Internal combustion engine

Abstract

To provide a small internal combustion engine.SOLUTION: An internal combustion engine includes: a plurality of chains that are wound around a crank shaft protruded from an internal combustion engine body so as to be located adjacent to each other in the axial direction and to which power is distributed from the crank shaft; a chain tensioner that applies tension to the chains; a chain guide that guides the chains; and a bracket mounted to the internal combustion engine body so as to be located astride at least one chain out of the plurality of chains. At least one of the chain tensioner and the chain guide is mounted to the bracket.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an internal combustion engine. [Background technology]

[0002] For example, Patent Document 1 describes that the power of the crankshaft of an internal combustion engine is distributed to two accessories and a camshaft via a single wrapped electric member (chain). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-156640 Summary of the Invention [Problem to be solved by the invention]

[0004] However, with the above configuration, the overall length of the chain increases, so the size of the internal combustion engine itself must also be increased accordingly.In contrast, if a configuration is used in which the power of the crankshaft is distributed to accessories, camshafts, etc. via multiple chains, each chain will be shorter, but the fastening areas of the chain guides and chain tensioners for each chain must be provided on the internal combustion engine itself so as not to interfere with each chain, which still increases the size.

[0005] SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has an object to provide a small-sized internal combustion engine. [Means for solving the problem]

[0006] The internal combustion engine of the present invention comprises a plurality of chains that are looped around a crankshaft protruding from the internal combustion engine body so as to be adjacent to each other in the axial direction and to which power is distributed from the crankshaft, a chain tensioner that applies tension to the chains, a chain guide that guides the chains, and a bracket attached to the internal combustion engine body so as to straddle at least one of the plurality of chains, and at least one of the chain tensioner and the chain guide is attached to the bracket.

[0007] In the above internal combustion engine, the bracket may have a bridge shape with a pair of bent ends in a direction substantially perpendicular to the axial direction, and may be fastened to the internal combustion engine body at the pair of ends.

[0008] In the above internal combustion engine, at least one of the chain tensioner and the chain guide may be fastened to a connecting portion that connects the pair of end portions.

[0009] In the above internal combustion engine, the internal combustion engine body may have a set of protrusions that are fastened to the set of ends of the bracket, and the at least one chain may pass between the set of protrusions.

[0010] In the above internal combustion engine, at least one of the chain tensioner and the chain guide may be fastened to the protruding portion together with the end portion. [Effects of the Invention]

[0011] According to the present invention, the internal combustion engine can be made smaller. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a plan view showing an example of a chain mechanism. [Figure 2] FIG. 2 is a cross-sectional view of the crankshaft taken along line AA in FIG. [Figure 3]FIG. 3 is a plan view showing an example of a bracket. [Figure 4] FIG. 4 is an enlarged view of the bracket and its surroundings. [Figure 5] FIG. 5 is a cross-sectional view taken along line BB in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0013] (Chain mechanism configuration) 1 is a plan view showing an example of a chain mechanism 91. The chain mechanism 91 is provided, for example, on a side surface 90s of a cylinder block 90, which is the main body of an engine 9. Here, the engine 9 is an example of an internal combustion engine, and the cylinder block 90 is an example of an internal combustion engine main body. Note that the chain mechanism 91 in this example is provided on a V-type engine 9, but is not limited to this and may be provided on other internal combustion engines.

[0014] 1 and 3 to 5 show an X-axis, a Y-axis, and a Z-axis that are perpendicular to each other. The X-axis and Y-axis are directions that are approximately parallel to the side surface 90s, and the Z-axis is a direction that is approximately perpendicular to the side surface 90s.

[0015] The chain mechanism 91 includes a bracket 1, multiple chains 81, 82, 84-86, fixed guides 50-53, movable guides 61, 62, chain tensioners 64, 610, 620, a crankshaft 70, and sprockets 71, 72, 74. The crankshaft 70 rotates when power is transmitted from a cylinder in a cylinder block 90. The power of the crankshaft 70 is distributed to each of the chains 81, 82, 84-86 by the following configuration.

[0016] Figure 2 is a cross-sectional view of crankshaft 70 taken along line AA in Figure 1. The axial direction of crankshaft 70 coincides with the direction of the Z axis. Chains 81 and 82 are wound around the circumferential surface of crankshaft 70 via sprocket 700, and chain 84 is wound around crankshaft 70 via sprocket 701. Chains 81, 82, and 84 are wound around crankshaft 70 in this order so as to be adjacent to each other in the axial direction of crankshaft 70.

[0017] 1 , sprocket 71 is connected to, for example, an intake camshaft (not shown) on the right bank side of engine 9, and has an integrated large diameter gear 710 and small diameter gear 711. Note that large diameter gear 710 is shown by a dotted line for convenience, as it is located outward of small diameter gear 711 when viewed from side surface 90s. Chain 81 extends from crankshaft 70 to the right bank side of engine 9 and is looped around large diameter gear 710. As a result, sprocket 71 rotates in conjunction with rotation of crankshaft 70.

[0018] Sprocket 75 is disposed near sprocket 71 on the right bank of engine 9 and is connected to, for example, an exhaust camshaft (not shown). Chain 85 is wound around small diameter gear 711 of sprocket 71 and sprocket 75. As a result, sprocket 75 rotates in conjunction with the rotation of crankshaft 70.

[0019] Movable guide 61 is disposed between crankshaft 70 and sprocket 75, outside the area surrounded by chain 81. Movable guide 61 extends from near crankshaft 70 toward the middle between sprocket 71 and sprocket 75, and is pressed against chain 81. The rear end of movable guide 61 is fastened by bolt 31 so as to be rotatable relative to cylinder block 90.

[0020] The chain tensioner 610 is disposed near the tip of the movable guide 61, and presses the tip of the movable guide 61 by, for example, a spring mechanism. This urges the movable guide 61 toward the chain 81, generating tension in the chain 81.

[0021] Fixed guide 51 is disposed between crankshaft 70 and sprocket 71 in an area surrounded by chain 81. Fixed guide 51 is a plate-like member with a substantially L-shaped cross section. Fixed guide 51 is fixed by bolts 33 in the area surrounded by chain 81, passes between chain 81 and side surface 90s, protrudes to the outside of chain 81, and is bent in the positive direction of the Z axis. A guide rail 500 that runs along the side surface of chain 81 is held in the bent portion of fixed guide 51. On the opposite side of fixed guide 51, guide rail 500 is held by fixed guide 50 near crankshaft 70.

[0022] Furthermore, sprocket 72 is connected to, for example, an intake camshaft (not shown) on the left bank side of engine 9, and has an integrated large diameter gear 720 and small diameter gear 721. Note that large diameter gear 720 is shown by a dotted line for convenience, as it is located outward of small diameter gear 721 when viewed from side surface 90s. Chain 82 extends from crankshaft 70 to the left bank side of engine 9 and is wound around large diameter gear 720. As a result, sprocket 72 rotates in conjunction with the rotation of crankshaft 70.

[0023] Sprocket 76 is disposed near sprocket 72 on the left bank of engine 9 and is connected to, for example, an exhaust camshaft (not shown). Chain 86 is wound around small diameter gear 721 of sprocket 72 and sprocket 76. As a result, sprocket 76 rotates in conjunction with the rotation of crankshaft 70.

[0024] The movable guide 62 is disposed between the crankshaft 70 and the sprocket 72, outside the area surrounded by the chain 82. The movable guide 62 extends from near the crankshaft 70 toward near the sprocket 72, and is pressed against the chain 82. The rear end of the movable guide 62 is fastened by a bolt 32 so as to be rotatable relative to the cylinder block 90.

[0025] The chain tensioner 620 is disposed near the tip of the movable guide 62, and uses, for example, a spring mechanism to press the tip of the movable guide 62. This biases the movable guide 62 toward the chain 82, generating tension in the chain 82.

[0026] Fixed guide 52 is disposed outside the area surrounded by chain 82, between crankshaft 70 and sprockets 72, 76. Fixed guide 52 is a plate-like member with a generally L-shaped cross section. Fixed guide 52 is fixed by bolts 34 outside the area surrounded by chain 82, and is bent in the positive direction of the Z axis in front of chain 82. A guide rail 520 that runs along the side of chain 82 is held in the bent portion of fixed guide 52. On the opposite side of fixed guide 52, guide rail 520 is held by fixed guide 53 near crankshaft 70.

[0027] The sprocket 74 is located on the right side near the crankshaft 70. A chain 84 is wound around the sprocket 74 and the crankshaft 70. For example, the sprocket 74 is connected to an oil pump (not shown). This allows the oil pump to be driven in conjunction with the crankshaft 70.

[0028] The fixed guides 50 and 53 and the chain tensioner 64 are fixed to the cylinder block 90 together with the bracket 1 in the vicinity of the crankshaft 70 .

[0029] Fixed guides 50 and 53 are examples of chain guides that respectively guide chains 81 and 82. Fixed guide 50 is fastened to cylinder block 90 by bolts 36 near crankshaft 70 within an area surrounded by chain 81. Fixed guide 50 is a plate-like member that extends along chain 81 between crankshaft 70 and another fixed guide 51, and has a substantially L-shaped cross section.

[0030] The fixed guide 50 covers the chain 81 from the outside of the cylinder block 90, extends to the outside of the area surrounded by the chain 81, and is bent in the negative direction of the Z axis. A guide rail 500 is held in the bent portion of the fixed guide 50.

[0031] Furthermore, fixed guide 53 is fastened to cylinder block 90 by bolts 38 near crankshaft 70 within an area surrounded by chain 82. Fixed guide 53 is a plate-like member that extends along chain 82 between crankshaft 70 and other fixed guides 52, and has a substantially L-shaped cross section.

[0032] The fixed guide 53 passes between the chain 82 and the side surface 90s, extends outward from the chain 82, and is bent in the positive direction of the Z axis. A guide rail 520 is held in the bent portion of the fixed guide 53.

[0033] The chain tensioner 64 applies tension to the chain 84. The chain tensioner 64 is disposed outside the area surrounded by the chain 84, near the crankshaft 70 and the sprocket 74. One end of the chain tensioner 64 is fastened by a bolt 37 so as to be rotatable relative to the cylinder block 90.

[0034] The chain tensioner 64 is biased by, for example, a spring mechanism provided around the axis of the bolt 37 so as to press against the side of the chain 84. This generates tension in the chain 84.

[0035] The bracket 1 is attached to the cylinder block 90 so as to straddle the chains 81, 82. Therefore, the fixed guides 50, 53 and the chain tensioner 64 can be provided without interfering with the chains 81, 82, and the space required for the chain mechanism 91 on the side surface 90s of the cylinder block 90 can be reduced.

[0036] (bracket shape) Fig. 3 is a plan view showing an example of the bracket 1. Fig. 3 shows the front, left side, right side, and bottom of the bracket 1. The front of the bracket 1 represents the bracket 1 when viewed from the front at the side surface 90s. The X-axis, Y-axis, and Z-axis in Fig. 3 represent a coordinate system for the bracket 1 on the bottom.

[0037] Bracket 1 is a plate-shaped metal member formed, for example, from sheet metal. Bracket 1 has plate-shaped fixed portions 10 and 15, bent portions 11 and 14, an inclined portion 13, and a central portion 12. Fixed portion 10, bent portion 11, central portion 12, inclined portion 13, bent portion 14, and fixed portion 15 are adjacent to each other in this order in the X-axis direction.

[0038] The fixed portion 10 has fastening holes 100 for the bolts 38 that fix the fixed guide 53. The fastening holes 100 penetrate the plate surface of the fixed portion 10 in the Z-axis direction. The plate surface of the fixed portion 10 faces the side surface 90s. The bent portion 11 is bent substantially at a right angle to the plate surface of the fixed portion 10.

[0039] The central portion 12 has a fastening hole 120 through which a bolt 37 for connecting the chain tensioner 64 is inserted. The fastening hole 120 passes in the Z-axis direction through a generally bowl-shaped fastening portion 121 that protrudes downward (in the negative Z-axis direction) from the central portion 12. The central portion 12 is bent at a substantially right angle to the bent portion 11 so as to face the side surface 90s.

[0040] The inclined portion 13 is inclined in the negative direction of the Z axis at a predetermined angle relative to the plate surface of the central portion 12. The bent portion 14 is bent at a predetermined angle relative to the inclined portion 13 so that its plate surface is approximately perpendicular to the plate surface of the central portion 12.

[0041] The fixed portion 15 has fastening holes 150 for the bolts 36 that fix the fixed guide 50. The fixed portion 15 is bent at a substantially right angle to the bent portion 14 so as to face the side surface 90s. The plate surfaces of the two bent portions 11, 14 are not parallel to each other, and the normals to the respective plate surfaces intersect at a predetermined angle.

[0042] In this way, bracket 1 has a bridge shape in which a pair of end portions in the X-axis direction are bent. Note that fixed portions 10 and 15, inclined portion 13, and bent portions 11 and 14 are an example of a pair of end portions of bracket 1 in a direction approximately perpendicular to the axial direction of crankshaft 70. Also, center portion 12 is an example of a connecting portion that connects inclined portion 13 and bent portion 11.

[0043] Furthermore, the central portion 12, the inclined portion 13, the bent portion 14, and one end 16 of the fixed portion 15 are bent in the positive direction of the Z axis. The fixed portion 10 and one end 17 of the bent portion 11 are also bent in the positive direction of the Z axis. This improves the strength of the bracket 1 compared to when it is not bent.

[0044] (Positional relationship between bracket and other parts) Figure 4 is an enlarged view of the periphery of bracket 1, and Figure 5 is a cross-sectional view taken along line BB in Figure 1. In Figure 4, fixed guides 50, 53 and chain tensioner 64 are indicated by dotted lines, and chains 81, 82 are indicated by dashed lines. Note that in Figures 4 and 5, components that are common to Figures 1 and 3 are given the same reference numerals, and descriptions thereof will be omitted.

[0045] The fixing portions 10, 15 at both ends of the bracket 1 are fastened to a pair of protrusions 90a, 90b on the side surface 90s by bolts 38, 36, respectively. The protrusions 90a, 90b protrude from the side surface 90s in the positive direction of the Z axis and have fastening holes 901, 900 for the bolts 38, 36. In this way, the bracket 1 has a bridge shape with both ends bent, and is fastened to the cylinder block 90 at the pair of fixing portions 10, 15. This allows space to be secured between the pair of fixing portions 10, 15 for passing the chain 82. Furthermore, because the bracket 1 has a bridge shape, the center portion 12 can be spaced further away from the side surface 90s than the fixing portions 10, 15.

[0046] A chain tensioner 64 is attached to the central portion 12. A recess 640 that is open to the outside of the cylinder block 90 (in the positive direction of the Z axis) is provided at the base, which is the center of rotation of the chain tensioner 64. A fastening hole 641 for a bolt 37 is formed at the bottom of the recess 640. The bolt 37 is threadedly engaged with the fastening hole 641 and the fastening hole 120 in the central portion 12. This allows the chain tensioner 64 to be attached to the central portion 12. Therefore, the chain tensioner 64 can apply tension to the chain 84 that is located outside the central portion 12.

[0047] Furthermore, when the side surface 90s is viewed from the front, the protrusion 90a is located within the area surrounded by the chain 82 and outside the area surrounded by the chain 81. The protrusion 90b is located within the area surrounded by the chain 81 and outside the area surrounded by the chain 82. With this arrangement, the bracket 1 is provided so as to straddle the chains 81 and 82.

[0048] The chain 82 passes under the central portion 12 between the bent portion 11 and the fixed portion 15 of the bracket 1. The chain 81 also passes under the central portion 12 and the inclined portion 13 between the protruding portions 90a and 90b. This allows the chain 81 to straddle the bracket 1 while suppressing the height of the bracket 1 (the distance from the side surface 90s).

[0049] Furthermore, fixed guide 53 is fastened to protrusion 90a together with fixed portion 10 of bracket 1 by bolt 38, and fixed guide 50 is fastened to protrusion 90b together with fixed portion 15 of bracket 1 by bolt 36. Bolt 38 passes through fastening hole 100 of fixed portion 10 and fastening hole 530 of fixed guide 53 in this order to be fixed to protrusion 90a, and bolt 36 passes through fastening hole 150 of fixed portion 15 and fastening hole 501 of fixed guide 50 in this order to be fixed to protrusion 90b.

[0050] In this way, the fixed guides 50, 53 are fastened to the protrusions 90a, 90b together with the fixed portions 10, 15 of the bracket 1. Therefore, fastening space for the fixed guides 50, 53 and the fixed portions 10, 15 can be saved on the side surface 90s.

[0051] As described above, the bracket 1 is attached to the cylinder block 90 so as to straddle the chains 81, 82, and the chain tensioner 64 and fixed guides 50, 53 are attached to the bracket 1. Therefore, the chain tensioner 64 and fixed guides 50, 53 can be fixed onto the cylinder block 90 without interfering with the chains 81, 82. This reduces the space required to fasten the chain tensioner 64 and fixed guides 50, 53 on the side surface 90s of the cylinder block 90, allowing the engine 9 to be made more compact.

[0052] In this example, the chain tensioner 64 is attached to the central portion 12 of the bracket 1, and the fixed guides 50 and 53 are attached to the fixed portions 10 and 15 of the bracket 1, respectively, but this is not limiting. For example, the fixed guide 50 may be attached to the central portion 12, or the chain tensioner 64 may be attached to the fixed portion 10, with the attachment form being determined depending on the design of the chain mechanism 91. Furthermore, although the bracket 1 only straddles the chains 81 and 82, it may also straddle another chain 84 that is looped around the crankshaft 70 depending on the design of the chain mechanism 91.

[0053] The above-described embodiment is a preferred example of the present invention, but the present invention is not limited to this and can be modified in various ways without departing from the spirit of the present invention. [Explanation of symbols]

[0054] 1 bracket, 9 engine (internal combustion engine), 10, 15 fixed portion (end), 11, 14 bending portion (end), 13 inclined portion (end), 12 center portion (connecting portion), 81, 82, 84 chain, 50, 53 fixed guide (chain guide), 64 chain tensioner, 90 cylinder block (internal combustion engine body), 90a, 90b convex portion

Claims

1. a plurality of chains that are wound around a crankshaft protruding from a main body of the internal combustion engine so as to be adjacent to each other in the axial direction, and to which power is distributed from the crankshaft; a chain tensioner that applies tension to the chain; a chain guide that guides the chain; a bracket attached to the internal combustion engine body so as to straddle at least one of the plurality of chains, At least one of the chain tensioner and the chain guide is attached to the bracket. Internal combustion engine.

2. the bracket has a bridge shape with a pair of bent ends in a direction substantially perpendicular to the axial direction, and is fastened to the internal combustion engine body at the pair of ends.

2. The internal combustion engine according to claim 1.

3. At least one of the chain tensioner and the chain guide is fastened to a connecting portion that connects the pair of end portions.

3. The internal combustion engine according to claim 2.

4. the internal combustion engine body has a pair of protrusions that are fastened to the pair of end portions of the bracket, The at least one chain passes between the pair of protrusions.

3. The internal combustion engine according to claim 2.

5. At least one of the chain tensioner and the chain guide is fastened to the protrusion together with the end portion.

5. The internal combustion engine according to claim 4.

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