Engine

Abstract

This engine (E) comprises: a crankshaft (2) that changes reciprocating motion of a piston (3) into rotational motion; a crankcase (4) that supports the crankshaft (2); first and second rotating bodies (21, 30a) that rotate in conjunction with the crankshaft (2); a first endless transmission member (23) that transmits the rotation of the crankshaft (2) to the first rotating body (21); a second endless transmission member (34) that transmits the rotation of the crankshaft (2) to the second rotating body (30a); a first guide body (36) that guides the first endless transmission member (23); and a second guide body (52) that guides the second endless transmission member (34). The first guide body (36) and the second guide body (52) are supported on the crankcase (4) by a common support member (50).

Description

engine Related Applications

[0001] This application claims priority from Japanese Patent Application No. 2023-203281, filed November 30, 2023, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to an engine used, for example, as a driving source for a vehicle.

[0003] An engine is sometimes used as a drive source for vehicles such as motorcycles (see, for example, Patent Document 1). In such an engine, power from a crankshaft drives devices such as an oil pump, a water pump, and intake and exhaust valves. The power from the crankshaft is transmitted to these devices using power transmission members such as a drive chain.

[0004] Japanese Patent Application Laid-Open No. 2014-065465

[0005] In such engines, in order to reduce the engine width dimension in the direction of the crankshaft axis, it is advantageous to arrange the sprockets on which the power transmission members that drive these devices are wound close to each other in the axial direction on the crankshaft. However, if the sprockets or the chains wound on them are arranged close to each other, there is a risk that the guide bodies that guide the chains will interfere with each other.

[0006] The disclosure of the present application provides an engine that can prevent interference of guide bodies.

[0007] The engine of the present disclosure comprises a crankshaft that converts the reciprocating motion of a piston into rotational motion, a crankcase that supports the crankshaft, first and second rotating bodies that rotate in conjunction with the crankshaft, a first endless transmission member that transmits the rotation of the crankshaft to the first rotating body, a second endless transmission member that transmits the rotation of the crankshaft to the second rotating body, a first guide body that guides the first endless transmission member, and a second guide body that guides the second endless transmission member, and the first guide body and the second guide body are supported on the crankcase by a common support member.

[0008] According to the engine of the present disclosure, the first guide body and the second guide body are supported on the crankcase by a common support member. This prevents interference between the first guide body and the second guide body. Furthermore, by using a common support member for support, the number of parts can be reduced and the space around the crankshaft can be used effectively.

[0009] Any combination of at least two features disclosed in the claims and / or the specification and / or the drawings is included in the present disclosure. In particular, any combination of two or more of the claims is included in the present disclosure.

[0010] The present disclosure will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and drawings are merely for illustration and explanation, and should not be used to define the scope of the present disclosure. The scope of the present disclosure is defined by the accompanying claims. In the accompanying drawings, the same part numbers in multiple drawings indicate the same parts.

[0023] Figure 1 is a side view of an engine according to a first embodiment of the present disclosure. Figure 2 is a front view of the engine. Figure 3 is a rear view of the engine. Figure 4 is a cross-sectional view of an endless transmission member and its guide body of the engine. Figure 5 is a cross-sectional view of a support structure for the guide body.

[0011] A preferred embodiment of the present disclosure will now be described with reference to Figures 1 to 5. The engine E of this embodiment is a reciprocating engine, and is used, for example, in an airplane in which a propeller is located at the tip of the fuselage. In this case, the engine E is housed within the fuselage, and engine power is transmitted to the propeller. The use of the engine E is not limited to this, and it can also be used, for example, as a drive source for a ship, or as a drive source for vehicles such as motorcycles and automobiles.

[0012] In the following description, the "width direction WD" refers to the direction in which the crankshaft 2 of the engine E extends, i.e., the axial direction of the crankshaft 2. In the width direction WD, the direction toward the width center is referred to as the "width inner side," and the direction away from the width center is referred to as the "width outer side." The "reciprocating direction VD" refers to the direction of reciprocating motion of the piston of the engine E. The direction perpendicular to both the "width direction WD" and the "reciprocating direction VD" is referred to as the "perpendicular direction PD."

[0013] The engine E of this embodiment is a six-cylinder engine with six cylinders aligned in the direction of the crankshaft 2. However, the number of cylinders is not limited to this and may be, for example, four. Furthermore, although the engine E of this embodiment is a gasoline engine, the fuel is not limited to gasoline. The crankshaft 2 converts the reciprocating motion of the pistons 3 into rotational motion.

[0014] The engine E has a crankcase 4 that supports the crankshaft 2, a cylinder 6 that protrudes from the crankcase 4 in one direction in the reciprocating direction VD, and a cylinder head 8 that is connected to the protruding end of the cylinder 6. In the following description, the direction in the reciprocating direction VD in which the cylinder 6 protrudes from the crankcase 4 is referred to as "upward," and the opposite side is referred to as "downward."

[0015] The crankcase 4 is divided into two parts, a lower crankcase 4a and an upper crankcase 4b. In this embodiment, the upper crankcase 4b and the cylinder 6 are integrally formed by molding. However, the upper crankcase 4b and the cylinder 6 may be separate bodies. In the following description, the integrated upper crankcase 4b and the cylinder 6 are referred to as a cylinder block 10.

[0016] The engine E further has a head cover 12 connected to the upper end of the cylinder head 8, and an oil pan 14 connected to the lower end of the crankcase 4. The cylinder head 8 and the cylinder head cover 12 form a cam chamber. The oil pan 14 stores engine oil, which is a type of lubricating fluid for the engine.

[0017] An intake port 16 opens on one side (right side in FIG. 1) of the cylinder head 8 in the orthogonal direction PD, and an exhaust port 18 opens on the other side (left side in FIG. 1) in the orthogonal direction PD. In the following description, the intake port side in the orthogonal direction PD will be simply referred to as the "intake side," and the exhaust port side will be simply referred to as the "exhaust side."

[0018] The intake port 16 and the exhaust port 18 are passages formed inside the cylinder head 8. The upstream end of the intake port 16 opens to one side of the cylinder head 8 in the orthogonal direction PD, and the downstream end opens to a combustion chamber 20 inside the cylinder 6. The upstream end of the exhaust port 18 opens to the combustion chamber 20 inside the cylinder 6, and the downstream end opens to the front of the other side of the cylinder head 8 in the orthogonal direction PD. An intake port 16 is formed for each cylinder. Similarly, an exhaust port 18 is formed for each cylinder.

[0019] External air is supplied as intake air from the intake port 16 to the combustion chamber 20, and fuel is injected into the combustion chamber 20 from the injector 22 to form a fuel-air mixture. The mixture in the combustion chamber 20 is ignited by the spark plug 24 and burns. Exhaust gas after combustion is discharged to the outside of the engine from the exhaust port 18.

[0020] The engine E of this embodiment is equipped with intake valves 17 that open and close intake ports 16, and exhaust valves 19 that open and close exhaust ports 18. The intake valves 17 and exhaust valves 19 are opened and closed by a valve mechanism 21. In this embodiment, two intake valves 17 and two exhaust valves 19 are provided for each cylinder.

[0021] The valve mechanism 21 opens and closes the intake valve 17 and the exhaust valve 19 in conjunction with the rotation of the crankshaft 2. In this embodiment, the valve mechanism 21 has an intake valve drive mechanism 21a and an exhaust valve drive mechanism 21b that are independent for the intake and exhaust sides. The intake valve drive mechanism 21a has an intake-side camshaft 21a provided with a cam that opens and closes the intake valve 17. The exhaust valve drive mechanism 21b has an exhaust-side camshaft 21b provided with a cam that opens and closes the exhaust valve 19.

[0022] 2, the engine E has a first endless transmission member 23 that transmits the rotation of the crankshaft 2 to the valve train 21. In this embodiment, a cam chain is used as the first endless transmission member 23. However, the first endless transmission member 23 is not limited to a chain and may be a drive belt.

[0023] As described above, in this embodiment, the intake-side and exhaust-side camshafts 21a, 21b constitute a first rotating body that rotates in conjunction with the crankshaft 2. The cam chain 23 constitutes a first endless transmission member that transmits the rotation of the crankshaft 2 to the first rotating bodies 21a, 21b.

[0024] The cam chain 23, which is a type of first endless transmission member, is disposed in a transmission member storage space CT. In this embodiment, the transmission member storage space CT is a cam chain tunnel CT in which the cam chain 23 is stored. The cam chain tunnel CT is formed in the cylinder 6 and the cylinder head 8 and extends in the reciprocating direction VD. In this embodiment, the cam chain tunnel CT is provided at an end in the engine width direction WD. A support structure and a guide structure for the cam chain 23 will be described later.

[0025] In the following description, the side of the width direction WD of the engine E on which the cam chain tunnel CT is arranged will be referred to as one side of the width direction WD, and the opposite side will be referred to as the other side of the width direction WD.

[0026] An output shaft 25 and a reduction gear mechanism 26 are provided on the other side of the engine E in the width direction WD. That is, in this embodiment, the output shaft 25 and the reduction gear mechanism 26 are disposed on the opposite side of the cam chain tunnel CT in the width direction WD. The rotational force of the crankshaft 2 is reduced in speed by the reduction gear mechanism 26 and transmitted to the output shaft 25. An aircraft propeller, a vehicle wheel, a turbine rotor blade, a compressor impeller, etc. are connected to the output shaft 25 directly or via a power transmission member.

[0027] As shown in Fig. 3, a generator GE is provided on one side of the engine E in the width direction WD. The generator GE is attached to an end of the crankshaft 2. The generator GE is covered in the circumferential direction and from the outside in the width direction WD by a generator cover 28. The generator cover 28 is attached to the crankcase 4 by a plurality of fastening members 29 such as bolts.

[0028] As shown in FIG. 1, in the engine E of this embodiment, a coolant pump 30 and a lubricating liquid pump 32 are disposed on one side of the engine E in the width direction WD, i.e., on the side where the cam chain tunnel CT is disposed.

[0029] The coolant pump 30 is driven in conjunction with the rotation of the crankshaft 2, and supplies coolant to cooled parts of the engine E. In other words, the pump shaft 30a of the coolant pump 30 constitutes a second rotating body that rotates in conjunction with the crankshaft 2. In this embodiment, water is used as the coolant.

[0030] In this embodiment, the pump shaft 30a of the coolant pump 30 is connected to the crankshaft 2 via a second endless transmission member 34 such as a chain. In other words, the second endless transmission member 34 transmits the rotation of the crankshaft 2 to the pump shaft 30a, which is a type of second rotating body. However, the second endless transmission member 34 is not limited to a drive chain and may be a drive belt. The support structure and guide structure of the second endless transmission member 34 will be described later.

[0031] The coolant pump 30 is disposed above the crankshaft 2 and closer to the cylinder head 8 in the reciprocating direction VD. In this embodiment, the coolant pump 30 is disposed on the upper part of the crankcase 4 on the intake port side of the engine E. The coolant pump 30 is also disposed closer to the intake port than the cylinder 6 in the orthogonal direction PD. In this embodiment, the coolant pump 30 is disposed above the crankshaft 2 inside the crankcase 4 and on the intake port side in the orthogonal direction PD.

[0032] The lubricating fluid pump 32 is driven in conjunction with the rotation of the crankshaft 2 to pressurize the lubricating fluid circulating through the engine. In other words, the pump shaft 32a of the lubricating fluid pump 32 constitutes a third rotating body that rotates in conjunction with the crankshaft 2. In this embodiment, engine oil is used as the lubricating fluid.

[0033] In this embodiment, the pump shaft 32a of the lubricating liquid pump 32 is connected to the crankshaft 2 via a second endless transmission member 34 that is also shared with the coolant pump 30. In other words, the second endless transmission member 34 transmits the rotation of the crankshaft 2 to both the second rotating body 30a and the third rotating body 32a.

[0034] In this embodiment, the lubricating liquid pump 32 is disposed in the oil pan 14. When the engine E starts, the lubricating liquid stored in the oil pan 14, i.e., the engine oil, is supplied to the lubricated parts of the engine E, lubricating the parts. After lubricating the parts, the lubricating liquid is returned to the oil pan 14.

[0035] 4 and 5, the support structure and guide structure of the first and second endless transmission members 23, 34 of the engine E of this embodiment will be described. As shown in Fig. 4, the cam chain 23, which is a type of first endless transmission member, is stretched over a first sprocket 41 provided on the crankshaft 2, a second sprocket 42 on the intake camshaft 21a, and a third sprocket 43 on the exhaust camshaft 21b.

[0036] The cam chain 23 is guided by a first guide body 36. Arrow A1 in Figure 4 indicates the rotation direction of the cam chain 23. In this embodiment, the first guide body 36 has a movable guide body 38 that guides the cam chain 23 between the crankshaft 2 and the intake-side camshaft 21a, and a fixed guide body 40 that is arranged to guide the cam chain 23 between the exhaust-side camshaft 21b and the crankshaft 2.

[0037] The movable guide body 38 and the fixed guide body 40 are molded products made of resin, for example. However, the materials and manufacturing methods of the movable guide body 38 and the fixed guide body 40 are not limited to these. The fixed guide body 40 is fixed with bolts at its upper end 40u to the cylinder head 8 and at its lower end 40d to the crankcase 4.

[0038] The movable guide body 38 rotates according to the tension of the cam chain 23. A tensioner 48 that adjusts the tension of the cam chain 23 is provided on the outer surface of the cylinder head 8 on the intake side in the orthogonal direction. The lower end of the movable guide body 38 is supported by a support member 50 on the crankcase 4, and the upper end is pressed by the tensioner 48. In other words, the movable guide body 38 rotates about the support member 50 as a support shaft. In other words, the support member 50 supports the movable guide body 38 so that it can be angularly displaced, and constitutes the axis of movement of the movable guide body 38.

[0039] The second endless transmission member 34 is arranged alongside the cam chain 23, which is a type of first endless transmission member, in the axial direction of the crankshaft 2, i.e., in the engine width direction WD. In this embodiment, the second endless transmission member 34 is arranged on the inside of the engine width direction WD, and the cam chain 23 is arranged on the outside of the engine width direction WD.

[0040] A drive chain, which is a type of second endless transmission member 34, is stretched over a fourth sprocket 44 provided on the crankshaft 2, a fifth sprocket 45 on the pump shaft 32a of the lubricating liquid pump 32, and a sixth sprocket 46 on the pump shaft 30a of the coolant pump 30.

[0041] The second endless transmission member 34 is guided by a second guide body 52. ​​An arrow A2 in Fig. 4 indicates the rotation direction of the second endless transmission member 34. The second guide body 52 in this embodiment is a molded product made of resin. However, the material and manufacturing method of the second guide body 52 are not limited to this.

[0042] The first guide body 36 and the second guide body 52 are arranged side by side in the axial direction of the crankshaft 2, i.e., in the engine width direction WD. In this embodiment, the second guide body 52 is arranged inside the engine width direction WD, and the first guide body 36 is arranged outside the engine width direction WD. In other words, the second guide body 52 is arranged closer to the fixed wall of the crankcase 4 to which the guide bodies 36 and 52 are fixed than the first guide body 36.

[0043] In this embodiment, the second guide body 52 has an upstream guide body 54 that guides the second endless transmission member 34 between the crankshaft 2 and the pump shaft 32a of the lubricating liquid pump 32, an intermediate guide body 56 that guides the second endless transmission member 34 between the pump shaft 32a of the lubricating liquid pump 32 and the pump shaft 30a of the coolant pump 30, and a downstream guide body 58 that guides the second endless transmission member 34 between the pump shaft 30a of the coolant pump 30 and the crankshaft 2.

[0044] The upper part of the upstream guide body 54 is fixed to the crankcase 4 by a fastening member 60 such as a bolt. The upper part of the intermediate guide body 56 is fixed to the crankcase 4 by a fastening member 62 such as a bolt.

[0045] A portion of the downstream guide body 58 close to the pump shaft 30a of the coolant pump 30 is fixed to the crankcase 4 by a fastening member 64 such as a bolt. In addition, a portion of the downstream guide body 58 close to the crankshaft 2 is fixed to the crankcase 4 by the support member 50 described above.

[0046] That is, the first guide body 36 and the second guide body 52 are supported on the crankcase 4 by a common support member 50. More specifically, the movable guide body 38 of the first guide body 36 and the downstream guide body 58 of the second guide body 52 are supported by the common support member 50. When viewed from the axial direction of the crankshaft 4, the support member 50 is disposed at a position adjacent to the intersection position where the first endless transmission member 23 and the second endless transmission member 34 intersect.

[0047] In this way, the downstream guide body 58 is supported on the crankcase 4 by the common support member 50, and is also supported on the crankcase 4 by the fastening member 64 at a position spaced apart from the common support member 50. In other words, in this embodiment, the fastening member 64 constitutes an "other support member" that supports the downstream guide body 58, i.e., the second guide body 52, at a position spaced apart from the common support member 50.

[0048] Next, the support structure of the common support member 50 will be described in detail with reference to Figure 5. A cylindrical boss 66 that protrudes outward in the width direction WD is formed on the crankcase 4. In this embodiment, the boss 66 has a stepped structure. Specifically, the boss 66 has a large diameter portion 68 on the inside in the width direction WD and a small diameter portion 70 on the outside in the width direction WD. A step portion 69 is formed between the large diameter portion 68 and the small diameter portion 70. A female thread portion 66a is formed in the hollow portion of the boss 66.

[0049] The downstream guide body 58 of the second guide body 52, which is made of resin, is fitted into the small diameter portion 70 of the boss 66. More specifically, a fitting hole 58a is formed in the downstream guide body 58 of the second guide body 52, and the small diameter portion 70 of the boss 66 is fitted into this fitting hole 58a. In this state, the inner end face 58b of the downstream guide body 58 in the width direction WD abuts against a stepped portion 69 of the boss 66, restricting the inward movement of the downstream guide body 58 in the width direction WD.

[0050] In this embodiment, the common support member 50 is configured as a shoulder bolt. Specifically, the support member 50 has a head 50a with which a tool is engaged and a shaft 50b extending axially from the head 50a. The shaft 50b of the support member 50 has a large diameter portion 50ba and a small diameter portion 50bb at its tip. A step portion 50bc is formed between the large diameter portion 50ba and the small diameter portion 50bb. The large diameter portion 50ba is connected to the head 50a at its base, and a male thread portion 50bd is formed at the tip of the small diameter portion 50bb.

[0051] A fitting hole 38a is formed in the movable guide body 38 of the first guide body 36. With the downstream guide body 58 fitted into the small diameter portion 70 of the boss portion 66, the support member 50 is inserted into the fitting hole 38a of the movable guide body 38 from the outside in the width direction WD and fastened to the female thread portion 66a of the boss 66. The step portion 50bc of the support member 50 abuts against the end face 66b of the boss 66.

[0052] At this time, the movable guide body 38 is disposed between the head portion 50a and the stepped portion 50bc of the support member 50 with a gap in the width direction WD, i.e., in the direction of the axis AX of the support member 50. In other words, the movable guide body 38 is supported by the crankcase 4 so as to be rotatable about the axis AX of the support member 50.

[0053] In this state, the stepped portion 50bc of the support member 50 and the movable guide body 38 restrict outward movement of the downstream guide body 58 of the second guide body 52 in the width direction WD. That is, the downstream guide body 58 is supported on the crankcase 4 by the support member 50 and the boss 66 between the stepped portion 69 of the boss 66 and the stepped portion 50bc of the support member 50. In this manner, in this embodiment, the common support member 50 and boss 66 support the movable guide body 38 of the first guide body 36 to be angularly displaceable on the crankcase 4, and the downstream guide body 58 of the second guide body 52 is supported on the crankcase 4.

[0054] According to the above configuration, the first guide body 36 and the second guide body 52 shown in Figure 4 are supported on the crankcase 4 by a common support member 50. This prevents interference between the first guide body 36 and the second guide body 52. ​​Furthermore, by using the common support member 50 for support, the number of parts can be reduced and the space around the crankshaft 2 can be used effectively.

[0055] In this embodiment, the first endless transmission member 23 and the second endless transmission member 34 are arranged side by side in the axial direction of the crankshaft 2, and the first guide body 36 and the second guide body 52 are arranged side by side in the axial direction of the crankshaft 2. With this configuration, even when the two guide bodies 36, 52 are arranged in positions that overlap in the axial direction of the crankshaft 2, interference between the first endless transmission member 23 and the second endless transmission member 34 can be prevented.

[0056] In this embodiment, the common support member 50 supports the movable guide body 38 of the first guide body 36 so that it can be angularly displaced. In other words, the common support member 50 constitutes the axis of movement of the movable guide body 38. Furthermore, the downstream guide body 58 of the second guide body 52 is supported by the common support member 50 and another support member 64 provided at a position away from the common support member 50. With this configuration, the movable guide body 38 can be supported so that it can be angularly displaced, and the downstream guide body 58 can be fixed and supported without rotation. Furthermore, because it is supported by the common support member 50, even if the movable guide body 38 is angularly displaced, it does not come into contact with the downstream guide body 58.

[0057] 5, in this embodiment, the second guide body 52 is disposed closer to the wall surface of the crankcase 2 to which the guide bodies 36, 52 are fixed than the movable guide body 38 of the first guide body 36. With this configuration, the movable guide body 38 can be spaced apart from the fixed wall of the crankcase, preventing the movable guide body 38 from interfering with the fixed wall and facilitating angular displacement of the movable guide body 38.

[0058] 4, in this embodiment, a common support member 50 is disposed adjacent to the intersection of the first endless transmission member 23 and the second endless transmission member 34 when viewed from the axial direction of the crankshaft 2. This configuration makes it possible to support both the first guide body 38 and the second guide body 52 with a single support member 50, without increasing their size.

[0059] In this embodiment, the first endless transmission member 23 is a cam chain 23 that drives the intake and exhaust valves 17, 19 (FIG. 1), and the second endless transmission member 34 is a drive chain that drives the pump shaft 30a of the coolant pump 30. The cam chain 23 extends from the crankshaft 2 toward the cylinder head 8. The coolant pump 30 is preferably located close to the parts to be cooled, such as the cylinder 6 and the cylinder head 8. Therefore, the cam chain 23 and the drive chain 34 tend to be close to each other, which could cause interference between the first guide body 36 and the second guide body 52. ​​According to this embodiment, the first guide body 36 and the second guide body 52 are supported on the crankcase 4 by a common support member 50, which prevents interference between the first guide body 36 and the second guide body 52.

[0060] In this embodiment, the rotation of the crankshaft 2 is transmitted to both the pump shaft 30a of the coolant pump 30 and the pump shaft 32a of the lubricating liquid pump 32 via the second endless transmission member 34. With this configuration, the two rotating bodies 30a, 32a can be driven by the single second endless transmission member 34, which reduces the width dimension of the engine compared to driving them with separate endless transmission members.

[0061] The engine of the present disclosure is preferably mounted on mobile objects such as aircraft, vehicles, etc. The engine of the present disclosure is also preferably mounted on off-road vehicles such as four-wheel buggies (all-terrain vehicles), utility vehicles, and recreational vehicles.

[0062] In the above embodiment, the movable guide body 38 of the first guide body 36 and the downstream guide body 58 of the second guide body 52 are supported on the crankcase 4 by a common support member 50, but the combination of guide bodies 36, 52 supported by a common support member 50 is not limited to this.

[0063] The engine of the present disclosure includes the following aspects 1 to 11. [Aspect 1] An engine comprising: a crankshaft that converts reciprocating motion of a piston into rotational motion; a crankcase that supports the crankshaft; first and second rotating bodies that rotate in conjunction with the crankshaft; a first endless transmission member that transmits the rotation of the crankshaft to the first rotating body; a second endless transmission member that transmits the rotation of the crankshaft to the second rotating body; a first guide body that guides the first endless transmission member; and a second guide body that guides the second endless transmission member, wherein the first guide body and the second guide body are supported on the crankcase by a common support member. [Aspect 2] The engine described in aspect 1, wherein the first endless transmission member and the second endless transmission member are arranged side by side in the axial direction of the crankshaft, and the first guide body and the second guide body are arranged side by side in the axial direction of the crankshaft. [Aspect 3] The engine according to aspect 1 or 2, wherein the common support member supports the first guide body so as to be angularly displaceable, and the second guide body is supported by the common support member and another support member provided at a position distant from the common support member. [Aspect 4] The engine according to aspect 3, wherein the second guide body is positioned closer to a crankcase fixed wall for fixing the guide body than the first guide body. [Aspect 5] The engine according to any one of aspects 1 to 4, wherein the support member is positioned adjacent to a position where the first and second endless transmission members intersect as viewed in the axial direction of the crankshaft. [Aspect 6] The engine according to any one of aspects 1 to 5, further comprising a tensioner that adjusts the tension of the first endless transmission member, wherein the first guide body has a movable guide body that rotates in accordance with the tension of the first endless transmission member, and the support member forms an axis of movement of the movable guide body. [Aspect 7] In the engine according to aspect 6, the first rotating body is a camshaft that drives an intake and exhaust valve, and the first endless transmission member is a cam chain.[Aspect 8] The engine according to aspect 7, wherein the second rotating body is a pump shaft of a coolant pump that supplies coolant to cooled parts of the engine. [Aspect 9] The engine according to any one of aspects 1 to 8, further comprising a third rotating body that rotates in conjunction with the crankshaft, wherein rotation of the crankshaft is transmitted to the third rotating body via the second endless transmission member. [Aspect 10] A mobile body equipped with the engine according to any one of aspects 1 to 9. [Aspect 11] An off-road vehicle equipped with the engine according to any one of aspects 1 to 9.

[0064] The present disclosure is not limited to the above embodiments, and various additions, modifications, or deletions are possible without departing from the spirit and scope of the present disclosure. For example, the engine E of the above embodiment can also be applied to saddle-type vehicles such as motorcycles, tricycles, and four-wheeled buggies (all-terrain vehicles). The engine E may be used in an outboard motor or as a propulsion source for aircraft. Additionally, the engine E may be used as a propulsion source for four-wheeled vehicles or small personal watercraft. The number of cylinders is not limited to six, and may be less than six, or seven or more. The engine E may be provided with a supercharger such as a turbocharger or a supercharger. Therefore, such configurations are also included within the scope of the present disclosure.

[0065] 2 Crankshaft 3 Piston 4 Crankcase 17 Intake valve 19 Exhaust valve 21a Intake side camshaft (first rotating body) 21b Exhaust side camshaft (first rotating body) 23 Cam chain (first endless transmission member) 30 Coolant pump 30a Pump shaft of coolant pump (second rotating body) 32 Lubricating liquid pump 32a Pump shaft of lubricating liquid pump (third rotating body) 34 Second endless transmission member 36 First guide body 38 Movable guide body 48 Tensioner 50 Common support member (moving axis of movable guide body) 52 Second guide body 64 Other support member E Engine

Claims

1. An engine comprising: a crankshaft that converts the reciprocating motion of a piston into rotational motion; a crankcase that supports the crankshaft; first and second rotating bodies that rotate in conjunction with the crankshaft; a first endless transmission member that transmits the rotation of the crankshaft to the first rotating body; a second endless transmission member that transmits the rotation of the crankshaft to the second rotating body; a first guide body that guides the first endless transmission member; and a second guide body that guides the second endless transmission member, wherein the first guide body and the second guide body are supported on the crankcase by a common support member.

2. An engine as described in claim 1, wherein the first endless transmission member and the second endless transmission member are arranged side by side in the axial direction of the crankshaft, and the first guide body and the second guide body are arranged side by side in the axial direction of the crankshaft.

3. An engine as claimed in claim 1 or 2, wherein the common support member supports the first guide body so as to be angularly displaceable, and the second guide body is supported by the common support member and another support member provided at a position spaced apart from the common support member.

4. An engine according to claim 3, wherein said second guide body is disposed closer to a crankcase fixing wall for fixing said guide body than said first guide body.

5. An engine as claimed in claim 1 or 2, wherein the support member is disposed at a position adjacent to the intersection position where the first and second endless transmission members intersect as viewed in the axial direction of the crankshaft.

6. An engine as claimed in claim 1 or 2, further comprising a tensioner for adjusting the tension of said first endless transmission member, said first guide body having a movable guide body which rotates in accordance with the tension of said first endless transmission member, and said support member constituting the axis of movement of said movable guide body.

7. An engine according to claim 6, wherein the first rotating body is a camshaft which drives an intake and exhaust valve, and the first endless transmission member is a cam chain.

8. An engine according to claim 7, wherein the second rotating body is a pump shaft of a coolant pump which supplies coolant to a part of the engine to be cooled.

9. An engine as claimed in claim 1 or 2, further comprising a third rotating body which rotates in conjunction with the crankshaft, the rotation of the crankshaft being transmitted to the third rotating body via the second endless transmission member.

10. A vehicle equipped with the engine according to claim 1 or 2.

11. An off-road vehicle equipped with an engine according to claim 1 or 2.

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