Cover structure for internal combustion engine

Abstract

To provide a cover structure of an internal combustion engine in which a mount attachment part with a mount bracket attached thereto is swollen outward from a cover member, and which can suppress vibration of the mount attachment part while increasing an outward swollen amount of the mount attachment part.SOLUTION: A lower wall 44C of a mount attachment part 44 of a chain cover 40 has: a central swollen part 44G that is swollen from a curved wall part 44D toward the inside of the chain cover 40, and formed of a curved surface connected to the outer peripheral edge of a central boss 45A; a left swollen part 44H that is swollen inward with respect to the chain cover 40 from a lower wall side left wall part 44E and the curved wall part 44D, and formed of a curved surface connected to the outer peripheral edge of an outside boss 42a; and a right swollen part 44I that is swollen inward with respect to the chain cover 40 from a lower wall side right wall part 44F and the curved wall part 44D, and formed of a curved surface connected to the outer peripheral edge of the outside boss 43a.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a cover structure for an internal combustion engine. [Background technology]

[0002] Conventionally, in an internal combustion engine that includes an engine body having a timing chain and a cover member that covers the timing chain, a bulge is provided on the upper part of the cover member, a mount bracket is fastened to the bulge, and the mount bracket is supported on the vehicle frame, thereby supporting the engine body on a side frame (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-6761 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the engine body is separated from the vehicle frame, the bulging portion bulges significantly from the cover member toward the vehicle frame. Therefore, in the internal combustion engine described in Patent Document 1, the bulging portion is easily vibrated in the vertical direction due to vibration of the mount bracket, and there is still room for improvement.

[0005] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a cover structure for an internal combustion engine in which the mount attachment portion to which the mount bracket is fastened bulges outward from the cover member, which can suppress vibration of the mount attachment portion while increasing the amount of outward bulge of the mount attachment portion. [Means for solving the problem]

[0006] The present invention relates to a cover member having a main body wall portion, a first side wall portion provided at one end in a width direction of the main body wall portion, and a second side wall portion provided at the other end in the width direction of the main body wall portion, the cover member covering a transmission member that transmits power from a crankshaft to a camshaft, the cover member being provided on each of the first side wall portion and the second side wall portion and fastened to an internal combustion engine body by a fastener, a plurality of central bosses located at a width direction central portion of the main body wall portion and fastened to the internal combustion engine body by a fastener, and a cover member fastened to the main body wall portion by a fastener. and a mount attachment portion that bulges outward from the internal combustion engine body and supports the internal combustion engine body on a vehicle body via a mount bracket, the mount attachment portion being a cover structure for an internal combustion engine having an upper wall to which the mount bracket is attached, a peripheral wall extending downward from the outer periphery of the upper wall, and a lower wall extending downward from the outer periphery of the peripheral wall, the lower wall being curved so as to gradually move away from the main body wall portion as it extends upward from the main body wall portion, and the upper end portion of the lower wall is connected to the tip portion of the peripheral wall in the bulging direction. the first side wall portion connects one widthwise end of the curved wall portion to the peripheral wall and the first side wall portion, and a second side wall portion connects the other widthwise end of the curved wall portion to the peripheral wall and the second side wall portion, the plurality of central bosses include a lower central boss provided on the curved wall portion, and the outer bosses include a first outer boss located on one widthwise side of the main body wall portion with respect to the lower central boss, and a second outer boss located on the other widthwise side of the main body wall portion with respect to the lower central boss. and 2 outer bosses, and the lower wall has a central bulge portion consisting of a curved surface that bulges inwardly from the curved wall portion into the cover member and is connected to the outer peripheral edge of the lower central boss, a first bulge portion consisting of a curved surface that bulges inwardly from the first lower-wall side wall portion and the curved wall portion into the cover member and is connected to the outer peripheral edge of the first outer boss, and a second bulge portion consisting of a curved surface that bulges inwardly from the second lower-wall side wall portion and the curved wall portion into the cover member and is connected to the outer peripheral edge of the second outer boss. Effect of the Invention

[0007] Thus, according to the present invention, in a cover structure for an internal combustion engine in which the mount attachment portion to which the mount bracket is fastened bulges outward from the cover member, the amount of outward bulging of the mount attachment portion can be increased while suppressing vibration of the mount attachment portion. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a front view of an internal combustion engine according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a top view of the internal combustion engine according to one embodiment of the present invention with the cylinder head cover removed. [Diagram 3] FIG. 3 is a front view of an upper portion of a chain cover for an internal combustion engine according to one embodiment of the present invention. [Figure 4] FIG. 4 is a perspective view of a chain cover for an internal combustion engine according to one embodiment of the present invention, as viewed obliquely from below and in front. [Diagram 5] FIG. 5 is an inner side view of a chain cover for an internal combustion engine according to one embodiment of the present invention. [Figure 6] FIG. 6 is a perspective view of a chain cover for an internal combustion engine according to one embodiment of the present invention, as viewed obliquely from above and rear on the right. [Figure 7] 7 is a cross-sectional view taken along the line VII-VII of FIG. [Figure 8] FIG. 8 is a cross-sectional view taken along the line VIII-VIII in FIG. [Figure 9] FIG. 9 is a cross-sectional view taken along the line IX-IX of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] A cover structure for an internal combustion engine according to one embodiment of the present invention has a main body wall portion, a first side wall portion provided at one end in a width direction of the main body wall portion, and a second side wall portion provided at the other end in the width direction of the main body wall portion, and has a cover member covering a transmission member that transmits power from a crankshaft to a camshaft, the cover member having outer bosses provided on the first side wall portion and the second side wall portion, respectively, and fastened to an internal combustion engine main body by fasteners, a plurality of central bosses located in a width direction central portion of the main body wall portion and fastened to the internal combustion engine main body by fasteners, and a mount attachment portion that bulges out in a direction away from the internal combustion engine main body with respect to the main body wall portion and supports the internal combustion engine main body to a vehicle body via a mount bracket, the mount attachment portion having an upper wall to which the mount bracket is attached, a peripheral wall extending downward from an outer circumferential edge of the upper wall, and a lower wall extending downward from the outer circumferential edge of the peripheral wall, the lower wall being curved so as to gradually move away from the main body wall portion as it moves upward from the main body wall portion the curved wall portion has an upper end connected to a tip end of the peripheral wall in a bulging direction, a first lower-wall side wall portion connecting one widthwise end of the curved wall portion to the peripheral wall and the first side wall portion, and a second lower-wall side wall portion connecting the other widthwise end of the curved wall portion to the peripheral wall and the second side wall portion, the plurality of central bosses including a lower central boss provided on the curved wall portion, and the outer bosses include a first outer boss located on one widthwise side of the main body wall portion with respect to the lower central boss, and a second outer boss located on one widthwise side of the main body wall portion with respect to the lower central boss. and a second outer boss located on the other side in the width direction, and the lower wall has a central bulge portion consisting of a curved surface that bulges inwardly from the curved wall portion into the cover member and is connected to the outer peripheral edge of the lower central boss, a first bulge portion consisting of a curved surface that bulges inwardly from the first lower-wall side wall portion and the curved wall portion into the cover member and is connected to the outer peripheral edge of the first outer boss, and a second bulge portion consisting of a curved surface that bulges inwardly from the second lower-wall side wall portion and the curved wall portion into the cover member and is connected to the outer peripheral edge of the second outer boss.

[0010] As a result, in an internal combustion engine cover structure according to one embodiment of the present invention, in an internal combustion engine cover structure in which the mount attachment portion to which the mount bracket is fastened bulges outward from the cover member, the amount of outward bulging of the mount attachment portion can be increased while suppressing vibration of the mount attachment portion. EXAMPLES

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a cover structure for an internal combustion engine according to the present invention will be described with reference to the drawings. 1 to 9 are diagrams showing a cover structure for an internal combustion engine according to one embodiment of the present invention. In Fig. 1 to Fig. 9, the up, down, front, rear, left and right directions are defined as follows.

[0012] The direction along the crankshaft is the front-to-rear direction of the engine, with the side where the timing chain is located being the front and the opposite side being the rear. The direction along the central axis of the cylinder is the up-down direction of the engine, with the cylinder head side being the top and the opposite side being the bottom. The direction intersecting the crankshaft and central axis of the cylinder is the left-to-right direction of the engine, with the left side of the central axis of the cylinder when looking at the crankshaft from the rear being the left and the right side of the central axis of the cylinder being the right.

[0013] First, the configuration will be described. 1, engine 1 includes an engine body 2 and a chain cover 40. Engine body 2 includes a cylinder block 3, a cylinder head 4, a cylinder head cover 5, and an oil pan 6. Engine 1 of this embodiment constitutes an internal combustion engine, and engine body 2 constitutes an internal combustion engine body.

[0014] A plurality of cylinders (not shown) are provided in the cylinder block 3, and the cylinders are arranged side by side in the front-rear direction of the engine 1. The engine 1 is installed so that a central axis 1C of the cylinder extends in the vertical direction.

[0015] Each cylinder houses a piston (not shown), and the pistons are connected to a crankshaft 7 via a connecting rod (not shown). The crankshaft 7 has a central axis of rotation that extends in the front-rear direction, and rotates around the central axis of rotation.

[0016] The pistons reciprocate in the cylinders to rotate the crankshaft 7 via connecting rods. The cylinder head 4 is formed with a plurality of intake ports and a plurality of exhaust ports, both of which are not shown.

[0017] The intake ports are connected to the cylinders and introduce intake air into the cylinders. The exhaust manifold is connected to the cylinders through exhaust ports, collects exhaust gas from the cylinders, and discharges it from an exhaust port to a catalytic converter (not shown).

[0018] 2, an intake camshaft 11 and an exhaust camshaft 12 are rotatably supported by the cylinder head 4. The intake camshaft 11 and the exhaust camshaft 12 are arranged side by side in the left-right direction of the engine 1 with their rotation central axes 11a and 12a extending parallel to the front-rear direction of the engine 1.

[0019] The intake camshaft 11 is provided with a plurality of intake cams 11A (two in the figure), and the intake cams 11A are arranged side by side in the direction of the rotation center axis 11a of the intake camshaft 11.

[0020] For example, two intake cams 11A are provided for one cylinder. An intake valve (not shown) is provided in the intake port, and the intake cam 11A operates the intake valve to open and close the intake port, thereby connecting or blocking the cylinder and the intake port.

[0021] The exhaust camshaft 12 is provided with a plurality of exhaust cams 12A (two in the figure), and the exhaust cams 12A are arranged side by side in the direction of a rotational center axis 12a of the exhaust camshaft 12. Hereinafter, the direction of the rotational center axes 11a, 12a will be referred to as the axial direction.

[0022] For example, two exhaust cams 12A are provided for one cylinder. An exhaust valve (not shown) is provided in the exhaust port, and the exhaust cam 12A operates the exhaust valve to open and close the exhaust port, thereby connecting or blocking the cylinder and the exhaust port.

[0023] An intake side valve timing controller 15 is attached to the axial front end (end) of the intake camshaft 11. The intake side valve timing controller 15 has an intake side housing member 23, and an intake sprocket 23S is provided on the outer periphery of the intake side housing member 23.

[0024] An exhaust-side valve timing adjuster 16 is attached to the axial front end (end) of the exhaust camshaft 12. The exhaust-side valve timing adjuster 16 has an exhaust-side housing member 24, and an exhaust sprocket 24S is provided on the outer periphery of the exhaust-side housing member 24.

[0025] The length of the intake side housing member 23 in the axial direction of the intake camshaft 11 and the exhaust camshaft 12 is formed to be longer than the length of the exhaust side housing member 24 .

[0026] 1, a crank sprocket 7S is provided at the front end of the crankshaft 7. A timing chain 8 is wound around the crank sprocket 7S, the intake sprocket 23S, and the exhaust sprocket 24S. The timing chain 8 in this embodiment constitutes a transmission member.

[0027] The intake side valve timing controller 15 may be configured from an exhaust side valve timing controller, and the exhaust side valve timing controller 16 may be configured from an intake valve timing controller. In this case, the intake camshaft 11 and the exhaust camshaft 12 are interchanged according to the valve timing controllers 15 and 16.

[0028] Power of the crankshaft 7 is transmitted to an intake camshaft 11 and an exhaust camshaft 12 via a timing chain 8. As a result, the intake camshaft 11 rotates, causing the intake cam 11A to open and close the intake valve, and the exhaust camshaft 12 rotates, causing the exhaust cam 12A to open and close the exhaust valve.

[0029] The intake valve timing controller 15 adjusts the relative rotation phase of the intake camshaft 11 with respect to the crankshaft 7, and adjusts the opening and closing timing (valve timing) of the intake valve.

[0030] The exhaust valve timing controller 16 adjusts the relative rotational phase of the exhaust camshaft 12 with respect to the crankshaft 7 to adjust the opening and closing timing (valve timing) of the exhaust valve. In this embodiment, the intake camshaft 11 and the exhaust camshaft 12 constitute a camshaft.

[0031] An oil pump 35 is provided in the cylinder block 3. The oil pump 35 is driven by the crankshaft 7 to supply oil stored in the oil pan 6 to each part of the engine 1.

[0032] The chain cover 40 is attached to the front end portion (end portion) of the cylinder block 3 and the front end portion (end portion) of the cylinder head 4 .

[0033] The chain cover 40 is formed such that the vertical direction of the chain cover 40 is longer than the horizontal direction of the chain cover 40 so that the longitudinal direction is along the vertical direction of the engine 1 and the transverse direction is along the left and right direction of the engine 1. As shown in Figures 2 and 5, the chain cover 40 has a vertical wall 41, a left side wall portion 42 and a right side wall portion 43.

[0034] The vertical wall 41 faces the front ends of the cylinder block 3 and the cylinder head 4 in the axial direction of the intake camshaft 11 and the exhaust camshaft 12 .

[0035] The left side wall portion 42 and the right side wall portion 43 protrude toward the engine body 2 from the right and left ends of the chain cover 40 in the width direction (short side direction, left-right direction) of the chain cover 40.

[0036] 1 and 3 to 5, a plurality of outer bosses 42A are provided on the left side wall 42, and the outer bosses 42A are arranged at intervals in the up-down direction in which the left side wall 42 extends. A plurality of outer bosses 43A are provided on the right side wall 43, and the outer bosses 43A are arranged at intervals in the up-down direction in which the right side wall 43 extends.

[0037] As shown in FIG. 1, bolts 33A and 33B are inserted into outer bosses 42A and 43A, and the bolts 33A and 33B are fastened to the front end of cylinder block 3 and the front end of cylinder head 4.

[0038] As a result, the chain cover 40 is fixed to the engine body 2 by the bolts 33A and 33B. In this embodiment, the vertical wall 41 forms a body wall, the left side wall portion 42 forms a first side wall, the right side wall portion 43 forms a second side wall, and the bolts 33A and 33B form fasteners.

[0039] As shown in FIG. 2, the chain cover 40 houses the timing chain 8, the intake side valve timing adjuster 15, and the exhaust side valve timing adjuster 16, and covers the timing chain 8, the intake side valve timing adjuster 15, and the exhaust side valve timing adjuster 16 from the front.

[0040] 1 and 2, the timing chain 8 is indicated by a phantom line. In this embodiment, the chain cover 40 constitutes a cover member. Note that the phantom line 55 in Figs. 1 and 3 indicates the boundary between the cylinder block 3 and the cylinder head 4.

[0041] The power of the crankshaft 7 is transmitted to the intake side housing member 23 of the intake side valve timing adjustment device 15 via a timing chain 8 .

[0042] An intake side vane rotor (not shown) is housed in the intake side housing member 23, and the intake side vane rotor rotates integrally with the intake camshaft 11. The intake side vane rotor divides the inside of the intake side housing member 23 into a plurality of advance angle chambers and a plurality of retard angle chambers (not shown).

[0043] The intake side valve timing controller 15 is provided with an intake side spool valve 25 (see FIG. 2). The intake side spool valve 25 rotates integrally with the intake camshaft 11 and is movable in the axial direction of the intake camshaft 11.

[0044] The power of the crankshaft 7 is transmitted to an exhaust side housing member 24 of the exhaust side valve timing adjustment device 16 via a timing chain 8 .

[0045] An exhaust-side vane rotor (not shown) is housed in the exhaust-side housing member 24, and the exhaust-side vane rotor rotates integrally with the exhaust camshaft 12. The exhaust-side vane rotor divides the inside of the exhaust-side housing member 24 into a plurality of advance chambers and a plurality of retard chambers (not shown).

[0046] The exhaust-side valve timing controller 16 is provided with an exhaust-side spool valve 26 (see FIG. 2). The exhaust-side spool valve 26 is installed on the rotation center axis 12a of the exhaust camshaft 12 so as to rotate integrally with the exhaust camshaft 12, and is freely movable in the axial direction of the exhaust camshaft 12.

[0047] As shown in Figure 2, an intake side vertical wall portion 41A and an exhaust side vertical wall portion 41B are provided on the upper part of the vertical wall 41 of the chain cover 40, and the intake side vertical wall portion 41A and the exhaust side vertical wall portion 41B are installed in parallel in the width direction (short side direction) of the chain cover 40.

[0048] The intake side vertical wall portion 41A faces the intake side valve timing control device 15 in the axial direction of the intake camshaft 11 and covers the intake side valve timing control device 15.

[0049] The exhaust side vertical wall portion 41B faces the exhaust side valve timing control device 16 in the axial direction of the exhaust camshaft 12 and covers the exhaust side valve timing control device 16.

[0050] The exhaust side vertical wall portion 41B is recessed toward the engine body 2 relative to the intake side vertical wall portion 41A. That is, the exhaust side vertical wall portion 41B is recessed toward the engine body 2 relative to the intake side vertical wall portion 41A, and the intake side vertical wall portion 41A bulges away from the engine body 2 relative to the exhaust side vertical wall portion 41B.

[0051] The intake side vertical wall portion 41A and the exhaust side vertical wall portion 41B are connected by a step portion 41C having a step in the axial direction of the intake camshaft 11. In other words, the intake side vertical wall portion 41A and the exhaust side vertical wall portion 41B are separated from each other in the axial direction of the intake camshaft 11 and the exhaust camshaft 12 by the step portion 41C.

[0052] As shown in FIGS. 1 and 2, the chain cover 40 is provided with an intake solenoid 31 and an exhaust solenoid 32.

[0053] 1 and 3, the intake side vertical wall portion 41A has an intake side through hole 41a into which the intake side solenoid 31 is inserted. The intake side solenoid 31 is attached to the intake side through hole 41a, and the intake side solenoid 31 is fixed to the intake side vertical wall portion 41A by bolts (not shown).

[0054] The exhaust side vertical wall portion 41B has an exhaust side through hole 41b into which the exhaust side solenoid 32 is inserted. The exhaust side solenoid 32 is attached to the exhaust side through hole 41b, and the exhaust side solenoid 32 is fixed to the exhaust side vertical wall portion 41B by a bolt 33C.

[0055] The intake side solenoid 31 operates the intake side spool valve 25 so that the intake side spool valve 25 moves in the axial direction of the intake camshaft 11 .

[0056] When the intake solenoid 31 moves to a position on the advance chamber side in the axial direction of the intake valve timing controller 15, oil supplied from the oil pump 35 is supplied to the advance chamber.

[0057] When oil is supplied to the advance chamber, the intake side vane rotor rotates relative to the intake side housing member 23, thereby adjusting the relative rotational phase of the intake camshaft 11 to the crankshaft 7 to the advance side, and adjusting the opening and closing timing of the intake valve to the advance side.

[0058] When the intake solenoid 31 moves to the retard side in the axial direction of the intake camshaft 11, oil supplied from the oil pump 35 is supplied to the retard chamber.

[0059] When oil is supplied to the retard chamber, the intake side vane rotor rotates relative to the intake side housing member 23, thereby adjusting the relative rotational phase of the intake camshaft 11 to the crankshaft 7 to the retard side, and adjusting the opening and closing timing of the exhaust valve to the retard side.

[0060] The exhaust side spool valve 26 is operated by the exhaust side solenoid 32, and similarly to the intake side valve timing adjuster 15, by supplying oil to either the advance chamber or the retard chamber, thereby adjusting the relative rotational phase of the exhaust camshaft 12 with respect to the crankshaft 7 to the advance side or the retard side, and adjusting the opening and closing timing of the exhaust valve to the advance side or the retard side.

[0061] As shown in FIGS. 3 and 4, a mount attachment portion 44 is provided on the upper portion of the vertical wall 41 of the chain cover 40.

[0062] The mount attachment portion 44 is located below the intake side vertical wall portion 41A and the exhaust side vertical wall portion 41B, and bulges out in a direction away from the engine body 2 (forward) relative to the chain cover 40.

[0063] As shown in FIG. 7, a side member 9 is provided in front of the engine 1, and the side member 9 extends in the front-rear direction of the vehicle.

[0064] As shown in FIG. 2, a mounting seat 44a is provided at the tip of the mount attachment portion 44, and the mounting seat 44a is provided with mount bosses 44b, 44c, and 44d to which bolts serving as fasteners (not shown) are fastened.

[0065] Bolt holes 44r, 44s, 44t through which bolts are inserted are formed in the inner peripheral surfaces of the mount bosses 44b, 44c, 44d.

[0066] 7, a mount member 51 is attached to the attachment seat 44a. The mount member 51 includes a mount bracket 51A, and a bolt is inserted into the rear end of the mount bracket 51A.

[0067] The bolts inserted into the rear end of the mount bracket 51A are then inserted into the bolt holes 44r, 44s, and 44t, and then fastened to nuts (not shown), thereby fastening the rear end of the mount bracket 51A to the attachment seat 44a.

[0068] The mount member 51 includes a vibration absorbing member 51B, which is attached to the side member 9. The front end of the mount bracket 51A is attached to the vibration absorbing member 51B, and the engine body 2 is elastically supported by the side member 9 via the mount member 51.

[0069] This allows the vibration of the engine 1 to be absorbed by the mount member 51, thereby suppressing the vibration transmitted from the engine 1 to the side member 9. The side member 9 of this embodiment constitutes the vehicle body.

[0070] 3 and 4, the mount attachment portion 44 has an upper wall 44A, a peripheral wall 44B, and a lower wall 44C. The upper wall 44A extends linearly forward from the vertical wall 41, and the attachment seat 44a is provided at the tip of the upper wall 44A in the protruding direction.

[0071] The peripheral wall 44B extends downward from the outer periphery of the upper wall 44A, and has mounting bosses 44b, 44c, and 44d provided on the inner side of the peripheral wall 44B.

[0072] The lower wall 44C has a curved wall portion 44D, a lower left side wall portion 44E and a lower right side wall portion 44F, and extends downward from the outer periphery of the peripheral wall 44B.

[0073] As shown in FIGS. 7 and 9, the curved wall portion 44D is curved so as to gradually move away from the vertical wall 41 as it moves from the vertical wall 41 toward the upper side.

[0074] Specifically, a lower end of the curved wall portion 44D is connected to the vertical wall 41. The curved wall portion 44D is curved so as to gradually move away from the vertical wall 41 from the lower end toward the upper side, and an upper end 44u is connected to a tip end 44e in the bulging direction of the peripheral wall 44B.

[0075] The mounting bosses 44b, 44c, and 44d extend from the mounting seat 44a to the curved wall portion 44D. The mounting bosses 44b, 44c, and 44d of this embodiment include bolt holes 44r, 44s, and 44t.

[0076] As shown in FIG. 4, the lower wall side left side wall portion 44E connects the left end portion 44h of the curved wall portion 44D to the peripheral wall 44B and the left side wall portion 42, and the lower wall side right side wall portion 44F connects the right end portion 44i of the curved wall portion 44D to the peripheral wall 44B and the right side wall portion 43.

[0077] In this embodiment, a left end 44h of the curved wall portion 44D constitutes one end in the width direction of the curved wall portion, and a right end 44i of the curved wall portion 44D constitutes the other end in the width direction of the curved wall portion.

[0078] As shown in FIGS. 4 and 7, the curved wall portion 44D is provided with a central bulge 44G, which is configured with a curved surface that bulges inwardly of the chain cover 40 from the curved wall portion 44D.

[0079] As shown in Figures 4 to 6, a left side bulge portion 44H is provided on the lower wall side left side wall portion 44E, and the left side bulge portion 44H is composed of a curved surface that bulges toward the inside of the chain cover 40 from the curved wall portion 44D and the lower wall side left side wall portion 44E.

[0080] A right bulge 44I is provided on the lower right side wall portion 44F, and the right bulge 44I is composed of a curved surface that bulges inwardly of the chain cover 40 from the curved wall portion 44D and the lower right side wall portion 44F.

[0081] 3 and 5, a central boss 45A is provided on the curved wall portion 44D of the lower wall 44C. The central boss 45A is located in the center of the vertical wall 41 in the width direction, and is fastened to the cylinder head 4 by a bolt 33D (see FIG. 1).

[0082] A central boss 45B is provided on the vertical wall 41. The central boss 45B is provided above the mount attachment portion 44 and is located between the intake side through-hole 41a and the exhaust side through-hole 41b and the upper wall 44A in the up-down direction of the chain cover 40.

[0083] The central boss 45B is located at the center of the vertical wall 41 in the width direction so as to be aligned vertically with the central boss 45A, and is fastened to the cylinder head 4 by a bolt 33E (see FIG. 1). In this embodiment, the central boss 45A constitutes a lower central boss, and the central boss 45B constitutes an upper central boss. The bolts 33D and 33E constitute fasteners.

[0084] A central boss 45C is provided at the lower part of the curved wall portion 44D and is located lower than the central boss 45A. The central boss 45C is located at the center in the width direction of the vertical wall 41 so as to be aligned in the up-down direction with the central boss 45A, and is fastened to the cylinder block 3 by a bolt 33F (see FIG. 1).

[0085] In this embodiment, the chain cover 40 is fixed to the engine body 2 by having the outer bosses 42A, 43A fastened to the cylinder block 3 and cylinder head 4 by bolts 33A and 33B, the central bosses 45A, 45B fastened to the cylinder head 4 by bolts 33D and 33E, and the central boss 45C fastened to the cylinder block 3 by bolt 33F.

[0086] As shown in Figures 1 and 4, of the outer bosses 42A, 43A, the outer boss 42a located on one widthwise side (left side) of the central boss 45A constitutes the first outer boss, and the outer boss 43a located on the other widthwise side (right side) of the central boss 45A constitutes the second outer boss.

[0087] The outer bosses 42a, 43a and the central boss 45A are disposed at the same height position in the height direction of the engine 1.

[0088] As shown in FIGS. 4 and 5, the left bulging portion 44H is connected to the outer peripheral edge of the outer boss 42a, and the right bulging portion 44I is connected to the outer peripheral edge of the outer boss 43a.

[0089] As shown in Figs. 6 and 7, the central boss 45A extends from the engine body 2 side to the central bulge 44G, and the central bulge 44G is connected to the outer circumferential edge of the front end portion of the central boss 45A.

[0090] Here, the lower wall side left wall portion 44E and the lower wall side right wall portion 44F are provided in the range from the central boss 45C to the peripheral wall 44B in the vertical direction, and the left side bulge portion 44H and the right side bulge portion 44I are provided on the upper parts of the curved wall portion 44D, the lower wall side left wall portion 44E and the lower wall side right wall portion 44F, respectively.

[0091] As shown in Figures 5 and 6, the vertical wall 41 is provided with a first rib 46A, a second rib 46B, a third rib 46C, a fourth rib 46D, a fifth rib 46E, a sixth rib 46F, a seventh rib 46G, an eighth rib 46H and a ninth rib 46I.

[0092] The first rib 46A protrudes from the peripheral wall 44B toward the engine body 2, and extends linearly in the vertical direction in the center in the width direction of the chain cover 40. The first rib 46A extends from the central boss 45B to the central boss 45A and the central bulging portion 44G, and connects the central boss 45B to the central boss 45A and the central bulging portion 44G.

[0093] The second rib 46B protrudes from the peripheral wall 44B and the lower left side wall portion 44E towards the engine body 2. The second rib 46B extends in a straight line diagonally downward to the left from the central boss 45B toward the left side bulging portion 44H, and connects the central boss 45B and the left side bulging portion 44H.

[0094] The third rib 46C protrudes from the peripheral wall 44B and the lower right side wall portion 44F towards the engine body 2. The third rib 46C extends in a straight line obliquely downward to the right from the central boss 45B toward the right side bulging portion 44I, and connects the central boss 45B and the right side bulging portion 44I.

[0095] The fourth rib 46D protrudes toward the engine body 2 side from the peripheral wall 44B and the curved wall portion 44D.

[0096] The fourth rib 46D extends in a straight line diagonally upward to the left from the central boss 45A and the central bulge 44G toward the center in the direction in which the second rib 46B extends, connecting the central boss 45A and the central bulge 44G to the center in the direction in which the second rib 46B extends.

[0097] As shown in FIG. 5, the connection portion at the center in the extension direction of the fourth rib 46D and the second rib 46B, i.e., the intersection point between the second rib 46B and the fourth rib 46D, constitutes a first intersection point 47A, and the first intersection point 47A is connected to the mount boss 44d (see FIG. 8).

[0098] As shown in FIGS. 5 and 6, the fifth rib 46E protrudes toward the engine body 2 from the peripheral wall 44B and the curved wall portion 44D.

[0099] The fifth rib 46E extends in a straight line diagonally upward to the right from the central boss 45A and the central bulge 44G toward the center in the direction in which the third rib 46C extends, connecting the central boss 45A and the central bulge 44G to the center in the direction in which the third rib 46C extends.

[0100] As shown in FIG. 5, the connecting portion at the center in the extension direction of the fifth rib 46E and the third rib 46C, i.e., the intersection of the third rib 46C and the fifth rib 46E, constitutes a second intersection 47B, and the second intersection 47B is connected to the mount boss 44b (see FIG. 8).

[0101] The sixth rib 46F protrudes from the curved wall portion 44D toward the engine body 2, and extends linearly in the vertical direction in the center of the chain cover 40 in the width direction.

[0102] The sixth rib 46F extends downward from the central boss 45A and the central bulging portion 44G to the central boss 45C, and connects the central boss 45A and the central bulging portion 44G to the central boss 45C.

[0103] The seventh rib 46G protrudes from the curved wall portion 44D towards the engine body 2. The seventh rib 46G extends in a straight line diagonally downward to the left from the central boss 45A and the central bulging portion 44G toward the left side bulging portion 44H, and connects the central boss 45A and the central bulging portion 44G to the left side bulging portion 44H.

[0104] The eighth rib 46H protrudes from the curved wall portion 44D towards the engine body 2. The eighth rib 46H extends in a straight line diagonally downward to the right from the central boss 45A and the central bulging portion 44G toward the right side bulging portion 44I, and connects the central boss 45A and the central bulging portion 44G to the right side bulging portion 44I.

[0105] The ninth rib 46I protrudes from the curved wall portion 44D toward the engine body 2. The ninth rib 46I extends linearly from the central boss 45A and the central bulging portion 44G toward the lower right side wall portion 44F, and connects the central boss 45A and the central bulging portion 44G to the lower right side wall portion 44F.

[0106] Next, the effect of the cover structure of the engine 1 according to this embodiment will be described. According to the cover structure of the engine 1 in this embodiment, the mount attachment portion 44 of the chain cover 40 has an upper wall 44A to which the mount bracket 51A is attached, a peripheral wall 44B extending downward from the outer circumferential edge of the upper wall 44A, and a lower wall 44C extending downward from the outer circumferential edge of the peripheral wall 44B.

[0107] The lower wall 44C curves gradually away from the vertical wall 41 as it moves upward from the vertical wall 41, and has a curved wall portion 44D whose upper end portion 44u is connected to a tip portion 44e in the bulging direction of the peripheral wall 44B, a lower wall side left side wall portion 44E which connects a left end portion 44h of the curved wall portion 44D to the peripheral wall 44B and the left side wall portion 42, and a lower wall side right side wall portion 44F which connects a right end portion 44i of the curved wall portion 44D to the peripheral wall 44B and the right side wall portion 43.

[0108] The chain cover 40 has an outer boss 42a located on the left side of the vertical wall 41 with respect to a central boss 45A provided on the curved wall portion 44D, and an outer boss 43a located on the right side of the vertical wall 41 with respect to the central boss 45A.

[0109] The lower wall 44C of the chain cover 40 has a central bulge portion 44G consisting of a curved surface that bulges inwardly of the chain cover 40 from the curved wall portion 44D and is connected to the outer peripheral edge of the central boss 45A, a left side bulge portion 44H consisting of a curved surface that bulges inwardly of the chain cover 40 from the lower wall side left side wall portion 44E and the curved wall portion 44D and is connected to the outer peripheral edge of the outer boss 42a, and a right side bulge portion 44I consisting of a curved surface that bulges inwardly of the chain cover 40 from the lower wall side right side wall portion 44F and the curved wall portion 44D and is connected to the outer peripheral edge of the outer boss 43a.

[0110] This connects the central bulge 44G, left bulge 44H and right bulge 44I, each of which is made of a curved surface with higher rigidity than a flat surface, to the curved wall portion 44D to reinforce the curved wall portion 44D, and the curved wall portion 44D enables the joint length between the curved wall portion 44D and each of the bulges 44G, 44H and 44I to be increased, thereby increasing the bonding strength of the bulges 44G, 44H and 44I to the curved wall portion 44D.

[0111] By connecting central bulge 44G to central boss 45A, left bulge 44H to outer boss 42a, and right bulge 44I to outer boss 43a, the connection rigidity of bosses 42a, 43a, 45A to bottom wall 44C can be further increased.

[0112] As a result, the mount mounting portion 44 is allowed to bulge significantly in the direction away from the engine body 2 relative to the vertical wall 41, and even in a situation where a vertical load F (see Figure 7) acts on the tip of the mount mounting portion 44, deformation of the mount mounting portion 44 can be suppressed, and vibration of the mount mounting portion 44 can be suppressed.

[0113] As described above, in the cover structure of the engine 1 in which the mount attachment portion 44 to which the mount bracket 51A is fastened bulges outward from the chain cover 40, the amount of outward bulge of the mount attachment portion 44 can be increased while suppressing vibration of the mount attachment portion 44.

[0114] Furthermore, according to the cover structure of the engine 1 of this embodiment, the chain cover 40 has a central boss 45B that is installed above the mount attachment portion 44 and aligned in the vertical direction with the central boss 45A, and a first rib 46A that extends from the central boss 45B to the central boss 45A and the central bulge portion 44G and connects the central boss 45B to the central boss 45A and the central bulge portion 44G.

[0115] This allows the central boss 45B to be connected to the central boss 45A and the central bulging portion 44G by the first rib 46A extending downward from the central boss 45B toward the central boss 45A.

[0116] Therefore, the first rib 46A can increase the vertical rigidity of the widthwise central portion of the mount attachment portion 44.

[0117] In addition, according to the cover structure of the engine 1 of this embodiment, there is a second rib 46B extending from the central boss 45B to the left side bulge portion 44H and connecting the central boss 45B and the left side bulge portion 44H, and a third rib 46C extending from the central boss 45B to the right side bulge portion 44I and connecting the central boss 45B and the right side bulge portion 44I.

[0118] This allows the central boss 45B and the left side bulging portion 44H to be connected by the second rib 46B extending diagonally downward to the left from the central boss 45B toward the left side bulging portion 44H, and allows the central boss 45B and the right side bulging portion 44I to be connected by the third rib 46C extending diagonally downward to the right from the central boss toward the right side bulging portion 44I.

[0119] Therefore, the second rib 46B and the third rib 46C can increase the rigidity in the width direction of the mount attachment portion 44. Therefore, the first rib 46A, the second rib 46B and the third rib 46C can increase the rigidity of the entire mount attachment portion 44.

[0120] In addition, when a vertical load F is applied to the mount attachment portion 44 from the mount bracket 51A when the engine 1 vibrates, this load F can be distributed by the first rib 46A, the second rib 46B and the third rib 46C to the central boss 45A and the central bulge portion 44G, the left side bulge portion 44H and the outer boss 42a, and the right side bulge portion 44I and the outer boss 43a.

[0121] As a result of the above, when a vertical load F is applied to the mount attachment portion 44 when the engine 1 vibrates, deformation of the mount attachment portion 44 can be more effectively suppressed, and vibration of the mount attachment portion 44 can be more effectively suppressed.

[0122] Furthermore, according to the cover structure of the engine 1 in this embodiment, the chain cover 40 has a fourth rib 46D that extends from the central boss 45A and the central bulge 44G to the center in the extension direction of the second rib 46B, and connects the central boss 45A and the central bulge 44G to the center in the extension direction of the second rib 46B.

[0123] In addition, the chain cover 40 has a fifth rib 46E that extends from the central boss 45A and the central bulge 44G to the center in the extension direction of the third rib 46C and connects the center in the extension direction of the third rib 46C to the central boss 45A and the central bulge 44G.

[0124] This prevents the vertical load applied to the second rib 46B from concentrating from the second rib 46B to the left bulge 44H and the outer boss 42a, and prevents the vertical load applied to the third rib 46C from concentrating from the third rib 46C to the right bulge 44I and the outer boss 43a.

[0125] Therefore, the vertical load F applied to the mount attachment portion 44 when the engine 1 vibrates can be evenly distributed to the central boss 45A and the central bulging portion 44G, the left bulging portion 44H and the outer boss 42a, and the right bulging portion 44I and the outer boss 43a. As a result, deformation of the mount attachment portion 44 can be more effectively suppressed, and vibration of the mount attachment portion 44 can be more effectively suppressed.

[0126] According to the cover structure of the engine 1 of this embodiment, the mount attachment portion 44 includes mount bosses 44b, 44c, and 44d that extend from the upper wall 44A toward the curved wall portion 44D and fasten the mount bracket 51A to the upper wall 44A.

[0127] If the intersection of the second rib 46B and the fourth rib 46D is defined as a first intersection 47A, and the intersection of the third rib 46C and the fifth rib 46E is defined as a second intersection 47B, the first intersection 47A is connected to the mount boss 44d, and the second intersection 47B is connected to the mount boss 44b.

[0128] This enables the second rib 46B and the fourth rib 46D, and the third rib 46C and the fifth rib 46E to increase the rigidity of the mount bosses 44b, 44d.

[0129] Therefore, when a vertical load F is applied to the mount attachment part 44 when the engine 1 vibrates, it is possible to suppress vibration of the mount bosses 44b, 44c, 44d to which the mount bracket 51A is fastened by the bolts, and more effectively suppress deformation of the mount attachment part 44. As a result, vibration of the mount attachment part 44 can be more effectively suppressed.

[0130] At least one of the first intersection 47A and the second intersection 47B may be connected to any one of the mount bosses 44b, 44c, and 44d.

[0131] For example, the first intersection 47A may be connected to mount boss 44d and the second intersection 47B may be unconnected to mount boss 44b, or the first intersection 47A may be unconnected to mount boss 44d and the second intersection 47B may be connected to mount boss 44b.

[0132] Although an embodiment of the invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made without departing from the spirit and scope of the invention, and all such modifications and equivalents are intended to be encompassed by the following claims. [Explanation of symbols]

[0133] 1...engine (internal combustion engine), 2...engine body (internal combustion engine body), 7...crankshaft, 8...timing chain (transmission member), 9...side member (vehicle body), 11...intake camshaft (camshaft), 12...exhaust camshaft (camshaft), 33A, 33B, 33D, 33E...bolt (fastener), 40...chain cover (cover member), 41...vertical wall (body wall portion), 42...left side wall portion (first side wall portion), 42a...outer boss (first outer boss), 43...right side wall portion (second side wall portion), 43a...outer boss (second outer boss), 44...mount attachment portion, 44A...upper wall, 44B...peripheral wall, 44b, 44c, 44d...mount boss, 44C...lower wall, 44D...curved wall portion, 44E ...lower wall side left wall portion (first lower wall side wall portion), 44e...tip portion (tip portion in the bulging direction of the peripheral wall), 44F...lower wall side right wall portion (second lower wall side wall portion), 44G...central bulge portion, 44H...left side bulge portion (first bulge portion), 44h...left end portion (one end portion in the width direction of the curved wall), 44I...right side bulge portion (second bulge portion), 44i...right end portion (other end portion in the width direction of the curved wall), 44u...upper end portion (upper end portion of the curved wall portion), 45A...central boss (lower central boss), 45B...central boss (upper central boss), 46A...first rib, 46B...second rib, 46C...third rib, 46D...fourth rib, 46E...fifth rib, 47A...first intersection, 47B...second intersection, 51A...mount bracket

Claims

1. a cover member that covers a power transmission member that transmits power from a crankshaft to a camshaft; a main body wall portion; a first side wall portion that is provided at one end of the main body wall portion in a width direction; and a second side wall portion that is provided at the other end of the main body wall portion in the width direction. the cover member includes outer bosses provided on the first side wall portion and the second side wall portion, respectively, and fastened to the internal combustion engine body by fasteners; a plurality of central bosses located at a widthwise central portion of the body wall portion, and fastened to the internal combustion engine body by fasteners; and a mount attachment portion that bulges out from the body wall portion in a direction away from the internal combustion engine body and supports the internal combustion engine body on a vehicle body via a mount bracket, the mount attachment portion is a cover structure for an internal combustion engine having an upper wall to which the mount bracket is attached, a peripheral wall extending downward from an outer circumferential edge of the upper wall, and a lower wall extending downward from an outer circumferential edge of the peripheral wall, the lower wall has a curved wall portion that curves gradually away from the main body wall portion as it moves upward from the main body wall portion, and an upper end portion of the curved wall portion is connected to a tip end portion of the peripheral wall in a bulging direction, a first lower-wall side wall portion that connects one widthwise end portion of the curved wall portion to the peripheral wall and the first side wall portion, and a second lower-wall side wall portion that connects the other widthwise end portion of the curved wall portion to the peripheral wall and the second side wall portion, The plurality of central bosses include a lower central boss provided on the curved wall portion, the outer bosses include a first outer boss located on one side of the body wall in the width direction with respect to the lower central boss, and a second outer boss located on the other side of the body wall in the width direction with respect to the lower central boss, a first bulge portion that bulges inwardly from the curved wall portion into the cover member and is connected to the outer circumferential edge of the first outer boss, and a second bulge portion that bulges inwardly from the second lower wall side wall portion and the curved wall portion into the cover member and is connected to the outer circumferential edge of the second outer boss.

2. the plurality of central bosses include an upper central boss that is disposed above the mount attachment portion and aligned in a vertical direction with the lower central boss, the cover member includes a first rib extending from the upper central boss to the lower central boss and the central bulge portion and connecting the upper central boss to the lower central boss and the central bulge portion; a second rib extending from the upper central boss to the first bulge and connecting the upper central boss and the first bulge; 2. The cover structure for an internal combustion engine according to claim 1, further comprising a third rib extending from said upper central boss to said second bulging portion and connecting said upper central boss and said second bulging portion.

3. the cover member includes a fourth rib extending from the lower central boss and the central bulge to a center portion in the extension direction of the second rib and connecting the lower central boss and the central bulge to the center portion in the extension direction of the second rib; 3. The cover structure for an internal combustion engine as described in claim 2, further comprising a fifth rib extending from the lower central boss and the central bulge to a center in the direction in which the third rib extends and connecting the center in the direction in which the third rib extends to the lower central boss and the central bulge.

4. the mount attachment portion includes a plurality of mount bosses extending from the upper wall toward the curved wall portion and fastening the mount bracket to the upper wall with a fastener; 4. The cover structure for an internal combustion engine according to claim 3, characterized in that, when an intersection of the second rib and the fourth rib is defined as a first intersection and an intersection of the third rib and the fifth rib is defined as a second intersection, at least one of the first intersection and the second intersection is connected to any one of the multiple mount bosses.

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