JP4561718B2 - Engine front structure - Google Patents

Description

  The present invention relates to a front structure of an engine. In particular, the present invention relates to the support of a chain guide that regulates the runout of a chain that transmits the power of a crankshaft to a camshaft.

  Conventionally, in an engine having a plurality of cylinders, a crankshaft sprocket, a camshaft sprocket, and a camshaft sprocket are connected to the front of the engine, which is one end in the column direction of the cylinder, A chain guide is provided between the crankshaft and the camshaft so as to be applied to the outer peripheral surface of the chain and to regulate the deflection thereof.

  The chain guide is usually connected to the front wall of the cylinder head of the engine, but there are two points: where to place the connecting position and how to secure the surface rigidity of the guide connecting part of the front wall. Must be considered. This is because the width of the front part of the engine needs to be increased depending on the coupling position, and the surface rigidity of the coupling part is related to the durability of the chain guide against the vibration of the chain.

The chain guide is usually coupled to the engine front wall on the outside of the chain and applied to the outer circumferential surface of the chain (see Patent Document 1). On the other hand, a plate is extended inside the chain from a shoe portion applied to the outer peripheral surface of the chain, and the plate is connected to the engine front wall inside the chain (see Patent Document 2). If the chain guide coupling portion is arranged inside the chain in this way, it is not necessary to secure a coupling space for the chain guide at the peripheral portion of the engine front wall, which is advantageous in reducing the width of the engine front wall.
JP 2001-349416 A JP 2004-316636 A

  However, the chain inner portion of the engine front wall (the central portion of the front wall) has a low surface rigidity, unlike the peripheral portion of the front wall. Therefore, when the chain guide coupling portion is provided on the engine front wall inside the chain, it is necessary to increase the surface rigidity of the coupling portion. This is to ensure the chain guide mounting rigidity and to reliably suppress the chain swing.

  On the other hand, it is conceivable to provide a rib or the like in the chain inner portion of the engine front wall.

  In other words, it is conceivable to increase the surface rigidity by partially increasing the thickness of the front wall and to connect the chain guide thereto, but this is disadvantageous for reducing the weight of the engine.

  Therefore, the present invention has been made in view of such a point, and the object of the present invention is to avoid the enlargement of the width of the front part of the engine, to surely suppress the tune fluctuation and to reduce the weight of the engine. It is to provide an advantageous engine front structure.

  In the present invention, a plate portion that couples the chain guide to the cylinder head is disposed inside the chain, and a curved portion that curves toward the outside of the engine is formed at a portion corresponding to the engine front end side tension bolt boss portion, Further, a bolt boss part for connecting the plate part is formed in the curved part.

  Specifically, in the invention of claim 1, a cylinder block having a plurality of cylinders arranged in a row, a cylinder head fastened to the cylinder block by a plurality of tension bolts, and a row of the plurality of cylinders The chain is wound around the crank sprocket of the crankshaft and the cam sprocket of the camshaft at the front of the engine, which is one end in the direction, and a chain guide that transmits the power of the crankshaft to the camshaft, and a chain guide that regulates the runout of the chain The cylinder head is formed with a boss portion for the tension bolt, and on the front wall side of the cylinder head, a cooling water extraction passage for taking cooling water out from the water jacket is formed. The chain guide includes a shoe part to which the outer peripheral surface of the chain is applied, and the chain part from the shoe part. Extending to the inside of the over emissions directed to a front structure of an engine having a plate portion which is bolted to the outer surface of the front wall of said cylinder head in said chain inside.

  The cooling water extraction passage extends from the water jacket to the cylinder head front wall side, bypassing the tension bolt boss located on the engine front end side, and extends to the side of the cylinder head. In the wall, a curved portion that curves toward the outside of the engine is formed at a portion corresponding to the engine front end side tension bolt boss portion so as to form the bypass cooling water outlet passage, A bolt boss portion for connecting the plate portion of the chain guide is formed.

  Thus, according to the present invention, since the chain guide is coupled to the inside of the chain of the cylinder head front wall, it is not necessary to secure a space for the coupling on the outer peripheral side of the chain, and the engine front width is increased. Can be avoided. Further, the surface rigidity of the portion of the cylinder head front wall where the chain guide bolt boss portion is disposed is enhanced by the formation of the curved portion. As a result, the chain guide is reliably supported by the front wall of the cylinder head, and the chain swing can be reliably suppressed.

  The curved portion that increases the surface rigidity of the front wall of the cylinder head is formed to form a cooling water extraction passage. A thick portion such as a rib is provided on the front wall of the cylinder head exclusively for coupling the chain guide. There is no need. That is, it is possible to secure a chain guide coupling portion with high surface rigidity by effectively using the curved portion for the cooling water extraction passage, which is advantageous for reducing the weight of the engine.

  According to a second aspect of the present invention, the front structure of the engine of the first aspect further includes a bearing member for pivotally supporting the camshaft, and the bearing member has a shape of an upper and lower half and the engine. It is disposed above a tension bolt seat located on the front end side, and is fastened to the cylinder head with a bolt.

  In other words, the fact that the bearing member is disposed above the seat for the engine front end side tension bolt means that the bearing for the bearing member fastening bolt and the seat for the tension bolt exceed the cylinder head when viewed from the side. That is, it is arranged in a positional relationship for wrapping. In other words, the cylinder head has a smaller amount of protrusion forward than the tension bolt boss portion in order to shorten the overall length of the engine. For this reason, there is no fastening space for the bearing member in front of the tension bolt boss portion, and the bearing member is disposed above the seat portion for the engine front end side tension bolt.

  Under such a background, in the present invention, in order not to impair the purpose of shortening the overall length of the engine, a curved portion that bypasses the above-described tension bolt is formed to form the cooling water extraction passage, and the curved portion is Effectively used for chain guide connection.

  Accordingly, it can be said that the structure in which the chain guide bolt boss portion is provided in the above-described curved portion is an effective means for securing the attachment rigidity of the chain guide while shortening the overall length of the engine.

  According to the first aspect of the present invention, since the chain guide is coupled to the inside of the chain on the front wall of the cylinder head, it is not necessary to secure a space for the coupling on the outer peripheral side of the chain. Thereby, the expansion of the engine front part width can be avoided. Further, the surface rigidity of the portion of the cylinder head front wall where the chain guide bolt boss portion is disposed is enhanced by the formation of the curved portion. As a result, the chain guide is reliably supported by the front wall of the cylinder head, and the chain swing can be reliably suppressed.

  The curved portion that increases the surface rigidity of the front wall of the cylinder head is formed to form a cooling water extraction passage. A thick portion such as a rib is provided on the front wall of the cylinder head exclusively for coupling the chain guide. There is no need. That is, it is possible to secure a chain guide coupling portion with high surface rigidity by effectively using the curved portion for the cooling water extraction passage, which is advantageous for reducing the weight of the engine.

  According to the second aspect of the present invention, the bearing member is disposed above the seat portion of the tension bolt boss portion located on the engine front end side. This eliminates the fastening space for the bearing member in front of the tension bolt boss portion, reduces the amount of cylinder head protruding forward from the tension bolt boss portion, and shortens the overall length of the engine. A curved portion that bypasses the tension bolt is formed to form the cooling water extraction passage without impairing the purpose of shortening the overall length of the engine, and this curved portion is effective for coupling the chain guide as described above. Used for Thereby, the mounting rigidity of the chain guide is ensured while shortening the overall length of the engine.

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

  FIG. 1 is a front view of a front structure of a horizontally mounted engine in which the cylinder row direction of the present invention is the vehicle width direction.

  1 is a front structure of an engine mounted on a vehicle, 2 is a cylinder block, 3 is a cylinder head, 4 is a crank sprocket, 5 is a cam sprocket, 6 is a chain, and 7 is a chain guide provided on the cylinder head 3. It is.

  A crankshaft 8 is pivotally supported at the lower part of the cylinder block 2, and the crank sprocket 4 is attached to one end of the crankshaft 8.

  The cylinder head 3 is fastened to the upper part of the cylinder block 2 by a plurality of tension bolts.

  Two camshafts, an intake side and an exhaust side, are pivotally supported on the upper portion of the cylinder head 3, and the cam sprocket 5 is attached to one end of the camshaft 9 on the exhaust side.

  The camshaft 9 is driven by a crankshaft 8 via a chain 6.

  That is, the chain 6 is wound around the crank sprocket 4 and the cam sprocket 5, and the rotation of the crankshaft 8 is transmitted to the camshaft 9 by this chain 6.

  A chain case 10 is attached to the front wall of the cylinder block 2. A chain cover (not shown) that covers the chain 6 and the like is attached across the chain case 10 and the front wall of the cylinder head 3.

  In the present embodiment, the direction in which the crankshaft 8 and the camshaft 9 extend (the depth direction in FIG. 1) is the front-rear direction of the engine 1, and the side where the chain 6 is arranged in the engine 1 (the front side in FIG. 1). On the other hand, the front side is called the rear side. Further, the left-right direction (left-right direction in FIG. 1) orthogonal to the front-rear direction of the engine 1 is referred to as the width direction of the engine 1.

 The chain guide 7 includes a shoe portion 7 a that is applied to the outer peripheral surface of the chain 6, and a plate portion 7 b that extends from the shoe portion 7 a to the inside of the chain 6.

  The plate portion 7 b is coupled to the outer surface of the front wall 3 a of the cylinder head 3 by a bolt 11 inside the chain 6.

  In the present embodiment, as described above, since the plate portion 7 b is coupled to the cylinder head 3 inside the chain 6, it is not necessary to secure a space for the coupling on the outer peripheral side of the chain 6. As a result, the enlargement of the front width of the engine 1 is avoided.

  In FIG. 1, reference numerals 21 to 24 denote chain guides that are supported (coupled) to the chain case 10 or the front wall of the cylinder head 3 outside the chain 6.

  FIG. 2 is an enlarged front view of the cylinder head 3 at the front portion of the engine 1.

  A bearing member 12 for supporting the camshaft 9 is fastened to the upper portion of the cylinder head 3 with bolts, and the bearing member 12 has an upper and lower halved shape.

  A curved portion 3c and a bolt boss portion 3d, which will be described in detail later, are provided on the front wall of the cylinder head 3.

  FIG. 3 is an enlarged plan view of the cylinder head 3 at the front portion of the engine 1.

  In the figure, for easy understanding, a plurality of cylinders 25 arranged in a row in the longitudinal direction of the engine 1 in the cylinder block 2 are indicated by wavy lines.

  A tension bolt seat 13 is formed on the upper surface of the cylinder head 3 at intervals in the front-rear direction, and a bolt seat for fastening the bearing member 12 to the cylinder head 3 at the front end. A portion 14 is formed.

  In the present embodiment, the tension bolt seat 13 and the bearing member fastening bolt seat 14 located on the most front end side of the engine have a positional relationship overlapping when viewed from the engine side. This is because the bearing member 12 is disposed above the seat portion 13 for the engine front end side tension bolt in order to shorten the overall length of the engine. As a result, the fastening space for the bearing member 12 in front of the engine front end side tension bolt boss portion is omitted, the amount of cylinder head 3 projecting forward from the engine front end side tension bolt boss portion is reduced, and the total engine length Is shortened.

  4 is a cross-sectional view taken along the line AA of FIG. 2 and shows a horizontal cross section of the cylinder head 3 portion positioned above the seat portion 13 for the engine front end side tension bolt shown in FIG.

  13B is a boss portion for the engine front end side tension bolt and corresponds to the seat portion 13 of the engine front end side tension bolt boss portion shown in FIG.

  Reference numeral 15 denotes a passage through which gas exhausted from the cylinder 25 shown in FIG. 3 passes (hereinafter, exhaust gas passage). The exhaust gas passage 15 extends to the side of the engine 1.

  A water jacket 16 through which cooling water circulates is provided in the cylinder head 3. In the present embodiment, the cooling water that has passed through the water jacket 16 flows out to the side of the cylinder head 3 on the front end side of the engine from the positional relationship between the horizontally placed engine and the radiator disposed at the front end portion of the vehicle body. .

  Therefore, a cooling water extraction passage 17 is formed on the front wall 3a side of the cylinder head 3 (the front side in FIG. 2, the lower side in FIG. 3) for taking out the cooling water that has passed through the water jacket 16 to the side of the engine 1. Has been.

  The cooling water outlet passage 17 bypasses the boss portion 13B for the engine front end side tension bolt from the water jacket 16 to the front wall 3a side (front side in FIG. 2) of the cylinder head 3 to the side of the cylinder head 3 (see FIG. 2 on the left).

  5 is a side view of the cylinder head 3 viewed from the left side, and FIG. 6 is a cross-sectional view taken along the line CC of FIG.

  As shown in FIGS. 5 and 6, the outlet 17 a of the cooling water outlet passage 17 is open on the side surface of the cylinder head 3.

  Reference numeral 3 b denotes a bolt hole for a tension bolt on the front end side of the engine 1. Since FIG. 6 is a cross-sectional view at a position deviated from the axis of the bolt hole 3b, the bolt hole appears thin.

  The outlet 17 a of the cooling water outlet passage 17 and the bolt hole 3 b for the tension bolt overlap with each other when viewed from the side of the cylinder head 3, but the cooling water outlet passage 17 is tensioned from the water jacket 16. The boss 13 for the bolt is detoured to the front side of the engine 1 (the front side in the figure).

  Next, in the present embodiment, a configuration for forming the above-described cooling water extraction passage 17 will be described in detail with reference to FIGS. 3, 4, and 7.

  As shown in FIGS. 3 and 4, in the present embodiment, in order to shorten the overall length of the engine, the bearing member 12 is disposed above the seat portion 13 for the engine front end side tension bolt so that the engine front end side tension is increased. The protruding amount of the cylinder head 3 from the bolt boss portion 13B is reduced.

  In order to form the above-described bypass cooling water outlet passage 17 without impairing the purpose of shortening the overall length of the engine, in the present embodiment, the front wall 3a of the cylinder head 3 is provided with the boss portion 13B for the engine front end side tension bolt. A curved portion 3c that is curved to the outside of the engine 1 is formed at a portion corresponding to (see FIG. 4). By forming the curved portion 3c, it is possible to form the cooling water extraction passage 17 in front of the engine front end side tension bolt boss portion 13B without impairing the purpose of shortening the overall length of the engine.

  FIG. 7 is a plan view showing the water jacket core 17 of the cylinder head 3.

  The core 17 includes a boss portion forming portion 17a for forming an engine front end side tension bolt boss portion, a cooling water extraction portion forming portion 17b having a shape corresponding to the inner surface of the curved portion 3c, and the core 17. A baseboard 17c for fixing in the cylinder head 3 is formed. The baseboard 17c forms the outlet portion of the cooling water extraction portion forming portion 17.

  The core 17 is disposed in the cylinder head 3 so that the end surface 17d contacts the inner surface of the curved portion 3c.

  Next, in the present embodiment, the configuration for coupling the chain guide 7 to the cylinder head 3 will be described again with reference to FIGS.

  In the present embodiment, as described above, the curved portion 3c is formed in order to form the cooling water extraction passage 17, and the plate portion 7c of the chain guide 7 is connected to the front wall 3a of the cylinder head 3 in this curved portion 3c. A bolt boss portion 3d is formed for coupling to the. Specifically, the bolt boss portion 3d is formed on the curved portion 3c so that a part thereof hangs on the skirt portion of the curved portion 3c. By having this configuration, the surface rigidity of the portion of the cylinder head front wall 3a where the bolt boss 3d is disposed is enhanced by forming the curved portion 3c.

  As is apparent from the above, in the present embodiment, in order to form the cooling water outlet passage 17 that bypasses the tension bolt described above, the curved portion 3c is formed in the cylinder head front wall 3a, and the curved portion A bolt boss 3d for attaching the chain guide 7 is formed on 3c, and as a result, the surface rigidity of the coupling portion of the chain guide 7 is increased. That is, in the present embodiment, the curved portion 3 c provided for forming the cooling water extraction passage 17 is effectively used to increase the surface rigidity of the coupling portion of the chain guide 7.

  Accordingly, when the engine 1 is driven, the vibration of the chain 6 is transmitted from the chain 6 through the shoe portion 7a and the plate portion 7b to the portion where the bolt boss portion 3d of the cylinder head front wall 3a is disposed. Since the surface rigidity of the portion where 3d is disposed is enhanced by the formation of the curved portion 3c, the chain guide 7 is reliably supported.

  As described above, according to this embodiment, since the chain guide 7 is coupled to the inside of the chain 7 of the cylinder head front wall 3a, it is not necessary to secure a space for the coupling on the outer peripheral side of the chain 7, and the width of the front portion of the engine Can be avoided. Further, the surface rigidity of the portion of the cylinder head front wall 3a where the bolt boss 3d is disposed is enhanced by the formation of the curved portion 3c. As a result, the chain guide 7 is reliably supported by the cylinder head front wall 3a, and the chain 6 can be reliably prevented from shaking.

  The curved portion 3c for increasing the surface rigidity of the cylinder head front wall 3a is formed so as to form the cooling water outlet passage 17, and the cylinder head front wall 3a has a rib or the like dedicated to the coupling of the chain guide 7. It is not necessary to provide a thick part. That is, the curved portion 3c for the cooling water extraction passage 17 can be effectively used to secure a chain guide coupling portion having high surface rigidity, which is advantageous for reducing the weight of the engine 1.

Further, according to the present embodiment, the bearing member 12 is fastened to the cylinder head 3 with a bolt above the seat portion 13 of the tension bolt boss portion 13B located on the engine front end side. Thereby, the fastening space for the bearing member 12 in front of the tension bolt boss portion 13B can be omitted, and the amount of the cylinder head 3 protruding forward from the tension bolt boss portion 13B can be reduced. Can be shortened.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims.

  For example, the bolt boss portion 3d may be formed on the curved portion 3c so that the entire bolt boss portion 3d hangs on the top of the curved portion 3c. Even if it does in this way, the effect similar to the above may be exhibited.

It is a front view of the front part structure of a horizontal engine which made the cylinder row direction of the present invention the vehicle width direction. It is an enlarged front view of the cylinder head in the front part of an engine. It is an enlarged plan view of a cylinder block at the front part of the engine. It is the sectional view on the AA line of FIG. It is the side view which looked at the cylinder head from the left. It is CC sectional view taken on the line of FIG. It is a top view which shows the water jacket core of a cylinder head.

Explanation of symbols

1 Engine front structure,
2 cylinder block,
3 cylinder head,
3a front wall,
3c curved part,
3d bolt boss,
4 Crank sprocket,
5 Cam sprocket,
6 Chain,
7 Chain guide,
7a shoe part,
7b Plate part,
8 crankshaft,
9 Camshaft,
12 bearing members,
13 Tension bolt boss seat,
13B Tension bolt boss,
17 Cooling water extraction passage.

Claims (2)

A cylinder block having a plurality of cylinders arranged in a row;
A cylinder head fastened to the cylinder block by a plurality of tension bolts;
A chain that is wound around the crank sprocket of the crankshaft and the cam sprocket of the camshaft, and transmits the power of the crankshaft to the camshaft, at the front of the engine that is one end side in the row direction of the plurality of cylinders;
A chain guide that regulates the runout of the chain,
In the cylinder head, a boss portion for the tension bolt is formed, and on the front wall side of the cylinder head, a cooling water extraction passage for taking cooling water out of the water jacket is formed.
The chain guide includes a shoe portion to which the outer peripheral surface of the chain is applied, and a plate portion that extends from the shoe portion to the inside of the chain and is bolted to the outer surface of the front wall of the cylinder head inside the chain. In the front structure of the engine,
The cooling water extraction passage extends from the water jacket to the cylinder head front wall side, bypassing the tension bolt boss portion located on the engine front end side, and extends to the side of the cylinder head.
In the front wall of the cylinder head, a curved portion curved toward the outside of the engine is formed at a portion corresponding to the engine front end side tension bolt boss portion so as to form the bypass cooling water outlet passage.
A front structure of an engine, wherein a bolt boss portion for connecting the plate portion of the chain guide is formed in the curved portion. A bearing member for supporting the camshaft;
2. The bearing member according to claim 1, wherein the bearing member has an upper and lower halved shape, is disposed above a seat portion for a tension bolt located on the engine front end side, and is fastened to the cylinder head by a bolt. The front structure of the engine described in 1.

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