JP2003065064A - Parallel four cylinder engine for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve running stability of a motor bicycle or the like by disposing the center of gravity of an engine close to the center of the engine, to make the engine compact, and to improve a damping effect of a balancer means. SOLUTION: A primary drive gear 32 is formed on a second crank web 8g of a crankshaft 8 as counted from the side opposite to a generator attachment portion 31. A clutch means 36 is provided on a counter shaft 27 at a position corresponding to a first crank web 8h as counted from the side opposite to the generator attachment portion 31. A clutch operation mechanism 54 is provided at an end of the counter shaft 27 opposite to the clutch means 36, which end corresponds to a first crank web 8a of the crankshaft 8 as counted from the side of the generator attachment portion 31. A balancer drive gear 79 is provided on a second cylinder crank web 8c or 8d as counted from the side of the generator attachment portion 31. An axis of the balancer means 73 is located in a space opposite to the counter shaft 27 with the crankshaft 8 interposed therebetween, as viewed in the axial direction of the crankshaft 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle parallel 4-cylinder engine mounted on a motorcycle or the like.

[0002]

2. Description of the Related Art As disclosed in Japanese Unexamined Patent Publication No. 11-193723, most parallel four-cylinder engines for vehicles mounted on motorcycles or the like have a cylinder assembly installed on the upper surface of a crankcase and inside the cylinder assembly. No. 1 cylinder, No. 2 cylinder, and cylinder bores (pistons) are arranged in parallel from the left in the direction of travel, and the crankshaft, counter shaft, and drive shaft are parallel to each other and extend in the vehicle width direction inside the crankcase. It is pivotally supported.

A power generator mounting portion is provided at one end of the crankshaft (usually the No. 1 cylinder side), and a primary drive is provided on the crankshaft near the opposite side (usually the No. 4 cylinder side) of the power generating apparatus mount. The gear is attached to one end (4
The first driven gear is provided on a clutch device axially mounted on the No. cylinder side), and the rotation of the crank shaft is transmitted to the counter shaft by the engagement of the clutch device.

Further, a transmission device having a large number of gears and a shift mechanism is arranged between the counter shaft and the drive shaft, and the rotation of the counter shaft is appropriately changed and transmitted to the drive shaft to obtain an engine output. Taken out.

Conventionally, a plurality of primary drive gears for the crankshaft are provided on the crankshaft (8 in the case of a four-cylinder engine).
(3) Of the provided crank webs, it was formed on the outer periphery of the crank web on the side farthest from the power generator mounting portion (that is, on the right side of the fourth cylinder).

[0006]

However, since the primary drive gear is formed on the outer periphery of the crank web on the right side of the fourth cylinder of the crankshaft, the primary driven gear, that is, the clutch device and the entire transmission device are correspondingly formed. The center of the engine must be offset toward the No. 4 cylinder side with respect to the engine center, and as a result, the center of gravity of the engine is offset toward the No. 4 cylinder side, which is a cause of impairing the running stability of the motorcycle and the like.

In addition, since the clutch cover for covering the outer surface of the clutch device projects to the outside of the engine, in the motorcycle, the clutch cover easily interferes with the rider's feet, and the engine width is widened to be compact. However, there was a problem that a dead space was generated in the crankcase.

Even if the clutch device is pulled toward the engine center side in order to solve the above problems, the clutch device needs a predetermined outer diameter to secure the clutch capacity, so that the clutch device outer peripheral portion (primary driven gear) is required.
And the crank shaft interfere with each other, and in order to avoid this, the distance between the crank shaft and the counter shaft must be widened, which also creates a dead space and impairs the compactness of the engine in the longitudinal direction.

The present invention has been made to solve the above-mentioned problems, and improves the running stability of a motorcycle or the like by bringing the center of gravity of the engine closer to the engine center side, and at the same time downsizes the engine, Another object of the present invention is to provide a parallel multi-cylinder engine for a vehicle, which can improve the vibration damping effect of the balancer device.

[0010]

In order to achieve the above object, in a parallel multi-cylinder engine for a vehicle according to the present invention, as described in claim 1, a crankshaft and a countershaft are axially supported in parallel, and A power generator mounting portion is provided at one end of the crankshaft, a primary drive gear is provided on the crankshaft near the opposite side of the power generator mounting portion, and a drive sprocket for driving the timing chain is provided near the center of the crankshaft. In a parallel four-cylinder engine for a vehicle in which the primary drive gear meshes with a primary driven gear provided in a clutch device mounted on one end of the counter shaft, in the parallel four-cylinder engine for vehicle, Formed on the second crank web, and installed the crankshaft anti-power generator. The clutch device is provided on the counter shaft facing the first crank web counted from the side of the crankshaft, and further, 1 is counted from the side of the counter shaft opposite to the clutch device side from the side of the crankshaft which is the power generator installation part. A clutch operation mechanism for operating the clutch device is provided at a position facing the second crank web.

With the above construction, the clutch device and the entire transmission device do not have to be offset to one side with respect to the engine center, and the center of gravity of the engine is brought closer to the engine center side to improve the running stability of the motorcycle and the like. The engine can be made compact in the width direction, and the clutch cover can be prevented from protruding outside the engine. Moreover, since the clutch operating mechanism is provided on the side of the crankcase opposite to the clutch device, the dead space in the crankcase can be effectively utilized.

Further, according to a second aspect of the present invention, there is provided a parallel multi-cylinder engine for a vehicle, wherein the crank web of the second cylinder counted from the side of the power generator installation portion of the crank shaft has a balancer device. A drive gear was provided, and the axial center of the balancer device was arranged in a space opposite to the counter shaft with the crank shaft interposed therebetween when viewed from the axial direction of the crank shaft.
By doing so, the balancer device can be provided in the front dead space in the crankcase to improve the layout inside the crankcase, and the size of the crankcase can be made smaller and compact accordingly.

Further, the parallel multi-cylinder engine for a vehicle according to the present invention is, as described in claim 3, sandwiched between the fastening bolts of the journal bearing supporting the crankshaft when viewed from the axial direction of the crankshaft. The axis of the balancer device is arranged in the area to be covered. As a result, the balancer device is located in the vicinity of the cylinder bore axis extension line and is disposed in the most rigid portion inside the crankcase, so that the balancer device can exert the maximum vibration damping effect. Therefore, the balancer device can be downsized, the space inside the crankcase can be effectively used, and the engine can be made compact.

In the parallel multi-cylinder engine for a vehicle according to the present invention, as described in claim 4, the clutch operating mechanism is hydraulically operated. In this way, the operating force at the time of releasing the clutch can be reduced, and the clutch spring can be strengthened by that amount, whereby the outer diameter and width of the clutch device can be reduced with the same clutch capacity. Therefore,
It is possible to prevent interference between the outer peripheral portion of the clutch device and the crank shaft, reduce the distance between the crank shaft and the counter shaft, and make the engine compact in the longitudinal direction. At the same time, the engine can be made compact in the width direction.

Further, in the vehicle parallel multi-cylinder engine according to the present invention, as described in claim 5, the clutch device increases the clutch capacity and reduces the back torque transmission to the crankshaft side. A cam unit is added. By doing so, the clutch capacity is increased by the clutch cam unit, so that the outer diameter and width of the clutch device can be reduced while maintaining the same clutch capacity, which can further contribute to downsizing of the engine in the length direction and the width direction.

[0016]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a vertical cross-sectional view of a parallel multi-cylinder engine for a vehicle according to the present invention as viewed from the left side, and FIG. 2 is a section II of FIG.
-II is a cross-sectional view showing an embodiment of the present invention as viewed from the direction of arrow II. The engine 1 is, for example, a parallel four-cylinder engine mounted on a motorcycle. The left side is the front side and the right side is the rear side in FIG. 1, and the cylinder assembly 3 is tilted forward on the upper surface of the crankcase 2. is set up.

The crankcase 2 has an upper case 4 and a lower case 5 and is divided into upper and lower parts.
An oil pan 6 is joined to the lower surface of the lower case 5, and a crank shaft 8 is axially supported along a vehicle width direction on a plurality of journal bearings 7 formed on the dividing surfaces of the upper case 4 and the lower case 5. Has been done. Each of the journal bearings 7 sandwiches six crank journals 10 provided on the crankshaft 8 and is tightened by a pair of tightening bolts 11 and 12 (see FIG. 8) to rotate the crankshaft 8 while maintaining high rigidity. Freely support the shaft.

The cylinder assembly 3 includes a cylinder block 14 and a cylinder head 1 in order from the bottom.
5. The head cover 16 is mounted on the cylinder block 14. Four cylinder bores 17 are formed inside the cylinder block 14 in parallel in the vehicle width direction. The four combustion chambers 18 aligned with each other are formed, and are the first cylinder, the second cylinder, the third cylinder, and the fourth cylinder in order from the left side in the traveling direction. The crankshaft 8 has two crank webs 8a to 8c for each cylinder.
8h (see FIG. 2) is provided.

Further, inside the cylinder head 15, an intake port 21 communicating with the combustion chamber 18 from the rear,
An exhaust port 22 that communicates with the combustion chamber 18 from the front is formed, a fuel injection device (not shown) is connected to the intake port 21, and an exhaust pipe (not shown) is connected to the exhaust port 22.

A piston 23 is slidably inserted in each cylinder bore 17, and these pistons 23
And the crank webs 8a to 8 that form a pair of the crank shafts 8
The crank pin 8j eccentrically interposed between h is connected by the connecting rod 24, and the reciprocating motion of the piston 23 in the cylinder bore 17 is converted into the rotary motion of the crank shaft 8 to be the output of the engine 1.

A counter shaft 27 and a drive shaft 28 are axially supported in the crankcase 2 in parallel with the crankshaft 8. These shafts 27 and 28 are also pivotally supported by the dividing surfaces of the upper case 4 and the lower case 5 like the crankshaft 8, and a six-stage transmission device 29 is formed between the shafts 27 and 28, for example. The transmission device 29 includes six drive gears A1 to A6 axially mounted on the counter shaft 27 side, six driven gears B1 to B6 axially mounted on the drive shaft 28 side, and a shift mechanism (not shown). The output of the engine 1 is taken out from a drive sprocket 30 provided integrally with the drive shaft 28 so as to rotate together.

One end of the crankshaft 8 (for example, the first cylinder side)
A taper-shaped power generator mounting portion 31 is provided in the rotor, and a rotor of a power generator (not shown) is fixed to the rotor integrally. Further, a primary drive gear 32 is provided near the opposite side of the power generator mounting portion 31 (close to the right end). The primary drive gear 32 is formed on the outer periphery of the crank web 8g on the left side of the second cylinder, that is, the fourth cylinder, from the side opposite to the power generator mounting portion 31 side.

Further, a drive sprocket 33 is provided near the center of the crankshaft 8. The drive sprocket 33 and the intake cam shaft and exhaust cam shaft (not shown) that are axially supported inside the cylinder head 15. A timing chain is wound between the driven chain and the driven sprocket, and when the timing chain is driven by the drive sprocket 33, the cam shaft is rotationally driven to operate the valve operating device in the cylinder head 15.

A clutch device 36 is mounted on the right end of the counter shaft 27 and is covered with a clutch cover 37. This clutch device 36 has a well-known multi-plate structure, and as shown in an enlarged view in FIG. 3, a primary driven gear 39 rotatably supported by a counter shaft 27 via a needle bearing 38 and a right side surface thereof. A clutch housing 40 provided integrally with the rotation, a plurality of drive plates 41 provided integrally with the inner peripheral portion of the clutch housing 40 so as to be integrally rotatable and axially slidable, and provided integrally with the counter shaft 27 so as to be rotatable. A clutch cam unit 42, a clutch sleeve 43 that is integrally provided on the outer periphery of the clutch sleeve 43, and an outer peripheral portion of the clutch sleeve 43 that is integrally rotatable and slidable in the axial direction.
And a plurality of driven plates 44 provided so as to alternately overlap with the clutch cam unit 42.
Clutch spring 46 on the spring stud 45 of the book
Pressure disk 4 which is integrally provided via
7 and a clutch push piece 49 that is inserted into the right end of the counter shaft 27 and comes into contact with the pressure disk 47 via the thrust bearing 48. An oil pump drive gear 51 that drives the oil pump 50 shown in FIG. 1 is provided integrally with the primary driven gear 39 so as to rotate.

The clutch device 36 is provided at a position facing the first crank web 8h counted from the side of the counter power generation device mounting portion 31 (that is, right end) of the crankshaft 8 and is positioned second from the right end as described above. The primary drive gear 32 formed on the outer periphery of the crank web 8g meshes with the primary driven gear 39 of the clutch device 36, and the rotation of the crankshaft 8 is transmitted to the clutch device 36.

The pressure disc 47 is pressed against the clutch sleeve 43 side by the urging force of the clutch spring 46, so that the drive plates 41 and the driven plates 44 are frictionally engaged with each other, thereby rotating the primary driven gear 39. Clutch housing 40 → drive plate 41 → driven plate 44 →
The clutch sleeve 43, the clutch cam unit 42, and the counter shaft 27 are transmitted in this order.

The counter shaft 27 is a hollow shaft, and the push rod 53 is slidably inserted in the hollow part of the counter shaft 27, while the counter shaft 27 is on the end (left end) side of the counter shaft 27 on the side opposite to the clutch device 36 and the crankshaft 8. Generator installation part 31
A clutch operating mechanism 54 is provided at a position facing the first crank web 8a counted from the side. The clutch operating mechanism 54 is hydraulically operated and is provided on the left side surface of the crankcase 2. The clutch operating mechanism 54 includes a hydraulic cylinder 55, a hydraulic piston 56, and a spring 57. A hydraulic hose extending from a clutch lever (not shown) is connected to the hydraulic cylinder 55, and a push rod 58 extending from the hydraulic piston 56 is inserted into the hollow portion of the counter shaft 27 and is in contact with the left end of the push rod 53.

When the clutch lever is gripped, hydraulic pressure is applied to the hydraulic cylinder 55 via the hydraulic hose, and the hydraulic piston 56 is pressed to the counter shaft 27 side (right side). This force presses the clutch push piece 49 via the push rods 58 and 53, and the clutch push piece 49
Presses the pressure disk 47. Therefore, the pressure disc 47 moves to the side opposite to the clutch sleeve 43 (right side) against the urging force of the clutch spring 46, whereby the frictional engagement between each drive plate 41 and each driven plate 44 is loosened and the primary disc is released. The rotation of the driven gear 39 rotates only the clutch housing 40 and each drive plate 41, and the rotation is not transmitted to the counter shaft 27. It should be noted that, for example, if the clutch lever is half held, the clutch spring 46 frictionally engages each drive plate 41 and each driven plate 44 with about half the urging force, so that a half-clutch state is established.

As shown in FIGS. 4 to 6, the clutch cam unit 42 is composed of a clutch cam inner 61 and a clutch cam outer 62. The clutch cam inner 61 is rotationally integrally provided on the counter shaft 27 by spline fitting and is fixed by a lock nut 63. The clutch sleeve 43 is rotationally integrally press-fitted on the outer periphery of the small diameter portion of the clutch cam, and the clutch cam inner periphery of the large diameter portion. Outer 6
2 are closely fitted.

On the outer circumference of the large diameter portion of the clutch cam inner 61, three cam projections 65 are formed at 120 ° intervals, and on the inner circumference of the clutch cam outer 62 there are also three cam recesses 66 at 120 ° intervals. By forming each cam convex portion 65 into each cam concave portion 66, the clutch cam inner 61 and the clutch cam outer 62 are rotationally integrated. The clutch cam outer 62 has 6
Six bolt holes 67 are formed at 0 ° intervals, and the above-described spring stud 45 is firmly fastened thereto.

As shown in FIG. 4B, each cam convex portion 65
Are fitted in the cam recesses 66 with a little margin along the rotational direction, and as shown in FIGS. 5B and 6B, the cam projections 65 and the cam recesses 66 are The contact surface 69 on the front side in the rotation advancing direction is a flat surface along the axial direction of the counter shaft 27, and the contact surface 70 on the rear side in the rotation advancing direction is an inclined surface with respect to the axial direction of the counter shaft 27. The outer width of each cam convex portion 65 is the same as the inner width of each cam concave portion 66.

During normal traveling, that is, when the clutch device 36 is connected, the rotation of the crankshaft 8 is transmitted to the countershaft 27, and the rear wheel of the motorcycle is being driven by the engine 1, the clutch spring 46 is attached. The rotation of the primary driven gear 39, the clutch housing 40, the drive plate 41, the clutch sleeve 43, the driven plate 44, and the pressure disc 47, which are integrally rotated by the force of the force, firstly causes the clutch cam outer 62 to rotate.
Is transmitted to the clutch cam inner 61 by the engagement of the cam concave portion 66 and the cam convex portion 65, and then transmitted to the counter shaft 27 and the transmission device 29.

At this time, as shown in FIG. 7A, the rotational force F1 of the clutch cam outer 62 (cam recess 66) is changed.
Is transmitted to each cam convex portion 65 (clutch cam inner 61) through the sloped contact surface 70, the thrust reaction force T caused by the slope cam action of the contact surface 70 causes the clutch cam outer 62 to move to the clutch cam inner 61. On the other hand, the dimension W is pushed toward the primary driven gear 39 side (left side) from the original position shown in FIG. 7B. As a result, the clutch spring 46 is compressed by the dimension W, and the drive plate 41 and the driven plate 44 are compressed.
The force for crimping, that is, the clutch capacity increases.

Further, when the engine brake is applied, the counter shaft 27 is reversely driven by the rotational force of the rear wheels, and as shown in FIG. 7B, the rotational force F2 of the cam convex portion 65 (clutch cam inner 61). Is transmitted to each cam concave portion 66 (clutch cam outer 62) through the contact surface 69, but since the contact surface 69 is not a slope, the thrust counteracting the clutch cam outer 62 toward the primary driven gear 39 side (left side). No force is generated.

Therefore, the clutch cam outer 62 is located on the side opposite to the primary driven gear 39 side (right side) by the dimension W as compared with the position during normal running in FIG. 7A, and the clutch spring 46 extends by that amount, so that the drive plate. The frictional engagement force (clutch capacity) that presses 41 and driven plate 44 together is weakened. For this reason, the impact (back torque) at the moment when the engine brake is applied slightly slips between the drive plate 41 and the driven plate 44, and it is reduced that the back torque is directly transmitted to the crankshaft 8 side and the riding comfort is deteriorated. And deterioration of durability of the engine 1 is avoided.

As described above, this engine 1
Forms the primary drive gear 32 on the second crank web 8g counted from the side of the counter power generation device mounting portion 31 of the crankshaft 8 and faces the first crank web 8h counted from the side of the counter power generation device mounting portion 31. A clutch device 36 is provided on the counter shaft 27, and a position facing the first crank web 8a from the end of the counter shaft 27 on the side opposite to the clutch device 36 and the power generator installation part 31 side of the crank shaft 8. Clutch operating mechanism 54
Since the clutch device 36 and the transmission device 29 do not have to be offset to one side with respect to the engine center EC (see FIG. 2), the center of gravity of the engine is brought closer to the engine center EC side so that a motorcycle or the like can travel. In addition to improving stability, the engine 1 can be made compact in the width direction, and the clutch cover 37 can be prevented from protruding outside the engine.

Moreover, since the clutch operating mechanism 54 is provided on the side of the crankcase 2 opposite to the clutch device 36, the dead space in the crankcase 2 can be effectively utilized. Further, since the clutch operating mechanism 54 is hydraulically operated, the operating force at the time of releasing the clutch can be reduced and the clutch spring 46 can be strengthened by that amount. As a result, for the same clutch capacity, the outer diameter of the clutch device 36 and The width can be reduced. Therefore, the interference between the outer peripheral portion of the clutch device 36 and the crank shaft 8 is prevented, the axial distance between the crank shaft 8 and the counter shaft 27 is narrowed, and the engine 1 is made compact in the lengthwise direction. Compactness can also be achieved.

Since the clutch cam unit 42 is added to the clutch device 36, the clutch cam unit 42 is
With the clutch capacity increasing function, the outer diameter and width of the clutch device 36 can be reduced while maintaining the same clutch capacity, and the engine 1 can be made more compact in the length direction and the width direction.

By the way, the engine 1 is provided with a balancer device 73 for alleviating the secondary vibration generated by the rotation of the crankshaft 8. 1 and 8
As shown in an enlarged scale, the balancer device 73 has an axial center extending in the vehicle width direction parallel to the crankshaft 8 and sandwiching the crankshaft 8 in the axial direction of the crankshaft 8 and on the opposite side of the countershaft 27. Space, ie here crankcase 2
The tightening bolts 11 of the journal bearing 7 should be positioned so that they are located in front of the inside of the (lower case 5).
It is arranged so as to be located in a region sandwiched between the twelve.

The balancer device 73 comprises a support shaft 74 and a balancer rotating body 75.
Both ends of 4 have two adjacent journal bearings 7,
The balancer rotating body 75 is rotatably supported by a middle portion of the support shaft 74 via a roller bearing 76. The balancer rotating body 75 has a balancer weight 7 at the right end thereof.
7 is integrally formed, a balancer driven gear 78 is provided at the left end, and this gear 78 meshes with a balancer drive gear 79 formed on the crankshaft 8.

The balancer drive gear 79 is provided on the crank web 8c on the left side of the second cylinder (second cylinder) counted from the side of the power generation device mounting portion 31 of the crank shaft 8. This balancer drive gear 79 has twice the number of teeth as the balancer driven gear 78, and when the crankshaft 8 rotates, the balancer rotating body 75 (balancer weight 7).
7) rotates at twice the rotational speed of the crankshaft 8, which cancels secondary vibrations associated with the rotation of the crankshaft 8.

As described above, the balancer drive gear 79 is provided on the left crank web 8c of the second cylinder, and the shaft center of the balancer device 73 is opposed to the counter shaft 27 with the crank shaft 8 sandwiched between them when viewed from the axial direction of the crank shaft 8. By arranging the balancer device 73 in the side space, the balancer device 73 is provided in the dead space in front of the crankcase 2 to improve the layout property inside the crankcase 2, and the size of the crankcase 2 is tightened by that amount to achieve compactness. You can

Further, the axial center of the balancer device 73 is arranged in a region sandwiched between the tightening bolts 11 and 12 of the journal bearing 7 supporting the crankshaft 8 in the axial direction of the crankshaft 8. 73 is located in the vicinity of the axial extension line 17a (see FIG. 1) of the cylinder bore 17, and is arranged in the most rigid portion inside the crankcase 2. Therefore, the balancer device 73 can exert the maximum vibration damping effect, the balancer device 73 can be downsized accordingly, the internal space of the crankcase 2 can be reduced, and the engine 1 can be made compact.

Moreover, by installing the balancer device 73 in the most rigid portion inside the crankcase 2,
It is not necessary to improve the strength of the crankcase 2 and other related parts with the support of the balancer device 73, and also in this respect, the engine 1 can be made compact and the cost can be reduced.

The balancer drive gear 79 is 2
It is not limited to the crank web 8c on the left side of the No. cylinder, but may be provided on the crank web 8d on the right side. Further, the configuration of the present invention is not limited to the parallel 4-cylinder engine, but can be applied to a parallel 6-cylinder engine, a V-type multi-cylinder engine, or the like.

[0047]

As described above, according to the in-vehicle four-cylinder engine according to the present invention, the center of gravity of the engine is brought closer to the engine center side to improve the running stability of the motorcycle and the like, and the engine is compact. To achieve
In addition, the vibration damping effect of the balancer device 73 can be improved.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a vehicle parallel multi-cylinder engine according to the present invention as viewed from the left side.

FIG. 2 is a cross-sectional view showing an embodiment of the present invention taken along the line II-II of FIG.

FIG. 3 is an enlarged view of a part III in FIG.

4A is an enlarged cross-sectional view of the clutch cam unit, and FIG. 4B is a cross-sectional view taken along line IVb-IVb of FIG.

5A is a right side view of the clutch cam inner alone, and FIG. 5B is a sectional view taken along the line Vb-Vb of FIG.

6A is a right side view of the clutch cam outer unit, and FIG. 6B is a sectional view taken along line VIb-VIb in FIG. 6A.

FIG. 7A is a sectional view showing a positional relationship between a cam convex portion and a cam concave portion during normal running, and FIG. 7B is a sectional view showing a positional relationship between a cam convex portion and a cam concave portion when an engine brake is applied.

FIG. 8 is an enlarged view of a portion VIII in FIG.

[Explanation of symbols]

1 engine 2 crankcase 7 Journal bearing 8 crankshaft 8a-8h crank web 11,12 tightening bolt 27 counter shaft 31 Power generator mounting part 32 Primary drive gear 33 drive sprocket 36 Clutch device 39 Primary driven gear 42 Clutch cam unit 54 Clutch operating mechanism 73 Balancer device 79 Balancer drive gear

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02B 77/00 F02B 77/00 L F16D 13/52 F16D 13/52 C 13/54 13/54 F16F 15 / 26 F16F 15/26 N

Claims (5)

[Claims] 1. A crank shaft and a counter shaft are supported in parallel, a power generator mounting portion is provided at one end of the crank shaft, and a primary drive gear is provided on the crank shaft near the opposite side of the power generator mounting portion. A drive sprocket for driving a timing chain is provided in the vicinity of the center of the crankshaft, and a parallel four-cylinder for a vehicle in which the primary drive gear is meshed with a primary driven gear provided in a clutch device axially mounted at one end of the counter shaft. In the engine, the primary drive gear is formed on the second crank web counted from the side of the crankshaft opposite to the power generation device mounting portion, and is opposed to the first crank web counted from the side of the crank shaft opposite the power generation device mounting portion. The above clutch device is provided on the counter shaft,
Further, a clutch operating mechanism for operating the clutch device is provided at a position opposite to the counter clutch device side end of the counter shaft and facing the first crank web counted from the crankshaft power generator mounting part side. A parallel multi-cylinder engine for vehicles. 2. The drive gear of the balancer device is provided on the crank web of the second cylinder counted from the side of the power generator installation portion of the crank shaft, and the axial center of the balancer device is the crank shaft when viewed in the axial direction of the crank shaft. The parallel multi-cylinder engine for a vehicle according to claim 1, wherein the parallel multi-cylinder engine for vehicles is arranged in a space on the opposite side of the counter shaft. 3. The vehicle parallel according to claim 2, wherein the axial center of the balancer device is arranged in a region sandwiched between tightening bolts of a journal bearing that supports the crankshaft as viewed in the axial direction of the crankshaft. Multi-cylinder engine. 4. A parallel multi-cylinder engine for a vehicle according to claim 1, wherein the clutch operating mechanism is hydraulically operated. 5. A clutch cam unit for increasing the clutch capacity and reducing back torque transmission to the crankshaft side is added to the clutch device.
A parallel multi-cylinder engine for a vehicle according to claim 4.