersects with pin oil passages 15g and 15h penetrating the axial center portions of the crank pins 12c and 12d in the radial direction. As a result, the lubricating oil supplied from the crank journal 11 is supplied to the sliding surface between the crankpin 12 and the connecting rod 7.

FIG. 4 is an enlarged cross-sectional view of the vicinity of the crankpin shown in part C of FIG.
As shown in FIG. 4, the pair of thinned portions 16, 16 formed on both sides of each crankpin 12 is provided on the crank web 13 side with respect to the boundary surface m between the crankpin 12 and the crank web 13. . In other words, the thinned portion 16 is provided only in the crank web 13 and does not reach the crank pin 12. Therefore, the inside of the crankpin 12 has a solid structure, and the oil passage 15 can be freely formed.
The boundary surface m is a plane provided at the boundary between the crankpin 12 and the crank web 13 and orthogonal to the axial direction of the crankpin 12.

  In the present embodiment, each hollow portion 16 is inserted into the crank web 13 after a movable mold (also referred to as “punch”) (not shown) corresponding to the hollow portion 16 is formed during forging of the crankshaft 10. It is formed by die cutting. At this time, the movable mold (not shown) is punched in a direction away from the main rotation axis CL of the crankshaft 10 (see symbols K2 and K3 in FIG. 4).

  And the side wall 16a or the bottom wall 16b of each thinning part 16 is formed along the extending direction K1 of the oil path 15 (more specifically, in parallel). More specifically, when the die cutting direction K2 of the thinned portion 16 is parallel to the extending direction K1 of the oil passage 15, the side wall 16a of the thinned portion 16 is parallel to the extending direction K1 of the oil passage 15. Formed. On the other hand, when the die cutting direction K3 of the thinned portion 16 is orthogonal to the extending direction K1 of the oil passage 15, the bottom wall 16b of the thinned portion 16 is formed in parallel to the extending direction K1 of the oil passage 15. Is done.

  As shown in FIGS. 2 and 5 (mainly FIG. 5), the lightening portions 16 of the crank webs 13 provided at the left and right ends of the crankshaft 10 are the lightening portions formed on the other crank webs 13. Compared to 16, it is formed larger. Hereinafter, with reference to FIG. 5, an explanation will be given by taking as an example the lightening portion 16 </ b> A formed in the rightmost crank web 13 </ b> A.

  As shown in FIG. 5, in the thinning portion 16A, the die cutting direction K2 is parallel to the extending direction K1 of the second oil passage 15b. Therefore, the side surface 16Aa on the second oil passage 15b side of the thinned portion 16A is parallel to the extending direction K1 of the second oil passage 15b.

  Here, as shown by an imaginary line (two-dot chain line) in FIG. 5, when it is assumed that the second oil passage 15b extends until it penetrates the crank web 13A at the right end, the side surface 16Aa of the thinned portion 16A. Needs to be provided at a position separated from the side face n of the second oil passage 15b (side face n closest to the crank journal 11e) by a cover thickness W or more (see reference numeral 16a ').

  On the other hand, in the present embodiment, the bottom 15b1 of the second oil passage 15b is from the boundary surface m between the crank pin 12d and the crank web 13A provided on the further end side (right side) of the crank pin 12d. Is also provided on the center side (crank pin 12d side) in the crankshaft direction. That is, since the right end crank web 13A is not provided with the second oil passage 15b, it is not necessary to consider the cover thickness W, and the side surface of the thinned portion 16A without considering the side surface n of the second oil passage 15b. A position of 16 Aa can be set. For this reason, the meat removal portion 16A can be freely enlarged.

Note that the end surface 16Ac, which is a part of the bottom surface of the thinned portion 16a, is formed substantially parallel to the boundary surface m between the crank pin 12d and the crank web 13A, and is formed close to the boundary surface m. ing.
The same applies to the lightening portion 16 formed in the leftmost crank web 13.

  The crankshaft structure according to this embodiment is basically configured as described above. Next, the function and effect of the crankshaft structure will be described.

According to the crankshaft structure according to the present embodiment, the pair of lightening portions 16, 16 are recessed in portions of the crank web 13 that are located on both sides of the crankpin 12 in the crankshaft direction. The oil passage 15 formed in this way and the thinned portion 16 do not interfere with each other. Therefore, since lubricating oil does not flow into the lightening portion 16, a member that closes the opening of the lightening portion 16 and its mounting process can be omitted, and the number of parts can be reduced and the manufacturing process can be simplified. be able to.
Further, since the pair of lightening portions 16 and 16 are recessed on both sides of the crankpin 12, the weight balance of the crankshaft 10 can be improved.

  Further, since the pair of thinned portions 16 and 16 are provided on the crank web 13 side with respect to the boundary surface m between the crankpin 12 and the crank web 13, the thinned portion 16 is formed inside the crankpin 12. Not. Therefore, the weight of the crankshaft 10 can be reduced without reducing the rigidity of the crankpin 12.

Further, as shown in FIG. 5, the second oil passage 15b communicates one crank journal 11d with two crank pins 12c, 12d disposed on both sides of the one crank journal 11d, Is drilled from the center side in the direction (crank journal 11c side) toward the end side in the crankshaft direction (crank journal 11e side), and the bottom 15b1 of the second oil passage 15b has two crank pins 12c and 12d. Of the crank pin in the crank shaft direction than the boundary surface m between the crank pin 12d on the end side in the crank shaft direction and the crank web 13A provided on the further end side of the crank pin 12d on the end side. The second oil passage 15b is not formed inside the crank web 13A on the end side. Therefore, the lightening portion 16A can be enlarged within a range that does not interfere with the boundary surface m, and the crank web 13A can be reduced in weight. Further, since the counterweight 14 can be reduced in weight by the amount that the crank web 13A is reduced in weight, the entire crankshaft 10 can be significantly reduced in weight.
The same applies to the thinned portion 16 and the first oil passage 15a formed in the crank web 13 at the left end of FIG.

Further, as shown in FIG. 5, the lightening portion 16A formed on the crank web 13A on the right end side is larger than the lightening portions 16 of the other crank webs 13 provided on the center side in the crankshaft direction. The end side of the crankshaft 10 is lighter than the center side. Therefore, the resonance frequency of the crankshaft 10 is increased, which is advantageous in terms of vibration and rigidity.
The same applies to the thinned portion 16 formed in the crank web 13 at the left end of FIG.

The oil passage 15 extends substantially linearly from the crank journal 11 to the crank pin 12, and the side wall 16 a or the bottom wall 16 b of the lightening portion 16 is substantially parallel along the extending direction K 1 of the oil passage 15. Therefore, the lightening portion 16 can be formed larger in the direction along the oil passage 15.
Incidentally, since the counterweight 14 can be made smaller by increasing the thickness of the lightening portion 16, the entire crankshaft 10 can be effectively reduced in weight.

  Further, the cutout portion 16 is a portion formed by punching a movable die in forging, and the cutout portion 16 is cut out in a direction away from the main rotation axis CL of the crankshaft 10. Therefore, it is possible to avoid interference between the movable mold and the crankshaft 10 when performing die cutting. For this reason, it is possible to easily perform die cutting while increasing the thickness of the meat removal portion 16.

  Further, according to the present embodiment, the cutout portion 16 is formed by punching the movable die in a direction away from the main rotation axis CL of the crankshaft 10 and in a direction parallel or orthogonal to the oil passage 15. Therefore, the side wall 16a or the bottom wall 16b of the thinned portion 16 can be easily made parallel to the extending direction K1 of the oil passage 15, and the thickened portion 16 can be easily enlarged.

  As mentioned above, although embodiment of this invention was described in detail with reference to drawings, this invention is not limited to this, In the range which does not deviate from the main point of invention, it can change suitably.

  For example, in the present embodiment, the pair of lightening portions 16 are formed in the crank webs 13 and 13 disposed on both sides of all the crankpins 12, but the present invention is not limited to this, and a plurality of cranks It is only necessary that the crank webs 13 and 13 disposed on both sides of at least one crankpin 12 of the pins 12 be provided with a pair of lightening portions 16.

  In the present embodiment, a total of two oil passages 15 are formed so that one crank journal 11 and two crankpins 12 are connected in a straight line, but the present invention is not limited to this, A total of four oil passages may be formed so that one crank journal 11 and one crank pin 12 are connected in a straight line.

  Further, the crankshaft structure of the present embodiment has been described by way of example when mounted on an automobile engine, but the present invention is not limited to this, and for example, an internal combustion engine other than an automobile such as a ship or general-purpose machine. Needless to say, this is applicable.

  In the present embodiment, the crankshaft 10 is manufactured by forging. However, the present invention is not limited to this, and may be manufactured by other manufacturing methods such as casting. .

Further, in the present embodiment, as shown in FIG. 2, in the crank webs 13 and 13 on both sides of all (four) crankpins 12, the pair of lightening portions 16 and 16 are located on the crank web 13 rather than the boundary surface m. However, the present invention is not limited to this, and is provided on at least one set of crank webs 13 and 13 among the plurality of sets of crank webs 13 and 13 provided on the crankshaft 10. It is only necessary that the pair of cutout portions 16 and 16 that are formed are disposed closer to the crank web 13 than the boundary surface m. According to such a configuration, the rigidity of a specific crankpin 12 among the plurality of crankpins 12 can be enhanced while reducing the weight of the crankshaft 10.
In other crank webs 13, the thinned portion 16 may be formed up to the crankpin 12 side across the boundary surface 16, or the thinned portion 16 may not be formed.

DESCRIPTION OF SYMBOLS 1 Engine 10 Crankshaft 11 Crank journal 12 Crankpin 13 Crank web 14 Counterweight 15 Oil path 16 Meat removal part

Claims (3)

A plurality of crank journals, a plurality of crank pins arranged between adjacent crank journals, a plurality of crank webs connecting the crank journals and the crank pins, and an oil from the crank journal to the crank pins A crankshaft structure of an internal combustion engine having a road,
The crank web has a pair of lightening portions recessed toward the crank pin at portions located on both sides of the crank pin in the crank shaft direction,
The pair of lightening portions are provided on the crank web side with respect to a boundary surface between the crank pin and the crank web. The oil passage communicates one crank journal and two crank pins arranged on both sides of the one crank journal, and is drilled from the center side in the crankshaft direction toward the end side in the crankshaft direction. Has been established,
The bottom of the oil passage is cranked more than the boundary surface between the crank pin on the end side in the crankshaft direction of the two crank pins and the crank web provided further on the end side of the crank pin on the end side. The crankshaft structure according to claim 1, wherein the crankshaft structure is provided on a central side in the axial direction.   3. The crankshaft according to claim 2, wherein a lightening portion formed on the crank web on the end side is larger than a lightening portion of another crank web provided on the center side in the crankshaft direction. Construction.

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