JP2013130080A - Chain case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a chain case capable of sending downward oil in an engine upper part for removing oil from a blow-by gas and sending the same to the engine upper part.SOLUTION: In the inside of the chain case C, there are formed a chain storage space Sa where a timing chain 11 is disposed, an oil guide space Sb for having an oil in an engine upper part flow downward, and a gas guide space Sc for having a blow-by gas from a crank chamber distributed upward. A case-like member 30 of a liquid-tight structure is provided as the gas guide space Sc. The case-like member 30 sucks in the blow-by gas in the crank chamber to a gas guide cylinder 34 in a lower position for sending out the same from a gas discharge cylinder 33 in an upper part.

Description

  The present invention relates to a chain case that houses a timing chain that transmits a driving force of a crankshaft of an engine to a camshaft, and more specifically, a configuration in which oil at the top of the engine is sent to the bottom of the engine and blow-by gas from the bottom of the engine is sent out to the top of the engine Regarding improvements.

  In Patent Document 1, as a chain case configured as described above, a groove portion extending in the vertical direction with respect to the chain case is formed, and a plate that closes the groove portion is provided in the chain case, so that the lower portion is formed inside the chain case. A structure is shown in which the opening is opened and a passage communicating with the hole of the cylinder head is formed at the upper portion, and blow-by gas is sent upward in this passage.

  In Patent Document 2, blow-by gas is introduced into a separator from a blow-by gas inlet formed on the side opposite to the sliding side of the chain guide inside the chain case, and the mist-like oil contained in the blow-by gas is introduced into the separator. The structure which isolate | separates and discharges from a discharge port is shown.

  In this Patent Document 2, a separator includes a plurality of fins and a plurality of fin members arranged at a predetermined interval in a space where blow-by gas is introduced, and is included in blow-by gas when the blow-by gas comes into contact therewith. The oil comes into contact with the fin and the fin member to form droplets and separate.

  Further, Patent Document 3 has a structure in which oil for lubricating a cam shaft of a cylinder head is sent downward in the chain case and returned to the oil pan, and the inside of the chain case is divided into an ascending region and a descending region of the chain. An oil passage system is shown in which ribs in the form of vertical walls are formed and oil from the cylinder head is sent to the down region side of the chain.

  In Patent Document 3, since the oil from the cylinder head is sent in the direction of the chain that moves in the downward direction, the problem of the oil splashing in contact with the chain is solved.

Japanese Patent Laid-Open No. 2003-41922 Japanese Patent Publication No. 7-99088 JP 2006-70758 A

  Blow-by gas is unburned gas (a type of exhaust gas) that leaks from the combustion chamber into the crankcase during engine operation. This blow-by gas is reduced to an intake system (for example, an intake manifold) of the engine to be burned in the combustion chamber of the engine. Moreover, in order to make it easy to return the blowby gas to the intake system, in Patent Document 1, a passage for guiding the blowby gas upward is formed inside the chain case.

  When blow-by gas contains oil mist, the oil adheres to the inner surface of the path where the blow-by gas is returned to the engine intake system to reduce the fluidity of the gas, and the amount of engine oil taken out. Therefore, a technique for removing oil contained in blow-by gas as described in Patent Document 2 is also necessary.

  Furthermore, the oil supplied to the camshaft of the cylinder head needs to be returned to the oil pan below the engine, and as described in Patent Document 3, a space for sending the oil inside the chain case downward may be formed. It is valid.

  For these reasons, as in the configuration described in Patent Document 1, a passage for sending blow-by gas upward is formed inside the chain case, and a lower end of the passage is opened to the lower portion of the chain case. As described in Document 3, it is conceivable to provide a section for sending oil downward in the chain case.

  However, in the configuration of Patent Document 1, since the lower end of the passage for sending the blow-by gas opens to the lower part of the chain case, it is conceivable that the blow-by gas containing a large amount of oil mist is sucked in the lower part of the inner space of the chain case. There is room.

  As described in Patent Document 2, in a configuration in which a chain case is provided with a separator and blowby gas from which oil has been removed by this separator is taken out from the outer wall of the chain case, it is necessary to connect a pipe to the outer surface of the chain case. The chain case is likely to be complicated, and it is difficult to say that it is effective in terms of cost.

  An object of the present invention is to rationally configure a chain case that can send oil in the upper part of the engine downward, remove oil from blow-by gas, and send it out to the upper part of the engine.

  A feature of the present invention is that a chain housing space that houses a timing chain that transmits the driving force of the crankshaft of the engine to the camshaft at the top of the engine, and an oil guide space through which oil at the top of the engine flows down to the bottom of the engine And a gas guide space through which the blow-by gas flowing out from an opening provided in the crank chamber of the engine flows upward is formed in the chain housing space, and the blow-by gas from the crank chamber is converted into the gas. The gas guide tube sucked into the guide space is directed from the lower part of the gas guide space toward the opening.

According to this configuration, the timing chain is housed in the chain housing space formed inside the chain case, the driving force of the crankshaft is transmitted to the camshaft, and the oil guide space formed inside the chain case allows oil in the upper part of the engine. Can flow down to the bottom of the engine. Further, blow-by gas flowing out from the opening formed in the crank chamber can be sent from the gas guide tube to the lower portion of the gas guide space, and can be circulated upward in the gas guide space. In particular, since the oil guide space and the gas guide space are formed separately, the oil flowing down from the upper part of the engine is not mixed into the blow-by gas, and has a gas guide tube directed in the direction of the crank chamber. Therefore, the blow-by gas inside the crank chamber can be sucked into the gas guide space without touching the oil mist existing inside the chain case.
Accordingly, a chain case has been constructed that can send the oil at the top of the engine downward, remove the oil from the blow-by gas, and send it out to the top of the engine.

  In the present invention, the gas guide space is formed by a case-like member supported inside the chain case, and the gas guide tube is provided in a state of communicating with a lower portion of the case-like member. A plurality of blow-by gas collision walls that change the flow direction of the blow-by gas may be provided inside.

  According to this, since the blow-by gas is introduced into the gas guide space constituted by the case-like member, it does not come into contact with the external oil mist. Further, since the blow-by gas contacts the blow-by gas collision wall when flowing upward in the case-like member, the oil mist contained in the blow-by gas can be removed in the form of droplets. As a result, blow-by gas from which oil mist has been removed can be sent out to the top of the engine.

  In the present invention, the gas guide tube is formed at one end portion in the width direction of the case-like member, and the oil separated from the blow-by gas is discharged at the other end portion in the width direction of the case-like member. A discharge hole may be formed.

  According to this, in the case-like member, the oil is discharged from a position away from the position where the blow-by gas is sucked, and the blow-by gas sucked into the case-like member can hardly be brought into contact with the oil.

  In the present invention, the timing chain is wound around a crank sprocket driven by the crankshaft and a cam sprocket that transmits a driving force to the camshaft, and the oil guide is placed in a space surrounded by the timing chain. A guide member that forms a space is arranged, and this guide member has an oil collecting portion that opens upward at the upper end, a discharge duct portion that causes oil to flow downward, and an oil collision wall that reduces the flow rate of oil inside May be provided.

  According to this, oil sent from the upper part of the engine to the inside of the chain case is caused to flow down into the guide member from the oil collecting part that opens upward in the space surrounded by the timing chain. It becomes possible to send out from the discharge duct part below the chain case. As a result, the oil falling from the upper part of the engine can be prevented from coming into contact with the timing chain, so that the atomization of the oil and the generation of bubbles can be suppressed, and the friction of the timing chain can be reduced. In addition, when oil flows down into the guide member, the oil falling speed can be suppressed by contact with the oil collision wall, and the inconvenience that the oil discharged from the discharge duct scatters inside the chain case and oil pan is suppressed. For example, bubbles are formed in the oil of the oil pan, and the inconvenience that the oil contains air is suppressed.

It is a longitudinal cross-sectional view which shows an engine and a chain case. It is sectional drawing which shows the structure of a chain case. It is a cross-sectional top view which shows arrangement | positioning of a case-shaped member and a guide member. It is a disassembled perspective view of a chain case, a case-like member, and a guide member. It is sectional drawing which shows the flow of the oil in a guide member. It is sectional drawing which shows the flow of blow-by gas in a case-like member.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Basic configuration]
As shown in FIGS. 1 and 2, the cylinder head 1, the cylinder block 2, the crankcase 3, and the oil pan 4 are connected in a form of overlapping each other and a crankshaft 5 that is rotatably supported by the crankcase 3. The engine is configured with a chain case C that covers the timing chain 11 that transmits the driving force of the cylinder to the cam shaft 6 of the cylinder head 1.

  This engine has a configuration in which a piston 7 is slidably accommodated in a cylinder bore of a cylinder block 2 and the piston 7 and a crankshaft 5 are connected by a connecting rod 8. One end of the crankshaft 5 is provided so as to protrude through the crankcase 3, and a crank sprocket 12 is provided at the protruding end.

  The cylinder head 1 is provided with an intake valve 9 and an exhaust valve (not shown), and two camshafts 6 in parallel with the crankshaft are rotatably supported at upper positions thereof. The head cover 15 is provided so as to cover the cylinder head 1. One end of each camshaft 6 is provided so as to protrude through the cylinder head 1, and a valve timing control mechanism 13 is provided at the protruding end, and a cam sprocket 14 is provided on the outer periphery of the case portion of the valve timing control mechanism 13. Is provided.

  The valve timing control mechanism 13 includes a rotor (not shown) that rotates integrally with the camshaft 6 so as to be relatively rotatable with respect to the case portion where the cam sprocket 14 is formed, and the relative angle can be adjusted by supplying oil. Thus, part of the supplied oil is discharged in a form that leaks from the gap between the case portion and the rotor. Although not shown in the drawing, an intake manifold is connected to one side surface of the cylinder head, and an exhaust manifold is connected to the other side surface.

  The head cover 15 is formed with a discharge pipe 15A for discharging blow-by gas, and a reduction hose 10 is connected to reduce the blow-by gas sent from the discharge pipe 15A to an intake system such as an intake manifold.

  As shown in FIG. 2, at the side position of the timing chain 11 wound around the crank sprocket 12 and the pair of cam sprockets 14, a chain guide 16 for guiding the timing chain 11, and the timing chain 11 A chain slipper 17 having a chain tensioner for applying tension is disposed. The above-described chain case C is provided at a position covering these, and the internal space of the chain case C is continuous with the internal space of the head cover 15 at the upper position and is connected with the oil storage space of the oil pan at the lower position. An oil pump 18 that sucks oil from the oil pan 4 by a driving force of the crankshaft 5 is provided at a lower position of the chain case C.

  The oil pump 18 is provided with a strainer 18A at the tip of the suction pipe, and the oil sucked through the strainer 18A is a bearing or cam surface of the cam shaft 6 of the cylinder head 1 from a lubricating oil path (not shown). Alternatively, it is supplied to the inner surface of the cylinder bore of the cylinder block 2, the bearing portion of the crankshaft 5, or the like. The oil from the oil pump 18 is supplied to the valve timing control mechanism 13 via an electromagnetic control valve (not shown).

  With this configuration, the crank sprocket 12 is driven and rotated by the rotational force of the crankshaft 5 when the engine is in operation, and this driving rotational force is transmitted from the timing chain 11 to the cam sprocket 14. As a result, the camshaft 6 is rotated in synchronization with the rotation of the crankshaft 5, and the intake valve 9 and the exhaust valve are opened and closed by contact with the cam portion of the camshaft 6. Further, when the engine is operating, the intake timing and the exhaust timing are controlled by the valve timing control mechanism 13.

  The oil supplied from the oil pump 18 to the valve timing control mechanism 13 and the camshaft 6 via the cylinder head 1 is discharged into a chain housing space Sa surrounded by the chain case C and the cylinder head 1 in a leaking form.

  In this engine, a crank chamber in which the crankshaft 5 is disposed is formed at a portion extending from the lower part of the cylinder block 2 to the crankcase 3. When the engine is in operation, uncombusted gas or the like escapes into the crank chamber during the compression stroke and blow-by gas is generated. In order to discharge this blow-by gas, a gas discharge opening 2A is formed in the wall surface of the cylinder block 2 facing the chain case C.

[Chain case]
As shown in FIGS. 2 to 4, the chain case C includes a main wall portion Ca in a posture orthogonal to the axis of the crankshaft 5, a side wall portion Cb surrounding the main wall portion Ca, and a flange formed on an outer peripheral portion of the side wall portion. The portion Cc is integrally formed of an aluminum alloy, and is supported by the engine in such a manner that the flange portion Cc is connected to the cylinder head 1, the cylinder block 2, the crankcase 3, and the oil pan 4.

  Inside the chain case C are a chain housing space Sa that houses the timing chain 11 described above, an oil guide space Sb that allows oil discharged from the upper part of the engine to flow down to the oil pan 4, and a blow-by gas from the lower part of the engine. Is formed in the head cover 15.

  The chain housing space Sa includes a portion of the crank sprocket 12 inside the chain case C, and a pair of linear portions extending upward from the outer peripheral position of the crank sprocket 12 along the chain guide 16 and the chain slipper 17. It is formed as a V-shaped region including

  The oil guide space Sb is disposed inside the inverted triangular space taken in by the timing chain 11 and is configured to include a resin guide member 20 supported by the chain case C. The oil guide space Sb is disposed at a position overlapping the timing chain 11 when viewed in a direction perpendicular to the axis of the crankshaft 5, and the guide member 20 is disposed in this space.

  The guide member 20 includes a guide main body 21 having an inverted triangular shape, side walls 22 projecting from the opposite ends of the guide main body 21 to the opposite side of the engine, and an oil that is wide in an oblique posture with the upper end bent to the engine side. It has a configuration in which a collecting part 23 and a discharge duct part 24 for sending oil obliquely downward from the lower part are integrally formed. By disposing the guide member 20 in the oil guide space Sb, the oil collecting portion 23 can be disposed immediately below the valve timing control mechanism 13. Therefore, the oil discharged from the valve timing control mechanism 13 can be effectively guided to the guide member 20. The guide body 21 is provided with a plurality of slanted oil collision walls 25 so as to suppress the straight downward flow of oil, and the plurality of oil collision walls 25 guide the oil in a zigzag manner. It is configured as follows. Further, the side wall 22 on both sides is formed with an oil introduction body 22A extending sideways, and an oil guide body 24A is formed on the extended side end (discharge side end) of the discharge duct portion 24. . The guide member 20 is a molded product of a resin material, but may be made of metal.

  The gas guide space Sc is disposed on the side opposite to the engine with respect to the guide member 20, and includes a case member 30 made of resin that is supported by the chain case C. The case-like member 30 includes a case main body 31 having a wall portion formed on the entire circumference, and a plate-like lid body 32 disposed at a position where the case main body 31 is closed. A gas discharge cylinder 33 for sending blow-by gas upward in a state communicating with the gas guide space Sc is formed in the upper part of the case body 31, and an engine direction in a state communicating with the gas guide space Sc in the lower part of the case body 31. A gas guide tube 34 that extends obliquely downward (a specific form of orientation) is formed, and a discharge hole 35 that discharges oil from the gas guide space Sc is formed in the lower portion of the case body 31.

  The case-like member 30 has a liquid-tight structure that prevents the intrusion of oil from the outside by joining the outer periphery of the case body 31 and the outer periphery of the lid 32 by a technique such as adhesion, welding, or caulking. A plurality of blow-by gas collision walls 36 are formed on the inner surface of the case body 31 in an oblique posture to suppress a linear rise by contacting the blow-by gas. The blow-by gas collision walls 36 zigzag the blow-by gas. The oil mist contained in the blow-by gas is guided to form droplets on the surface of the blow-by gas collision wall 36 and removed. The oil droplets are discharged from a discharge hole 35 below the case body 31.

  The gas guide tube 34 is formed at one end in the width direction of the case-like member 30 (lateral direction in FIG. 2), and the discharge hole 35 is formed at the other end in the width direction of the case-like member 30. Thus, the distance between the oil discharged to the discharge hole 35 and the blow-by gas sucked from the gas guide cylinder 34 is increased, so that the sucked-by gas does not easily contain oil. In particular, among the plurality of blow-by gas collision walls 36, the lowermost one has an extending end (an extending end in the width direction of the case-like member 30) set in the vicinity above the discharge hole 35. As a result, the dropletized oil falls vertically downward by its own weight from the extended end of the blowby gas collision wall 36, and the blowby gas sucked from the gas guide tube 34 passes in a direction substantially orthogonal to the oil dropping direction. Therefore, by shortening the contact time with the oil during the passage, the blow-by gas is less likely to contain the oil.

  The gas guide tube 34 of the case-like member 30 is set at the center position in the width direction of the chain case C, and the protruding end of the gas guide tube 34 is inserted into the gas discharge opening 2A formed on the side wall of the crank chamber.

[Installation of chain case]
On the inner surface of the main wall portion Ca of the chain case C, a concave portion Cd that can be supported in a form in which the case-like member 30 is fitted is formed. From such a configuration, the case-like member 30 is fitted into the recess Cd of the chain case C and fixed, and the chain case C in which the guide member 20 is fixed to the chain case C in contact with the case-like member 30 is mounted on the engine. Is done. By this mounting, the oil collecting portion 23 of the guide member 20 is disposed below the pair of valve timing control mechanisms 13, and the oil introduction body 22 </ b> A is disposed at a position for receiving the oil flowing down on both sides of the cylinder head 1. In addition, the protruding end of the gas guide tube 34 of the case-like member 30 is inserted into the gas discharge opening 2A, and the upper end of the gas discharge tube 33 of the case-like member 30 reaches the vicinity of the internal space of the head cover 15. The timing chain 11 is disposed on both sides of each other.

  In this state where the chain case C is mounted on the engine, the timing chain 11 transmits the rotational driving force of the crankshaft 5 to the pair of valve timing control mechanisms 13 so that the pair of camshafts 6 are rotationally driven. A part of the oil fed from the oil pump 18 is supplied for lubrication of the cam shaft 6 of the cylinder head 1, and this oil is discharged from the cylinder head 1 in a leaking form. A part of the oil sent out from the oil pump 18 is supplied to the valve timing control mechanism 13 and discharged in a leaking form.

  The oil discharged from the drain hole 1D and the oil discharged from the valve timing control mechanism 13 are sent from the oil collecting portion 23 of the guide member 20 to the inside of the guide body 21 and flow down on both sides of the cylinder head 1. The oil is sent from the oil introduction body 22A to the inside of the guide body 21. When the oil flows down inside the guide body 21, as shown in FIG. 5, the oil collision wall 25 sends the oil in a zigzag manner, so that the flow velocity is suppressed and air mixing is also suppressed. The oil reaching the lower end portion is sent from the discharge duct portion 24 to the upper surface of the oil guide body 24A, and is returned from the outer end of the oil guide body 24A to the inside of the oil pan 4 through a space where oil is reduced. In particular, when the oil is returned to the oil pan, the flow velocity of the oil is reduced and the oil guide body 24A falls from a low position at the outer end, so that air is not formed in the oil of the oil pan 4 and air is supplied to the oil. Not included.

  The blow-by gas generated in the crank chamber is sent from the gas guide tube 34 into the internal space of the case-like member 30 and comes into contact with the blow-by gas collision wall 36 when being sent upward as shown in FIG. The oil mist contained in the mist is formed into droplets on the surface of the blow-by gas collision wall 36 and dropped to the lower portion, and returned to the space of the oil pan 4 from the discharge hole 35. The blow-by gas is sent from the upper end of the case-like member 30 into the space of the head cover 15 by the gas discharge cylinder 33. In particular, since the protruding end (right end in FIG. 6) of the lowest blow-by gas collision wall 36 extends in the direction of the discharge hole 35, the oil can be smoothly guided to the discharge hole 35. It becomes possible. The blow-by gas sucked from the gas guide tube 34 is sent upward in a form that wraps around the lower side of the projecting end, and the direction in which the blow-by gas wraps around is orthogonal to the direction in which the oil falls from the projecting end. Since the contact time is short and the contact time is short, the inconvenience of including oil in blow-by gas is suppressed.

[Another embodiment]
The present invention may be configured as follows in addition to the embodiment described above.

  You may comprise gas guidance space Sc by arrange | positioning the cover body 32 in the position which covers the recessed part Cd of the chain case C. FIG. When configured in this manner, the lid 32 is provided with a gas guide tube 34 protruding from the upper portion, a gas discharge path for sending blow-by gas such as the gas guide tube 34 upward is formed in the upper portion, and a lower portion is formed. An oil discharge path for discharging oil such as the discharge hole 35 is provided.

  In this alternative embodiment, it is also effective to provide a plurality of blow-by gas collision walls 36 on at least one of the inner surface of the lid 32 and the inner surface of the recess Cd. With such a configuration, the blow-by gas generated in the crank chamber is sucked into the gas guide space Sc from the gas guide tube 34 and comes into droplets from the oil mist by contacting the plurality of blow-by gas collision walls 36 to discharge the oil. The blow-by gas is discharged to the oil pan through the path, and sent to the internal space of the head cover 15 from the gas discharge path.

  With this configuration, the gas guide space Sc can be formed with a small number of parts without forming the case-like member 30.

  INDUSTRIAL APPLICABILITY The present invention can be used in a chain case that internally forms a path for returning oil at the top of the engine to the oil pan and a path for sending blow-by gas from the bottom of the engine upward.

2A opening (gas exhaust opening)
5 Crankshaft 6 Camshaft 11 Timing Chain 12 Crank Sprocket 14 Cam Sprocket 20 Guide Member 23 Oil Collection Portion 24 Discharge Duct Portion 25 Oil Collision Wall 30 Case-Shaped Member 34 Gas Guide Tube 35 Discharge Hole 36 Blow-by Gas Collision Wall Sa Chain Housing Space Sb Oil guide space Sc Gas guide space

Claims (4)

A chain housing space for housing a timing chain that transmits the driving force of the crankshaft of the engine to the camshaft at the top of the engine;
An oil guide space where the oil at the top of the engine flows down to the bottom of the engine,
The gas guide space for circulating the blow-by gas flowing out from the opening provided in the crank chamber of the engine is formed in the chain housing space in a state of being separated from each other,
A chain case in which a gas guide cylinder for sucking blow-by gas from the crank chamber into the gas guide space is directed from the lower part of the gas guide space toward the opening.   The gas guide space is formed by a case-like member supported inside the chain case, and the gas guide tube is provided in a state of communicating with a lower portion of the case-like member. The chain case according to claim 1, further comprising a plurality of blow-by gas collision walls that change a gas flow direction.   The gas guide tube is formed at one end in the width direction of the case-shaped member, and a discharge hole for discharging oil separated from the blow-by gas is formed at the other end in the width direction of the case-shaped member. The chain case according to claim 2 formed. The timing chain is wound around a crank sprocket driven by the crankshaft and a cam sprocket that transmits a driving force to the camshaft, and the oil guide space is formed in a space surrounded by the timing chain. A guide member is placed,
The guide member includes an oil collecting portion that opens upward at an upper end, a discharge duct portion that causes oil to flow downward, and an oil collision wall that changes an oil flow direction inside. The chain case according to any one of the above.

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