JPH02215932A - Unit swing type engine - Google Patents

Abstract

PURPOSE:To prevent an engine from going to be oversized as a whole by installing a cam driving chamber in one side of a cylinder and a spark plug in the other side, respectively, while setting up an intake valve in the backside and an exhaust valve in the front side each, and installing an intake port extendedly in the direction of an inverse cam driving chamber. CONSTITUTION:A unit swing type engine 7 is constituted of a one-cylinder engine with a cylinder 14 being fitted with both intake and exhaust valves 31, 32 on the head and tilted rearward. A cam driving chamber is set up in one side of this cylinder 14, and a spark plug is set up in the other side. The intake valve 32 is set up at the rear side and the exhaust valve 31 in the front side respectively, and since an intake port 34 ranging to a combustion chamber is installed extendedly in direction of an inverse cam driving chamber, the projection of a cylinder head 15 to the rear can be restrained. Thus, the whole engine is prevented from going to be oversized and, what is more, a large storage space can be formed in a body cover.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a unit swing type engine used for driving, for example, a scooter.

[Conventional technology]

The engine used to drive scooters, etc. is 2.
A unit swing type engine, in which a transmission case supporting the rear wheels is integrally extended to one side of the crankcase of a single-cycle cycle engine, is widely used.

[Problem to be solved by the invention]

However, this type of two-stroke engine has a problem in that lubricating oil tends to mix into the exhaust gas.

Therefore, in order to solve this problem, it is conceivable to configure the engine with a 4-stroke engine, but in a 4-stroke engine, the cylinder head is equipped with intake and exhaust valves and the mechanism that drives them, so the cylinder head is a 2-stroke engine. The problem arises that the overall size of the engine becomes larger as a result. Therefore, when mounted on a scooter or the like, it becomes extremely difficult to create a space within the vehicle body cover to store a helmet or the like. The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a unit swing type engine that can prevent the overall size of the engine from increasing even if it is configured with a four-stroke engine.

[Means to solve the problem]

The unit swing type engine according to the present invention is composed of a single cylinder engine having intake and exhaust valves attached to the engine head and a cylinder inclined backward, and a cam drive chamber is arranged on one side of the cylinder, A spark plug is disposed on the other side, an intake valve is disposed on the rear side, an exhaust valve is disposed on the front side, and an intake port connected to the combustion chamber extends in a direction opposite to the cam drive chamber.

[Effect]

In the engine of the present invention, the cylinder head is prevented from protruding rearward, and the cylinder can be tilted significantly rearward.

〔Example〕

Hereinafter, one embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a side view showing a scooter equipped with a unit swing type engine according to the present invention, and FIG.
3 is a cross-sectional view taken along the line mm in FIG. 1, and the reference numeral 1 in FIG. The vehicle has a footrest plate 4, and a vehicle body cover 5 that covers the lower part of the seat 3 is provided at the rear. Reference numeral 6 denotes a body frame extending in the longitudinal direction of the scooter 1, which includes a front frame 6a made of one tube, and two tubes branched left and right from the rear end of the front frame 6a. It is composed of a rear frame 6b and the like.

7 is a unit swing type engine. This unit swing type engine 7 is disposed in the vehicle body cover 5 below the seat 3, and includes a forced air-cooled 4-cycle engine 8 and a power transmission mechanism including a belt 10 for transmitting the power of this engine 8 to the rear. , and a transmission case 11 that accommodates this power transmission mechanism and supports the rear end 9. 1
2 is a unit swing type engine 7 attached to the rear frame 6b
This is a bracket for swingingly supporting the

Reference numeral 13 denotes a shock absorber that absorbs the vertical movement of the rear part of the transmission case 11, and the rear end of the transmission case 11 and the rear frame 6b.
It is interposed between.

The engine 8 includes a cylinder body 14 tilted toward the rear, a cylinder rad 15, and a crankcase 16.
The engine case 17 is integrally formed with the inner part of the transmission case 11. One cylinder 7L 14 a is provided inside the cylinder body 14, and a cylinder sleeve 22 holding a piston 21 is held therein. The cylinder sleeve 22 is attached to the cylinder body 1 by an oval-shaped fixed Fi 23 that presses the sleeve from below.
It is fixed at 4. A combustion chamber 24 is formed at the upper end of the cylinder hole 14a, and a cam drive chamber 25 for driving a camshaft, which will be described later, is integrally formed on the left side. Combustion chamber 2
4 is formed into a substantially hemispherical shape in order to uniformly cool the head side and reduce thermal distortion. The crankcase 16 is formed in a box shape with an opening opened downward, and supports a crankshaft 27 connected to the piston 21 via a controller 26 by both side walls so as to be rotatable in the vehicle width direction. An oil pan 28 that closes the opening is attached to the lower end with a screw.

A spark plug 29 is screwed onto the right side of the cylinder head 15 so as to face the center of the combustion chamber 24. Further, a large number of cooling fins 30 are provided on the outer peripheral surface of the cylinder body 14.
...is protruding horizontally.

FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3. An exhaust valve 31 is provided on the front side of the cylinder head 15, and an intake valve 32 is provided on the rear side. The exhaust boat 33 is connected to the combustion chamber 24 via the exhaust valve 31 and extends forward, and the intake boat 3 is connected to the combustion chamber 24 via the intake valve 32.
4 extends toward the right side as shown in FIGS. 5 and 6. Specifically, the intake boat 34 extends upward and rearward as it goes to the right side.
Its center line is completely different from the center line of the intake valve 32 when viewed from the side.

35 is an exhaust side valve seat member having a valve seat on which the exhaust valve 31 is seated, and 36 is an intake side valve seat member having a valve seat on which the intake valve 32 is seated. These members are formed into a substantially cylindrical shape having a valve shaft guide hole, and each has an exhaust side mounting hole 37 extending in the direction of the valve shaft of the intake and exhaust valve. It is inserted into the intake side mounting hole 38 from the outside so as to be freely inserted and removed, and is mounted in such a manner that rotation in the direction around the axis is restricted. 39.40 is exhaust side mounting hole 37
This is a locking portion that is provided in the vicinity of the combustion chamber of the intake side mounting hole 38 and locks the intake and exhaust valve seat member inserted from the outer 5 side. 41.42 is the exhaust side valve seat member 35.42 via the fixing collar 43.44. The intake side valve seat member 36 is attached to the locking portion 39.40.
This is a fixed flange that serves as a pressing member that presses against the cylinder head 15, and is formed in an oval shape and is fastened to the cylinder head 15 by two fixing screws 50 and 50 at both ends. 45.46
is the exhaust valve 31. This is a spring that biases the intake valve 32 in the closing direction, and the exhaust side valve seat member 35. It is assembled to the intake side valve seat member 36.

A camshaft 47 drives the intake and exhaust valves via a rocker arm, has a metal camshaft gear 48 at its left end, and is rotatably supported by a bearing integrally formed with the cylinder head 15. 49 is a cylinder head cover that covers the camshaft 47 and the intake and exhaust valves. Rad cover 49 to this cylinder
The mating surfaces of the cylinder head 15 and the cylinder head 15 are inclined downward to the left in order to facilitate the assembly of the camshaft gear 48 and the formation of the intake boat 34. As shown in FIG. 7, an oil passage 51 for pumping lubricating oil to the camshaft 47 is formed in the bearing portion that supports the right end portion of the camshaft 47. As shown in FIG. 52
Reference numeral 53 indicates a lid body attached to the bearing portion, and 53 indicates a pipe made of aluminum, iron, or the like forming a portion of the oil passage 51 from the cylinder head 15 to a lubricating device to be described later.

This pipe 53 is cast when the engine case 17 is manufactured. Therefore, cutting work for forming the oil passage 51 is kept to a minimum.

To explain the support of the crankshaft 27 in detail, a shaft hole 55 is provided in the right side wall of the crankcase 16 to support the right end portion of the crankshaft 27 via a metal bearing 54. On the other hand, the crankshaft 2 is attached to the left side wall of the crankcase 16.
A holding hole 56 is opened and has a size that allows the No. 7 crank arm 27a to be inserted therethrough. That is, the crankshaft 27 is inserted and assembled from the left side of the crankcase 16. 57 is a holding member fitted into the holding hole 56. This holding member 57 is formed in a shape in which a disc that fits into the holding hole 56 and a disc provided outside the holding hole 56 are connected by a peripheral wall extending along the periphery, and the crankshaft 27 is inserted through the disc. In addition, an accommodating portion 57a is provided for accommodating a metal camshaft driving gear 58 mounted on the crankshaft 27 by the peripheral wall.

This storage portion 57a is positioned below the camshaft gear 48 and forms the lower end of the cam drive chamber 25.

Reference numeral 59 denotes a ball bearing that is fitted into a recessed portion provided on the inner peripheral edge of the crank arm side of the holding member 57 and supports the crankshaft 27 . Between the camshaft drive gear 58 and the camshaft gear 48 are two intermediate gears 61.6 made of synthetic resin.
1. Therefore, the metal gears do not mesh with each other, and the meshing noise is suppressed to a low level.

62 is a lubricating device inserted into the crankcase 16 from below. This lubricating device 62 includes a strainer 63, an oil pump 66 driven by a drive gear 65 meshing with an oil pump drive gear 64, a relief valve device 67 for adjusting discharge pressure, and a filter 68, which are mounted on a mounting base 69. It is assembled integrally. And the mounting base 69
is attached to the crankcase 16 with screws, and the downstream side of the filter 68 is connected to the pipe 53. Therefore, the lubricating device 62 can be easily assembled, and the oil passage provided in the crankcase 16 also has a hour wheel structure.

Further, the crankshaft 27 protrudes laterally beyond both side walls of the crankcase 16, and a generator 71 is mounted on the right end thereof.
A cooling fan 72 is fixed to its outer surface with rivets. A V-belt type automatic speed change power transmission device 73 that transmits the rotation of the crankshaft 27 to the rear wheel 9 via a V-belt is attached to the left end.

74 is the outside of the cooling fan 72 and the cylinder body 1
This is a shroud that covers the periphery of the engine 4 and forms a cooling air passage, and is attached to the engine 8 using mounting screws (not shown) or the like. An air intake lower 5 is provided at a portion of the shroud 74 facing the cooling fan 72.

The intake boat 34 is connected to a carburetor 76 disposed on the right rear side of the cylinder head 15 via an intake manifold 77. 78 is an air cleaner disposed behind the carburetor 76 and connected via a joint 79. On the other hand, an exhaust pipe 81 is connected to the exhaust boat 33, and this exhaust pipe 81 extends from the front side of the cylinder body 14 toward the rear through the lower side of the shroud 74, and extends below the air cleaner 78. The muffler 82 is connected to the muffler 82 disposed in the muffler 82 .

83 is a muffler mounting stay that is attached to the engine 8 and supports the muffler 82. This muffler mounting stay 8
3 is larger than the cooling fan 72 and is formed into a plate shape that covers the sides of the crankcase 16. 83a is an opening provided in the center of the muffler mounting stay 83, and this opening 83a has a shape that is approximately the same as the outer shape of the cooling fan 72, and is large enough to allow the cooling fan 72 to be inserted therethrough. The muffler mounting stay 83 is disposed on the crankcase side 16 of the cooling fan 72 so that the cooling fan 72 and the opening 83a overlap in the crankshaft direction, and is attached to the crankcase side with a mounting screw 84. It is attached to 16.

Reference numeral 85 denotes a storage box that is housed within the vehicle body cover 5 and whose upper opening can be opened and closed by the seat 3. This storage box 85
is supported by the rear frame 6b and has an inner space in which a helmet 86 can be accommodated.

In the unit swing type engine configured in this way, the cam drive chamber 25 and the spark plug 29 are arranged separately on the left and right, and the intake boat 34 is arranged on the side of the spark plug 29, which has a small shape. 34 can extend laterally. An air cleaner 78 and a carburetor 7 are provided at the rear right side of the cylinder head 15.
The air-fuel mixture supplied through the cylinder head 15 can be sucked in from the side of the cylinder head 15 and discharged toward the front. This prevents interference between the cylinder head 15 of a four-stroke engine, which tends to be large due to the provision of intake and exhaust valves 32, 31, camshaft 47, etc., and the intake system, which includes the carburetor 76, etc. , the cylinder body 14 can be sufficiently tilted rearward at a large angle. the result,
To prevent the cylinder head 15 from protruding forward and increasing in size, a helmet 8 is placed in front of the cylinder head 15.
A storage space capable of storing 6 can be formed.

In the above embodiment, an example was described in which the intake boat 34 was formed so that the center line of the intake boat 34 and the center line of the intake valve 32 coincided with each other when viewed from the side. There's no need to do it.

〔Effect of the invention〕

As explained above, according to the present invention, the engine is constituted by a single cylinder engine having an intake and exhaust valve mounted on the head and a cylinder inclined backward, and a cam drive chamber is disposed in an example part of the cylinder, The spark plug is placed on the other side, the intake valve is placed on the rear side, the exhaust valve is placed on the front side, and the intake boat connected to the combustion chamber is extended in the direction opposite to the cam drive chamber, so the cylinder head moves rearward. It is possible to suppress protrusion.

Therefore, since the cylinder can be tilted significantly backwards, it is possible to prevent the overall engine from increasing in size even though it is configured as a 4-cycle engine, and it is possible to create a relatively large storage space within the vehicle body cover. .

/ / / / /

[Brief explanation of the drawing]

Fig. 1 is a side view showing a scooter equipped with a unit swing type engine according to the present invention, and Fig. 2 is a side view of a scooter equipped with a unit swing type engine according to the present invention.
Figure 3 is a cross-sectional view along line ■■ in Figure 1, Figure 4 is a cross-sectional view along line IV-I' in Figure 3, Figure 5 is a cross-sectional view along line IV-I' in Figure 4,
6 is a plan view of the cylinder head, and FIG. 7 is a sectional view taken along the line ■-■ in FIG. 6. 7111. Unit swing type engine, 14...
Cylinder body, 15... Cylinder head, 25...
・, cam drive chamber, 29... spark plug, 31...
・Exhaust valve, 32... Intake valve, 34... Intake boat, 76... Carburetor. Patent applicant Yamaha Motor Co., Ltd.

Claims (1)

[Claims] A unit swing type engine in which a transmission case supporting the rear wheels is integrally extended to one side of the engine crankcase. It consists of a cylinder engine, in which a cam drive chamber is arranged on one side of the cylinder, a spark plug is arranged on the other side, the intake valve is arranged on the rear side, the exhaust valve is arranged on the front side, and a combustion chamber is arranged. A unit swing type engine with an intake port connected to the cam drive chamber extending in the direction opposite to the cam drive chamber.