JP7032370B2 - Internal combustion engine - Google Patents

Description

The present invention faces the cylinder head from the axial direction of the camshaft, and rises from the plate surface of the cover body toward the cylinder head along the plate-shaped cover body covering the timing chain chamber and the outer edge of the cover body. It is formed on the plate surface along a virtual plane including the mating surface of the cylinder head and the head cover so as to connect the side wall extending downward from the mating surface of the cylinder head and the head cover and mating with the cylinder head at the top surface. With respect to an internal combustion engine including a timing chain cover with reinforcing ribs.

Patent Document 1 discloses a timing chain cover having a plate-shaped cover body facing the cylinder head and the head cover from the axial direction of the camshaft and covering the timing chain chamber. In the timing chain cover, a side wall (enclosing wall) is formed which is continuous along the outer edge of the cover body and rises from the plate surface of the cover body toward the cylinder head and the head cover. The top surface of the side wall is in close contact with the cylinder head and head cover in a liquid-tight manner. Reinforcing ribs are formed on the plate surface of the cover body so as to cross the plate surface and connect the side walls to each other. Reinforcing ribs suppress the vibration of the cover body.

Patent Document 2 discloses a timing chain cover having a side wall that rises from the plate surface of the cover body toward the cylinder head along the outer edge of the cover body. The upper end and side wall of the cover body are separated by the mating surface of the cylinder head and the head cover. The top surface of the side wall is in close contact with the cylinder head in a liquid-tight manner. An annular body that accepts the insertion of a variable valve timing mechanism (VTC) connected to the intake camshaft is integrally formed at the upper end of the cover body.

Japanese Unexamined Patent Publication No. 2009-174477 Japanese Unexamined Patent Publication No. 2017-218922

When the VTC is supported by an annular body as in Patent Document 2, if a flange portion continuous from the cover body is formed around the annular body, the rigidity of the flange portion is weakened due to the influence of the mounting hole of the VTC. The sealing property between the head cover and the end face of the flange portion deteriorates due to the vibration of the flange portion.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an internal combustion engine capable of increasing the rigidity of the flange portion of the timing chain cover in spite of the formation of the mounting hole of the variable valve timing mechanism. ..

According to the first aspect of the present invention, a plate-shaped cover body that faces the cylinder head from the axial direction of the camshaft and covers the timing chain chamber, and a plate surface of the cover body along the outer edge of the cover body. Rises toward the cylinder head, extends downward from the mating surface of the cylinder head and the head cover, and forms a virtual plane including the mating surface so as to connect the side wall to be mated to the cylinder head at the top surface and the side walls to each other. Along with a first reinforcing rib formed on the plate surface, the cover body extends upward from the mating surface and faces the sprocket of the intake camshaft and the sprocket of the exhaust camshaft at the end face of the outer peripheral edge. The variable valve has a flange portion that forms a mating surface with the head cover, and accepts the insertion of a variable valve timing mechanism connected to at least one of the intake camshaft and the exhaust camshaft into the flange portion. In an internal combustion engine including a timing chain cover in which a mounting hole for supporting a timing mechanism is formed, a second reinforcing rib continuously extending from the first reinforcing rib toward the outer peripheral edge of the flange portion is provided on the plate surface. It is formed.

According to the second side surface, in addition to the configuration of the first side surface, the second reinforcing rib is a plate surface of the cover body, the first region of the intake camshaft facing the sprocket, and the plate of the cover body. In terms of surface, it includes a long rib extending toward the outer peripheral edge of the flange portion between the exhaust camshaft and a second region facing the sprocket.

According to the third side surface, in addition to the configuration of the first side surface, the second reinforcing rib includes a short rib extending between the mounting hole and the side wall toward the outer peripheral edge of the flange portion.

According to the fourth side surface, in addition to the configuration of the third side surface, the flange portion has a boss protruding from the plate surface of the flange portion and screwing a fastener for connecting the variable valve timing mechanism to the cover body. Formed and the short ribs are connected to the boss.

According to the fifth side surface, in addition to the configuration of the first side surface, the second reinforcing rib is a plate surface of the cover body, the first region of the intake camshaft facing the sprocket, and the plate of the cover body. In terms of surface, a long rib extending toward the outer peripheral edge of the flange portion between the second region of the exhaust camshaft facing the sprocket and an outer peripheral edge of the flange portion between the mounting hole and the side wall portion. Includes short ribs extending towards.

According to the first aspect, the second reinforcing rib can reinforce the decrease in rigidity due to the formation of the mounting hole. Since the second reinforcing rib suppresses the vibration of the flange portion, the sealing property between the head cover and the end face of the flange portion is improved.

According to the second side surface, the long rib can suppress the tilt of the flange portion, and the sealing property between the head cover and the end face of the flange portion is improved.

According to the third aspect, the short rib can reinforce the decrease in rigidity due to the formation of the mounting hole. The vibration of the flange portion can be reduced.

According to the fourth aspect, the rigidity of the support structure of the variable valve timing mechanism can be increased.

According to the fifth aspect, by surrounding the mounting hole with the long rib, the short rib, and the first reinforcing rib, the decrease in rigidity due to the formation of the mounting hole can be reinforced. The vibration of the flange portion can be reduced.

It is a perspective view schematically showing a part of the internal combustion engine which concerns on one Embodiment of this invention. It is a top view which shows schematic structure in a cylinder head with a head cover removed. It is a top view which shows roughly the plate surface which faces a cylinder head in a timing chain cover.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 schematically shows a part of an internal combustion engine according to an embodiment of the present invention. The internal combustion engine 11 includes a cylinder head 13 coupled to a cylinder block (not shown), a timing chain cover 14 coupled to the cylinder block and the cylinder head 13 from the axial direction of the camshaft, and a cylinder head 13 and a timing chain cover. A head cover 15 coupled to the 14 from above is provided. A cylinder bore is formed in the cylinder block to partition a cylindrical space coaxial with the cylinder axis. The cylinder bore accommodates the piston so that it can reciprocate along the cylinder axis. A combustion chamber is partitioned between the piston and the cylinder head 13 for each cylinder.

The timing chain cover 14 has a plate-shaped cover body 16 facing the cylinder block and the cylinder head 13 from the axial direction of the camshaft, and the plate surface of the cover body 16 to the cylinder head 13 along the outer edge of the cover body 16. A side wall 18 extending downward from the flush mating surface 17b is provided on the mating surface 17a of the cylinder head 13 and the head cover 15 so as to stand up toward the cylinder head 13. The mating surface 17a and the mating surface 17b are defined in one plane. The top surface of the side wall 18 is liquid-tightly superposed on the cylinder block and the cylinder head 13. The cover body 16 covers the timing chain chamber. The timing chain cover 14 is coupled to the cylinder block and the cylinder head 13 with fasteners such as bolts 19 having an axial center parallel to the axis of the camshaft.

As shown in FIG. 2, a valve operating mechanism 21 is supported on the cylinder head 13. The valve mechanism 21 includes an intake camshaft 22 that rotates around the axis CSi parallel to the rotation axis of the crankshaft, and an exhaust camshaft 23 that also rotates around the axis CSe parallel to the rotation axis of the crankshaft. Be prepared. A sprocket 25 is coupled to the intake camshaft 22 in a timing chain chamber 24 at a shaft end projecting to the outside of the cylinder head 13. A sprocket 26 is coupled to the exhaust camshaft 23 in a timing chain chamber 24 at a shaft end projecting to the outside of the cylinder head 13. The timing chain 27 is wound around two sprockets 25, 26 and a sprocket (not shown) fixed to the crankshaft. A driving force is transmitted to the timing chain 27 based on the rotation of the crankshaft. The intake camshaft 22 and the exhaust camshaft 23 rotate in synchronization with the rotation of the crankshaft by the action of the timing chain 27.

As shown in FIGS. 1 and 2, the cover body 16 extends upward from the flat surface PLh including the mating surfaces 17a of the cylinder block and the cylinder head 13, and extends upward from the sprocket 25 of the intake camshaft 22 and the sprocket 26 of the exhaust camshaft 23. It has a flange portion 28 facing the surface. The flange portion 28 forms a mating surface 29 with the head cover 15 at the end surface of the outer peripheral edge. The end surface of the flange portion 28 is in close contact with the ceiling wall 15a of the head cover 15 in a liquid-tight manner. The head cover 15 is coupled to the cylinder head 13 and the timing chain cover 14 with fasteners such as bolts 31 having an axial center orthogonal to the plane PLh including the mating surface 17a. The mating surface 29 is continuous from the mating surface 17b.

A variable valve timing mechanism 32 is coaxially connected to the intake camshaft 22. The variable valve timing mechanism 32 changes the phase of the intake camshaft 22 based on, for example, the power of the electric motor. The cover body 16 is formed with a mounting hole 33 for receiving the insertion of the variable valve timing mechanism 32 from the outside of the timing chain cover 14. The variable valve timing mechanism 32 is inserted into the mounting hole 33 and supported by the cover body 16. The variable valve timing mechanism 32 is coupled to the timing chain cover 14 with fasteners such as the axis CSi of the camshafts 22 and 23 and the bolt 34 having an axis parallel to CSe.

A variable valve timing mechanism 35 is coaxially connected to the exhaust camshaft 23. The variable valve timing mechanism 35 changes the phase of the exhaust camshaft 23 based on, for example, hydraulic power. The variable valve timing mechanism 35 is coupled to, for example, the cylinder head 13. The cover body 16 faces the variable valve timing mechanism 35 from the axial direction of the exhaust camshaft 23.

An engine mount mounting portion 36 is formed on the outer surface of the cover body 16 at a position below the flat surface PLh including the mating surface 17a of the cylinder head 13 and the head cover 15. The mounting portion 36 is partitioned by a mounting surface 36a formed by an upward flat surface. For example, three female screw holes 37 are formed in the mounting surface 36a. The axis of the female screw hole 37 is orthogonal to, for example, the mounting surface 36a. The engine mount is attached to the attachment portion 36 with a fastener such as a bolt screwed into the female screw hole 37. The engine mount is coupled to the vehicle body frame. Here, the mounting portion 36 is arranged below the region facing the variable valve timing mechanism 35.

As shown in FIG. 3, on the top surface of the side wall 18, a receiving surface 18a extending in a plane orthogonal to the axes CSi and CSe of the camshafts 22 and 23 is formed. The receiving surface 18a is liquid-tightly received by the cylinder head 13.

The cover body 16 is formed with a first reinforcing rib 41 extending in parallel with a flat surface PLh including the mating surface 17a of the cylinder head 13 and the head cover 15 so as to connect the side walls 18 to the plate surface facing the cylinder head 13. Will be done. Above the first reinforcing rib 41, the cover body 16 is defined with a first region 42 facing the sprocket 25 of the intake camshaft 22 and a second region 43 facing the sprocket 26 of the exhaust camshaft 23. In the first region 42, a mounting hole 33 that accepts the insertion of the variable valve timing mechanism 32 and supports the variable valve timing mechanism 32 is formed.

The outer peripheral edge 44 of the flange portion 28 is a flat surface 44a formed at the upper end and extending in parallel with the flat surface PLh including the mating surface 17a, and a flat surface descending from one end (intake camshaft 22 side) of the flat surface 44a toward the mating surface 17b. It is partitioned by a slope 44b formed by the above surface and a curved surface 44c extending from the other end of the flat surface 44a (on the exhaust camshaft 23 side) while curving toward the mating surface 17b. A positioning protrusion 45 projecting from the slope 44b is formed on the outside of the slope 44b in the axial direction of the camshafts 22 and 23. The end face of the head cover 15 can be pressed against the positioning protrusion 45. The positioning protrusion 45 can regulate the displacement of the head cover 15 along the slope 44b in the axial direction of the camshafts 22 and 23.

A second reinforcing rib 46 is formed on the plate surface of the cover body 16 so as to continuously extend from the first reinforcing rib 41 toward the outer peripheral edge of the flange portion 28. The second reinforcing rib 46 has a long rib 46a extending between the first region 42 and the second region 43 toward the outer peripheral edge of the flange portion 28, and the outer peripheral edge of the flange portion 28 between the mounting hole 33 and the side wall 18. Includes a short rib 46b extending towards the slope 44b). The long rib 46a extends linearly in the tangential direction with respect to the contour of the mounting hole 33. The long rib 46a is connected to the surrounding wall of the mounting hole 33. The long rib 46a gradually reduces the height from the plate surface toward the outer peripheral edge (plane 44a) from the boss 47 having a height higher than that of the first reinforcing rib 41 in the axial direction of the camshafts 22 and 23.

The short rib 46b extends linearly in the tangential direction with respect to the contour of the mounting hole 33. A boss 48 is formed around the mounting hole 33, which protrudes from the plate surface of the flange portion 28 and into which a bolt 34 for connecting the variable valve timing mechanism 32 is screwed into the cover main body 16. The short rib 46b is connected to one boss 48 at one end.

In the internal combustion engine 11 according to the present embodiment, in the cover body 16 of the timing chain cover 14, the flange portion 28 extends upward from the mating surface 17b and faces the sprocket 25 of the intake camshaft 22 and the sprocket 26 of the exhaust camshaft 23. It has a flange portion 28 that forms a mating surface 29 with the head cover 15 on the outer peripheral peripheral flat surface 44a, the inclined surface 44b, and the curved surface 44c. Upon closing the timing chain chamber 24, the flange portion 28 of the cover body 16 faces the sprocket 25 of the intake camshaft 22 and the sprocket 26 of the exhaust camshaft 23 and functions as a side wall (enclosure wall) of the head cover 15. When closing the space in the cylinder head 13, it is sufficient that the ceiling wall 15a of the head cover 15 overlaps the end surface of the flange portion 28. The side wall (part of the enclosure) facing the sprocket 25 of the intake camshaft 22 and the sprocket 26 of the exhaust camshaft 23 from the head cover 15 can be omitted. As a result, the shape of the head cover 15 can be simplified.

The timing chain cover 14 rises from the plate surface of the cover body 16 toward the cylinder head 13 along the outer edge of the cover body 16 and extends downward from the flat surface PLh including the mating surface 17a of the cylinder head 13 and the head cover 15 to form a cylinder. It has a side wall 18 fitted to the head 13 at the top surface. On the plate surface of the cover main body 16, the first reinforcing rib 41 is formed in parallel with the flat surface PLh including the mating surfaces 17a and 17b so as to connect the side walls 18 to each other. In forming the flange portion 28, a second reinforcing rib 46 is formed on the plate surface of the cover main body 16 so as to continuously extend from the first reinforcing rib 41 toward the outer peripheral edge of the flange portion 28. Since the second reinforcing rib 46 suppresses the vibration of the flange portion 28, the sealing property between the head cover 15 and the end surface of the flange portion 28 is improved.

At this time, the variable valve timing mechanism 32 accepts the insertion of the variable valve timing mechanism 32 connected to at least one of the intake camshaft 22 and the exhaust camshaft 23 (here, the intake camshaft 22) into the flange portion 28. A mounting hole 33 is formed to support the. The second reinforcing rib 46 can reinforce the decrease in rigidity due to the formation of the mounting hole 33, and the vibration of the flange portion 28 can be reduced.

In the present embodiment, the second reinforcing rib 46 is the first region 42 facing the sprocket 25 of the intake camshaft 22 on the plate surface of the cover body 16, and the sprocket 26 of the exhaust camshaft 23 on the plate surface of the cover body 16. A long rib 46a extending toward the outer peripheral edge of the flange portion 28 is included between the second region 43 facing the flange portion 28. The long rib 46a can suppress the tilt of the flange portion 28. As a result, the sealing property is improved between the end face of the head cover 15 and the flange portion 28.

In the present embodiment, the second reinforcing rib 46 includes a short rib 46b extending between the mounting hole 33 and the side wall 18 toward the outer peripheral edge of the flange portion 28. The short rib 46b can reinforce the decrease in rigidity due to the formation of the mounting hole 33, and the vibration of the flange portion 28 can be reduced. Here, by surrounding the mounting hole 33 with the long rib 46a, the short rib 46b, and the first reinforcing rib 41, the decrease in rigidity due to the formation of the mounting hole 33 can be reinforced. The vibration of the flange portion 28 can be reduced.

The flange portion 28 is formed with a boss 48 that protrudes from the plate surface of the flange portion 28 and is screwed with a bolt 34 that connects the variable valve timing mechanism 32 to the cover main body 16. The short rib 46b is connected to the boss 48. Therefore, the rigidity of the support structure of the variable valve timing mechanism 32 can be increased.

In the present embodiment, the variable valve timing mechanism 32 controls the phase of the intake camshaft 22 based on the power of the electric motor, and the variable valve timing mechanism 35 controls the phase of the exhaust camshaft 23 based on the hydraulic power, but the intake cam. The phase of the shaft 22 may be controlled based on hydraulic power, or the phase of the exhaust camshaft 23 may be controlled based on the power of the electric motor.

11 ... Internal combustion engine, 13 ... Cylinder head, 14 ... Timing chain cover, 15 ... Head cover, 16 ... Cover body, 17a ... Mating surface (of cylinder head and head cover), 18 ... Side wall, 22 ... Camshaft (intake camshaft) , 23 ... camshaft (exhaust camshaft), 24 ... timing chain chamber, 25 ... (intake side) sprocket, 26 ... (exhaust side) sprocket, 28 ... flange part, 29 ... mating surface (of flange part and head cover), 32 ... Variable valve timing mechanism, 33 ... Mounting hole, 34 ... Fastener (bolt), 41 ... First reinforcing rib, 42 ... First area, 43 ... Second area, 44 ... Outer peripheral edge (of flange), 46 ... second reinforcing rib, 46a ... long rib, 46b ... short rib, 48 ... boss, PLh ... (including mating surface) flat surface.

Claims (5)

A plate-shaped cover body (16) that faces the cylinder head (13) from the axial direction of the camshafts (22, 23) and covers the timing chain chamber (24).
Along the outer edge of the cover body (16), the cover body (16) rises from the plate surface toward the cylinder head (13), and the mating surface (17a) of the cylinder head (13) and the head cover (15) rises. A side wall (18) extending downward from the cylinder head (13) and fitted to the cylinder head (13) at the top surface.
A first reinforcing rib (41) formed on the plate surface along a virtual plane (PLh) including the mating surface (17a) is provided so as to connect the side walls (18) to each other.
The cover body (16) extends upward from the mating surface (17a) and faces the sprocket (25) of the intake camshaft (22) and the sprocket (26) of the exhaust camshaft (23), and the end surface of the outer peripheral edge. It has a flange portion (28) forming a mating surface (29) with the head cover (15), and the flange portion (28) has at least the intake camshaft (22) or the exhaust camshaft (23). In an internal combustion engine including a timing chain cover (14) in which a mounting hole (33) is formed to accept insertion of a variable valve timing mechanism (32) connected to either one and support the variable valve timing mechanism (32). ,
An internal combustion engine characterized in that a second reinforcing rib (46) extending continuously from the first reinforcing rib (41) toward the outer peripheral edge of the flange portion (28) is formed on the plate surface. In the internal combustion engine according to claim 1, the second reinforcing rib (46) is a plate surface of the cover body (16) and has a first region (25) facing the sprocket (25) of the intake camshaft (22). The outer peripheral edge (28) of the flange portion (28) is between the plate surface of the cover body (16) and the second region (43) of the exhaust camshaft (23) facing the sprocket (26). An internal combustion engine comprising a long rib (46a) extending towards 44). In the internal combustion engine according to claim 1, the second reinforcing rib is a short length extending between the mounting hole (33) and the side wall (18) toward the outer peripheral edge (44) of the flange portion (28). An internal combustion engine comprising a rib (46b). In the internal combustion engine according to claim 3, the flange portion (28) is fastened so as to protrude from the plate surface of the flange portion (28) and to connect the variable valve timing mechanism (32) to the cover body (16). An internal combustion engine characterized in that a boss (48) into which a tool (34) is screwed is formed, and the short rib (46b) is connected to the boss (48). In the internal combustion engine according to claim 1, the second reinforcing rib (46) is
The first region (42) facing the sprocket (25) of the intake camshaft (22) on the plate surface of the cover body (16) and the exhaust camshaft ( A long rib (46a) extending toward the outer peripheral edge (44) of the flange portion (28) between the second region (43) facing the sprocket (26) of the 23).
An internal combustion engine comprising a short rib (46b) extending between the mounting hole (33) and the side wall (18) toward an outer peripheral edge (44) of the flange portion (28).

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