JPH09144555A - Four-cycle engine of small number of cylinders - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of large vibration in an engine so that its assembly work can be easily performed, even in the case of improving an output of the engine. SOLUTION: Five or less cylinders 7 are mountably/demountably tightened to a crankcase 2 supporting a crankshaft 4, an output shaft 37 transmitting power of the crankshaft 4 to a flywheel 42 is provided. The cylinder 7 is constituted by a cylinder main unit 9 having a cylinder hole 8 and a cylinder head 10 mounted in this cylinder main unit 9. An axial direction one end of the cylinder hole 8 is opened toward inside the crankcase 2, the other end is closed in the cylinder head 10. A reduction gear mechanism 39 is interposed between the crankshaft 14 and the output shaft 37, the cylinder main unit 9 and the cylinder head 10 are integrally molded with each other, a balancer 46 is connected to be associated with the crankshaft 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a minority four-cycle engine having five or less cylinders.

[0002]

2. Description of the Related Art In the above-mentioned four-cycle engine having a small number of cylinders, the number of constituent parts is small and the number of sliding points is small, so that the number of mechanical parts is small as compared with a multi-cylinder four-cycle engine having six or more cylinders. It is said that there is little loss and good fuel economy.

[0003]

However, since the above-mentioned few-cylinder four-cycle engine usually has a small output, there is a possibility that the output will be insufficient for mounting the engine on a vehicle for driving the vehicle, for example. .

Therefore, it is conceivable to rotate the engine at a high speed to improve the output. Especially, in the case of an engine having a small number of cylinders, the period of the explosive stroke (crank angle) between the cylinders is long. However, there is a problem that the vibration becomes large.

Further, as described above, it is desired to improve the engine output while facilitating the engine assembling work.

The present invention has been made by paying attention to the above circumstances, and is intended to improve the output of the engine.
And even if it does in this way, it makes it a subject to prevent big vibration from generating in an engine.

It is another object of the present invention to facilitate the assembling work of the engine even when the output of the engine is improved as described above.

[0008]

The minority cylinder four-cycle engine of the present invention for achieving the above object is as follows.

According to the first aspect of the invention, not more than five cylinders 7 are detachably fastened to the crankcase 2 that supports the crankshaft 4, and the power of the crankshaft 4 is transmitted to the flywheel (driven side) 42. A cylinder body 9 having a cylinder hole 8 and a cylinder head 10 attached to the cylinder body 9.
When one end of the cylinder hole 8 in the axial direction is opened toward the inside of the crankcase 2 and the other end is closed by the cylinder head 10, the cylinder hole 8 is placed between the crankshaft 4 and the output shaft 37. A reduction mechanism 39 is provided, and the cylinder body 9 and the cylinder head 10 are integrally molded with each other,
A balancer 46 is interlockingly connected to the crankshaft 4.

According to the invention of claim 2, in addition to the invention of claim 1, a mating surface 3 of the crankcase 2 and the cylinder 7 is provided.
The output shaft 37 is supported between 5 and 36.

The invention of claim 3 is the invention of claim 1 or 2.
In addition to the above invention, the auxiliary machine 6 is installed on the same axis 38 as the output shaft 37.
The rotary shaft 72 of No. 8 is located, and this rotary shaft 72 is interlocked with the output shaft 37.

According to a fourth aspect of the present invention, in addition to any one of the first to third aspects of the present invention, the crankcase 2 is divided into first and second cases 30 and 31, and the first and second cases are divided.
The cases 30 and 31 are detachable from each other, while the balancer 46 is composed of a pair of first and second balancers 47 and 48, of which the balance shaft 49 of the first balancer 47 is the first and second cases 30, 31 mating surfaces 55, 56 of each other
And the balance shaft 49 of the second balancer 48 is supported by the crankcase 2.
The balance weight 50 of the second balancer 48 is detachably attached to the balance shaft 49 of the second balancer 48 by fitting the balance weight 50 of the second balancer 48 into the through hole 57 formed in the second balancer 48. .

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

In the figure, reference numeral 1 is a one-cylinder four-cycle engine (internal combustion engine) that uses gasoline as fuel, and this engine 1 is installed in an automobile, which is a vehicle. Also,
An arrow Fr in the drawing indicates the front of the automobile in the horizontal direction.

The engine 1 has a crankcase 2 made of aluminum alloy casting, and a crankshaft 3 is housed in a crank chamber 3 in the crankcase 2. An axis 5 of the crankshaft 4 extends horizontally in the vehicle width direction, and the crankshaft 4 is supported by the crankcase 2 so as to be rotatable around the axis 5.

A cylinder 7 made of aluminum alloy casting projects from the crankcase 2 toward the front upper side, and the cylinder 7 has a cylinder body 9 having a cylinder hole 8. An opening at one end in the axial direction of the cylinder hole 8 is opened toward the crank chamber 3 in the crank case 2.
Cylinder heads 10 are integrally formed on the projecting end of the cylinder body 9, and the cylinder head 10 closes the opening at the other end, which is the front end side of the cylinder hole 8. As described above, since the cylinder body 9 and the cylinder head 10 are integrally formed, the rigidity of the cylinder 7 is improved, and therefore, the accuracy thereof is kept good. A cylinder head cover 11 is attached to the cylinder head 10.

In FIG. 1, a piston 14 is fitted in the cylinder hole 8 so as to be slidable in the axial direction of its axis 12. The crankshaft 4 and the piston 14 are interlockingly connected to each other by a connecting rod 15. When the piston 14 is on the top dead center side, the space closed by the piston 14 in the cylinder hole 8 is defined as a combustion chamber 16, and the combustion chamber 16 is provided with an ignition plug facing a discharge part.

An intake passage 19 and an exhaust passage 20 for communicating the outside of the cylinder 7 with the combustion chamber 16 are formed in the cylinder head 10, and the intake passage 19 is provided with a throttle valve 21. Intake valve 2 for opening and closing the openings of the intake passage 19 and the exhaust passage 20 to the combustion chamber 16
3 and an exhaust valve 24 are provided.

A valve mechanism 26 for opening and closing the intake valve 23 and the exhaust valve 24 is provided. The valve mechanism 26 is provided with a pair of cam shafts 27, 27 that cam-engage the intake valve 23 and the exhaust valve 24.

1 to 4, the crankcase 2 is shown.
Is divided into a first case 30 and a second case 31 in a direction along the axis 12 of the cylinder hole 8 (almost in the front-rear direction), and the cylinder 7 is projectingly provided on the first case 30. In the crank chamber 3, each end of the crank shaft 4 is sandwiched between an end surface of the first case 30 on the side of the second case 31 and a pair of left and right crank supports 32, 32. The cylinder 7, the first case 30, and the crank support 32 are detachably fastened together by a plurality of fasteners 33, so that the cylinder 7 is fastened to the crankcase 2 and the crankshaft. Four
Is supported by the crankcase 2 while being sandwiched between the first case 30 and the crank support bodies 32, 32.

In FIGS. 1 and 4, the output shaft 37 is rotatably supported about its axis 38 between the first case 30 fastened to each other as described above and the mating surfaces 35 and 36 of the cylinder 7. The output shaft 37 is connected to the crankshaft 4 described above.
It is installed in parallel with.

Here, as described above, since the cylinder 7 is detachably fastened to the crankcase 2, it is possible to easily open the gap between the mating surfaces 35 and 36 by this attachment / detachment. By this opening, the output shaft 37 can be inserted and removed between the mating surfaces 35 and 36, and the output shaft 37 is inserted into the mating surfaces 35 and 36 by the insertion.
It can be easily supported between 36.

1 to 4, a reduction gear mechanism 39 is provided between the crankshaft 4 and the output shaft 37. The reduction mechanism 39 is composed of a small-diameter drive gear 40 attached to the crankshaft 4 and a large-diameter driven gear 41 attached to the output shaft 37 and meshing with the drive gear 40. An output shaft 37 is interlockingly connected to the crankshaft 4. A flywheel 42, which is the driven side, is attached to one end of the output shaft 37, and a transmission is connected to the flywheel 42 via a main clutch. The output side of the transmission is the same as the driven side. Is connected to a traveling wheel.

That is, when the crankshaft 4 of the engine 1 is rotated at a high speed in order to improve the output of the engine 1, the high speed rotation of the crankshaft 4 is reduced to a desired rotation speed by the speed reduction mechanism 39. Is transmitted to the traveling wheel side.

The output shaft 37 is connected to the cam shafts 27, 27.
Are linked and linked by a chain winding transmission means 43, and linked with the crankshaft 4 so that the intake valve 23 and the exhaust valve 24 are linked together.
Is opened and closed at a predetermined crank angle.

A balancer 46 is provided which is operatively connected to the crankshaft 4 and absorbs vibrations caused by the reciprocating motion of the piston 14 and the like. The balancer 46 has a pair of upper and lower first balancer 47 and second balancer 48 which are provided above and below the crankshaft 4 in a distributed manner. The first balancer 47 and the second balancer 48 each include a balance shaft 49 extending parallel to the crankshaft 4.
And a balance weight 50 attached to the balance shaft 49.

1 and 3, the first balancer 47 described above.
The balance shaft 49 and the balance weight 50 are integrally formed with each other, and the balance shaft 49 and the end face of the first case 30 on the side of the second case 31 in the crank chamber 3,
The balance shaft support 52 is sandwiched between the balance shaft support 52 and the balance shaft support 52.
A plurality of fasteners 53 are detachably fastened to the one end face. Thereby, the balance shaft 49 of the first balancer 47 is supported by the crankcase 2 so as to be rotatable around its axis. In this case, the first
The balance shaft 49 of the balancer 47 is the first case 30 described above.
Is located between the mating surfaces 55 and 56 of the second case 31.

1 and 4, the second balancer 48 described above.
In the crank chamber 3, the balance shaft 49 of
It is removably fitted into a pair of through holes 57, 57 formed in the case 30, and is supported on the inner peripheral surface side of these through holes 57, 57, whereby the balance shaft 49 of the second balancer 48 is The crankcase 2 is supported so as to be rotatable about its axis. Also, the crank chamber 3
In the above, the balance weight 50 is detachably fastened to the balance shaft 49 supported by the crankcase 2 by the fastener 58 as described above.

The crankshaft 4 and the first balancer 47,
The interlocking gears 60 to 62 of the same diameter, which are attached to the respective balance shafts 49 of the second balancer 48, mesh with each other, whereby the first balancer 47 and the second balancer 48 move at the same speed as the crankshaft 4. It is linked so as to rotate in the reverse direction, so that the vibration is absorbed as described above.

Therefore, since the balancer 46 reduces the vibration of the engine 1 as a whole, the friction of each part is reduced and the mechanical loss of the engine 1 is reduced.

Further, as described above, since the first and second balancers 47 and 48 are both supported by the crankcase 2, the first and second balancers 47 and 48 are respectively supported by individual members. In comparison, the occurrence of an error between the first and second balancers 47 and 48 is suppressed, and the two balancers 47 and 48 are accurately supported in parallel with each other.

Moreover, as described above, the second balancer 4
Since the balance shaft 49 of No. 8 is fitted into the through hole 57 formed in the first case 30 and is supported on the inner peripheral surface side of the through hole 57, compared with the balance shaft 49 supported across a plurality of members. The bearing strength is strong.

As described above, since the first and second balancers 47 and 48 are accurately and firmly supported, the friction is reduced and the mechanical loss is suppressed during these rotations. To be done.

As described above, the first balancer 47
The balance shaft 49 of the first and the second is detachable from each other.
Since the cases 30 and 31 are located between the mating surfaces 55 and 56 of each other, the balance shaft 4 of the first balancer 47 is located between the mating surfaces 55 and 56 opened by the attachment and detachment.
It is easy to insert 9 or to support the crankcase 2.

Further, as described above, the second balancer 48
Since the balance weight 50 is detachably attached to the balance shaft 49, the balance weight 50 is removed when the balance weight 50 is removed from the balance shaft 49.
The balance shaft 49 through the through hole 57 without disturbing
Can be easily inserted into.

In FIGS. 1 and 4, an auxiliary machine 68 interlockingly connected to the output shaft 37 is provided. The auxiliary machine 68 includes an oil pump 69 and a water pump 70, and the oil pump 69 and the water pump 70 are respectively provided with a housing 71.
And a rotating shaft 72 supported by the housing 71 and a rotor 73 attached to the rotating shaft 72.

The oil pump 69 and the water pump 70 are arranged side by side along the axis 38 of the output shaft 37, and their respective rotary shafts 72, 72 are positioned on the axis 38 of the output shaft 37. Connected to each other.

The power of the crankshaft 4 is the output shaft 37.
When the oil pump 69 and the water pump 70 are driven by being transmitted to the rotary shafts 72, 72 via the oil, the lubricating oil discharged from the oil pump 69 is
Lubricate the bearings of the output shaft 37 and the balance shaft 49.
The water discharged from the water pump 70 is sent to the water jacket 74 formed in the cylinder 7 to cool it.

Although the above is based on the illustrated example, the engine 1 may be any one of 2 to 5 cylinders.
In the case of three cylinders or five cylinders, the balancer 46 is composed of a single balance shaft. On the other hand, the balance shaft 49 of the second balancer 48 includes a first case 30 and a second case 3.
Alternatively, the crankcase 2 may be supported by being positioned between the mating surfaces 55 and 56 of one.

[0040]

The effects of the present invention are as follows.

According to the invention of claim 1, five or less cylinders are detachably fastened to the crankcase which supports the crankshaft, and an output shaft for transmitting the power of the crankshaft to the driven side is provided. The cylinder is composed of a cylinder body having a cylinder hole and a cylinder head attached to the cylinder body, one end of the cylinder hole in the axial direction is opened toward the inside of the crankcase, and the other end is closed by the cylinder head. In a four-cycle engine with a small number of cylinders, a reduction mechanism is interposed between the crank shaft and the output shaft, the cylinder body and the cylinder head are integrally formed with each other, and a balancer is linked to the crank shaft.

Therefore, if the crankshaft of the engine is rotated at a high speed, and the high speed rotation of the crankshaft is reduced to a desired rotation speed by the reduction mechanism, the output of the engine is transmitted to the driven side at a desired rotation speed. Can be made.

Therefore, by providing the speed reduction mechanism, the engine can be rotated at high speed, that is, the output of the engine can be improved.

By the way, when the engine of a small number of cylinders is rotated at a high speed, the vibration is apt to become large as described above. In the present invention, however, the cylinder body and the cylinder head are integrally formed with each other to form a cylinder as described above. Therefore, the rigidity of the cylinder is improved, and the accuracy between the inner peripheral surface of the cylinder hole and the piston sliding on the inner peripheral surface is kept good. Therefore, the friction at the time of sliding can be suppressed small, and the vibration can be suppressed correspondingly.

Moreover, since the balancer is interlocked with the crankshaft as described above, the vibration can be further suppressed. Therefore, although the output of the engine is improved, the vibration of the engine can be suppressed small.

According to the second aspect of the present invention, the output shaft is supported between the mating surfaces of the crankcase and the cylinder.

Here, as described above, since the cylinder is detachably fastened to the crankcase, the attachment / detachment can easily open the gap between the mating surfaces.

Therefore, the output shaft can be easily supported between the mating surfaces, that is, the engine can be easily assembled.

According to the third aspect of the present invention, the rotary shaft of the auxiliary machine is located on the same axis as the output shaft, and the rotary shaft is linked to the output shaft.

Therefore, it is easy to center the output shaft and the rotary shaft of the auxiliary machine to each other, and the output shaft and the rotary shaft can be accurately connected.

Therefore, the mechanical loss at the time of transmitting the power from the output shaft to the rotary shaft is suppressed to be small, and the output of the engine is improved.

According to the fourth aspect of the present invention, the crankcase is divided into the first and second cases, and the first and second cases are detachable from each other, while the balancer includes the pair of first and second cases.
A second balancer, of which the balance shaft of the first balancer is positioned between the mating surfaces of the first and second cases and supported by the crankcase, and the balance shaft of the second balancer is The balance weight of the second balancer is detachably attached to the balance shaft of the second balancer by being fitted into the through hole formed in one case and supported on the inner peripheral surface side of the through hole.

Therefore, since the first and second balancers are both supported by the crankcase, the first and second balancers are supported by individual members, respectively, as compared with the case where the first and second balancers are supported by individual members. It is possible to suppress the occurrence of an error between the balancers, and both balancers are accurately supported in parallel with each other.

Moreover, as described above, since the balance shaft of the second balancer is fitted into the through hole formed in the first case and supported by the inner peripheral surface side of the through hole, the balance shaft extends over a plurality of members. The bearing strength is stronger than that of bearings that are supported.

Therefore, since the first and second balancers are supported accurately and firmly, the occurrence of mechanical loss in these rotations is suppressed, and the output of the engine is improved.

Further, as described above, since the balance shaft of the first balancer is located between the mating surfaces of the first and second cases which are detachable from each other, the mating surfaces opened by the above detachment. It is easy to insert the balance shaft of the first balancer between them and to support it on the crankcase, that is, to easily assemble the engine.

Further, as described above, since the balance weight is detachable from the balance shaft of the second balancer, when the balance weight is removed from the balance shaft, the balance weight does not interfere with the balance shaft. Can be easily fitted into the through hole, and if the balance weight is attached to the balance shaft after this fitting, the assembly of the second balancer is completed.

Therefore, although the second balancer is firmly supported by the crankcase as described above, it can be easily assembled, that is, the engine can be easily assembled.

[Brief description of the drawings]

FIG. 1 is an overall side sectional view.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view taken along line 3-3 in FIG. 1;

FIG. 4 is a sectional view taken along line 4-4 of FIG. 1;

[Explanation of symbols]

 1 Engine 2 Crankcase 3 Crank Chamber 4 Crankshaft 5 Shaft Center 7 Cylinder 8 Cylinder Hole 9 Cylinder Body 10 Cylinder Head 30 1st Case 31 2nd Case 35, 36, 55, 56 Mating Face 37 Output Shaft 38 Shaft Center 39 Speed Reduction Mechanism 42 Flywheel (driven side) 46 Balancer 47 First balancer 48 Second balancer 49 Balance shaft 50 Balance weight 57 Through hole 68 Auxiliary equipment 72 Rotating shaft

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area F16F 15/26 8917-3J F16F 15/26 LC4

Claims (4)

[Claims] 1. A cylinder having not more than five cylinders detachably fastened to a crankcase supporting a crankshaft, an output shaft for transmitting the power of the crankshaft to a driven side is provided, and the cylinder having a cylinder hole. A four-cycle engine of a small number of cylinders, which comprises a main body and a cylinder head attached to the cylinder main body, one end of the cylinder hole in the axial direction is opened toward the inside of the crankcase, and the other end is closed by the cylinder head. A four-cycle engine of a small number of cylinders in which a reduction mechanism is interposed between the crank shaft and the output shaft, the cylinder body and the cylinder head are integrally formed with each other, and a balancer is interlockingly connected to the crank shaft. 2. The minority cylinder four-cycle engine according to claim 1, wherein an output shaft is supported between mating surfaces of the crankcase and the cylinder. 3. A minority-cylinder four-cycle engine according to claim 1, wherein a rotary shaft of the auxiliary machine is located on the same axis as the output shaft, and the rotary shaft is linked to the output shaft. . 4. A crankcase is divided into a first case and a second case, and the first and second cases are detachable from each other,
On the other hand, the balancer is composed of a pair of first and second balancers,
Among these, the balance shaft of the first balancer is located between the mating surfaces of the first and second cases and supported by the crankcase, and the balance shaft of the second balancer is formed in the first case. The balance weight of the second balancer is detachably mounted on the balance shaft of the second balancer. A 4-cylinder engine with a small number of cylinders.