CROSS-REFERENCE TO RELATED APPLICATION
This application claims priority to Japanese Patent Application No. 2023-195950 filed on Nov. 17, 2023, incorporated herein by reference in its entirety.
BACKGROUND
1. Technical Field
The present disclosure relates to an engine.
2. Description of Related Art
An oil pan is connected to a crankcase of an engine so as to block an opening portion at a lower portion of the crankcase (see Japanese Unexamined Patent Application Publication No. 2015-124697 (JP 2015-124697 A), for example).
SUMMARY
Rigidity is low around the opening portion of the crankcase. Therefore, vibrations caused by the combustion stroke, rotation of a crankshaft, and the like are easily transmitted to the periphery of the opening portion of the crankcase. As a result, the vibrations may be transmitted to the oil pan, and vibration noise may increase.
Thus, it is an object of the present disclosure to provide an engine in which vibration noise is suppressed.
The above object can be achieved by an engine including: a crankcase that has an opening portion in a lower portion; and an oil pan connected to the lower portion of the crankcase so as to block the opening portion, in which the crankcase includes a reinforcing plate portion formed integrally with the crankcase so as to span the opening portion.
The crankcase may include a rib portion that extends from an edge of the opening portion to the reinforcing plate portion.
The engine may further include an oil strainer; the reinforcing plate portion may include a through hole; the oil strainer may include a pipe member and a case member; the case member may have an inlet port and an outlet port; the pipe member may be fixed to a lower surface of the reinforcing plate portion so as to communicate with the through hole; and the case member may be fixed to an upper surface of the reinforcing plate portion such that the inlet port communicates with the through hole.
The case member may protrude from the reinforcing plate portion and cover a part of the opening portion when the crankcase is seen from above.
According to the present disclosure, it is possible to provide an engine in which vibration noise is suppressed.
BRIEF DESCRIPTION OF THE DRAWINGS
Features, advantages, and technical and industrial significance of exemplary embodiments of the disclosure will be described below with reference to the accompanying drawings, in which like signs denote like elements, and wherein:
FIG. 1 is a schematic configuration diagram of an engine;
FIG. 2 is a top view of a crankcase and an oil pan of a comparative example;
FIG. 3 is a top view of the crankcase and the oil pan of the present embodiment;
FIG. 4 is a top view of an oil strainer, a crankcase, and an oil pan; and
FIG. 5 is a cross-sectional A-A view of FIG. 4.
DETAILED DESCRIPTION OF EMBODIMENTS
FIG. 1 is a schematic configuration diagram of an engine 1. The engine 1 includes a cylinder block 2, a cylinder head 3, a head cover 4, a chain cover 5, a crankcase 6, and an oil pan 7. The cylinder head 3 is attached to an upper portion of the cylinder block 2. The head cover 4 is attached to an upper portion of the cylinder head 3 and an upper portion of the chain cover 5. The crankcase 6 is attached to a lower portion of the cylinder block 2. The oil pan 7 is attached to a lower portion of the crankcase 6. The chain cover 5 is attached to a side surface of the cylinder block 2, a side surface of the cylinder head 3, and a side surface of the crankcase 6.
A plurality of cylinder 2a in which the piston 2b is accommodated are provided in the cylinder block 2. In FIG. 1, only a pair of cylinder 2a and a piston 2b are shown. In the cylinder head 3, an intake valve 3a for opening and closing the cylinder 2a and an intake camshaft 3c and an exhaust camshaft 3d for driving the exhaust valve 3b are provided. In the crankcase 6, a crankshaft 6a that rotates by reciprocating motion of the piston 2b is provided. A chain 5a that transmits the rotation of the crankshaft 6a to the intake camshaft 3c and the exhaust camshaft 3d is accommodated in the chain cover 5. Engine oil for lubricating the sliding portion of the engine 1 is stored in the oil pan 7.
Before describing the crankcase 6 of the present embodiment, the crankcase 6x of the comparative example will be described. FIG. 2 is a view of the crankcase 6x and the oil pan 7 from above. In FIG. 2, the chain cover 5 is disposed on the upper side of the paper surface of the crankcase 6x. The crankcase 6x includes a bottom wall portion 61 and a side wall portion 62 formed at a peripheral edge of the bottom wall portion 61. An opening portion 63 communicating with the oil pan 7 is formed in the bottom wall portion 61. The engine oil stored in the oil pan 7 is supplied to each sliding portion of the engine 1 by an oil pump via an oil strainer to be described later. The engine oil used for lubrication is recovered again into the oil pan 7 via the opening portion 63. As shown in FIG. 2, the opening portion 63 is formed in the bottom wall portion 61 to be large. Therefore, the rigidity of the periphery of the opening portion 63 is low, and the opening is easily deformed. Therefore, vibrations caused by the combustion stroke, the crankshaft 6a, and the like are easily transmitted to the periphery of the opening portion 63. As a result, vibration may be transmitted to the oil pan 7, and the vibration noise may increase.
FIG. 3 is a view of the crankcase 6 and the oil pan 7 of the present embodiment viewed from above. In the crankcase 6, the reinforcing plate portion 64 is formed so as to span the opening portion 63. In other words, the reinforcing plate portion 64 extends from one of the opposite edges of the opening portion 63 to the other. The reinforcing plate portion 64 is formed integrally with the crankcase 6. The reinforcing plate portion 64 is formed in a flat plate shape. This ensures rigidity around the opening portion 63. As a result, the vibration is suppressed from being transmitted to the oil pan 7, and the vibration noise is suppressed.
Further, a plurality of rib portions 67 extend from the edge of the opening portion 63 to the reinforcing plate portion 64. Such a rib portion 67 also ensures rigidity around the opening portion 63 and suppresses vibration noise. In this embodiment, the number of the rib portions 67 extending from the edge of the opening portion 63 to the reinforcing plate portion 64 is two, but the present disclosure is not limited thereto.
As shown in FIG. 3, a through hole 65 is formed in the reinforcing plate portion 64. The through hole 65 is formed by an oil strainer, which will be described later, in order to secure the suction of the engine oil. Two bolt holes 66 are formed in the reinforcing plate portion 64. A bolt for attaching the oil strainer to the reinforcing plate portion 64 is inserted into the bolt hole 66.
FIG. 4 is a top view of the oil strainer 8, the crankcase 6, and the oil pan 7. FIG. 5 is a cross-sectional A-A view of FIG. 4. The oil strainer 8 includes a pipe member 8a and a case member 8b. The pipe member 8a is fixed to the lower surface of the reinforcing plate portion 64. The case member 8b is fixed to the upper surface of the reinforcing plate portion 64. Specifically, the pipe member 8a and the case member 8b are fixed by the bolt B via the reinforcing plate portion 64.
The pipe member 8a includes a distal end 81a and a base end 82a. The distal end 81a faces the bottom surface of the oil pan 7. The base end 82a communicates with the through hole 65 of the reinforcing plate portion 64. In the case member 8b, a filter medium 81c for filtering the engine oil is provided. The case member 8b includes an inlet 81b and an outlet 82b. The inlet 81b communicates with the through hole 65 of the reinforcing plate portion 64. An oil pump is attached to the outlet 82b via a pipe (not shown). Accordingly, the engine oil stored in the oil pan 7 is supplied to the respective sliding portions by the oil pump via the pipe member 8a, the through hole 65 of the reinforcing plate portion 64, and the case member 8b. Thus, the intake of the engine oil by the oil strainer 8 is ensured. The oil strainer 8 is supported in a stable state by the reinforcing plate portion 64.
As shown in FIG. 4, when the case member 8b is viewed from above, a part of the case member 8b protrudes from the reinforcing plate portion 64 and covers a part of the opening portion 63. Therefore, when the engine oil is collected in the oil pan 7, the engine oil is suppressed from falling directly to the stored engine oil of the oil pan 7 through the opening portion 63. As a result, generation of air bubbles in the engine oil stored in the oil pan 7 is suppressed. As a result, a decrease in oil pressure caused by bubbles in the engine oil is suppressed, and the sliding portions of the engine 1 are appropriately lubricated.
Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present disclosure described in the claims.
Patent Application
20250163835
