JP2008240575A - Engine lubrication equipment - Google Patents

Abstract

An engine lubrication apparatus capable of suppressing hydraulic hunting in the entire engine speed range is provided.
A main oil pan 24 attached to the lower surface of a crankcase 22 of an engine, an oil pump 46 for supplying oil in the main oil pan to each part of a lubricating portion of the engine via a bubble separator 42, main oil A sub-oil pan 28 disposed in the engine crank chamber and having a smaller capacity than the pan, and a balancer 30 disposed below the sub-oil pan, each coupled to a pair of balancer shafts and the balancer shafts The balancer includes a pair of gears 34 that mesh with each other, an oil introduction passage 36 that guides oil from the auxiliary oil pan to the meshing portions of the pair of gears of the balancer, and oil from the meshing portions of the pair of gears to the main oil pan. An oil return passage 40 for returning the oil.
[Selection] Figure 1

Description

  The present invention relates to an engine lubrication device that supplies oil to lubrication parts of moving parts such as a piston and a crankshaft by circulating oil in the engine, and more particularly to an engine lubrication device including a balancer.

  Engines mounted on vehicles and the like incorporate many moving parts such as crankshafts, camshafts, and pistons, as well as lubricating parts (supporting parts, sliding parts, etc.) and hydraulic operating parts (variable moving parts) of each moving part. A lubrication device for supplying oil to a valve mechanism or the like is provided. In this lubricating device, oil discharged from an oil pump driven by the engine flows in the cylinder block, and a part thereof is supplied to the crankshaft, piston, and the like. The other oil passes through the cylinder block and is then supplied to the camshaft of the cylinder head. The oil supplied in this way is used for lubrication and cooling of each moving part, smooth operation of the hydraulic operation part, and the like, and then returned to the oil pan.

  By the way, when the oil stored in the oil pan is sucked up by the oil pump and supplied to the lubrication unit and the hydraulic operation unit, many bubbles are mixed in the oil due to the stirring of the oil by each moving part and the hydraulic operation unit. It is known that When oil containing such bubbles is used in a lubrication unit or a hydraulic operation unit, an oil film breaks or malfunctions on the lubrication surface. Therefore, a lubricating device equipped with a bubble separation system that removes such mixed bubbles, for example, It is disclosed in Patent Document 1 and Patent Document 2. In these, a swirling flow of oil is generated inside the bubble separator, and the bubbles are separated and removed from the oil by utilizing a difference in centrifugal force acting on the oil and the bubbles.

Japanese Unexamined Patent Publication No. 2000-210503 JP-A-2003-254029

  By the way, when the bubbles are separated using the bubble separator as described above, when the particle size of the bubbles mixed in the oil is small and the speed of the swirl flow is large, the separation action is sufficiently performed, and the bubbles are separated. It is possible to remove.

  However, the supply amount of oil discharged from the oil pump driven by the engine changes in accordance with the engine speed, and the amount of oil supplied to each part of the engine is small on the low rotation side of the engine. On the low rotation side of an engine with such a small amount of supplied oil, once bubbles are mixed in the oil, the bubbles stay in the oil without being uniformly mixed and tend to grow into bubbles having a large particle size.

  For this reason, even when a bubble separator is used, in the case of oil mixed with bubbles having such a large particle size, the oil and bubbles randomly flow into the bubble separator, and the swirling flow velocity can be maintained. This makes it difficult to achieve a sufficient separation effect. As a result, there is a risk of causing hydraulic hunting when introduced into the oil pump.

  An object of the present invention is to provide an engine lubrication device that can eliminate such problems and suppress hydraulic hunting in the entire engine speed range.

  In order to achieve the above object, an engine lubrication apparatus according to an embodiment of the present invention includes a main oil pan attached to a lower surface of a crankcase of an engine, and oil in the main oil pan through an air bubble separator. An oil pump supplied to each part of the lubrication part, a sub-oil pan smaller than the capacity of the main oil pan and disposed in the crank chamber of the engine, and a balancer disposed below the sub-oil pan. A balancer comprising a pair of balancer shafts and a pair of gears coupled to and engaged with each of the balancer shafts, and an oil introduction passage for guiding oil from the sub oil pan to the meshing portion of the pair of gears of the balancer And an oil return passage for returning oil to the main oil pan from the meshing portions of the pair of gears.

  According to this structure, the oil supplied to each part of the lubrication part of the engine and used for lubrication or the like is collected in the auxiliary oil pan disposed in the crank chamber of the engine, and the pair of balancers via the oil introduction passage. Guided to the gear mesh. The oil is actively agitated by the meshing of the gear, and in the case of oil mixed with bubbles having a large particle size, the bubbles are partially degassed and the bubbles are subdivided into small particle sizes, and the oil return passage is opened. To the main oil pan. Thereafter, the oil in which the bubbles in the main oil pan are subdivided into small particle diameters is supplied to each part of the lubricating part of the engine via the bubble separator by the oil pump. Thus, in the oil in which the bubbles are subdivided into small particle diameters, the bubbles are sufficiently defoamed in the bubble separator, so that the occurrence of hydraulic hunting is suppressed.

  Here, it is preferable that the oil introduction passage is provided with a throttle for adjusting the amount of oil guided to the meshing portion of the pair of gears.

  According to this configuration, since the amount of oil guided to the meshing portions of the pair of gears is adjusted to be substantially constant, it is possible to efficiently perform the bubble subdividing action when the oil is stirred by the meshing of the gears.

  The capacity of the sub oil pan may be set to be substantially equal to the amount of oil circulated to the engine when the engine is running at a low speed.

  According to this configuration, when the oil supply amount, that is, the circulation amount increases at the time of high engine rotation, the capacity of the sub oil pan is exceeded, overflows from the sub oil pan, and falls to the main oil pan. Accordingly, it is possible to prevent an increase in the bubble mixing rate due to excessive stirring of the oil due to the meshing of the gears.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings.

  In FIG. 1, the engine 10 is an in-line four cylinder (only one cylinder is shown), and includes a cylinder block 12 and a cylinder head 14 disposed thereon.

  The cylinder block 12 is made of a metal such as cast iron or aluminum. A plurality of cylinder bores are formed in the cylinder block 12, and a piston 16 is accommodated therein so as to be able to reciprocate. A crankshaft 18 is rotatably supported on the cylinder block 12 by a journal, and the shaft 18 and the piston 16 are connected by a connecting rod 20. The reciprocating motion of the piston 16 is converted into a rotational motion by the connecting rod 20 and the crankshaft 18. On the other hand, on the cylinder head 14, a cam shaft (not shown) having a cam on the outer periphery is rotatably supported by a journal. The camshaft is drivingly connected to the crankshaft 18 by a timing belt (or timing chain) (not shown). As described above, the cylinder block 12 and the cylinder head 14 incorporate a large number of moving parts such as the piston 16, the crankshaft 18, and the camshaft, and a hydraulic actuator that changes the phase of the camshaft.

  A crankcase 22 is formed integrally or separately at the lower portion of the cylinder block 12, and a main oil pan 24 having an open upper surface is attached to the lower surface of the crankcase 22. The main oil pan 24 is intended to store oil and has a large capacity. A space surrounded by the crankcase 22 and the main oil pan 24 forms a crank chamber 26.

  At the upper part in the crank chamber 26, an upper surface is opened and a sub oil pan 28 having a smaller capacity than the main oil pan 24 is disposed. The auxiliary oil pan 28 is for collecting the oil after lubricating the lubrication part of each moving part and the oil discharged from the hydraulic operation part, and the cylinder block 12 is fixed by fixing means such as a stay (not shown). Alternatively, it is fixed to the crankcase 22. The oil overflowing from the sub oil pan 28, in other words, overflowing, falls to the main oil pan 24 and is stored. Here, the capacity of the auxiliary oil pan 28 is set to be substantially equal to the amount of oil circulated when the engine 10 is rotating at a low speed, that is, the amount of oil recovered in the auxiliary oil pan 28.

  In the crank chamber 26, a balancer 30 of the engine 10 is disposed below the auxiliary oil pan 28. The balancer 30 includes a pair of unillustrated balancer shafts rotatably accommodated in a housing 32 fixed to the crankcase 22, and a pair of gears 34 that are respectively coupled to the balancer shafts and mesh with each other. As is well known, each balance shaft has an unbalanced weight biased to one side, and is rotated in opposite directions by the crankshaft 18 at twice the rotational speed. The engine 10 of this embodiment, which is a four-cylinder engine, has four pistons 16, and when two of them are at top dead center, the other two are at bottom dead center. The unbalance weight is always positioned below when any piston 16 is at the top dead center or the bottom dead center, and the secondary inertia force generated by the rotation of the crankshaft 18 is canceled by the pair of balance shafts. It is configured to be. Note that the inertial force in the lateral direction due to the rotation of the unbalance weight is canceled between the pair of balance shafts.

  Further, the auxiliary oil pan 28 is formed with an oil introduction passage 36 for guiding oil from the bottom portion to the meshing portion of the pair of gears 34 of the balancer 30, and is formed integrally or separately. Is provided with a throttle 38 for adjusting the amount of oil passing therethrough. On the other hand, the housing 32 of the balancer 30 is integrally or separately formed with an oil return passage 40 that returns oil from the bottom to the main oil pan 24.

  Further, in the present embodiment, a centrifugal bubble separator 42 is provided in the main oil pan 24, and its inlet is opened into oil stored via a strainer (not shown), and its outlet is It is connected to an oil pump 46 through a communication pipe 44. The oil pump 46 is driven by the crankshaft 18 and supplies oil to an oil supply passage (not shown) formed in the cylinder block 12 via an oil filter (not shown). The oil flows through the cylinder block 12, and a part of the oil is supplied to the crankshaft 18, the piston 16, and the like. The other oil passes through the cylinder block 12 and is then supplied to the camshaft and the like of the cylinder head 14.

  Next, the operation and effect of the lubricating device according to the present embodiment configured as described above will be described with reference to the graphs of FIGS. 2 (a) and 2 (b).

  When the engine 10 is operated, the oil in the main oil pan 24 is sucked through the bubble separator 42 by the operation of the oil pump 46 and supplied to the oil supply passage. A part of this oil passes through an oil passage in the cylinder block 12 and is supplied to a lubricating part of a moving part such as the piston 16 and the crankshaft 18. A part of the oil is guided to a path in the cylinder head 14 and supplied to a lubricating part or a hydraulic operating part of a moving part such as a camshaft. Then, the oil that has passed through these lubrication portions and the like flows down through the return passage, and is received and collected by the sub oil pan 28. Thereafter, the oil is guided from the bottom of the auxiliary oil pan 28 to the meshing portion of the pair of gears 34 in the housing 32 of the balancer 30 through the oil introduction passage 36. The oil is stirred at the meshing portion of the pair of gears 34 and then returned from the bottom of the housing 32 to the main oil pan 24 through the oil return passage 40 and again by the oil pump 46 through the bubble separator 42. Sucked. Oil circulates in the engine 10 through such a path.

  At this time, a small amount of oil circulates in the engine 10 when the engine 10 is running at a low speed, but the capacity of the sub oil pan 28 is set to be substantially equal to the small amount of oil. The total amount of the oil circulating in 10 is once recovered in the auxiliary oil pan 28 and guided to the meshing portion of the pair of gears 34 in the housing 32 of the balancer 30.

  On the other hand, since a large amount of oil circulates in the engine 10 when the engine 10 rotates at a high speed, a part of the oil is once recovered in the auxiliary oil pan 28 as described above and exceeds the recovered amount of the auxiliary oil pan 28. That portion overflows from the sub oil pan 28 and falls to the main oil pan 24.

  Therefore, the oil collected in the auxiliary oil pan 28 and guided to the meshing portion of the pair of gears 34 in the housing 32 of the balancer 30 is actively agitated by the meshing of the gear, and bubbles with a large particle diameter are formed. In the case of the mixed oil, it is partially defoamed and the bubbles are subdivided into small particle diameters and returned to the main oil pan 24 via the oil return passage 40. Then, the oil in the main oil pan 24 in which the bubbles are subdivided into small particle diameters is supplied by the oil pump 44 to each part of the engine lubrication unit via the bubble separator 42.

  Here, the relationship between the engine speed and the particle size of the bubbles in the oil when the oil pump 44 is driven by the crankshaft 18 is shown in the graph of FIG. A dotted line A in this graph is a case of a conventional lubrication apparatus that does not use the present invention, and shows that the particle diameter of bubbles in oil increases on the low rotation side where the rotation speed of the engine 10 is low. On the other hand, when the lubricating device of the present invention is used, as described above, on the low-speed rotation side of the engine, the entire amount of oil circulating in the engine 10 is once recovered in the auxiliary oil pan 28 and the balancer 30 Since the particle size is subdivided by being agitated by the meshing portions of the pair of gears 34, as shown by the solid line B, the particle size of the bubbles in the oil becomes small. Accordingly, the particle diameter of the bubbles in the oil is reduced as a whole in the entire engine speed range.

  Further, the relationship between the engine speed and the hydraulic pressure discharged from the oil pump 46 is shown in the graph of FIG. Similarly, a dotted line A in this graph is a case of a conventional lubrication apparatus that does not use the present invention, and the oil-in-air bubbles have a large particle size on the low rotation side where the engine 10 has a low rotation speed, and hydraulic hunting occurs. Show. On the other hand, when the lubrication apparatus of the present invention is used, as described above, since the bubble particle size is subdivided and sufficiently defoamed in the bubble separator 42, as shown by the solid line B, Occurrence of hydraulic hunting is suppressed.

  In the present embodiment, the oil introduction passage 36 is provided with a throttle 38 for adjusting the amount of oil guided to the meshing portion of the pair of gears of the balancer 30. Therefore, even if there is a fluctuation in the amount of oil circulation due to a fluctuation in the rotation speed of the engine 10 and thus the rotation of the oil pump 46, the amount of oil guided to the meshing portion of the pair of gears is adjusted to be substantially constant. It is possible to efficiently perform the bubble subdividing action when the oil is stirred by the meshing of the gears.

  Further, since the capacity of the sub oil pan 28 is set to be substantially equal to the oil circulation amount when the engine 10 is at a low rotation, the oil supply amount and the oil circulation amount at the time of a high rotation of the engine 10 are large. If it increases, the recovery amount of the secondary oil pan 28 is exceeded, and the secondary oil pan 28 overflows and falls to the main oil pan. Accordingly, it is possible to prevent an increase in the bubble mixing rate due to excessive stirring of the oil due to the meshing of the gears.

It is a cross-sectional schematic diagram which shows one Embodiment of this invention. (A) is a graph which shows the relationship between an engine speed and the particle size of the bubble in oil, (b) is a graph which shows the relationship between an engine speed and the hydraulic pressure discharged from an oil pump.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine 12 Cylinder block 14 Cylinder head 16 Piston 22 Crankcase 24 Main oil pan 26 Crank chamber 28 Sub oil pan 30 Balancer 34 A pair of gears 36 Oil introduction path 38 Restriction 40 Oil return path 42 Bubble separator 46 Oil pump

Claims (3)

A main oil pan attached to the lower surface of the engine crankcase;
An oil pump for supplying the oil in the main oil pan to each part of the lubricating part of the engine via a bubble separator;
A sub-oil pan smaller than the capacity of the main oil pan and disposed in the crank chamber of the engine;
A balancer disposed below the auxiliary oil pan, the balancer comprising a pair of balancer shafts and a pair of gears respectively coupled to the balancer shafts and meshing with each other;
An oil introduction passage for guiding oil from the sub oil pan to the meshing portion of the pair of gears of the balancer;
An oil return passage for returning oil from the meshing portions of the pair of gears to the main oil pan;
An engine lubrication device comprising:   2. The engine lubrication device according to claim 1, wherein the oil introduction passage is provided with a throttle for adjusting an amount of oil guided to the meshing portion of the pair of gears.   3. The engine lubrication device according to claim 1, wherein a capacity of the sub oil pan is set to be substantially equal to an amount of oil circulated to the engine when the engine is rotating at a low speed. 4.

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