JP2010203514A - Oil hole structure of crankshaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oil hole structure of a crankshaft for eliminating stress concentration generated in a crank pin opening part. <P>SOLUTION: This oil hole structure has an oil inlet passage (20) arranged by opening on an outer peripheral surface of a main journal (2), an oil communicating passage (40) connected to the oil inlet passage (20) and provided and connected to a crank pin (3) and the main journal (2) so that oil flows inside the crank pin (3), and an oil outlet passage (30) connected to the oil communicating passage (40) and extended in the radial direction of the crank pin (3) toward a pin opening part (3a) arranged and opened on an outer peripheral surface of the crank pin (3), and the oil outlet passage (30) has a tapered part (31) having the cross-sectional area increasing toward the pin opening part (3a) of the crank pin (3). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to an oil hole structure of a crankshaft.

  2. Description of the Related Art Conventionally, an oil hole structure of a crankshaft that supplies oil to a crank pin through an oil hole opened on an outer peripheral surface of a main journal of the crankshaft is known (particularly, Patent Document 1). And the oil hole is provided with the fixed cross section.

JP-A-7-27126

  The oil hole of the crankshaft is provided to lubricate the oil to prevent wear of the portion where the bearing and the crankpin or the main journal are in contact with each other and to cool the heat generated in the crankshaft.

  However, high stress is generated in the pin opening portion of the oil hole provided to be opened on the outer peripheral surface of the crank pin by the torsion torque of the crank shaft. And there is a concern that stress concentrates on the open end or chamfered corner of the pin opening, resulting in insufficient strength.

  The present invention has been made paying attention to such conventional problems, and an object of the present invention is to provide an oil hole structure of a crankshaft that eliminates stress concentration generated in an opening of a crankpin.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

  The present invention is connected to the oil inlet passage (20) provided on the outer peripheral surface of the main journal (2) and the oil inlet passage (20) so that the oil flows into the crankpin (3). An oil communication passage (40) provided in communication with the crank pin (3) and the main journal (2), and connected to the oil communication passage (40), and opened on an outer peripheral surface of the crank pin (3). An oil outlet passage (30) extending in a radial direction of the crank pin (3) toward a pin opening (3a) provided as a pin opening, and the oil outlet passage (30) It has a taper part (31) in which a cross-sectional area is enlarged, so that it is near the said pin opening part (3a) of a pin (3), It is characterized by the above-mentioned.

  According to the present invention, one end is open to the crank pin, the other end is connected to an oil communication passage provided in communication with the main journal, and an oil outlet passage for supplying lubricating oil to the sliding surface of the crank pin is provided in the crank. Provided from the inside of the pin. The outlet oil passage has a tapered portion whose cross-sectional area is enlarged as it is closer to the pin opening. Since it comprises in this way, the stress concentration which had arisen in the pin opening part by twisting of a crankshaft can be disperse | distributed to the whole taper part of an oil exit channel | path. Therefore, the stress concentration at the opening of the crankpin is eliminated, and there is no fear of insufficient strength.

It is a figure which shows the oil hole structure of the crankshaft of 1st Embodiment. It is a figure which shows the 4th cylinder part of 1st Embodiment with a perspective view. It is a figure which shows the cross-section of the oil path of the crankpin of 1st Embodiment. It is a figure which shows the cross-section of the oil path of the crankpin of 2nd Embodiment. It is a figure which shows the cross-section of the oil path of the crankpin of 3rd Embodiment.

  Hereinafter, an embodiment for carrying out the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a diagram illustrating an oil hole structure of a crankshaft according to the first embodiment.

  The oil hole structure 10 of the crankshaft 1 is an oil passage that is provided in the crankshaft 1 and supplies lubricating oil that is fed from the main gallery to the main journal 2 to the crankpin 3 (not shown). The oil hole structure 10 is provided for each cylinder. The oil hole structure 10 is provided between the crankpin 3 and the main journal 2 closer to the end of the crankshaft 1 among the main journals 2 arranged on both sides of the crankpin 3. The oil hole structure 10 includes an oil inlet passage 20 provided in the main journal 2, an oil outlet passage 30 provided in the crank pin 3, and an oil communication passage 40 that communicates between the two.

  First, the structure of the crankshaft 1 will be described.

  The crankshaft 1 is for an inline 4-cylinder engine. The crankshaft 1 includes a main journal 2, a crankpin 3, a crank web 4, a flywheel mounting flange portion 5, and a crankshaft pulley mounting portion 6. The crankshaft 1 converts the rotational motion into a reciprocating motion of the piston via a connecting rod connected to the crankpin 3.

  The main journal 2 is a rotating shaft of the crankshaft 1. Although not shown, the main journal 2 is supported by the cylinder block via a bearing and a bearing cap. The main journal 2 is provided with an oil inlet passage 20 on the diameter and an oil communication passage 40 that is connected to the oil inlet passage 20 and extends through the crank web 4 to the crankpin 3.

  The crankpin 3 is a shaft that is inserted into the large end hole of the connecting rod in the case of a single link mechanism, and is a shaft that is inserted into the pin hole of the lower link in the case of a multilink mechanism. The crank pin 3 is a member that connects the main journals 2 that are the main shafts of the crankshaft 1 through the crank web 4, and is provided eccentrically in the radial direction with respect to the main journal 2. The crankpin 3 is provided with an oil outlet passage 30 on the radius and an oil communication passage 40 that allows the oil outlet passage 30 and the oil inlet passage 20 to communicate with each other.

  The crank web 4 includes a crank arm 4a and a counterweight 4b. The crank arm 4 a is a member that connects the main journal 2 and the crank pin 3. The counterweight 4b is also called a balance weight, and is provided on the opposite side of the crankpin 3 in order to improve the balance of the center of gravity that is biased toward the crankpin 3 side. The crank web 4 is provided with an oil communication passage 40 therethrough.

  The flywheel mounting flange portion 5 is provided at the rear end portion of the crankshaft 1. The flywheel mounting flange portion 5 is mounted with a flywheel which is a disc and has a rotational inertial mass. The flywheel reduces rotation unevenness due to intermittent generation of in-cylinder combustion pressure of each cylinder.

  The crankshaft pulley mounting portion 6 is provided at the front end portion of the crankshaft 1 on the side opposite to the flywheel mounting flange portion 5. A crankshaft pulley is attached to the crankshaft pulley attaching portion 6. The crankshaft pulley drives auxiliary machinery.

  Next, the oil hole structure 10 of the crankshaft 1 will be described with reference to FIG.

  FIG. 2 is a perspective view of the fourth cylinder portion of the first embodiment. As described above, the oil hole structure 10 of the crankshaft 1 includes the oil inlet passage 20, the oil communication passage 40, and the oil outlet passage 30.

  The oil inlet passage 20 is provided in the main journal 2. The oil inlet passage 20 passes through the center of the main journal 2 in the diameter direction, and has a total of two journal openings 2a on the outer peripheral surface corresponding to both ends of the diameter. The journal opening 2a is provided so as to open on the side as viewed from the axial direction. The oil inlet passage 20 is connected to the oil communication passage 40 in the vicinity of one of the journal openings 2a. Lubricating oil is supplied from a journal opening 2 a provided on the outer peripheral surface of the main journal 2 and flows to the oil communication passage 40 through the oil inlet passage 20. The oil inlet passage 20 has a constant cross section.

  The oil communication passage 40 is provided in the main journal 2, the crank web 4 and the crankpin 3. One end of the oil communication passage 40 is connected to the oil inlet passage 20 of the main journal 2 and the other end is connected to the oil outlet passage 30 of the crankpin 3. The oil communication passage 40 is provided obliquely through the crank web 4 so as to connect the vicinity of one journal opening 2a of the oil inlet passage 20 and the oil outlet passage 30 at the center of the crankpin 3 in a straight line. . The oil communication passage 40 has a constant cross section.

  The oil outlet passage 30 is provided in the crankpin 3. The oil outlet passage 30 is provided in parallel to the oil inlet passage 20 in the radial direction from the center of the crankpin 3, and has one pin opening 3 a on the outer peripheral surface of the crankpin 3. Of the two journal openings 2a, the pin opening 3a is provided so as to open in the same direction as the journal opening 2a opposite to the journal opening 2a in which the oil communication passage 40 is provided in the vicinity. One end of the oil outlet passage 30 is opened on the outer peripheral surface, and the other end of the crankpin 3 is connected to the oil communication passage 40 at the center side. The oil outlet passage 30 has a tapered cross section rather than a constant cross section.

  Next, the details of the oil outlet passage 30 will be described with reference to FIG. FIG. 3 is a diagram showing a cross-sectional structure of the oil outlet passage of the crankpin according to the first embodiment. The oil outlet passage 30 is a conical tapered portion 31 having a uniform taper angle as a whole. The oil outlet passage 30 has a cross-sectional area that is enlarged from the center of the crank pin 3 toward the pin opening 3a. Further, when the ratio of the hole diameter of the oil outlet passage 30 to the pin diameter of the crankpin 3 is increased, the stress concentration on the hole diameter of the oil outlet passage 30 is increased. Further, the torsional stress, that is, the shear stress acting on the crankpin 3 has a linear distribution in proportion to the radius of the crankpin 3 and is maximized on the outer peripheral surface. The hole diameter of the pin opening 3a is set in consideration of the fact that high stress is likely to occur in the pin opening 3a provided on the outer peripheral surface of the crank pin 3. The hole diameter on the center side of the oil outlet passage 30 is set in consideration of pressure loss due to a change in cross section (hole diameter) from the connected oil communication passage 40.

  According to the present embodiment, the oil outlet passage 30 has a conical shape in which the cross-sectional area is increased as it is closer to the pin opening 3a. As a result, it is possible to eliminate the corners of the chamfered portion of the pin opening 3a, which has conventionally been concentrated in stress, and make the oil outlet passage 30 a uniform surface. When there is no chamfered portion, the angle of the end portion of the pin opening 3a, that is, the intersection of the outer peripheral surface of the crankpin 3 and the oil outlet passage 30 becomes an obtuse angle. The stress concentrated on the pin opening 3 a can be distributed and received over the entire tapered surface of the oil outlet passage 30.

(Second Embodiment)
FIG. 4 is a view showing a cross-sectional structure of the oil outlet passage of the crankpin according to the second embodiment. In the following description, the same functions as those described above are denoted by the same reference numerals, and redundant description will be omitted as appropriate.

  In the present embodiment, the cross-sectional shape in the vicinity of the pin opening 3a of the tapered portion 31 of the oil outlet passage 30 is a funnel shape that warps outward.

  According to the present embodiment, the change in the cross-sectional area of the tapered portion 31 near the pin opening 3a is smoother than the shape of the first embodiment. Therefore, the stress concentration in the pin opening 3a can be further relaxed.

(Third embodiment)
FIG. 5 is a view showing a cross-sectional structure of the oil outlet passage of the crankpin according to the third embodiment.

  In the present embodiment, the oil outlet passage 30 includes a tapered portion 31 and a straight portion 32. The tapered portion 31 is provided on the pin opening 3 a side, and the straight portion 32 is provided on the center side of the crank pin 3. The tapered portion 31 has a depth that is a quarter of the pin diameter D of the crank pin 3 from the pin opening 3a. The taper portion 31 has a conical shape having a uniform taper angle. The straight portion 32 has a constant cross section.

  According to the present embodiment, the depth of the tapered portion 31 of the oil outlet passage 30 is set to a quarter of the pin diameter D of the crankpin 3. By securing the taper depth necessary for stress relaxation of the pin opening 3a, the stress concentration of the pin opening 3a can be reliably relaxed, and the diameter of the hole on the center side of the oil outlet passage 30 can be sufficiently increased. Since it can be ensured, the flow efficiency of the lubricating oil is also good.

  Particularly in the case of a multi-link engine, the pin width of the crankpin 3 is set to be a thin shaft with a small pin diameter compared to the single-link engine. With the oil outlet passage 30 as in the present invention, the aspect ratio of the hole diameter of the pin opening 3a to the pin width can be made equal. Therefore, sufficient lubricating oil can be supplied to the sliding surface of the crankpin 3. Further, the hole diameter of the oil passage other than the tapered portion 31 of the oil outlet passage 30 can be set to be small according to the pin diameter of the crank pin 3.

  Without being limited to the embodiments described above, various modifications and changes are possible within the scope of the technical idea, and it is obvious that these are also included in the technical scope of the present invention.

  For example, in the embodiment, the pin opening portion of the oil hole structure of the crankshaft is provided to open on the side surface side of the crank arm as viewed from the axial direction of the crankshaft. Good. By bringing the pin opening close to the highly rigid portion of the crank web, the stress in the pin opening can be reduced. Further, it is not necessary to provide the tapered portion of the oil outlet passage in all the oil hole structures of the crankshaft. A tapered portion may be provided only in the oil outlet passage provided in the crank pin at the rearmost end on the flywheel side where the twist of the crankshaft increases.

DESCRIPTION OF SYMBOLS 1 Crankshaft 2 Main journal 2a Journal opening part 3 Crank pin 3a Pin opening part 4 Crank web 4a Crank arm 4b Counterweight 5 Flywheel attachment flange part 6 Crankshaft pulley attachment part 10 Oil hole structure 20 Oil inlet passage 30 Oil outlet passage 40 Oil communication passage

Claims (7)

An oil inlet passage that is opened in the outer peripheral surface of the main journal;
An oil communication passage connected to the oil inlet passage and provided to communicate from the main journal to the crank pin through the crank web so that oil flows inside the crank pin;
An oil outlet passage that is connected to the oil communication passage and extends in a radial direction of the crank pin toward a pin opening provided to be opened on an outer peripheral surface of the crank pin;
With
The oil outlet passage has a tapered portion whose cross-sectional area is enlarged as it approaches the pin opening of the crank pin.
The oil hole structure of the crankshaft is characterized by that. The taper part is a funnel shape in which the vicinity of the pin opening part warps outward,
The oil hole structure of a crankshaft according to claim 1. The tapered portion is provided in the entire oil outlet passage.
The oil hole structure for a crankshaft according to claim 1 or 2, wherein the oil hole structure is a crankshaft. The taper portion has a depth set to a quarter or more of the crankpin diameter.
The oil hole structure for a crankshaft according to claim 1 or 2, wherein the oil hole structure is a crankshaft. The tapered portion is provided only in the oil outlet passage formed in the crank pin at the rearmost end closest to the flywheel.
The oil hole structure of a crankshaft according to any one of claims 1 to 4, wherein the oil hole structure is a crankshaft. The pin opening is provided at one place on one crank pin.
The oil hole structure for a crankshaft according to any one of claims 1 to 5, wherein the oil hole structure is a crankshaft. The pin opening is provided on the top side of the crank arm.
The oil hole structure for a crankshaft according to any one of claims 1 to 6, wherein the oil hole structure is a crankshaft.

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