JP3070407B2 - Vehicle engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle engine.

[0002]

2. Description of the Related Art As shown in FIG. 4, a cylinder head 2 of an engine 1 provided with a valve gear 3 is provided on a crankshaft 4 and is provided in a cam chain chamber 5 by a cam chain drive sprocket. 6 and cam chain 7
It is common to drive the camshaft 8 of the valve train 3 via the.

In the engine 1, gas having a pressure generated in a combustion chamber 9 includes a piston 10 and a cylinder 1.
It is a well-known fact that a small amount of the gas leaks into the crankcase 12 through the gap with the crankcase 12. Further, since the pressure of the gas in the crankcase 12 constantly fluctuates with the vertical movement of the piston 10, when the crankcase 12 is sealed, the pressure of the gas in the crankcase 12 hinders the movement of the piston 10. Become. Therefore, it is necessary to provide a means for releasing the gas in the crankcase 12 to the outside.

Conventionally, this gas (hereinafter referred to as blow-by gas) has been discharged into the atmosphere from a breather hole provided in the crankcase 12, but since the blow-by gas is one of the sources of air pollution, the blow-by gas is not shown. A breather device has been provided, which is a mechanism that recirculates the air to a fresh air intake device, from which it is sent again to the combustion chamber 9 for reburning.

[0005] In most of the four-cycle engine 1, a breather chamber 13 of the breather device is provided in a cylinder head cover 14 of the engine 1, and a hose 15 connected to a fresh air intake device is connected to the breather chamber 13. .

During operation of the engine 1, the blow-by gas leaked into the crankcase 12 is mixed with lubricating oil and guided to a breather chamber 13 through an oil return passage (not shown) and the like. After the oil was separated by the above, the oil was returned to the crankcase 12 via the cam chain chamber 5 and the like, and the blow-by gas was again sucked into the combustion chamber 9 via the fresh air intake device.

On the other hand, an engine 1 used for a motorcycle
As shown in FIG. 5, a transmission mechanism 16 is provided integrally with the main body of the engine 1, and usually shares the crankcase 12. In the multi-cylinder engine 1,
In general, an upper and lower two-part type crankcase 12 is used, and a crankshaft 4 and a countershaft 1 are used.
7 and the drive shaft 18 are often arranged such that the shafts 4, 17, 18 are parallel to the mating surface 19 of the upper and lower crankcases 12.

[0008]

Since the engine has many sliding parts and rotating parts inside, lubricating oil is supplied to each part using a lubricating device, and the frictional resistance of each part is reduced by the action of the lubricating oil. It is designed to fully demonstrate the function of the engine.

However, a part of the lubricating oil that has lubricated the crankshaft sometimes flows into the cam chain chamber. Further, the oil separated from the blow-by gas in the breather chamber also flows into the cam chain chamber.
The lubricating oil that has flowed in is agitated by the cam chain and easily accumulates in the cam chain chamber. as a result,
Problems such as engine breather failure and mechanical loss due to lubrication oil agitation occur.

On the other hand, in order to improve the separability of the blow-by gas and oil in the breather chamber, it is desirable to increase the capacity of the breather chamber and to form a maze structure in the breather chamber. Since the space for accommodating the valve mechanism is small, it is difficult to increase the capacity of the breather chamber. If measures such as partially expanding the head cover are taken, the engine cannot be made compact. If the capacity of the breather chamber is small, lubricating oil may blow up due to the pressure difference between the inside of the crankcase.

Furthermore, if the breather chamber has a maze structure, the cylinder head cover becomes complicated and the cost increases.

Further, when each shaft is arranged in parallel on a mating surface of a vertically divided crankcase,
When the front and rear dimensions of the crankcase increase and the transmission mechanism is serviced, the crankshaft must also be removed, so that the service of the transmission mechanism alone is impossible.

If the crankcase is divided into left and right parts, it is possible to shorten the front-rear dimension of the crankcase, but it becomes difficult to form a bearing at the intermediate portion of the crankshaft, and the rigidity against the explosion load is low. It is not suitable for a parallel multi-cylinder engine.

The present invention has been made in consideration of the above circumstances, and has as its object to provide a vehicle engine that prevents lubricating oil flowing into a cam chain chamber from being agitated by the cam chain.

Another object of the present invention is to make it possible to shorten the front-rear dimension of the crankcase while ensuring sufficient rigidity against an explosion load, to enable maintenance of the transmission mechanism alone, and to provide a breather chamber with a simple structure. Another object of the present invention is to provide a vehicle engine capable of increasing the capacity of a vehicle.

[0016]

According to a first aspect of the present invention, there is provided a vehicle engine provided on a crank journal of a crankshaft and provided in a cam chain chamber. The cam chain drive sprocket drives the valve gear via the cam chain, while detecting the rotation of the ignition signal rotor provided on the crank journal with the ignition signal sensor to determine the ignition timing of the ignition plug. In the vehicle engine to be controlled, the outer diameter of the ignition signal rotor is made larger than the outer diameter of the crank journal, and the ignition signal rotor is arranged between the crank journal and the cam chain drive sprocket. The ignition signal sensor is disposed immediately below the signal rotor, and the ignition signal sensor is mounted on the cam. While attached to sensor mounting bracket having an outer peripheral shape along the inner wall of the En chamber, the sensor mounting bracket which is secured to the crankcase,
A lubricating oil return hole is formed in the crankcase immediately below the ignition signal sensor.

Further, in order to solve the above-mentioned problem, as described in claim 2, an upper crankcase,
In a vehicle engine provided with a crankcase configured to be able to be divided into three from a center crankcase and a lower crankcase, a crankshaft is arranged on a mating surface between the upper crankcase and the center crankcase, and the center crank is provided. Along with placing the counter shaft and drive shaft of the transmission mechanism on the mating surface of the case and the lower crankcase,
A breather chamber is formed by a lower portion of the upper crankcase and an upper portion of the center crankcase, and a tightening direction of a bolt for tightening the upper crankcase and the center crankcase is parallel to a sliding direction of a piston. is there.

[0018]

According to the present invention having the above-described structure, a cam chain drive sprocket provided on a crank journal of a crankshaft and disposed in a cam chain chamber drives a valve train via a cam chain.
The rotation of an ignition signal rotor provided on the crank journal is detected by an ignition signal sensor to control the ignition timing of a spark plug, and the outer diameter of the ignition signal rotor of the vehicle engine is changed to the outer diameter of the crank journal. Because the ignition signal rotor is disposed between the crank journal and the cam chain drive sprocket, the lubricating oil that lubricates the crank journal falls down on the ignition signal rotor, and The ignition signal sensor is disposed immediately below the signal rotor, and the ignition signal sensor is mounted on a sensor mounting bracket having an outer peripheral shape along the inner wall of the cam chain chamber, and the sensor mounting bracket is fixed to a crankcase. On the other hand, the crankcase immediately below the ignition signal sensor Since the lubricating oil return hole is formed, the lubricating oil falling in the cam chain chamber can be efficiently guided to the oil return hole, and the lubricating oil flowing into the cam chain chamber is agitated by the cam chain. Can be prevented.

Also, in a vehicle engine provided with a crankcase configured to be able to be divided into three parts from an upper crankcase, a center crankcase, and a lower crankcase, a joint surface between the upper crankcase and the center crankcase is provided. By arranging a crankshaft and arranging a countershaft and a drive shaft of the transmission mechanism on the mating surface of the center crankcase and the lower crankcase, the shafts can be arranged in a triangular shape, and the front and rear dimensions of the crankcase And the maintenance of the transmission mechanism alone becomes possible, while the breather chamber is formed by the lower part of the upper crankcase and the upper part of the center crankcase to increase the capacity of the breather chamber with a simple structure. Is possible In addition, because of the parallel to the sliding direction of the piston fastening direction of the bolt tightening and the upper crankcase and the center crank case,
It is possible to sufficiently secure the rigidity of the crankcase against the explosion load.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a right side view showing an example of a water-cooled 4-cycle parallel 4-cylinder engine for a motorcycle to which the present invention is applied. FIG. 2 is a sectional view taken along the line II-II in FIG. 1, and FIG. 3 is a sectional view taken along the line III-III in FIG.

As shown in FIGS. 1, 2 and 3, the outer shape of the engine 20 mainly comprises a cylinder head cover 21, a cylinder head 22, a cylinder block 23, and a crankcase 24.

A crankshaft 25 is arranged in the crankcase 24. The crankshaft 25 includes a crank journal 25a and a crank web 25b. A balance weight 25c is provided on one side of the crank web 25b, and a crank pin 25d is provided on the other side of the crank web 25b. The large end 27a of the connecting rod 27 is connected to the crank pin 25d via a bearing 26, and the piston 29 is connected to the small end 27b of the connecting rod 27 via a piston pin 28.

A piston 29 is provided in the cylinder block 23.
Are slidably accommodated in the vertical direction in the figure. Further, a combustion chamber 30 is formed in a space between the cylinder head 22 and the piston 29, and a spark plug 31 is screw-connected to the center of the combustion chamber 30 from the outside.

The reciprocating stroke of the piston 29 is converted into a rotational movement by the crankshaft 25, and the countershaft 34 of the transmission mechanism 33 is transmitted from a primary drive gear 32 provided on the right side of the crankshaft 25 via a clutch mechanism (not shown). And the drive shaft 35.

The crankcase 24 includes an upper crankcase 24a, a center crankcase 24b, and a lower crankcase 24c, and is, for example, divided into three parts in the vertical direction. Each of the crankcases 24a, 24b,
The mating surfaces 36 and 37 of 24c are arranged in parallel,
Cylinder block 23 and upper crankcase 24a
The mating surface 38 of each of the crankcases 24a, 24b, 2
4c are arranged in parallel with the mating surfaces 36, 37, and the mating surfaces 36, 37, 38 are arranged so as to be perpendicular to the sliding direction 39 of the piston 29.

A bearing 40 of the crankshaft 25 is provided inside a mating surface 36 between the upper crankcase 24a and the center crankcase 24b, and a mating surface 3 between the center crankcase 24b and the lower crankcase 24c.
7, bearings (not shown) for the counter shaft 34 and the drive shaft 35 are separately provided in the upper and lower portions.
4 and 35 are pivotally supported so as to be parallel to each other.

A breather chamber 41 is arranged on the crankcase 24 behind the cylinder block 23. The breather chamber 41 is formed by a lower portion of the upper crankcase 24a and an upper portion of the center crankcase 24b.

The crank journal 25a of the crankshaft 25 is supported by a bearing 40 inside the mating surface 36 between the upper crankcase 24a and the center crankcase 24b.
The tightening direction of the bolt 42 for tightening b is the piston 29
Is set to be parallel to the sliding direction 39 of.

In the cylinder head 22, a valve train 4 including a camshaft 43, an intake / exhaust valve 44 and the like is provided.
5 are provided. A cam sprocket 46 is provided at one end of the camshaft 43, and the cam sprocket 46 is operatively connected to a cam chain drive sprocket 48 provided on the crankshaft 25 by a cam chain 47. The rotation of the crankshaft 25 is transmitted to the camshaft 43 via the cam chain 47, so that the valve train 45 is operated. The upper part of the cylinder head 22 is closed by the cylinder head cover 21.

On the other hand, a cam chain chamber 49 is formed on the right side of the crankshaft 25. This cam chain room 4
Inside the crankshaft 25, a disk-shaped ignition signal rotor 50 made of a magnetic material is spline-fitted to the right end of the crankshaft 25, for example. The ignition signal rotor 50 is formed integrally or integrally with the cam chain drive sprocket 48. The ignition signal rotor 50 is disposed between the crank journal 25a and the cam chain drive sprocket 48. Further, the outer diameter of the ignition signal rotor 50 is larger than the outer diameter of the crank journal 25a.
It is set to about twice the size.

The ignition signal rotor 50 has, for example, a plurality of projections 50a arranged at equal intervals on an outer peripheral portion thereof. An ignition signal sensor 51 is disposed immediately below the signal rotor 50. The ignition signal sensor 51 includes, for example, a magnetic circuit, and an ignition signal rotor 50.
The magnetic sensor detects the passage of the protrusion 50a due to the rotation of the motor, converts the change in the amount of magnetism into an electric signal (pulse wave), performs arithmetic processing, and controls the ignition timing of the ignition plug 31.

The ignition signal sensor 51 is mounted on a sensor mounting bracket 52.
2 is fixed to the center crankcase 24b with screws 53 or the like. The outer peripheral shape of the sensor mounting bracket 52 is substantially along the inner wall of the cam chain chamber 49. A return hole 54 for lubricating oil is formed in the center crankcase 24b immediately below the ignition signal sensor 51.

A starter clutch 55 is provided at the right end of the crankshaft 25. This starter clutch 5
5 is provided with a starter gear 56, which is connected to a drive gear 57 of a starter motor (not shown) via an idle gear (not shown). The starter clutch 55 has a function of transmitting the power of a starter motor to the crankshaft 25 when the engine 20 starts, and is automatically disconnected after the engine 20 starts.

The engine 20 includes an engine lubrication device 5
The lubricating oil stored in an oil pan 59 provided below the lower crankcase 24c is supplied by an oil pump 60 via an oil filter 61 to a crankshaft 25, a valve gear 45, a transmission mechanism 33, and the like. Of the engine 20. In addition, reference numeral 62
Is a strainer for removing relatively large foreign matter in the lubricating oil. The lubricating oil that has lubricated each part of the engine 20 falls naturally in the crankcase 24, and the oil return hole 5
The oil is returned to the oil pan 59 via the oil return passage 4 and an oil return passage (not shown), and is recirculated.

Next, the operation of this embodiment will be described.

Of the lubricating oil that has lubricated the various parts of the engine 20, the crank journal 25 of the crankshaft 25
The lubricating oil that has lubricated the right end flows into the cam chain chamber 49, but an ignition signal rotor 50 larger than the outer diameter of the crank journal 25a is provided in front of the cam chain drive sprocket 48 and closer to the crank journal 25a. Therefore, the lubricating oil hits the ignition signal rotor 50 and falls downward.

Further, the outer peripheral shape of the sensor mounting bracket 52 is formed substantially along the inner wall of the cam chain chamber 49,
By using the sensor mounting bracket 52 as a guide for lubricating oil, the lubricating oil that has fallen downward on the ignition signal rotor 50 and the lubricating oil that has dropped from the cylinder head 22 into the cam chain chamber 49 can be efficiently removed. The oil can be led to the oil return hole 54. Therefore, the lubricating oil flowing into the cam chain chamber 49 is not agitated by the cam chain 47, and does not accumulate in the cam chain chamber 49. As a result, problems such as a breather failure of the engine 20 and mechanical loss due to stirring of the lubricating oil can be prevented.

Further, the crankcase 24 is divided into three parts in the vertical direction, and the mating surfaces 36 and 37 of the upper crankcase 24a and the center crankcase 24b are used to connect the crankshaft 25, and the center crankcase 24b and the lower crankcase 24c. By supporting the counter shaft 34 and the drive shaft 35 with the mating surfaces 36, 37, the shafts 25, 34, 35 can be arranged in a triangular shape, without changing the dimension between the shafts 25, 34, 35. The front and rear dimensions of the crankcase 24 can be reduced.

Further, by dividing the crankcase 24 into three parts in the vertical direction, the crank journal 25a is pivotally supported by mating surfaces 36 and 37 between the upper crankcase 24a and the center crankcase 24b. , 24b can be secured in parallel with the sliding direction 39 of the piston 29, so that the rigidity of the crankcase 24 against the explosion load of the engine 20 can be sufficiently ensured.

Further, by dividing the crankcase 24 into three in the vertical direction, the transmission mechanism 33 can be maintained alone by merely removing the lower crankcase 24c without removing the crankshaft 25.

Further, on the crankcase 24, behind the cylinder block 23, an upper crankcase 24a
And the upper part of the center crankcase 24b, the rigidity of the crankcase 24 is increased, and the capacity of the breather chamber 41 can be increased with a simple structure. Separability from oil is improved.

[0043]

As described above, according to the vehicle engine of the present invention, the cam chain is driven by the cam chain drive sprocket provided on the crank journal of the crankshaft and disposed in the cam chain chamber via the cam chain. In a vehicle engine that drives a valve device and detects the rotation of an ignition signal rotor provided on the crank journal with an ignition signal sensor to control the ignition timing of an ignition plug, Since the diameter is larger than the outer diameter of the crank journal and the ignition signal rotor is disposed between the crank journal and the cam chain drive sprocket, the lubricating oil that lubricates the crank journal hits the ignition signal rotor downwardly. , And directly under the ignition signal rotor. A fire signal sensor is disposed, and the ignition signal sensor is mounted on a sensor mounting bracket having an outer peripheral shape along an inner wall of the cam chain chamber. The sensor mounting bracket is fixed to a crankcase, while the ignition signal sensor is mounted on the sensor mounting bracket. Since the lubricating oil return hole is formed in the crankcase immediately below the sensor for lubrication, the lubricating oil falling in the cam chain chamber can be efficiently guided to the oil return hole, and lubrication flowing into the cam chain chamber Oil can be prevented from being agitated by the cam chain.

Also, in a vehicle engine provided with a crankcase configured to be divided into three parts from an upper crankcase, a center crankcase, and a lower crankcase, a mating surface between the upper crankcase and the center crankcase is provided. By disposing a countershaft and a drive shaft of the transmission mechanism on the mating surface of the center crankcase and the lower crankcase, the shafts can be arranged in a triangular shape, and the front and rear of the crankcase can be arranged. While the size can be shortened and the transmission mechanism alone can be maintained, the breather chamber is formed by the lower part of the upper crankcase and the upper part of the center crankcase, so that the breather chamber has a large capacity with a simple structure. Transformation It becomes ability, also because of the parallel to the sliding direction of the piston fastening direction of the bolt tightening and the upper crankcase and the center crankcase can sufficiently secure the rigidity of the crankcase against explosion weighted.

[Brief description of the drawings]

FIG. 1 is a right side view of a water-cooled four-cycle parallel four-cylinder engine for a motorcycle showing one embodiment of a vehicle engine according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is a cross-sectional view of a conventional engine showing a drive device and a breather device of a valve train.

FIG. 5 is a longitudinal sectional view of an engine having a vertically split crankcase.

[Explanation of symbols]

Reference Signs List 20 vehicle engine 22 cylinder head 23 cylinder block 24 crankcase 24a upper crankcase 24b center crankcase 24c lower crankcase 25 crankshaft 25a crank journal 29 piston 31 spark plug 33 transmission function 34 counter shaft 35 drive shaft 36 upper crankcase and Mating surface with center crankcase 37 Mating surface with center crankcase and lower crankcase 38 Mating surface with cylinder block and upper crankcase 39 Piston sliding direction 41 Breather chamber 42 Bolt for tightening crankcase 45 Valve train 47 Cam chain 48 cam chain drive sprocket 49 cam chain chamber 50 ignition signal rotor Ignition signal sensor 52 sensor mounting bracket 54 lubricating oil return hole 58 engine lubricating system

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02B 67/06 F01M 1/06 F01M 11/00 F01M 13/04 F02B 77/00 F02F 7/00

Claims (2)

(57) [Claims] 1. A cam chain drive sprocket disposed on a crank journal of a crankshaft and disposed in a cam chain chamber drives a valve train via a cam chain, while an ignition signal provided on the crank journal is provided. An ignition signal sensor that detects the rotation of the ignition rotor to control the ignition timing of an ignition plug, wherein the ignition signal rotor has an outer diameter larger than the crank journal outer diameter, and the ignition signal rotor Is disposed between the crank journal and the cam chain drive sprocket, and the ignition signal sensor is disposed immediately below the ignition signal rotor. The ignition signal sensor is disposed on the outer periphery along the inner wall of the cam chain chamber. It is attached to a sensor mounting bracket having a shape, and this sensor mounting bracket While being fixed to the crankcase,
A vehicle engine, wherein a return hole for lubricating oil is formed in the crankcase immediately below the ignition signal sensor. 2. A vehicle engine comprising a crankcase configured to be divided into three parts from an upper crankcase, a center crankcase, and a lower crankcase, wherein a mating surface of the upper crankcase and the center crankcase is provided. A countershaft and a drive shaft of the transmission mechanism are arranged on the mating surface of the center crankcase and the lower crankcase, and a breather is formed by a lower portion of the upper crankcase and an upper portion of the center crankcase. An engine for a vehicle, wherein a tightening direction of a bolt for tightening the upper crankcase and the center crankcase is parallel to a sliding direction of a piston while forming a chamber.