JP2017180533A - Crank shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a crank shaft having a function of an oil jet for jetting a lubrication oil to a piston.SOLUTION: A crank shaft includes: a crank journal 10 which is a rotary shaft; and a counterweight 40 protruding to the outer peripheral side from the crank journal 10. The counterweight 40 includes a protrusion 42 standing in the direction crossing a surface of the counterweight on its outer peripheral edge part. A glanular or mist-like lubrication oil which has hit the surface 40m of the counterweight 40 is collected at the protrusion 42, and by scattering the collected lubrication oil L to the outer periphery by a centrifugal force by the rotation of the counterweight 40, the oil is jetted to a piston 2, and the piston 2 is cooled.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a crankshaft of an internal combustion engine.

  A crankshaft of an internal combustion engine such as an automobile rotates with the reciprocating motion of a piston connected via a connecting rod. A crank journal rotatably supported by a bearing of a cylinder block, and a connecting rod A crankpin to be connected and a counterweight for adjusting the rotation balance of the crankshaft are provided.

  An internal combustion engine is known in which an oil jet for injecting lubricating oil to a piston is provided below a cylinder bore of a cylinder block in order to cool the piston (for example, Patent Document 1).

JP 2000-199414 A

  The counterweight of the crankshaft requires a mass (size) that can suppress the occurrence of vibration during rotation of the crankshaft. Therefore, there is a demand for the counterweight to increase the amount of protrusion protruding from the crank journal to the outer peripheral side.

  However, the amount of protrusion (size) of the counterweight is limited because it is necessary to secure a gap with the oil jet provided below the cylinder bore.

  The present invention has been made in view of the above circumstances, and one of its purposes is to provide a crankshaft having the function of an oil jet that injects lubricating oil onto a piston.

  A crankshaft according to an aspect of the present invention is a crankshaft comprising a crank journal that is a rotating shaft and a counterweight that protrudes outward from the crank journal, and the counterweight is disposed at an outer peripheral edge thereof. A ridge standing in a direction intersecting the surface of the counterweight is provided.

  The crankshaft is provided with a protrusion on the counterweight, whereby the granular or mist-like lubricating oil hitting the surface of the counterweight can be collected by the protrusion. Specifically, since the counterweight is rotating, if the lubricating oil hitting the counterweight surface flows to the ridge, it stays at the corner between the surface and the ridge without falling from the counterweight and stays there. It is possible to concentrate the lubricating oil. The collected lubricating oil is scattered to the outer periphery by centrifugal force due to the rotation of the counterweight. When the scattered lubricating oil hits the piston, the piston can be cooled. At this time, since the lubricating oil is scattered after being concentrated by the protrusions, it is scattered with a certain amount of mass compared to a case where the lubricating oil is not concentrated by the protrusions. That is, the crankshaft has an oil jet function. Therefore, in addition to the injection of lubricating oil by the conventional oil jet, the cooling performance of the piston can be improved by injecting the lubricating oil by the crankshaft. Further, the oil jet can be downsized, and the oil jet itself can be omitted.

  Since the oil jet can be reduced in size or omitted, the crankshaft can increase the amount of protrusion of the counterweight, and the degree of freedom of its size and shape can be improved. The balance weight is more easily balanced when the outer peripheral side is made heavier. The crankshaft can increase the protruding amount of the balance weight and can make the outer peripheral side of the balance weight heavier by providing protrusions on the outer peripheral edge thereof. Therefore, the inner peripheral side of the balance weight can be lightened, and the weight of the entire balance weight can be reduced. If the oil jet is omitted, the cost can be reduced, the manufacturing process can be reduced, and the productivity can be improved.

In the crankshaft which concerns on embodiment, it is the cross-sectional view which cut | disconnected the cylinder block by the plane orthogonal to the axial direction of a crankshaft. It is arrow (II)-(II) schematic sectional drawing of FIG.

  Embodiments of the crankshaft of the present invention will be described below with reference to the drawings. FIG. 1 shows a state where the crankshaft is rotated 90 ° from a state where the piston is at the top dead center. FIG. 2 is a partially enlarged view of the counterweight portion of the crankshaft shown in FIG. In the figure, the same reference numerals indicate the same names.

〔Crankshaft〕
The crankshaft 1 of the embodiment converts the reciprocating motion of the piston 2 of each cylinder in the internal combustion engine into a rotational motion, and serves as an output rotation shaft of the internal combustion engine. The crankshaft 1 includes a crank journal 10 rotatably supported by a bearing (not shown) of a cylinder block 100, a crank pin 20 to which a connecting rod 3 connected to a piston 2 is swingably connected, A crank arm 30 that connects the journal 10 and the crank pin 20 is provided. The crank arm 30 includes a counterweight 40 that protrudes outward from the crank journal 10 at a position facing the crankpin 20 with the crank journal 10 in between. The counterweight 40 is provided to suppress the occurrence of vibration during rotation of the crankshaft 1 and adjust the rotation balance of the crankshaft 1. The crankshaft 1 is generally a forged product made of carbon steel or special steel.

  The internal combustion engine typically includes a main body 110 in which a cylinder bore 112 is formed, a cylinder block 100 having a skirt portion 120 below the main body 110, and a cylinder head that houses a valve system and forms a combustion chamber (see FIG. And an oil pan 200 for storing lubricating oil for the main motion system and the valve train. In the internal combustion engine of this example, an oil pan 200, a cylinder block 100, and a cylinder head are stacked in this order from below, and a cylinder head cover (not shown) is attached above.

  The crankshaft 1 according to the first embodiment is characterized in that the outer periphery of the counterweight 40 is provided with a ridge 42 standing in a direction intersecting the surface 40m of the counterweight 40. The protrusion 42 has a function of collecting granular or mist-like lubricating oil that hits the surface 40 m of the counterweight 40 and injecting the concentrated lubricating oil L to the piston side. Lubricating oil L collected by the ridges 42 falls from above the cylinder block 100 (such as the cylinder bore 112 that houses the piston 2), or a lubricating oil passage formed in the crankshaft 1 itself (not shown). And the like that the lubricating oil in the oil pan 200 drifts in the form of a mist under the cylinder block 100. Hereinafter, the counterweight 40 provided in the crankshaft 1 will be described in detail.

-Counterweight The counterweight 40 has a substantially fan shape when viewed from the axial center of the crank journal 10 (see FIG. 1). The counterweight 40 has a substantially left-right symmetric shape across a straight line connecting the axis of the crank journal 10 and the axis of the crankpin 20. The counterweight 40 includes a ridge 42 along a fan-shaped arc portion.

  The ridge 42 is erected in a direction that intersects the surface 40 m of the counterweight 40. In this example, the protrusion 42 is erected in a direction perpendicular to the surface 40 m of the counterweight 40 as shown in FIG. By doing so, it is possible to suppress the lubricating oil L that hits the surface 40 m of the counterweight 40 and has settled on the ridge 42 from getting over the ridge 42 and scattering to the outside of the counterweight 40. The ridge 42 can be erected so that the angle formed with the surface 40 m of the counterweight 40 is an acute angle of less than 90 °. When the ridge 42 and the surface 40m of the counterweight 40 have an acute angle, the lubricating oil L can be easily retained at the corners of the ridge 42 and the surface 40m, and the remaining lubricating oil can be easily collected.

  As shown in FIG. 1, the protrusion 42 is provided with a continuous portion along the arc portion of the counterweight 40. Since the counterweight 40 is rotating, the lubricating oil L is scattered on the outer periphery of the counterweight 40 by the centrifugal force. By having a continuous part in the protrusion 42, the time which stays in the protrusion 42 until the lubricating oil L scatters can be lengthened, and it is easy to concentrate the lubricating oil L by that much. In this example, the protrusion 42 is provided from one end of the arc portion to the other end except for an injection port 44 described later.

  A cut that does not have the protrusion 42 is provided in the middle of the protrusion 42 that is continuously provided along the arc portion of the counterweight 40. This break is an injection port 44 for injecting the lubricating oil L collected by the protrusion 42 to the outside of the counterweight 40. In this example, the injection port 44 is provided on a straight line connecting the axis of the crank journal 10 and the axis of the crank pin 20. Since the injection port 44 (the protrusion 42) is provided at the outer peripheral edge portion of the counterweight 40, the flying distance of the lubricating oil L injected from the injection port 44 is larger than that provided in the inner peripheral region. can do.

  As shown in FIG. 1, the protrusion 42 has a thickness (the length between the outer peripheral surface and the inner peripheral surface of the protrusion 42, the upper and lower portions in FIG. The length in the direction) is gradually reduced. Specifically, the protrusion 42 is a surface whose outer peripheral surface is along the arc portion of the counterweight 40, and the inner peripheral surface is an inclined surface that approaches the outer peripheral surface toward the injection port 44. By having the ridge 42 have a continuous portion inclined toward the injection port 44, the lubricating oil L collected by the two ridges 42 provided across the injection port 44 can be further concentrated in the injection port 44. it can. Wall portions 46 that protrude toward the center of the crank journal 10 are formed at both ends of the arc portion of the protrusion 42 so that the concentrated lubricating oil L is not scattered from both ends.

[Action]
When the internal combustion engine is operated using the crankshaft 1, the piston 2 reciprocates and the crankshaft 1 rotates. Lubricating oil is supplied to components that require lubrication and cooling in an internal combustion engine. At this time, the lubricating oil may fall from above the cylinder block 100 (such as the cylinder bore 112 that houses the piston 2), or the lubricating oil may leak from the lubricating oil path formed in the crankshaft 1 itself. When the dropped or leaked lubricating oil hits the surface 40m of the counterweight 40, the counterweight 40 is rotating, so that the lubricating oil flows to the outer peripheral side through the surface 40m of the counterweight 40 by the centrifugal force due to the rotation. Then, it reaches the ridge 42 (see FIG. 2).

  Further, below the cylinder block 100, the lubricating oil in the oil pan 200 drifts in a mist form. When this mist-like lubricating oil adheres to the surface 40m of the counterweight 40, the counterweight 40 is rotating. Therefore, the lubricating oil is transmitted along the surface 40m of the counterweight 40 by the centrifugal force caused by the rotation, to the outer peripheral side. Flow and arrive at the ridge 42 (see FIG. 2).

  As shown in FIG. 2, the lubricating oil L that has flowed onto the ridge 42 stays at the corner between the surface 40 m of the counterweight 40 and the ridge 42 without being scattered to the outer periphery due to the centrifugal force generated by the rotation of the counterweight 40. . The remaining lubricating oil L is collected and becomes a liquid lubricating oil.

  Since the protrusion 42 has a continuous portion in which an inclined surface is formed along the arc portion of the counterweight 40, the concentrated lubricating oil L flows toward the lower side of the inclined surface as shown in FIG. Since the injection port 44 is provided in the lower portion of the inclined surface in the middle of the ridge 42, the lubricating oil L concentrated in the injection port 44 is caused by the centrifugal force generated by the rotation of the counterweight 40 to move from the injection port 44 to the outer periphery of the counterweight 40. Is injected into. The aggregated lubricating oil L is in a liquid state and has a certain amount of mass, so that it is ejected vigorously from the injection port 44. The piston 2 is cooled when the lubricating oil L injected from the injection port 44 hits the piston 2.

〔effect〕
In the crankshaft 1, the counterweight 40 is provided with the protrusions 42, so that the granular lubricating oil hitting the surface 40 m of the counterweight 40 and the adhering mist-like lubricating oil are removed by centrifugal force due to the rotation of the counterweight 40. The liquid lubricating oil L can be efficiently aggregated. Since the ridges 42 are erected in a direction perpendicular to the surface 40 m of the counterweight 40, the lubricating oil that has flowed onto the ridges 42 gets over the ridges 42 and scatters to the outside of the counterweight 40. And the lubricating oil L can be collected reliably.

  The two protruding ridges 42 having the inclined surfaces that are continuously provided are arranged with the lower inclined surface facing each other, and the injection port 44 is provided therebetween, so that the lubricating oil that has flowed to the protruding ridges 42 is provided. Can be efficiently collected in the injection port 44. The counterweight 40 can inject the lubricating oil L collected in liquid form from the injection port 44 while rotating, so that the lubricating oil L can be injected to the piston 2. That is, the crankshaft 1 has an oil jet function. Therefore, the cooling performance of the piston 2 can be improved by injecting the lubricating oil by the crankshaft 1 in addition to the injection of the lubricating oil by the conventional oil jet. Further, the oil jet can be downsized, and the oil jet itself can be omitted. Since the oil jet can be reduced in size or omitted, the crankshaft 1 can increase the amount of protrusion of the counterweight 40 toward the outer peripheral side, improve the degree of freedom of its size and shape, and realize weight reduction.

  Further, since the crankshaft 1 can make the lubricating oil drifting below the cylinder block 100 in a mist state into a liquid lubricating oil, the mist-like lubricating oil in the cylinder block 100 can be reduced. When the counterweight 40 is not provided with the protrusion 42, even if mist-like lubricating oil adheres to the surface 40 m of the counterweight 40, the cylinder block 100 is used as it is as mist-like lubricating oil by the centrifugal force generated by the rotation of the counterweight 40. This is because they often drift inside.

  During operation of the internal combustion engine, gas containing unburned gas (blow-by gas) may leak into the crankcase (cylinder block 100) from the combustion chamber. Therefore, blow-by gas leaked into the crankcase is returned to the intake system, and the cylinder block 100 is provided with a blow-by gas passage (PCV gas passage, not shown). If mist-like lubricating oil is drifting in the crankcase, the blow-by gas leaking into the crankcase is mixed with the mist-like lubricating oil, and there is a possibility that the blow-by gas passes through the PCV gas passage in this mixed state. is there. With the crankshaft 1, the mist-like lubricating oil in the crankcase (cylinder block 100) can be reduced, so the lubricating oil mixed with the blow-by gas can be reduced, and the lubricating oil can enter the PCV gas passage. Can be suppressed.

  The present invention is not limited to these exemplifications, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. For example, the thickness and length of the ridge, the angle formed between the ridge and the surface of the counterweight, and the like can be changed.

  The crankshaft of the present invention can be suitably used for a crankshaft of an internal combustion engine in which an oil jet that injects lubricating oil onto a piston is omitted.

DESCRIPTION OF SYMBOLS 1 Crankshaft 10 Crank journal 20 Crank pin 30 Crank arm 40 Counterweight 40m Surface 42 Projection 44 Injection port 46 Wall part 2 Piston 3 Connecting rod 100 Cylinder block 110 Main body 112 Cylinder bore 120 Skirt part 200 Oil pan L Lubricating oil

Claims (1)

A crankshaft comprising a crank journal that is a rotating shaft and a counterweight that protrudes outward from the crank journal,
The counterweight is a crankshaft provided with a ridge standing on the outer peripheral edge thereof in a direction intersecting the surface of the counterweight.

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