JP2010281278A - Lubricating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the sliding stability at a sliding location between various kinds of members of a lubricating device applied to an operation machine, such as, engine. <P>SOLUTION: The lubricating device includes a particle substance S added to lubricating oil, and sectioned grooves 56 formed in a sliding surface 55 for supplying the lubricating oil. Each of the grooves 56 for holding the particle substance S is wider than the outline dimension of a part of the particle substance S, deeper or shallower than the outline dimension of the particle substance S. The surface of the particle substance S is, preferably, porous. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a lubricating device applied to a working machine such as an engine.

  In an operating machine such as an internal combustion engine, for example, by using a lubricating oil, the sliding state of sliding portions between various members is kept good. In particular, internal combustion engines are required to maintain a better sliding environment between various members in accordance with recent demands for higher performance and higher output.

  Patent Document 1 discloses that a bearing effect is provided between an engine piston and a cylinder by adding a non-dissolvable, heat-resistant spherical or nearly spherical substance to engine oil from 0.1 to 30 microns. Disclose it.

  Patent Document 2 discloses the use of a lubricant composition containing a) a lubricious organic material, b) inorganic particles, and c) a silicon compound or an organometallic compound so as to reduce the friction coefficient. According to the description in Patent Document 2, for example, the inorganic particles are preferably true spherical silica particles obtained by reacting metal silicon and oxygen, and the inorganic particles have a particle size of 0.01 to 3 μm is preferred.

JP-A-8-20791 JP 2005-325305 A JP 2005-89218 A

  By the way, the thickness of the oil film at the sliding portion between the various members varies depending on the state of the working machine. And when the thickness of an oil film is thinner than predetermined thickness, it is difficult to supply the said spherical substance and particle | grains stably to such a location. Therefore, there is a limit to improving the lubrication performance by adding the spherical substances and particles to the lubricating oil.

  Therefore, the present invention has been made in view of the above points, and an object thereof is to more stably improve sliding at various sliding positions between various members.

  The lubrication apparatus according to the present invention includes a particulate material added to the lubricating oil and a groove formed on a sliding surface to which the lubricating oil can be supplied, the particulate material being capable of holding the particulate material. It is characterized by having a groove larger than a part of the outer shape.

  Preferably, the surface portion of the particulate material is porous.

  The groove may have a depth shallower than the diameter of the particulate matter and a width larger than the diameter of the particulate matter, or a depth deeper than the diameter of the particulate matter, and the particulate matter It can have a width greater than the diameter.

It is a figure for demonstrating the lubricating device of 1st Embodiment based on this invention applied to the internal combustion engine. 1 is a conceptual cross-sectional view around a cylinder block and a crankcase of an internal combustion engine to which a lubricating device according to a first embodiment of the present invention is applied. FIG. 3 is a schematic sectional view of a part of a sliding portion between a piston and a cylinder in FIG. 2. It is a conceptual diagram of a block-on-ring friction tester. It is a graph which shows the experimental result as an example. It is a cross-sectional schematic diagram of a part of a sliding portion between a piston and a cylinder of an internal combustion engine to which a lubricating device according to a second embodiment of the present invention is applied.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the accompanying drawings. First, the first embodiment will be described.

  The lubricating device 10 according to the first embodiment of the present invention is applied to an internal combustion engine. Although not shown, in an internal combustion engine, as is known, an air-fuel mixture of air introduced from an intake system and fuel injected from a fuel injection valve is burned in a combustion chamber, and a piston is reciprocated in a cylinder. Rotate the crankshaft. The exhaust gas generated by the combustion of the air-fuel mixture in the combustion chamber is discharged through an exhaust system (not shown).

  Here, FIG. 1 conceptually shows the main flow of the lubricating oil (oil) in the lubricating device 10 applied to the internal combustion engine. The internal combustion engine includes a lubricating device 10 for reducing friction and wear at a sliding portion between various members of the internal combustion engine. The lubricating device 10 is configured to supply oil to these sliding portions. The internal combustion engine lubrication device 10 includes an oil strainer 14, an oil pump 16, and an oil filter 18. An oil strainer 14 is disposed in the oil stored in the oil pan 20, and an oil pump 16 is connected to the oil strainer 14. Then, relatively large foreign matter is removed from the oil stored in the oil pan 20 by the oil strainer 14, and the oil from which the oil has been removed is sucked up by the oil pump 16 and pumped from the oil pump 16 to the oil filter 18. Then, after relatively small foreign matter is removed by the oil filter 18, the oil is distributed through the main oil hole 22 to the sliding portions which are the bearing portions and sliding portions inside the internal combustion engine 12. Lubrication and cooling are achieved.

  For example, the oil guided to the cylinder head 24 is supplied to the chain tensioner plunger 25 and the camshaft journal 26. In addition, oil is supplied to the chain 30 via the oil jet 28. Further, oil is supplied to the crankshaft journal 32, and further, oil is supplied to the piston 38 via the crankpin 34 and the oil jet 36. And the oil supplied to each bearing part and sliding part of the internal combustion engine 12 returns to the oil pan 20 by natural fall or the like. For example, the oil pumped to the cylinder head 24 passes through an oil return hole or a chain cover set in the cylinder head 24 and is returned to the oil pan 20. Such an oil flow is only an example. In the lubricating device according to the present invention, various oil flows are allowed, and therefore various configurations can be provided.

  Here, as schematically shown in FIG. 2, an oil jet hole 44 as an oil jet 36 is provided in the large end portion 42 of the connecting rod 40. The oil jet 36 can inject oil 48 into the cylinder 46. Thereby, the oil 48 is supplied to the back surface side of the piston 38 (the side opposite to the top surface of the piston 36 facing the combustion chamber). The oil supplied to the back surface side of the piston 38 reaches the inner wall surface (cylinder bore wall or cylinder liner) 52 of the cylinder 46 of the cylinder block 50, and the reciprocating motion of the piston 38 in the cylinder 46 leads to the inner wall surface 52 of the cylinder 46. It is guided (supplied) between the pistons 38 and exerts a lubricating and cooling effect between them. The oil jet 36 may be provided in the cylinder block 50.

  FIG. 3 is an enlarged schematic cross-sectional view of a contact portion (sliding portion) between the inner wall surface 52 of the cylinder 46 and the skirt portion 54 of the piston 38 in the region surrounded by the circle C in FIG. A plurality of grooves 56 are provided on the outer surface 55 of the skirt portion 54 of the piston 38. The groove 56 can be formed by machining. For example, the groove 56 is formed by laser processing.

  Incidentally, a plurality of particulate substances S are added to the oil used in the lubricating device 10. The addition (mixing) of the particulate matter S to the oil may be performed before or after the oil is added to the lubricating device 10, or may be performed simultaneously with the injection of the oil into the lubricating device 10. Here, the particulate matter S is added to the oil by being put into the lubricating device 10 at the same time as the injection of the oil into the lubricating device 10.

  Here, the particulate matter S is spherical silica (silica) having a plurality of meso-sized pores (mesopores). Spherical silica having such mesopores is disclosed in Patent Document 3, for example. The spherical silica having mesopores is in a monodispersed state in which the particles are not aggregated. Moreover, the particulate matter S according to the first embodiment, which is such a silica, has mesopores having a number and size such that 40 to 60% of the total volume becomes a hollow space. So it is entirely porous. Therefore, the spherical silica having such mesopores can be referred to as monodispersed mesoporous silica (MMSS). However, the particulate matter S may be partially porous as long as a part thereof, particularly the surface portion thereof, is porous. The particulate matter S is not limited to the spherical silica having such mesopores, and may be other particulate matter such as other silica particles, and is chemically and thermally stable to oil. Yes, good physical strength.

  Each of the plurality of particulate substances S is generally spherical. And the variation in the particle size between these particulate substances is minimized, and the average particle size is about 600 nm. Preferably, the average particle diameter of the plurality of particulate substances S is 600 nm or more and 3000 nm or less. However, even the smallest of the particulate substances S used should have a diameter larger than 400 nm. This is for suppressing aggregation of the plurality of particulate substances S. The “spherical shape” is not limited to a true sphere, and includes a substantially sphere whose minimum diameter is 80% or more of the maximum diameter. However, although the non-spherical particulate matter is not used as the particulate matter of the first embodiment, in the present invention, for example, a non-spherical particulate matter may be used as the particulate matter.

  Since such particulate matter S is porous as described above, oil can be held in the pores of the particulate matter S. Therefore, when there is abundant oil around, each particulate matter S can act as an oil absorbing material that absorbs and holds oil inside. On the other hand, when there is no or little oil around, each particulate matter S can act as an oil supply source that supplies oil to the surroundings. Silica is hard, excellent in heat resistance, and chemically stable against oil. Therefore, even if the silica as the particulate matter S is supplied together with oil to various parts of the internal combustion engine, it does not hinder various functions of the oil.

  As described above, the outer surface 55 of the skirt portion 54 of the piston 38 in FIG. Each of the grooves 56 is a groove larger than a part of the outer shape of the particulate matter S so that the particulate matter S can be held. That is, each of the grooves 56 is formed to have an opening larger than a part of the outer shape of the particulate matter S. Specifically, each of the grooves 56 is designed to have a depth D shallower than the diameter of the particulate matter S and a width (minimum opening width) W larger than the diameter of the particulate matter S. . Accordingly, when the oil is supplied between the piston 38 and the cylinder 46 as described above, when the particulate matter S is supplied between them, some of the particulate matter S enters the groove 56. I can get in. However, the depth D is longer than half the diameter of the particulate matter S. However, since each of the grooves 56 has a depth shallower than the diameter of the particulate matter S, a part of the particulate matter S in the groove 56 protrudes to the outside of the groove 56. Therefore, when the particulate matter S is present in the groove 56 at the sliding portion between the inner wall surface 52 of the cylinder 46 and the skirt portion 54 of the piston 38, the particulate matter S can move between them. That is, when the particulate matter S itself rotates, the particulate matter S exhibits a bearing effect and functions as a lubricant. Since the piston 38 reciprocates in the cylinder 46 with respect to the cylinder 46 as indicated by the white arrow in FIG. 3, the rotational direction of the particulate matter S in the groove 56 changes according to the movement of the piston 38. .

  The particulate matter S that can enter the groove 56 in this way is caused by the reciprocating motion of the piston 38 and is discharged from the groove 56 together with the oil or sequentially to the supplied oil. The oil pan 20 can be returned. Therefore, the particulate matter S can circulate in the internal combustion engine as well as the oil, and can remain in the groove 56. The particulate matter S can pass through the oil strainer 14 and the oil filter 18.

  Furthermore, as described above, the particulate matter S can exhibit a function of absorbing oil or discharging and supplying oil. Therefore, when the particulate matter S stays (is held) or enters / exits in the groove 56, there is oil at the sliding portion between the inner wall surface 52 of the cylinder 46 and the skirt portion 54 of the piston 38. The state is always reasonably preferably maintained. Therefore, the lubrication state of the sliding portion between the inner wall surface 52 of the cylinder 46 and the skirt portion 54 of the piston 38 can be maintained well.

  Thus, the size of the particulate matter S is such that the particulate matter S added to the oil can be held on the outer surface 55 which is a sliding surface (the surface of two or more sliding members) capable of supplying oil. By providing the grooves 56 formed on the basis of the thickness, the sliding (sliding) of the sliding surface can be improved. Further, since the particulate matter S is made porous, the oil can be continuously supplied to the sliding portion more stably, and the slip can be further improved.

  Such a groove may be formed on the inner wall surface 52 of the cylinder 46, which is a sliding surface. Here, the sliding portion between the skirt portion 54 of the piston 38 and the inner wall surface 52 of the cylinder 46 has been described. However, the same groove is formed in the other portion, and the sliding effect of the other portion is also caused by the particulate matter. Can be demonstrated. For example, other sliding locations include the piston ring surface of the piston 38, a camshaft journal, and a crankshaft journal. However, in each sliding location, the groove may be formed in a direction that intersects the sliding direction of at least two or more members. For example, the groove may be formed so as to extend in a direction perpendicular to the sliding direction of at least two or more sliding members or in an oblique direction. The groove may be formed in a spiral shape at the sliding portion. For example, the groove 56 may be formed around the piston 38 in a spiral shape.

Here, as described above, the change in the sliding state between the members due to the addition of spherical silica having mesopores as the particulate matter S to the oil was confirmed by experiments, and the result will be described. An experiment was conducted using a block-on-ring friction tester 60 conceptually shown in FIG. In this testing machine 60, a ring test piece 64 having a substantially lower half immersed in a test oil 62 that is a mixed oil of oil and silica was rotated. Then, the ring test piece 62 was brought into contact with the block test piece 66 to which a load L was applied and slid between the block test piece 66. And the friction between them was evaluated. However, an oil having a kinematic viscosity of 4.2 mm ² / s was used as the oil, and 1% by weight of silica was contained in the oil. Further, SCM carburized steel having a surface roughness of 0.1 μm Rz JIS was used as the block test piece 66, and carburized steel having a surface roughness of 0.5 μm Rz JIS was used as the ring test piece 64. The temperature of the test oil 62 was set to 80 ° C.

  Then, test oil 1 to which silica was not added, test oil 2 to which silica having an average particle diameter of 610 nm was added, and test oil 3 to which silica having an average particle diameter of 270 nm was added were used as test oils 62, respectively. The experiment was conducted. The experimental results show that the horizontal axis represents the sliding speed (mm / s) of the block test piece 66, and the vertical axis represents the friction coefficient (μ) between the block test piece 66 and the ring test piece 64. This is shown in the graph of FIG.

  As apparent from FIG. 5, at any sliding speed, the friction coefficient when the test oil 2 to which silica having an average particle diameter of 610 nm was added was used as the test oil 62 was lower than the friction coefficient in other cases. This is considered to be because, as described above, oil is continuously supplied to the sliding surfaces, which are the sliding portions, by silica as described above. Another reason is that in the test oil 2 to which silica having an average particle diameter of 270 nm was added, the silica was small in size, so that silica agglomeration occurred in part.

  From this result, it can be understood that the average particle diameter of the silica is good enough to prevent the silica from agglomerating, and good enough to continuously supply moderate oil to the sliding part. From this point, as described above, the average particle diameter of the plurality of particulate substances S is preferably 600 nm or more and 3000 nm or less.

  Next, a second embodiment of the lubricating device according to the present invention will be described. In the second embodiment, the depth of the groove is deeper than the diameter of the particulate matter. In the second embodiment, two kinds of particulate substances S1 and S2 having different average particle diameters are added to the oil. Except for these points, the lubricating device of the second embodiment generally has the same configuration as the lubricating device 10 of the first embodiment. Therefore, in the following, those differences will be mainly described, and the same or similar components are denoted by the same or similar reference numerals as used above, and description thereof will be omitted. Note that the modification described with respect to the first embodiment can also be applied to the second embodiment, and the same effects as the first embodiment can also be exhibited in the second embodiment.

  In the second embodiment, as shown in FIG. 6, the particulate material S1 having approximately the same average particle size as the particulate material S, and an average particle larger than the average particle size of the particulate material S1. Particulate matter S2 having a diameter can be mixed with oil and circulated in the internal combustion engine. And the groove | channel 156 is designed so that it may have a depth deeper than the diameter of the large-diameter particulate matter S2, and a width larger than the diameter of the particulate matter S2. Therefore, both the particulate substances S1 and S2 can enter the groove 156.

  The size and shape of the groove 156 is such that at least the particulate matter S2 is applied to the sliding portion even if the oil film thickness at the sliding portion is reduced due to the state of the internal combustion engine, for example, the fluctuation of the engine rotation speed or the engine load. It should be designed so that it can be held.

  Two kinds of particulate matter can enter the groove 156 of the sliding surface 55, but some of the plurality of other grooves (not shown) are partitioned so that only the particulate matter S2 can enter. Is formed. Therefore, the groove can be designed according to the gap between at least two members of the sliding portion. In addition, three or more types of particulate substances having different average particle diameters may be added to the oil.

  As described above, the present invention has been described based on the above-described two embodiments and modifications thereof. However, the present invention is not limited to these embodiments and the like, and other embodiments are allowed. The present invention includes all modifications, applications, and equivalents included in the spirit of the present invention defined by the claims. Therefore, the present invention should not be construed as being limited, and can be applied to any other technique belonging to the scope of the idea of the present invention.

DESCRIPTION OF SYMBOLS 10 Lubricator 14 Oil strainer 16 Oil pump 18 Oil filter 20 Oil pan 22 Main oil hole 24 Cylinder head 26 Camshaft journal 28 Oil jet 30 Chain 32 Crankshaft journal 34 Crankpin 36 Oil jet 38 Piston 40 Connecting rod 42 Large end 44 Oil jet hole 48 Oil 50 Cylinder block 52 Inner wall surface 54 Piston 55 Outer surface 56, 156 Groove S, S1, S2 Particulate matter

Claims (4)

Particulate matter added to the lubricating oil;
Lubrication comprising a groove formed on a sliding surface to which the lubricating oil can be supplied, the groove being larger than a part of the outer shape of the particulate material so as to hold the particulate material. apparatus.   The lubricating device according to claim 1, wherein a surface portion of the particulate matter is porous.   The lubricating device according to claim 1, wherein the groove has a depth shallower than a diameter of the particulate matter and a width larger than a diameter of the particulate matter.   The lubricating device according to claim 1, wherein the groove has a depth deeper than a diameter of the particulate matter and a width larger than a diameter of the particulate matter.

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