JP2007023846A - Chain lubricating mechanism for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a chain lubricating mechanism making working man-hour unnecessary and reducing cost in smoothly lubricating a timing chain with effectively using a member arranged closely to an intake cam sprocket of a DOHC type serial internal combustion engine. <P>SOLUTION: An oil passage is provided inside of an intake rocker shaft 51 and a one shaft end of the intake rocker shaft is extended to a neighborhood of the timing chain 24 and locus of the timing chain 24 is positioned on an extended line thereof. Oil flowing out of the one shaft end of the intake rocker shaft is supplied to the timing chain at a terminal side section of a meshing part with the intake cam sprocket. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a chain oil supply mechanism that supplies lubricating oil to a chain that drives a camshaft of an internal combustion engine.

  Generally, in an oil supply mechanism that supplies lubricating oil to a chain wound between a cam sprocket and a crank sprocket of an internal combustion engine, the lubricating oil is supplied to the chain by an oil jet provided in the vicinity of the crank sprocket. To lubricate.

  By the way, in an OHC (overhead camshaft) type internal combustion engine, there is a large level difference between the crank sprocket and the cam sprocket, so the lubricating oil supplied to the chain by an oil jet near the crank sprocket. Falls into the oil pan as it is, or is blown off with a small curvature of the crank sprocket, and the lack of lubricating oil in the chain near the cam sprocket cannot be denied. Therefore, due to poor lubrication of the chain, pins and link plates are worn and deformed, causing the chain to stretch, causing valve timing deviations and the like, leading to performance degradation of the internal combustion engine, and increasing meshing noise with the cam sprocket There is a fear.

Therefore, conventionally, a part of the lubricating oil supplied to the sliding portion between the journal portion of the camshaft and the bearing portion is introduced into the oil jet through the lubricating oil passage, and this oil jet causes the chain near the cam sprocket to be introduced. The chain is lubricated smoothly by supplying lubricating oil so that the lubricating oil supplied in the vicinity of the upper cam sprocket is also guided to the vicinity of the lower crank sprocket with a difference in height. Is known (see, for example, Patent Document 1).
JP 2001-27109 A

  However, in the above conventional one, a part of the lubricating oil supplied to the sliding portion between the journal portion of the camshaft and the bearing portion is guided to the oil jet, and a lubricating oil passage is separately formed in the camshaft housing. In such a case, a new lubricating oil passage is formed as described above, which requires processing steps and is disadvantageous in terms of cost.

  The present invention has been made in view of such a point, and the purpose thereof is to effectively utilize a member disposed in the vicinity of a cam sprocket of an OHC type internal combustion engine and smoothly lubricate the chain. An object of the present invention is to provide a chain oil supply mechanism for an internal combustion engine that can reduce the cost while reducing the number of processing steps.

  In order to achieve the above object, in the present invention, in an OHC type internal combustion engine in which a camshaft is driven by a chain and a rocker arm is rotated around the axis of the rocker shaft by a cam on the camshaft, On the premise of a chain oil supply mechanism that supplies lubricating oil, a lubricating oil passage is provided inside the rocker shaft. The locus of the chain is positioned on the extended line at the tip of the rocker shaft so that the lubricating oil flowing out from the lubricating oil passage is supplied to the chain.

Due to this specific matter, the lubricating oil flows out to the locus of the chain located on the extension line at the tip of the rocker shaft through the lubricating oil passage inside the rocker shaft arranged in the vicinity of the cam sprocket. Lubricating oil can be smoothly supplied to the chain near the cam sprocket through the rocker shaft with a cost-effective configuration that does not require processing steps like a new oil passage formed in the camshaft housing. It becomes possible.

  Here, when the portion where the extension line of the tip of the rocker shaft intersects the locus of the chain is a meshing portion with the cam sprocket that meshes with the chain, even if the lubricating oil that has flowed out of the rocker shaft hits the chain and scatters, The scattered lubricating oil is caught by the cam sprocket and further entangled with the chain, so that the lubricating oil can be smoothly supplied to the chain near the cam sprocket.

  Further, in order to achieve the above object, as another solution means, similarly, on the premise of a chain oil supply mechanism in an OHC type internal combustion engine, a lubricating oil passage is provided inside the rocker shaft. And the nozzle which injects the lubricating oil from the said lubricating oil channel | path toward a chain, and is supplied to the front-end | tip of the said rocker shaft is provided.

  Due to this specific matter, the lubricating oil is injected and supplied to the chain by the nozzle at the tip of the rocker shaft through the lubricating oil passage inside the rocker shaft arranged in the vicinity of the cam sprocket. Lubricating oil can be smoothly supplied to the chain in the vicinity of the cam sprocket through the rocker shaft with a configuration that is inexpensive and does not require processing steps as is newly formed in the shaft housing. In addition, the direction and amount of lubricating oil can be easily adjusted by the nozzle, and it is possible to provide a highly flexible oiling mechanism.

  Here, when lubricating oil from the nozzle is injected and supplied toward the meshing portion with the cam sprocket that meshes with the chain, the tip of the rocker shaft is directed toward the meshing portion between the chain and the cam sprocket. Even if the lubricated lubricating oil hits the chain and scatters, the scattered lubricating oil is caught by the cam sprocket and further entangled with the chain, making it possible to smoothly lubricate the chain near the cam sprocket. .

  In particular, the following configurations are listed as specifying the traveling direction of the chain.

  That is, the chain is advanced substantially downward from the portion where the lubricating oil is supplied from the lubricating oil passage.

  Because of this specific matter, the chain supplied with lubricating oil in the vicinity of the cam sprocket travels substantially downward along with the supplied lubricating oil, so there is a lot of opportunity for the lubricating oil to adhere to the chain and there is no waste oil supply mechanism. It can be configured.

  In addition, the lubricating oil is sufficiently entangled with the chain until it is transported along with the chain to the lower crank sprocket side and blown off with a small curvature of the crank sprocket, so that lubrication is further promoted in the vicinity of the crank sprocket. It is possible to make it easy to secure the oil pressure of the lubricating oil by eliminating the need to supply the lubricating oil by an oil jet, and to reduce the chance of mixing the lubricating oil and blow-by gas in the vicinity of the crank sprocket. It becomes possible to suppress deterioration of oil effectively.

Furthermore, a chain guide for guiding the chain is provided between the portion of the chain wound between the cam sprocket and the crank sprocket and the portion where the lubricating oil is supplied from the lubricating oil passage to the meshing portion with the crank sprocket. In this case, the lubricating oil supplied to the chain in the vicinity of the cam sprocket is guided to the chain guide before being guided to the lower crank sprocket, and contributes to lubrication with the guide shoe of the chain guide. Thus, it is possible to effectively suppress the generation of noise and wear.

  In short, by positioning the chain locus on the extension line of the rocker shaft tip near the cam sprocket and supplying the lubricating oil flowing out from the lubricating oil passage to the chain, it is inexpensive without forming a new lubricating oil passage. With this configuration, lubricating oil can be smoothly supplied to the chain near the cam sprocket through the rocker shaft.

  The best mode for carrying out the present invention will be described below in detail with reference to the drawings.

  FIG. 1 shows a DOHC type in-line internal combustion engine E to which a chain oil supply mechanism according to Embodiment 1 of the present invention is applied. Reference numeral 1 denotes a cylinder block of the in-line internal combustion engine E. The head 11 is fixed, and an oil pan 13 is attached to the lower portion via a crankcase 12.

  The cylinder head 11 is provided with an intake camshaft 14 and an exhaust camshaft 15 as camshafts. Further, as shown in FIG. 2, a crankshaft 16 is disposed in the crankcase 12. The camshafts 14 and 15 are rotationally driven by the crankshaft 16. Such a camshaft drive mechanism 2 will be described in detail below.

  The camshaft drive mechanism 2 rotates integrally with a first crank sprocket 21 serving as a crank sprocket connected to the one shaft end side of the crankshaft 16 so as to rotate integrally with one shaft end of the intake camshaft 14 of the cylinder head 11. An intake cam sprocket 22 (appearing in FIG. 1) as a connected cam sprocket, and an exhaust cam sprocket 23 (appearing in FIG. 1) connected to one end of the exhaust camshaft 15 of the cylinder head 11 in a rotationally integrated manner. ) And a timing chain 24 as a chain that is wound around the first crank sprocket 21 and the cam sprockets 22 and 23, and the cam sprockets 22 and 23 are driven to rotate by the driving rotation of the first crank sprocket 21. Yes. In this case, since the intake and exhaust camshafts 14 and 15 are arranged in the cylinder head 11 at the upper part of the cylinder block 1 and the crankshaft 16 is arranged in the crankcase 12 at the lower part of the cylinder block 1, the first crank sprocket 21 is arranged. There is a large difference in height between the intake and exhaust cam sprockets 22,23.

An oil pump drive mechanism 3 that rotates the oil pump 32 by the crankshaft 16 is provided below the camshaft drive mechanism 2. The oil pump drive mechanism 3 includes a second crank sprocket 31 that is rotatably connected to the crankcase 12 side (right side in FIG. 2) of the crankshaft 16 from the first crank sprocket 21, and one shaft end of the oil pump 32. An oil pump sprocket 32 a that is integrally connected to the oil pump, and an oil pump drive chain that is wound around the second crank sprocket 31 and the oil pump sprocket 32 a and that rotates the oil pump sprocket 32 a by the driving rotation of the second crank sprocket 31. 33. The camshaft drive mechanism 2 and the oil pump drive mechanism 3 are externally attached by a timing chain cover 4 made of an aluminum alloy attached on the front side (one shaft end side) of the cylinder head 11, the cylinder block 1 and the crankcase 12. It is covered and housed from the side.

  Between the first crank sprocket 21 and the exhaust cam sprocket 23, a chain tensioner device 25 that adjusts the tension of the timing chain 24 at the stretched portion of the timing chain 24 located between the sprockets 21 and 23. Is provided. On the other hand, a chain provided between the intake cam sprocket 22 and the first crank sprocket 21 is provided with a guide shoe 26a that is slidably in contact with the stretched portion of the timing chain 24 located between the two sprockets 22 and 21. A guide 26 is provided. In this case, one shaft end of the crankshaft 16 protrudes outward from the timing chain cover 4, and a crank pulley 41 is connected to the one shaft end of the crankshaft 16 so as to rotate together.

  Further, as shown in FIG. 3, the cylinder head 11 is provided with an intake rocker shaft 51 and an exhaust rocker shaft (not shown). A rocker arm (not shown) is rotatably supported on each rocker shaft 51, and the rocker arm is rotated around the axis of the rocker shaft 51 by a cam (not shown) on each camshaft 14, 15. By moving them, an intake valve and an exhaust valve (not shown) are opened and closed.

  As shown in FIG. 4, an oil passage 52 (lubricating oil passage) is provided in the intake rocker shaft 51, and the oil pump 32 of the oil pump drive mechanism 3 is provided in the oil passage 52. A part of the oil (lubricating oil) pumped by the rotational drive is supplied. One shaft end of the intake rocker shaft 51 (downstream end of the oil passage 52) extends to the vicinity of the timing chain 24, and the locus of the timing chain 24 is located on the extended line. Then, the oil in the oil passage 52 that has flowed out from the one shaft end of the intake rocker shaft 51 is an intake air where the extension line of one shaft end (tip) of the intake rocker shaft 51 and the locus of the timing chain 24 intersect. The timing chain 24 is refueled at the end portion of the meshing portion with the cam sprocket 22. In this case, the timing chain 24 travels substantially downward from a portion where oil is supplied from the oil passage 52 (end portion of the meshing portion with the intake cam sprocket 22).

  Therefore, in the first embodiment, the oil from one shaft end (the downstream end of the oil passage 52) of the intake rocker shaft 51 is supplied to the oil passage 52 inside the intake rocker shaft 51 disposed in the vicinity of the intake cam sprocket 22. The oil flows out into the timing chain 24 at the locus of the timing chain 24 located on the extension line of the intake rocker shaft 51, that is, the end side portion of the meshing portion with the intake cam sprocket 22, and is supplied with oil. The construction of the meshing portion between the timing chain 24 and the intake cam sprocket 22 through the intake rocker shaft 51 with a low cost configuration without requiring processing steps as in the case where a passage is newly formed in the camshaft housing. Oil can be smoothly supplied to the end portion.

  In addition, when oil is supplied to the end side portion of the meshing portion between the timing chain 24 and the intake cam sprocket 22, even if the oil that has flowed out of the intake rocker shaft 51 hits the timing chain 24 and is scattered, the oil is scattered. The oil is caught by the intake cam sprocket 22 and further entangled with the timing chain 24, which is very advantageous in smoothly supplying lubricating oil to the timing chain in the vicinity of the intake cam sprocket 22.

Further, since the timing chain 24 advances substantially downward from a portion where oil is supplied from the oil passage 52 (a portion on the end side of the meshing portion with the intake cam sprocket 22), the vicinity of the intake cam sprocket 22 Since the timing chain 24 supplied with the oil advances substantially downward together with the supplied oil, there is a great opportunity for the oil to adhere to the timing chain 24, so that an oil supply mechanism can be configured without waste.

  The oil is sufficiently entangled with the timing chain 24 until the oil is transported together with the timing chain 24 to the lower first crank sprocket 21 side and blown off with a small curvature of the first crank sprocket 21, thereby further promoting lubrication. Therefore, oil supply by an oil jet in the vicinity of the first crank sprocket 21 is not required, and it is possible to easily secure the oil pressure of the oil, and the oil and blow-by gas in the vicinity of the first crank sprocket 21. Oil deterioration can be effectively suppressed by reducing the chance of mixing with oil.

  Further, a chain guide 26 is provided between the end portion of the meshing portion with the intake cam sprocket 22 and the meshing portion with the first crank sprocket 21 to guide the stretched portion of the timing chain 24 positioned therebetween. Therefore, the oil supplied to the timing chain 24 at the end portion of the meshing portion with the intake cam sprocket 22 is guided to the chain guide 26 until it is guided to the first crank sprocket 21 below. This contributes to the lubrication of the chain guide 26 with the guide shoe 26a, and the lubrication with the guide shoe 26a is promoted to effectively suppress the generation of noise and wear.

  Next, a second embodiment of the present invention will be described with reference to FIG.

  In this embodiment, the structure of the tip of the rocker shaft is changed. The rest of the configuration excluding the tip of the rocker shaft is the same as that of the first embodiment, and the same parts are denoted by the same reference numerals and detailed description thereof is omitted.

  That is, in this embodiment, as shown in FIG. 5, the oil from the oil passage 52 is injected at high speed toward the timing chain 24 at one shaft end (tip) of the intake rocker shaft 51 to supply the oil. A hollow nozzle 6 (nozzle) having a reduced inner diameter is press-fitted and attached by brazing. The oil from the hollow nozzle 6 is jetted in a concentrated manner toward the end portion of the meshing portion between the timing chain 24 and the intake cam sprocket 22 and supplied.

  Therefore, in the second embodiment, the oil is supplied to the timing chain 24 by the hollow nozzle 6 at the tip of the intake rocker shaft 51 via the oil passage 52 in the intake rocker shaft 51 disposed in the vicinity of the intake cam sprocket 22. And the intake cam sprocket 22 are injected and supplied with oil toward the end portion of the meshing portion, so that an oil passage is newly formed in the camshaft housing, so that it does not require processing steps and cost. With an inexpensive configuration, oil can be smoothly supplied to the timing chain 24 at the end portion of the meshing portion with the intake cam sprocket 22 through the intake rocker shaft 51. Moreover, the oil supply direction and the amount of oil can be easily adjusted by the hollow nozzle 6, and a highly flexible oil supply mechanism can be provided.

Further, oil is injected and supplied toward the end portion of the meshing portion between the timing chain 24 and the intake cam sprocket 22, whereby the timing chain 24 and the intake cam sprocket 22 are inserted from the tip of the intake rocker shaft 51. Even if the oil sprayed toward the end portion of the meshing portion hits the timing chain 24 and scatters, the scattered oil is caught by the intake cam sprocket 22 and further entangled with the timing chain 24, and the intake cam sprocket 22 This is very advantageous in smoothly supplying lubricating oil to the timing chain in the vicinity.

  In addition, this invention is not limited to said each Example, The other various modifications are included. For example, in each of the above embodiments, the oil passage 52 is provided in the intake rocker shaft 51. However, an oil passage may be provided also in the exhaust rocker shaft.

  Further, in the second embodiment, oil is injected in a concentrated manner toward the end portion of the meshing portion between the timing chain 24 and the intake cam sprocket 22 by the hollow nozzle 6 at the tip of the intake rocker shaft 51 to supply the oil. However, the hollow nozzle at the tip of the intake rocker shaft may cause oil to be injected diffusively from the end side portion of the meshing portion between the timing chain and the intake cam sprocket toward the chain guide and be supplied. Of course, the oil injection from the hollow nozzle at the tip of the intake rocker shaft may be optimized in consideration of wear, noise, oil foaming property, and the like.

  Further, in each of the above embodiments, the case where the chain oil supply mechanism is applied to the DOHC type in-line internal combustion engine E has been described. However, the present invention is applied to the SOHC type in-line internal combustion engine and the SOHC type or DOHC type V-type internal combustion engine. May be.

1 is an exploded perspective view of a DOHC type in-line internal combustion engine to which a chain oil supply mechanism according to Embodiment 1 of the present invention is applied. FIG. 3 is a longitudinal side view of the vicinity of the timing chain cover of the serial internal combustion engine. It is the perspective view which looked at the timing chain of the meshing part vicinity with a cam sprocket similarly from diagonally upward. Similarly, it is the front view which looked at the timing chain near the meshing part with the cam sprocket from the front of the internal combustion engine. It is the top view which looked at the timing chain of the meshing part vicinity with the cam sprocket of the DOHC type serial internal combustion engine to which the chain oil supply mechanism concerning Example 2 of this invention is applied.

Explanation of symbols

14 Camshaft for intake (camshaft)
21 1st crank sprocket (crank sprocket)
22 Intake cam sprocket (cam sprocket)
24 Timing chain (chain)
26 Chain Guide 51 Intake Rocker Shaft (Rocker Shaft)
52 Oil passage (lubricating oil passage)
6 Hollow nozzle (nozzle)
E In-line internal combustion engine (internal combustion engine)

Claims (6)

In an OHC type internal combustion engine in which a camshaft is driven by a chain and a rocker arm is rotated about the axis of the rocker shaft by a cam on the camshaft, a lubricating oil is supplied to the chain. Because
A lubricating oil passage is provided inside the rocker shaft,
A chain oil supply mechanism for an internal combustion engine, wherein a locus of the chain is positioned on an extension line at a tip of the rocker shaft so that the lubricating oil flowing out from the lubricating oil passage is supplied to the chain. In the internal combustion engine chain oil supply mechanism according to claim 1,
A chain oil supply mechanism for an internal combustion engine, wherein a portion where the extension line of the tip of the rocker shaft and the locus of the chain intersect is a meshing portion with a cam sprocket that meshes with the chain. In an OHC type internal combustion engine in which a camshaft is driven by a chain and a rocker arm is rotated about the axis of the rocker shaft by a cam on the camshaft, a lubricating oil is supplied to the chain. Because
A lubricating oil passage is provided inside the rocker shaft,
A chain oil supply mechanism for an internal combustion engine, characterized in that a nozzle for injecting and supplying lubricating oil from the lubricating oil passage toward the chain is provided at the tip of the rocker shaft. In the chain oil supply mechanism for an internal combustion engine according to claim 3,
A chain oil supply mechanism for an internal combustion engine, wherein the lubricating oil from the nozzle is injected and supplied toward a meshing portion with a cam sprocket with which the chain meshes. In the chain oil supply mechanism for an internal combustion engine according to any one of claims 1 to 4,
A chain oil supply mechanism for an internal combustion engine, characterized in that the chain advances substantially downward from a portion where the oil is supplied from the oil passage. In the chain oil supply mechanism for an internal combustion engine according to any one of claims 1 to 5,
The chain is wound between the cam sprocket and the crank sprocket,
A chain oil supply mechanism for an internal combustion engine, characterized in that a chain guide for guiding the chain is provided between a portion where the lubricating oil is supplied from the lubricating oil passage to the chain and a meshing portion with the crank sprocket. .

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