JP2006200681A - Lubricating oil passage structure of crankshaft of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lubricating oil passage structure of a crankshaft of an engine capable of improving lubricity of a sliding face between a crank pin and a connecting rod while reducing occurrence of stress concentration. <P>SOLUTION: In this lubricating oil passage structure, an oil hole 20 has a first oil hole 21 and a second oil hole 22. The first oil hole 21 is extended from a crank journal 31 to a part in the vicinity of an outer peripheral face of the crank pin 32. An extension line of a shaft core A<SB>1</SB>of the first oil hole 21 crosses the outer peripheral face of the pin 32 at a position where it is offset on the opposite side to the journal 31 for the center in the direction of shaft core of the pin 32. A part on a pin 32 side of the first oil hole 21 is arranged at a position where it is offset on a rotation direction side of the crankshaft 30 for a shaft core A<SB>p</SB>of the pin 32 when viewed in the direction of shaft core of the crankshaft 30. A shaft core A<SB>2</SB>of the second oil hole 22 passes through a central position in the direction of shaft core of the pin 32 and is extended into the inside from the outer peripheral face of the pin 32 to communicate the second oil hole 22 with the first oil hole 21. A chamfered part 23 whose width is increased when approaching the opposite side to the direction of rotation is formed in an opening end part 22a of the second oil hole 22. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lubricating oil passage structure for a crankshaft of an engine.

  2. Description of the Related Art Conventionally, a lubricating oil passage structure of an engine crankshaft for supplying lubricating oil from a crank journal supported on a cylinder block to a crankpin that supports a connecting rod is known. This lubricating oil passage structure includes, for example, a straight oil hole formed in the crankshaft so as to communicate the outer peripheral surface of the crank journal and the outer peripheral surface of the crankpin. Then, the lubricating oil is supplied from the outer peripheral surface of the crank journal to the outer peripheral surface of the crankpin through the oil hole by the centrifugal force accompanying the rotation of the crankshaft, and the sliding surface between the crankpin and the connecting rod is lubricated. .

  Here, when the oil hole is offset to the one side with respect to the axis of the crank pin, the shape of the one side at the end of the oil hole on the crank pin side becomes relatively sharp, and stress is applied to the sharp part. Concentration occurs. This is not preferable because the torsional strength of the crankshaft is lowered.

Therefore, in Patent Documents 1 and 2, a chamfered portion is formed at the end of the oil hole on the crankpin side. Thereby, there is no sharp point of the oil hole, and the occurrence of stress concentration is reduced.
Japanese Utility Model Publication No. 6-153818 JP-A-10-122228

  However, in Patent Documents 1 and 2, although the chamfered portion is formed as described above, the sharpened portion of the oil hole is eliminated. It easily flows and leaks in the axial direction, leading to a decrease in the lubricity of the sliding surface.

  In addition, if the chamfered portion is enlarged, the amount of lubricating oil leakage increases, and there is a demand that the chamfered portion not be as large as possible.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a linear oil for supplying lubricating oil from a crank journal supported by a cylinder block to a crank pin that supports a connecting rod. An object of the present invention is to provide a technology for improving the lubricity of a sliding surface between a crankpin and a connecting rod while reducing the occurrence of stress concentration in a lubricating oil passage structure of a crankshaft of an engine having a hole.

  According to a first aspect of the present invention, there is provided a lubricating oil passage structure for a crankshaft of an engine provided with a linear oil hole for supplying lubricating oil from a crank journal supported by a cylinder block to a crank pin for supporting a connecting rod. The oil hole extends from the crank journal to the vicinity of the outer peripheral surface of the crankpin, and the extension line of the shaft core is offset to the opposite side of the crank journal with respect to the axial center of the crankpin. The first oil hole intersecting the outer peripheral surface of the crankpin and the shaft core pass through the center position in the axial direction of the crankpin, and extend from the outer peripheral surface of the crankpin toward the axial center of the crankpin. A second oil hole communicating with the hole, and the second oil hole has an axis that is perpendicular to the perpendicular to the outer peripheral surface of the crank pin as viewed in the axial direction of the crank pin. In order to incline by a predetermined angle, the extension line of the shaft core is configured to pass through a position offset toward the rotation direction side of the crankshaft with respect to the shaft core of the crankpin in the axial direction view of the crankpin. The end of the second oil hole on the outer peripheral surface side of the crank pin is formed with a chamfered portion whose width increases toward the opposite side to the rotation direction of the crankshaft. is there.

  Thereby, the sharp part of the 1st oil hole can be eliminated by forming the 2nd oil hole and the chamfer. Therefore, occurrence of stress concentration can be reduced.

  In addition, a chamfered portion is formed at the end of the second oil hole on the outer peripheral surface side of the crankpin so that the width increases toward the opposite side of the crankshaft rotation direction. The part opposite to the direction can be made relatively large. Therefore, the lubricating oil supplied from the oil hole to the outer peripheral surface of the crankpin is likely to flow to the side opposite to the rotation direction of the crankshaft. Therefore, the lubricating oil is sufficiently supplied to the side opposite to the rotation direction of the crankshaft on the outer peripheral surface of the crankpin, that is, to the sliding direction side of the connecting rod with respect to the crankpin without increasing the chamfered portion as a whole. be able to. Therefore, the thickness of the oil film on the sliding surface between the crankpin and the connecting rod can be sufficiently secured, and the lubricity of the sliding surface can be improved.

  According to a second invention, in the first invention, the crank pin side portion of the first oil hole includes an axis of the crank journal and an axis of the crank pin as viewed in the axial direction of the crank shaft. Is arranged at a position offset to the rotation direction side of the crankshaft with respect to a straight line connecting the two.

  Thereby, the crank pin side portion of the first oil hole is offset to the crank shaft rotation direction side with respect to the straight line connecting the crank journal axis and the crank pin axis when viewed from the crank shaft axis direction. Therefore, the lubricating oil can be supplied more fully on the outer circumferential surface of the crankpin on the side opposite to the direction of rotation of the crankshaft, that is, on the sliding direction side of the connecting rod with respect to the crankpin. . Therefore, the lubricity of the sliding surface can be further improved.

  According to the present invention, by forming the second oil hole and the chamfered portion, the sharpened portion of the first oil hole can be eliminated, and the occurrence of stress concentration can be reduced. In addition, since the chamfered portion whose width becomes wider toward the opposite side of the rotation direction of the crankshaft is formed at the end of the second oil hole on the outer peripheral surface side of the crankpin, the chamfered portion is enlarged as a whole. Therefore, the lubricating oil can be sufficiently supplied to the side opposite to the rotation direction of the crankshaft on the outer peripheral surface of the crankpin, that is, to the sliding direction side of the connecting rod with respect to the crankpin. Therefore, the thickness of the oil film on the sliding surface between the crankpin and the connecting rod can be sufficiently secured, and the lubricity of the sliding surface can be improved. As a result, the lubricity of the sliding surface can be improved while reducing the occurrence of stress concentration.

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

  An engine crankshaft lubricating oil passage structure 10 according to an embodiment of the present invention includes a linear oil hole 20 for supplying lubricating oil from a crank journal 31 of a crankshaft 30 to a crankpin 32.

As shown in FIG. 1, the crankshaft 30 includes a plurality of crank journals 31 disposed on the same axis _{AJ at} predetermined intervals and a plurality of pairs disposed between adjacent crank journals 31. And a plurality of crank pins 32 disposed between each pair of crank webs 33 and offset by a predetermined amount with respect to the axis _AJ of the crank journal 31. ing. The crankshaft 30 rotates around the crank journal 31. The crank journal 31 is rotatably supported on a cylinder block (not shown) via a bearing (not shown). The crank pin 32 rotatably supports a large end portion of a connecting rod (not shown) via a bearing. The axis A _P of the crank pin 32 is parallel to the axis A _J of the crank journal 31. In FIG. 1, two crank journals 31, a pair of crank webs 33, and one crank pin 32 are illustrated.

  As shown in FIGS. 1 to 4, the oil hole 20 is formed inside the crankshaft 30 so as to communicate an oil hole 24 described later and an outer peripheral surface of the crankpin 32. The oil hole 20 is configured by a two-stage passage that connects the first oil hole 21 and the second oil hole 22. The second oil hole 22 is a part of the oil hole 20 and is also a chamfered portion of the first oil hole 21.

The first oil hole 21 extends from the crank journal 31 to the vicinity of the outer peripheral surface of the crank pin 32. The opening end 21a on the crank pin 32 side of the first oil hole 21 is connected to the second oil hole 22 (see FIGS. 3 and 4). The extension line of the axial center A ₁ of the first oil hole 21 is the crank journal 31 (the right side of the crank journal 31 shown in FIG. And the outer peripheral surface of the crank pin 32 at a position slightly offset to the opposite side (left side in FIG. 1). The first oil hole 21 is a side view of the crank shaft 30 is inclined with respect to the axis A _P of the axis A _J and the crank pin 32 of the crank journal 31 (see FIG. 1). A portion of the first oil hole 21 on the crank journal 31 side (that is, a portion formed inside the crank journal 31 in the first oil hole 21) is a crankshaft as viewed in the axial direction of the crankshaft 30 (crank journal 31). Position offset from the straight line L connecting the axis A _J (center) of the journal 31 and the axis A _P (center) of the crank pin 32 to the opposite side (right side in FIG. 2) of the rotation direction of the crankshaft 30. It is arranged. A portion of the first oil hole 21 on the crank pin 32 side (that is, a portion formed inside the crank pin 32 in the first oil hole 21) is a straight line as viewed in the axial direction of the crankshaft 30 (crank pin 32). It is arranged at a position that is offset to the rotation direction side (left side in FIG. 2) of the crankshaft 30 with respect to L (or the axis A _P of the crankpin 32). That is, the first oil hole 21 is inclined toward the rotation direction side of the crankshaft 30 as viewed in the axial direction of the crankshaft 30.

The second oil hole 22, the axial center A ₂ runs through the axis direction center position of the crank pin 32 (see FIG. 1). The second oil hole 22 extends from the outer peripheral surface of the crank pin 32 toward the axis A _{P of the} crank pin 32 (that is, the inside of the crank pin 32), and the opening end 21a of the first oil hole 21 on the crank pin 32 side. Communicate. That is, the second oil hole 22 is formed in the crank pin 32 so as to communicate the outer peripheral surface of the crank pin 32 and the open end 21 a of the first oil hole 21. The opening area of the second oil hole 22 is larger than the opening area of the opening end 21a of the first oil hole 21 (see FIG. 3). As shown in FIG. 5, the second oil hole 22 is configured such that the axis A ₂ is inclined by a predetermined angle θ with respect to a perpendicular P perpendicular to the outer peripheral surface of the crank pin 32 as viewed in the axial direction of the crank pin 32. , extension of the shaft a ₂ is through a position offset in the rotational direction of the crank shaft 30 with the axis a _P of the crank pin 32 in the axial direction as viewed in the crank pin 32. In Figure 5, the perpendicular P is a straight line connecting the axis A _P of the outer circumferential surface of the intersection and the crank pin 32 of axis A ₂ and the crank pin 32 of the second oil hole 22.

As shown in FIGS. 1 to 5, the chamfer width of the second oil hole 22 on the outer peripheral surface side of the crank pin 32 (that is, the outlet end of the oil hole 20) has a chamfered width in the rotation direction of the crankshaft 30. A chamfered portion 23 is formed which becomes wider as it goes to the opposite side (that is, the sliding direction side of the connecting rod with respect to the crank pin 32; the right side in FIG. 3). That is, the chamfered portion 23 has a portion on the side opposite to the rotation direction of the crankshaft 30 larger than a portion on the rotation direction side of the crankshaft 30. The chamfered portion 23 is formed in a substantially crescent-shaped concave curved surface (see FIG. 3), and the axis A ₃ coincides with the axis A ₂ of the second oil hole 22 (see FIG. 5).

  An oil hole 24 is further formed in the crank journal 31 so as to extend in the radial direction of the crank journal 31 and supply lubricating oil from the cylinder block to the sliding surface between the crank journal 31 and the cylinder block. ing.

-Oil hole processing-
Hereinafter, the processing steps of the oil hole 20 will be described with reference to FIGS. 5 and 6. First, drilling is performed. That is, the semi-finished product of the crankshaft 30 is drilled using a drill for drilling (not shown). In this drilling process, the extension line of the axial center of the drilling drill intersects the outer peripheral surface of the crankpin 32 at a position slightly offset to the opposite side of the crank journal 31 with respect to the axial center direction of the crankpin 32. Other than that, it is almost the same as the conventional drilling process. Thus, the first oil hole 21 is formed. In addition, the sharp part has arisen in the edge part by the side of the crankpin 32 of the 1st oil hole 21 after a drilling process.

Next, chamfering is performed. That is, drilling is performed using the chamfering drill 40 (see FIG. 6) on the outer peripheral surface of the crankpin 32 after drilling (specifically, near the end of the first oil hole 21 on the crankpin 32 side). The chamfering drill 40 has a tip portion formed in a two-stage shape, the second oil hole 22 is formed in the first stage portion 40a, and the chamfered portion 23 is formed in the second stage portion 40b. It has become. In this chamfering process, the shaft _AD of the chamfering drill 40 is generally perforated so as to coincide with the perpendicular P shown in FIG. 5 when viewed in the axial direction of the crank pin 32. In this embodiment, the chamfering is performed. The axis _AD of the drill 40 is tilted by a predetermined angle θ with respect to the perpendicular P as viewed in the direction of the axis of the crankpin 32 (that is, the extension line of the axis _AD is viewed in the direction of the axis of the crankpin 32). , is offset in the rotational direction of the crank shaft 30 with the axis a _P of the crank pin 32) perforating. Thus, the second oil hole 22 and the chamfered portion 23 are formed simultaneously. That is, a two-stage chamfer is formed.

Here, as described above, since the second oil hole 22 and the chamfered portion 23 are formed as the chamfered portion of the first oil hole 21, the sharpened portion of the first oil hole 21 is eliminated. In addition, as described above, since the axis A _D chamfering drill 40 is perforated in a state inclined by a predetermined angle θ with respect to the perpendicular P in the axial direction as viewed in the crank pin 32, the axial center A ₂ crank A second oil hole 22 that is inclined by a predetermined angle θ with respect to the perpendicular P as viewed in the axial direction of the pin 32 is formed, and the opening end portion 22a of the second oil hole 22 has a rotational direction of the crankshaft 30. A chamfer 23 having a wide opposite side is formed. In addition, since the second oil hole 22 and the chamfered portion 23 are simultaneously formed by the chamfering drill 40 as described above, the axial centers A ₂ and A _{3 of} the second oil hole 22 and the chamfered portion 23 coincide with each other. In addition, the formation range of the chamfered portion 23, the size of the chamfered portion 23, and the like can be adjusted by adjusting the drilling amount of the chamfering process.

-Lubricating oil supply operation for engine crankshaft lubricating oil passage structure-
Hereinafter, the operation of supplying the lubricating oil in the lubricating oil passage structure 10 of the crankshaft of the engine will be described. First, the crankshaft 30 rotates. Then, the lubricating oil is supplied from the outer peripheral surface of the crank journal 31 to the outer peripheral surface of the crank pin 32 through the oil holes 24 and 20 by the centrifugal force accompanying the rotation of the crankshaft 30. Here, as described above, the chamfered portion 23 is formed so as to be offset toward the opposite side to the rotational direction of the crankshaft 30 at the opening end portion 22a of the second oil hole 22, so that the crankpin 32 extends from the oil hole 20. The lubricating oil supplied to the outer peripheral surface of the crankshaft 30 tends to flow to the side opposite to the rotation direction of the crankshaft 30.

-Effect-
As described above, according to the present embodiment, the sharpened portion of the first oil hole 21 can be eliminated by forming the second oil hole 22 and the chamfered portion 23. Therefore, occurrence of stress concentration can be reduced.

  In addition, since the chamfered portion 23 whose chamfer width becomes wider toward the opposite side to the rotation direction of the crankshaft 30 is formed in the opening end portion 22a on the outer peripheral surface side of the crankpin 32 of the second oil hole 22, A portion of the chamfer 23 opposite to the rotation direction of the crankshaft 30 can be made relatively large. Therefore, the lubricating oil supplied from the oil hole 20 to the outer peripheral surface of the crankpin 32 is likely to flow on the opposite side to the rotation direction of the crankshaft 30. Therefore, without increasing the chamfered portion 23 as a whole, the lubricating oil is applied to the side opposite to the rotation direction of the crankshaft 30 on the outer peripheral surface of the crankpin 32, that is, to the sliding direction side of the connecting rod with respect to the crankpin 32. Can be fully supplied. Therefore, the thickness of the oil film on the sliding surface between the crankpin 32 and the connecting rod can be sufficiently secured, and the lubricity of the sliding surface can be improved.

  As a result, the lubricity of the sliding surface can be improved while reducing the occurrence of stress concentration.

Further, the second oil hole 22 passes through the axial center position of the crank pin 32 without passing through the position where the axial center A ₂ is offset with respect to the axial center of the crank pin. Compared with the case where it is offset, the amount of leakage of the lubricating oil can be suppressed.

Further, a portion of the first oil hole 21 on the crank pin 32 side is defined with respect to a straight line L connecting the axis A _J of the crank journal 31 and the axis A _P of the crank pin 32 as viewed in the axial direction of the crankshaft 30. Since it is disposed at a position offset to the rotation direction side of the crankshaft 30, the lubricating oil is disposed on the opposite side of the outer peripheral surface of the crankpin 32 from the rotation direction of the crankshaft 30, that is, with respect to the crankpin 32 of the connecting rod. It can supply more fully by the sliding direction side. Therefore, the lubricity of the sliding surface can be further improved.

  In the present embodiment, the portion of the first oil hole 21 on the crank pin 32 side is disposed at a position that is offset to the rotation direction side of the crankshaft 30 with respect to the straight line L in the axial direction of the crankshaft 30. However, the present invention is not limited to this. For example, the straight line L may be disposed at a position offset to the opposite side of the rotation direction of the crankshaft 30. However, from the viewpoint of improving the lubricity of the sliding surface, it is preferable that the sliding surface is disposed at a position offset to the rotation direction side of the crankshaft 30 with respect to the straight line L.

  Further, in the present embodiment, the oil hole 20 is formed in the crankshaft 30 so as to communicate the oil hole 24 and the outer peripheral surface of the crank pin 32, but the outer peripheral surface of the crank journal 31 and the crank pin 32 are formed. It may be formed so as to communicate with the outer peripheral surface.

  The present invention is not limited to the embodiments, and can be implemented in various other forms without departing from the spirit or main features thereof.

  As described above, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is indicated by the claims, and is not restricted by the text of the specification. Further, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

  As described above, the present invention provides a lubricating oil passage for a crankshaft of an engine provided with a linear oil hole for supplying lubricating oil from a crank journal supported on a cylinder block to a crankpin that supports a connecting rod. Useful for structure.

It is a side view of the crankshaft concerning the embodiment of the present invention. It is a front view of a crankshaft. It is a top view of a crankshaft. It is a perspective view of the crankpin vicinity. It is a figure which shows the mode of a chamfering process. It is a front view of the drill for chamfering.

Explanation of symbols

10 engine crankshaft lubricating oil passage structure 20 oil hole 21 first oil hole 22 second oil hole 23 chamfer 30 crankshaft 31 crank journal 32 crankpins 33 crank web 40 for chamfering drill A ₁ axis of the first oil hole Core A ₂ Center axis of the second oil hole A ₃ Center axis of the chamfer A _J Center axis of the crank journal A _P Center axis of the crank pin A _D Center axis of the chamfering drill L Center axis of the crank journal and the axis of the crank pin Straight line P connecting the core

Claims (2)

A lubricating oil passage structure of a crankshaft of an engine having a linear oil hole for supplying lubricating oil from a crank journal supported by a cylinder block to a crankpin supporting a connecting rod;
The oil hole extends from the crank journal to the vicinity of the outer peripheral surface of the crank pin, and the crank shaft is extended at a position where the extension line of the shaft core is offset to the opposite side of the crank journal with respect to the axial center of the crank pin. A first oil hole that intersects the outer peripheral surface of the pin, and the shaft core passes through the center position in the axial direction of the crank pin, and extends from the outer peripheral surface of the crank pin toward the axial center of the crank pin. A second oil hole communicating with the
The second oil hole has an axis extending from the crank pin so that the axis is inclined at a predetermined angle with respect to a perpendicular perpendicular to the outer peripheral surface of the crank pin as viewed in the axial direction of the crank pin. It is configured to pass through a position that is offset to the rotational direction side of the crankshaft with respect to the axial center of the crankpin in the axial direction view,
An end portion of the second oil hole on the outer peripheral surface side of the crank pin is formed with a chamfered portion whose width increases toward the opposite side to the rotation direction of the crankshaft. Crankshaft lubricating oil passage structure. In the lubricating oil passage structure of the crankshaft of the engine according to claim 1,
The crankshaft side portion of the first oil hole is in the direction of rotation of the crankshaft with respect to a straight line connecting the axis of the crank journal and the axis of the crankpin as viewed in the axial direction of the crankshaft. A lubricating oil passage structure for a crankshaft of an engine characterized by being disposed at a position offset to

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