JP2013096389A - Monoblock engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a monoblock engine capable of improving manufacturability of an engine, by reducing the number of parts.SOLUTION: A camshaft driving mechanism includes: an intermediate shaft 29 orthogonal to the axis of a crankshaft 7 and the axis of a camshaft 6; a first bevel gear 32 synchronously rotating with the crankshaft 7; a second bevel gear 33 arranged in a lower end part of the intermediate shaft 29 and meshing with the first bevel gear 32; a third bevel gear 34 arranged in an upper end part of the intermediate shaft 29; and a forth bevel gear 35 for synchronously rotating with the camshaft 6 and meshing with the third bevel gear 34. A storage part 31 for storing the intermediate shaft 29 and a bearing 19 for supporting the intermediate shaft 29 is integrally formed with an engine block main part 1. An oil pump 39 can also be integrated with the engine block main part 1 by arranging the oil pump 39 driven by the intermediate shaft 29 in the storage part 31.

Description

  The present invention relates to a monoblock engine used in a vehicle or the like, and relates to a monoblock engine in which a cylinder head, a cylinder, and an upper half of a crankcase are integrated.

  An example of such a monoblock engine is described in Patent Document 1 below. In the monoblock engine described in Patent Document 1, an intermediate pulley is driven by a gear attached to a crankshaft end, and a driving force is transmitted from the intermediate pulley to a pulley on the camshaft side via a belt. For this reason, an opening for assembly and maintenance is formed on the outer wall that covers the gears and pulleys, and a cover that covers this opening and a sealing material that seals between the cover and the engine block are required. The structure was complicated. On the other hand, in the following Patent Document 2, a bevel gear is used as a cam shaft driving mechanism for driving a cam shaft with a crank shaft. Specifically, the axis of the intermediate shaft housed in the housing part separate from the engine block is arranged in a direction perpendicular to the axis of the crankshaft and the camshaft, and bevel gears are attached to both ends of the intermediate shaft, A bevel gear that rotates synchronously with the crankshaft and a bevel gear that rotates synchronously with the camshaft are provided, the bevel gear of the crankshaft and the bevel gear on the crankshaft side of the intermediate shaft are engaged, and the bevel gear of the camshaft and the bevel gear of the intermediate shaft are engaged. If such a camshaft drive mechanism is used, the engine can be made smaller than an engine that drives the camshaft with a chain or belt.

Japanese Utility Model Publication No. 60-97346 JP-A-11-153005

However, in the engine of Patent Document 2, since the storage portion that stores the intermediate shaft is separate from the engine block, the number of parts of the engine increases as in Patent Document 1, and the manufacturability of the engine deteriorates. Arise.
The present invention has been made paying attention to the problems as described above, and an object thereof is to provide a monoblock engine capable of reducing the number of parts and improving the manufacturability of the engine. is there.

  In order to solve the above-described problems, an embodiment of the invention has a main part of an engine block in which a cylinder head and a cylinder and an upper half of a crankcase are integrated, and a camshaft disposed in the cylinder head is connected to a camshaft. In a monoblock engine in which a camshaft drive mechanism for transmitting a driving force is arranged at an end of any one of the engine blocks in the axial direction of the crankshaft, the camshaft drive mechanism has an axis that is the axis of the crankshaft and An intermediate shaft orthogonal to the axis of the camshaft, a first bevel gear that rotates synchronously with the crankshaft, a second bevel gear that is disposed at one end in the axial direction of the intermediate shaft and meshes with the first bevel gear, A third bevel gear disposed at the other end of the intermediate shaft in the axial direction and a fourth bevel gear that rotates in synchronization with the cam shaft and meshes with the third bevel gear. It is constituted by a Rugiya a monobloc engine, wherein a housing portion for housing the bearings supporting the intermediate shaft and the intermediate shaft is formed integrally with said engine block main portion.

In the monoblock engine, an oil pump driven by the intermediate shaft is disposed in the storage portion.
In the monoblock engine, an oil pump case for housing the constituent members of the oil pump is integrally formed in the housing portion.

In the monoblock engine, at least one of the bearings may be disposed between the oil pump and the second bevel gear in the axial direction of the intermediate shaft.
A bearing member disposed between the oil pump and the second bevel gear, wherein a closing member that closes an opening at an axial end of the oil pump case is attached to an inner periphery of a recess formed in the housing portion; A monoblock engine attached to the closing member.

  Thus, according to the embodiment of the invention, the main part of the engine block in which the cylinder head and the upper half of the cylinder and the crankcase are integrated is provided, and the driving force is applied from the crankshaft to the camshaft disposed in the cylinder head. When the transmitting camshaft drive mechanism is disposed at the end of one of the engine blocks in the axial direction of the crankshaft, the crankshaft and the intermediate shaft orthogonal to the camshaft axis and the crankshaft rotate synchronously. A first bevel gear; a second bevel gear disposed at one end in the axial direction of the intermediate shaft and meshing with the first bevel gear; a third bevel gear disposed at the other end in the axial direction of the intermediate shaft; and a camshaft And a fourth bevel gear that rotates in synchronization with the third bevel gear to form a camshaft drive mechanism, and a storage portion that stores an intermediate shaft and a bearing that supports the intermediate shaft is an engine. It was formed integrally with the lock main part. With this configuration, the number of parts can be reduced and the manufacturability of the engine can be improved.

In addition, the oil pump driven by the intermediate shaft is arranged in the storage part, so that the oil pump can be integrated with the main part of the engine block, further reducing the number of parts and further improving the manufacturability of the engine. It becomes possible.
Further, by integrally forming the oil pump case for housing the components of the oil pump in the housing portion, it is possible to further reduce the number of parts and further improve the manufacturability of the engine.

  Also, by arranging at least one of the bearings between the oil pump and the second bevel gear in the axial direction of the intermediate shaft, the bearing receives a balance between the force received by the intermediate shaft from the second bevel gear and the force received from the oil pump by the bearing. While being able to support well, the components of the oil pump can be assembled without being obstructed by the bearing, and the manufacturability of the engine can be further improved.

  In addition, a closing member that closes the opening at the axial end of the oil pump case is attached to the inner periphery of the recess formed in the housing portion, and a bearing disposed between the oil pump and the second bevel gear is attached to the closing member. As a result, a bearing having an outer diameter smaller than the outer diameter of the oil pump can be used, and the bearing can be downsized.

It is a perspective view showing one embodiment of the monoblock engine of the present invention. It is an internal structure figure of the monoblock engine of FIG. It is a longitudinal cross-sectional view of the monoblock engine of FIG. It is a bottom view of the monoblock engine of FIG.

Next, an embodiment of a monoblock engine of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view showing an external appearance of the monoblock engine of the present embodiment, FIG. 2 is an internal structure diagram of the monoblock engine of FIG. 1, and FIG. 3 is a longitudinal sectional view of the monoblock engine of FIG. The monoblock engine of the present embodiment is a parallel two-cylinder engine mounted on a vehicle such as a motorcycle or a four-wheeled vehicle, or a device such as a generator, and may be mounted in various directions. The upper part of FIG. 1 is defined as the upper part of the engine.

  Since the monoblock engine of the present embodiment is a monoblock, a cylinder head 2, a cylinder 3, and an upper crankcase (upper crankcase) 4, which are generally called, are integrated to form an engine block main portion 1. It has become. The engine block main part 1 is an aluminum die-cast part, for example. A cylinder bore 5 is formed in the cylinder 3 of the engine block main portion 1, a valve mechanism including a camshaft 6 is disposed in the cylinder head 2, and a crankshaft 7 is disposed in the upper crankcase 4. A head cover 8 is attached above the cylinder head 2 and a lower crankcase (lower crankcase half) 9 is attached below the upper crankcase 4 to constitute a monoblock engine as a whole. In FIG. 1, the symbol A indicates the joint surface between the cylinder head 2 and the head cover 8, and the symbol B indicates the joint surface between the upper crankcase 4 and the lower crankcase 9.

  A combustion chamber 10 is formed at the lower end of the cylinder head 2 corresponding to the upper end of the cylinder bore 5. An intake port 11 and an exhaust port 12 are connected to the combustion chamber 10, and a valve seat 13 is provided at each end of the combustion chamber 10 of the intake port 11 and the exhaust port 12. Further, a valve stem guide 14 is attached to each of the intake port 11 and the exhaust port 12, and the valve stems of the intake valve 15 and the exhaust valve 16 are inserted into the respective valve stem guides 14. A valve spring 17 is attached to the end of the intake valve 15 and the exhaust valve 16 opposite to the valve face, that is, the valve stem end side via a retainer and a cotter. An ignition plug (not shown) is attached to the combustion chamber 10.

  A cam journal 18 is rotatably supported by the cylinder head 2 and the head cover 8 via a bearing 19. The cam journal 18 is located immediately above the center of each of the two combustion chambers 10, and an intake cam 20 and an exhaust cam 21 are provided on both sides of each cam journal 18. Between the intake cam 20 and the valve stem end of the intake valve 15, and between the exhaust cam 21 and the valve stem end of the exhaust valve 16, a rocker arm 22 with a roller is interposed, and each rocker arm 22 with a roller and the cylinder head 2 are interposed. A hydraulic lash adjuster 23 is interposed between them.

  In the present embodiment, as will be described in detail later, the valve stem end side opens with respect to the vertical line of FIG. 3, that is, the axis line (center line) of the cylinder bore 5. Thus, it is inclined by an angle θ radially. This is to facilitate the seat surface processing of the valve seat 13. Note that the cam surfaces of the intake cam 20 and the exhaust cam 21, the cam contact surface of the rocker arm 22 with a roller, and the valve stem end contact surface are all orthogonal to the axis of the intake valve 15 and the axis of the exhaust valve 16, that is, The contact surfaces are formed so as to be in plane contact with each other.

  A piston 24 is accommodated in each cylinder bore 5. The piston 24 is connected to the crankpin 25 of the crankshaft 7 by a connecting rod (connecting rod) 26. The crankshaft 7 has a crank journal 27 rotatably supported by the upper crankcase 4 and the lower crankcase 9 via a bearing metal 28. As is well known, when the piston 24 reciprocates in the cylinder bore 5 as the air-fuel mixture in the combustion chamber 10 burns and explodes, the reciprocating motion is extracted as the rotational motion of the crankshaft 7.

  As is well known, in a four-cycle engine, the camshaft 6 needs to rotate at a rotation speed ratio that is ½ of the rotation speed of the crankshaft 7 and at a predetermined phase with respect to the rotation angle of the crankshaft 7. Therefore, a camshaft drive mechanism that transmits the driving force of the crankshaft 7 to the camshaft 6 is required. In this embodiment, a bevel gear and an intermediate shaft are used for this cam shaft drive mechanism. The intermediate shaft 29 is disposed so that the axis is perpendicular to the axis of the camshaft 6 and the axis of the crankshaft 7, that is, the axis is oriented in the vertical direction, and a bearing (bearing that supports the upper end and the lower end thereof rotatably. ) 19 together with the main part 1 of the engine block and the cylindrical storage part 31 formed integrally. The storage portion 31 has an approximately semi-cylindrical shape with a hollow inside, but the upper end portion on the cylinder head 2 side and the lower end portion on the upper crankcase 4 side are solid, and the solid portion has a circular hole shape. A recess 30 is formed, and a bearing 19 and a closing member described later are accommodated in the recess 30.

  For example, as shown in FIGS. 2 and 3, a first bevel gear 32 is formed integrally with the crankshaft 7 at the illustrated left end portion of the crankshaft 7, so that the crankshaft 7 and the first bevel gear 32 are synchronized. Rotate. A second bevel gear 33 that meshes with the first bevel gear 32 is formed integrally with the intermediate shaft 29 at the lower end portion of the intermediate shaft 29. Further, an intermediate shaft 29 and an individual third bevel gear 34 are attached to the intermediate shaft 29 by a fixing tool such as a bolt (not shown) at the upper end portion of the intermediate shaft 29. Further, a fourth bevel gear 35 that meshes with the third bevel gear 34 is formed integrally with the cam shaft 6 at the left end portion of the cam shaft 6 in the figure, so that the cam shaft 6 and the fourth bevel gear 35 rotate synchronously. . The gear ratio between the first bevel gear 32 and the second bevel gear 33 is 1, and the gear ratio between the third bevel gear 34 and the fourth bevel gear 35 is 2. As a result, the camshaft 6 has a rotational speed of the crankshaft 7. Rotates at a rotation speed ratio of 1/2.

  A cylindrical chamber-like oil pump case 36 is formed continuously above the concave portion 30 in the solid portion below the storage portion 31 described above. In the oil pump case 36, an outer rotor 37 and an inner rotor 38, which are components of the oil pump, are housed, and the inner rotor 38 is rotated by the intermediate shaft 29, and thereby, for example, a trochoid type oil pump 39 is configured. In addition, a closing member 40 called a covered cylindrical spacer whose upper end is closed is tightly attached to the inner periphery of the recess 30 below the oil pump case 36, and the oil pump case is covered by the upper cover of the closing member 40. 36 is closed, and a bearing 19 that supports the lower end of the intermediate shaft 29 is press-fitted into the inner periphery of the closing member 40.

  When assembling this camshaft drive mechanism, for example, before assembling the camshaft 6 and the crankshaft 7, the outer rotor 37 and the inner rotor 38 are housed in the oil pump case 36 from below the main portion of the engine block 1 in the figure. After that, the closing member 40 is assembled to the inner periphery of the lower recess 30, and the lower bearing 19 is press-fitted into the inner periphery of the closing member 40. Next, the intermediate shaft 29 is inserted into the inner ring of the lower bearing 19 and press-fitted from the lower side of the main portion of the engine block 1 with the second bevel gear 33 facing downward. Thereafter, the upper bearing 19 is press-fitted into the inner periphery of the upper recess 30 and the outer periphery of the upper end of the intermediate shaft 29, and then the third bevel gear 34 is attached to the upper end of the intermediate shaft 29 with a fixture. Thereafter, when the crankshaft 7 is assembled, the first bevel gear 32 and the second bevel gear 33 are engaged, and when the camshaft 6 is assembled, the third bevel gear 34 and the fourth bevel gear 35 are engaged to complete the camshaft drive mechanism.

  Incidentally, in this embodiment, as described above, the axis of the intake valve 15 and the axis of the exhaust valve 16 are radiated by an angle θ so that the valve stem end side opens with respect to the axis (center line) of the cylinder bore 5. Inclined. Therefore, the seat surface of the valve seat 13 is similarly inclined. The upper half of FIG. 4 shows a state in which the valve seat processing tool 100 of the present embodiment is inserted from the lower end of the cylinder bore 5 while being inclined with respect to the axis of the cylinder bore 5 by the angle θ. Thus, the valve seat processing tool 100 does not interfere with the cylinder bore 5 by tilting the valve seat processing tool 100 with respect to the axis of the cylinder bore 5. In addition, since the valve operating system is radially arranged by inclining the axis of the intake valve 15 and the axis of the exhaust valve 16, the combustion chamber 10 can be hemispherical and combustion performance can be improved. Can do. The lower half of FIG. 4 is a case where the conventional valve seat processing unit 101 is used, and the valve seat processing tool 101 is not inclined with respect to the axis of the cylinder bore 5. It will interfere with the cylinder bore 5.

  As described above, the monoblock engine of the present embodiment has the engine block main portion 1 in which the cylinder head 2, the cylinder 3, and the upper crankcase 4 are integrated, and the camshaft 6 disposed in the cylinder head 2 is connected to the crankshaft 7. When the camshaft drive mechanism for transmitting the driving force is disposed at the end of one of the engine blocks in the axial direction of the crankshaft 7, the intermediate shaft 29 orthogonal to the axis of the crankshaft 7 and the axis of the camshaft 6 is used. A first bevel gear 32 that rotates synchronously with the crankshaft 7, a second bevel gear 33 that is disposed at one end in the axial direction of the intermediate shaft 29, that is, a lower end portion, and meshes with the first bevel gear 32, A third bevel gear 34 disposed at the other end in the axial direction, that is, the upper end, and a fourth bevel gear that rotates in synchronization with the cam shaft 6 and meshes with the third bevel gear 34. Constitute a cam shaft drive mechanism and a 5, and the housing section 31 for housing the bearing 19 for supporting the intermediate shaft 29 and the intermediate shaft 29 is formed integrally with the engine block main unit 1. With this configuration, the number of parts can be reduced and the manufacturability of the engine can be improved. In addition, it is necessary to supply oil to the bevel gears 32 to 35 and the bearing 19 of the intermediate shaft 29. However, by forming the storage portion 31 integrally with the engine block main portion 1, the number of sealing portions for sealing the oil can be reduced. It is possible to improve the reliability against oil leakage.

  Further, since the oil pump 39 driven by the intermediate shaft 29 is disposed in the storage portion 31, the oil pump 39 can be integrated with the engine block main portion 1, and the number of parts can be further reduced and the engine can be manufactured. It is possible to further improve the performance. Further, the noise during the engagement of the bevel gears 32 to 35 can be reduced by the damping action of the oil in the oil pump 39.

Further, the oil pump case 36 for housing the components of the oil pump 39, that is, the outer rotor 37 and the inner rotor 38, is integrally formed in the housing portion 31, thereby further reducing the number of parts and further improving the manufacturability of the engine. Is possible.
Further, since the lower bearing 19 is disposed between the oil pump 39 and the second bevel gear 33 in the axial direction of the intermediate shaft 29, the force received by the intermediate shaft 29 from the second bevel gear 33 and the force received from the oil pump 39. Can be supported by the bearing 19 in a well-balanced manner, and the components of the oil pump 39, that is, the outer rotor 37 and the inner rotor 38 can be assembled without being obstructed by the bearing 19, thereby further improving the manufacturability of the engine. It becomes possible.

  Further, a closing member 40 that closes the opening at the axial end of the oil pump case 36 is attached to the inner periphery of the recess 30 formed in the storage portion 31 and is disposed between the oil pump 39 and the second bevel gear 33. By attaching the bearing 19 to the closing member 40, the bearing 19 having an outer diameter smaller than the outer diameter of the oil pump 39 can be used, and the bearing 19 can be downsized. Moreover, the internal diameter of the recessed part 30 for inserting the structural member of the oil pump 39, ie, the outer rotor 37 and the inner rotor 38, can also be made small.

1 is an engine block main part 2 is a cylinder head 3 is a cylinder 4 is an upper crankcase (the upper half of the crankcase)
5 is cylinder bore 6 is camshaft 7 is crankshaft 8 is head cover 9 is lower case 10 is combustion chamber 11 is intake port 12 is exhaust port 13 is valve seat 14 is valve stem guide 15 is intake valve 16 is exhaust valve 17 is valve spring 18 is a cam journal 19 is a bearing 20 is an intake cam 21 is an exhaust cam 22 is a rocker arm with a roller 23 is a hydraulic lash adjuster 24 is a piston 25 is a crank pin 26 is a connecting rod 27 is a crank journal 28 is a bearing metal 29 is an intermediate shaft 30 is Recessed portion 31 is storage portion 32 is first bevel gear 33 is second bevel gear 34 is third bevel gear 35 is fourth bevel gear 36 is an oil pump case 37 is an outer rotor 38 is an inner rotor 39 is an oil pump 40 is a closing member

Claims (5)

A camshaft drive mechanism having an engine block main part in which the cylinder head and the upper half of the cylinder and the crankcase are integrated, and transmitting a driving force from the crankshaft to a camshaft disposed in the cylinder head, In the monoblock engine disposed at the end of the engine block in one of the axial directions,
The camshaft drive mechanism is
An intermediate shaft whose axis is perpendicular to the axis of the crankshaft and the axis of the camshaft;
A first bevel gear that rotates synchronously with the crankshaft;
A second bevel gear disposed at one end in the axial direction of the intermediate shaft and meshing with the first bevel gear;
A third bevel gear disposed at the other end in the axial direction of the intermediate shaft;
A fourth bevel gear configured to rotate synchronously with the camshaft and mesh with the third bevel gear;
A monoblock engine characterized in that a housing portion for housing the intermediate shaft and a bearing that supports the intermediate shaft is formed integrally with the main portion of the engine block.   The monoblock engine according to claim 1, wherein an oil pump driven by the intermediate shaft is disposed in the storage portion.   The monoblock engine according to claim 2, wherein an oil pump case for housing the constituent members of the oil pump is formed integrally with the housing portion.   4. The monoblock engine according to claim 2, wherein at least one of the bearings is disposed between the oil pump and the second bevel gear in an axial direction of the intermediate shaft. A closing member that closes the opening at the axial end of the oil pump case is attached to the inner periphery of the recess formed in the storage portion,
The monoblock engine according to claim 4, wherein a bearing disposed between the oil pump and the second bevel gear is attached to the closing member.

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