JP2005042665A - Lubricating device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sufficiently lubricate the cam surface of a camshaft during low speed operation, and also to avoid an increase in an amount of oil retained in a head cover during high speed operation, in a lubricating device for an internal combustion engine. <P>SOLUTION: This lubricating device for the internal combustion engine is provided with the camshaft 8 having the cam surface 27 and driving a valve, an oil supply pipe 23 provided with an oil injection opening to lubricate the cam surface 27, a supply passage (in the order of 9, 10, 19 and 22) to supply oil from an oil pan 31 to the oil supply pipe 23, and a valve element 24 to completely shut off oil supply to the oil supply pipe 23 (also to the injection opening) when the supply passage becomes a set pressure or more. The lubricating device has a second supply passage (in the order of 9, 10, 12, 13, 15, 16 and 18) to supply oil from the oil pan 31 to the journal section 17 of the camshaft 8, and is designed that even when oil supply to the oil supply pipe 23 is shut off by the valve element 24, oil supply to the journal section 17 through the second supply passage is not shut off. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a configuration of a lubricating device for an internal combustion engine.

  2. Description of the Related Art Conventionally, an internal combustion engine having a configuration in which a blow-by gas reducing device is provided from a crank chamber to a air cleaner side through a head cover (for example, a rocker cover) is known.

  For example, in the configuration disclosed in Patent Document 1, as shown in FIG. 1, the lower crank chamber (14) of the crankcase (1) communicates with the rocker cover (7) through the blow-by gas passage (15). The oil separator (17), which is attached to the upper part of the rocker cover (7) and separates oil and gas, guides only blow-by gas to the air cleaner (19) through the blow-by gas hose (18). Yes.

  On the other hand, in order to lubricate the valve operating mechanism (8) provided inside the rocker cover (7), the oil from the oil pan (2) is pumped by the oil pump toward the passage (10) of the cam shaft (9). In addition, oil is supplied to the journal portion of the cam shaft (9), the cam surface of the cam (11), the sliding surface of the rocker arm (12), and the like to lubricate and cool each portion. The oil inside the rocker cover (7) is returned to the oil pan (2) by naturally falling in the oil return passage (13).

  In such an internal combustion engine, the discharge amount of the oil pump increases in proportion to the rotational speed of the internal combustion engine, but the flow rate of oil returning through the oil return passage (13) is limited. In particular, in the case of the configuration of a V-shaped engine or in circumstances such as running on a slope even in an in-line engine, the oil return passage (13) becomes slanted, and the oil return property is ensured well. Difficult to do. For this reason, especially at high speed operation, oil may accumulate in the rocker cover (7) and the oil may be ejected from the blow-by gas outlet.

This phenomenon called “oil blowing” is desired to be surely prevented because the amount of oil in the oil pan (2) decreases and causes seizure of the internal combustion engine. Patent Document 1 also points out the same problem, and in order to solve this problem, an oil amount adjustment for narrowing the oil passage when the oil supplied to the valve mechanism (8) exceeds a set hydraulic pressure during high-speed operation. The structure which provides a valve (20) is proposed.
Japanese Utility Model Publication No. 57-40613

  However, the configuration of Patent Document 1 is a configuration in which oil is pumped toward the passage (10) of the camshaft (9) to lubricate the journal portion, etc., so that the oil pump discharge rate is particularly low. Sometimes, there is little oil leaking from the journal part, leading to insufficient oil supply, and there is a risk that the cam surface of the cam shaft (9) will be insufficiently lubricated.

  In addition to the method of supplying the valve operating mechanism (8) through the passage (10) of the cam shaft (9), an oil supply pipe is provided above the cam shaft (9). A method is conceivable in which oil is pressure-fed to an oil supply pipe and oil is jetted out from an injection port provided in the oil supply pipe in a shower manner to lubricate the cam surface and the like.

  However, in the method using the oil supply pipe, a large amount of oil is likely to be ejected from the injection port during high-speed operation with a large discharge amount of the oil pump, and the oil passage is opened by the oil amount adjusting valve (20) as in Patent Document 1. Even if the oil is squeezed, the oil supply becomes excessive, and it is difficult to prevent the aforementioned “oil blowing”.

Means and effects for solving the problems

  The problems to be solved by the present invention are as described above. Next, means for solving the problems and the effects thereof will be described.

  That is, a lubricating device for an internal combustion engine according to a first aspect of the present invention includes a cam shaft that has a cam surface and drives a valve, an oil supply pipe that includes an injection port that injects oil to lubricate the cam surface, and the oil supply pipe. A supply path for supplying oil from the oil pan to the valve, and a valve body that completely cuts off the supply of oil to the injection port when the hydraulic pressure in the supply path exceeds a set value. .

  With this configuration, shower-type lubrication using an oil supply pipe is realized, and the cam surface of the camshaft and the like can be sufficiently lubricated and cooled particularly during low-speed operation of the internal combustion engine. Further, when the hydraulic pressure of the supply path becomes equal to or higher than a set value due to high speed operation, the valve body completely shuts off the oil supply to the injection port, so that shower lubrication from the oil supply pipe is not performed at all. Therefore, it is possible to avoid excessive oil supply which is a concern during high-speed operation, and to prevent an increase in the amount of oil remaining in the head cover. As a result, the ejection of oil from the blow-by gas outlet and the accompanying decrease in the amount of oil in the oil pan can be avoided, and troubles such as seizure can be prevented in advance.

  According to a second aspect of the present invention, there is provided a lubrication apparatus for an internal combustion engine having a second supply path for supplying oil from an oil pan to a journal portion of the camshaft. The oil supply through the second supply path to the journal portion of the camshaft is not blocked even when the supply of oil is interrupted.

  With this configuration, during low-speed operation of the internal combustion engine, oil is guided to the journal portion of the camshaft through the second supply path to lubricate the journal portion, and shower-type lubrication using an oil supply pipe is realized. In particular, the cam surface of the camshaft and the like can be sufficiently lubricated and cooled during low-speed operation of the internal combustion engine where the amount of oil supplied to the journal portion is small and an oil splash amount cannot be expected. Further, when the hydraulic pressure of the supply path becomes a set value or more with high speed operation, the valve body completely shuts off the oil supply to the injection port, and shower lubrication is completely stopped. Oil supply through the second supply path to the journal portion of the cam shaft is not shut off. Therefore, an increase in the amount of oil remaining in the head cover is avoided, while the journal portion is reliably lubricated, and the cam surface and the like are also removed by oil splash from the journal portion to which a large amount of oil is supplied by high-speed operation. It can be lubricated moderately.

  In the lubricating device for an internal combustion engine according to a third aspect of the present invention, the valve body is provided with a biasing spring that biases the valve body in a valve opening direction, and when the hydraulic pressure of the supply path becomes a set value or more, The valve body moves against the urging force of the urging spring, thereby completely shutting off the supply of oil to the injection port.

  With this configuration, the configuration for opening and closing the valve body can be simplified, and the manufacturing cost can be reduced.

  Next, embodiments of the invention will be described. FIG. 1 is a schematic cross-sectional view showing an overall configuration of an internal combustion engine provided with a lubricating device according to an embodiment of the present invention, and FIG. 2 is a partial plan view of a plan view showing the inside of a head cover. FIG. 3 is a schematic cross-sectional view showing a state in which the valve element completely shuts off the oil supply to the oil supply pipe during high-speed operation of the internal combustion engine.

  An internal combustion engine schematically illustrated in FIG. 1 includes a cylinder block 1, a cylinder head 3 fixed to the upper portion of the cylinder block 1 via a head gasket 2, a camshaft case 4 fixed to the upper portion of the cylinder head 3, It has.

  The camshaft case 4 has a vertically divided structure comprising a bearing portion 5 and a cam cap 6, and a journal portion 17 of the camshaft 8 is rotatably supported by a bearing surface 7 formed by both. . The camshaft 8 rotates in synchronization with a crankshaft (not shown) of the internal combustion engine and drives an exhaust valve (not shown).

  An oil pan 31 is attached to the lower portion of the cylinder block 1 to collect lubricating oil. This lubricating oil is pumped up by an oil pump 32 driven by the crankshaft of the internal combustion engine.

  A pressure feeding path 9 is formed in the cylinder block 1, and the pressure feeding path 9 communicates with an oil introduction path 10 formed in the cylinder head 3 through a hole formed in the head gasket 2. The pressure feed passage 9 is fitted with an orifice 11 for adjusting the oil amount.

  The oil introduction passage 10 opens on the upper surface of the cylinder head 3. A recess 12 is formed on the lower surface of the bearing portion 5 of the camshaft case 4 so as to face the opening. The recess 12 communicates with a journal introduction passage 13 formed in the cylinder head 3. The journal introduction passage 13 is fitted with an orifice 14 for adjusting the oil amount.

  A distribution passage 15 formed in the cylinder head 3 so as to be parallel to the cam shaft 8 communicates with the journal introduction passage 13. A plurality of journal supply passages 16 are obliquely extended from the distribution passage 15 in correspondence with a plurality of journal portions 17 provided on the camshaft 8 (see the plan view of FIG. 2) (see FIG. 2). 1 shows only one). The journal supply passage 16 is connected to a lubrication passage 18 formed in the camshaft case 4, and one end of the lubrication passage 18 opens in the bearing surface 7 of the camshaft case 4.

  On the other hand, an oil hole 19 is formed in the bearing portion 5 of the camshaft case 4 so as to be connected to the oil introduction passage 10. One end of the oil hole 19 communicates with a joint portion of the camshaft case 4 between the bearing portion 5 and the cam cap 6. A supply groove 20 is formed on the cam cap 6 side of the camshaft case 4.

  On the upper surface of the cam cap 6, a cylindrical oil supply pipe introduction pipe 21 is erected. The supply groove 20 communicates with the internal space of the oil supply pipe introduction pipe 21 via a lubricating oil hole 22 formed through the cam cap 6 so as to branch from the supply groove 20. .

  An oil supply pipe 23 is installed in an obliquely upper direction of the cam shaft 8 in parallel with the cam shaft 8 (see also FIG. 2). An opening 25 is formed in the inner wall of the oil supply pipe introduction pipe 21, and this opening 25 is connected to the internal space of the oil supply pipe 23. As shown in FIG. 2, the oil supply pipe 23 is provided with an injection port 28 at a position corresponding to the cam surface 27 of the camshaft 8. Can be lubricated.

  A cylindrical valve body 24 is fitted on the inner wall of the oil supply pipe introduction pipe 21 formed in a cylindrical shape so as to be slidable in the vertical direction while maintaining oil tightness. As shown in FIG. 1, the valve body 24 is movable to a position where the valve body 24 is raised to block the opening 25 and a position where the valve body 24 is lowered to open the opening 25. The valve body 24 is provided with an urging spring 26 so that an urging force in the direction in which the valve body 24 is lowered (that is, the valve opening direction) is always applied.

  When the internal combustion engine is operated with the above configuration, the oil pumped up from the oil pan 31 by the oil pump 32 passes through the pressure feed path 9 and the oil introduction path 10 and then branches into two hands. One of the branched parts reaches the inside of the oil supply pipe introduction pipe 21 through the oil hole 19, the supply groove 20, and the lubricating oil hole 22, and is then introduced into the oil supply pipe 23 from the opening 25. In the oil supply pipe 23, the oil is distributed to a plurality of injection ports 28 and is injected from the respective injection ports 28 to the respective cam surfaces 27 of the cam shaft 8 in a shower shape. Thus, the cam surface 27 is lubricated and cooled.

  The other branched portion reaches the distribution passage 15 via the recess 12 and the journal introduction passage 13, and is supplied from the distribution passage 15 to the bearing surface 7 via the respective journal supply passage 16 and the lubrication passage 18. Thus, the journal portion 17 of the cam shaft 8 is lubricated and cooled. In particular, during high-speed rotation at a high discharge speed from the oil pump 32, oil supplied between the journal portion 17 and the bearing surface 7 leaks from the journal portion 17 and splashes as the cam shaft 8 rotates. The oil splash splashes and lubricates and cools each part such as the cam surface 27 of the cam shaft 8 and an exhaust valve (not shown).

  As described above, in this embodiment, oil is directly guided to the bearing surface 7 of the journal portion 17 through the journal introduction passage 13, the distribution passage 15, the journal supply passage 16, and the lubrication passage 18, and a shower type using an oil supply pipe 23. In particular, the cam surface 27 of the camshaft 8 is sufficiently provided even during low-speed operation of an internal combustion engine in which the amount of oil leakage or oil splash from the journal portion 17 and the bearing surface 7 cannot be expected. It can be lubricated and cooled.

  In the present embodiment, the pressure feeding path 9, the oil introduction path 10, the oil hole 19, the supply groove 20, the lubricating oil hole 22, and the oil supply pipe introduction pipe 21 correspond to the “supply path” of the present invention. The pressure feed path 9, the oil introduction path 10, the recess 12, the journal introduction path 13, the distribution path 15, the journal supply path 16, and the lubrication path 18 correspond to the “second supply path” of the present invention. The lubrication apparatus according to the present embodiment includes the valve body 24, the urging spring 26, and the oil supply pipe 23 in addition to the supply path and the second supply path.

  The internal combustion engine shown in FIGS. 1 to 3 is a twin cam type internal combustion engine, and the camshaft 8 shown in FIG. 1 is used as a camshaft (exhaust-side camshaft) for driving an exhaust valve. It is configured. A thick chain line on the right side of FIG. 1 indicates the center line of the internal combustion engine. On the opposite side of the center line, a cam shaft (supply side cam shaft for driving an intake valve, not shown) is shown. ) Is similarly supported by the camshaft case 4.

  A lubrication device is provided to lubricate the camshaft on the supply side (not shown). Although not shown in detail, the air supply side camshaft lubrication device has substantially the same configuration as the exhaust side camshaft lubrication device shown in FIG. 1, and includes an oil supply pipe 23 for lubricating the cam surface, An oil supply pipe introduction pipe 21, a valve body 24, an urging spring 26, and a journal introduction passage 13, a distribution passage 15, a journal supply passage 16, and a lubrication passage 18 for lubricating the journal portion are configured.

  The camshaft case 4 has a plurality of bearing surfaces 7 corresponding to the plurality of journal portions 17 formed on the exhaust-side camshaft 8. On the surface 7, a semicircular arc-shaped groove 29 is formed on the lower surface of the cam cap 6 (the surface that constitutes the bearing surface 7 in sliding contact with the journal portion 17). The groove 29 has one end communicating with the supply groove 20 and the other end lubricated by the above-described supply-side camshaft via a relay oil passage 33 formed between the bearing portion 5 and the cam cap 6. Connected to the oil passage of the device.

  A head cover 35 is provided on the camshaft case 4 so as to cover the camshaft 8, the air supply / exhaust valve, the oil supply pipe introduction pipe 21, and the oil supply pipe 23. An oil return passage (not shown) is formed inside the head cover 35, and the oil return passage communicates with the oil pan 31. With this configuration, the oil pan 31 is sent through the oil pump 32 to the lubricating device of the exhaust camshaft 8 and the lubricating device of the air supply camshaft (not shown), and the camshaft and the air supply / exhaust valve The oil that lubricates and cools the oil and flows down into the head cover 35 is returned to the oil pan 31 by dropping by its own weight in the oil return passage.

  The blow-by gas reduction device for the internal combustion engine with respect to such a lubrication device is configured as follows, as in Patent Document 1 described above. That is, the lower crank chamber 34 of the cylinder block 1 communicates with the head cover 35 through a blow-by gas passage (not shown). An oil separator (not shown) is attached to the upper portion of the head cover 35. The gas in the head cover 35 is separated by passing through the oil separator, sent to the air cleaner via the blow-by gas hose, and again subjected to combustion.

  Next, the operation of the valve body 24 will be described. That is, during high-speed operation of the internal combustion engine, the discharge speed of the oil pump 32 driven by the crankshaft increases, so that the pressure in the supply path (the pressure feed path 9, the oil introduction path 10, the oil hole 19, etc.) increases. . However, in the present embodiment, when the pressure in the supply path increases in this way and exceeds a predetermined pressure defined by the spring force of the biasing spring 26, the valve body 24 is attached as shown in FIG. Ascending against the spring 26, the inlet portion (the opening 25) of the oil supply pipe 23 is completely closed, and the oil supply to the oil supply pipe 23 (the oil supply to the injection port 28) is completely shut off. To do. As a result, since shower lubrication from the oil supply pipe 23 is not performed at all, it is possible to prevent an increase in the amount of oil remaining in the head cover 35 which is a concern during high-speed operation, and to prevent oil from being blown out from the blow-by gas outlet. It can be avoided. This means that a decrease in the amount of oil in the oil pan 31 can be avoided and troubles such as seizure can be prevented in advance.

  In particular, in the present embodiment, the valve body 24 is configured not to restrict the supply of oil to the oil supply pipe 23 (the injection port 28) but to completely shut off during high-speed operation (high hydraulic pressure). The effect of preventing oil stagnation in the head cover 35 is great.

  In the present embodiment, even when the valve body 24 completely shuts off the oil supply to the oil supply pipe 23 (the injection port 28), the second supply path (the recess 12, the journal introduction path 13, the distribution path). 15, journal supply passage 16, lubrication passage 18, etc.), the supply of oil to the journal portion 17 to the camshaft 8 is not blocked. As a result, the oil supplied to the journal portion 17 overflows from the journal portion 17 and is splashed by the cam shaft 8 rotating at high speed, and can be sufficiently distributed and lubricated to the surrounding exhaust valve, the cam surface 27 and the like. . Therefore, even if the supply of pressure oil to the oil supply pipe 23 is completely stopped, the lubrication / cooling effect of the cam surface 27 and the like of the camshaft 8 is sufficient, and troubles such as seizure are reliably avoided.

  Although the embodiment of the present invention has been described above, the technical scope of the present invention is not limited to the configuration of the above embodiment, and can be implemented by being modified as shown below, for example.

  (1) In the present embodiment, a twin cam type internal combustion engine is illustrated, but the present invention is not limited to this, and only one cam shaft is arranged, and the intake valve and the exhaust are disposed on the one cam shaft via a rocker arm. The present invention can be similarly applied to an internal combustion engine that drives both valves.

  (2) In the present embodiment, the second supply path guides the oil from the outside of the cam shaft 8 to the journal portion 17. However, the present invention is not limited to this, and an internal passage is formed in the axial direction of the cam shaft 8. Alternatively, the oil may be pumped toward the internal passage, and oil may be supplied from the internal passage between the journal portion 17 and the bearing surface 7 to lubricate each journal portion 17.

  (3) The supply path or the second supply path may be provided with a filter or the like for filtering impurities as necessary.

  (4) In addition to the configuration using the biasing spring 26, for example, the valve body 24 is driven by a solenoid or driven by static electricity to supply oil to the oil supply pipe 23 (the injection port 28). A configuration for controlling the supply stop is also conceivable. At this time, for example, a pressure sensor is provided in the lubricating oil hole 22 or the like, and when the detected value of the pressure sensor exceeds a predetermined threshold value, the valve body 24 is driven to completely open the opening 25. What is necessary is just to control so that it may interrupt. However, when the urging spring 26 is used as in the above embodiment, there is an advantage that the valve body 24 can be opened and closed with a simple configuration.

  (5) The valve drive structure may be anything that drives the valve with a cam shaft having a cam surface. The cam surface drives the valve via a valve retainer, or the cam surface drives the valve via a rocker arm. It may be driven.

  (6) In the above-described embodiment, the valve body 24 is provided in the supply pipe introduction pipe 21 of the supply pipe 23. However, even in other cases, for example, the valve body is in the oil passage near the injection port 28. May be provided.

1 is a schematic cross-sectional view showing an overall configuration of an internal combustion engine including a lubricating device according to an embodiment of the present invention. The top view partial cross section which shows the mode in a head cover. The schematic cross section which showed a mode that the valve body completely interrupted supply of the oil with respect to an oil supply pipe at the time of high speed driving | operation of an internal combustion engine.

Explanation of symbols

8 Cam Shaft 17 Journal 23 Oil Supply Pipe 24 Valve Element 27 Cam Surface 28 Injection Port 31 Oil Pan 35 Head Cover

Claims (3)

A camshaft having a cam surface and driving a valve;
An oil supply pipe having an injection port for injecting oil to lubricate the cam surface;
A supply path for supplying oil from the oil pan to the oil supply pipe;
A valve body that completely shuts off the supply of oil to the injection port when the hydraulic pressure of the supply path is equal to or higher than a set value;
A lubricating device for an internal combustion engine, comprising: The internal combustion engine lubrication device according to claim 1,
A second supply path for supplying oil from an oil pan to the journal portion of the camshaft;
Even when the supply of oil to the injection port is blocked by the valve body, the supply of oil through the second supply path to the journal portion of the camshaft is not blocked. An internal combustion engine lubrication device. A lubricating device for an internal combustion engine according to claim 1 or 2,
The valve body is provided with a biasing spring that biases the valve body in the valve opening direction,
When the oil pressure in the supply path exceeds a set value, the valve body moves against the urging force of the urging spring, thereby completely shutting off the oil supply to the injection port. , A lubricating device for an internal combustion engine.

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