JP4163559B2 - Power unit for motorcycle - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motorcycle power unit that is connected to a vehicle body frame and is mainly used for a motor tasker. And a belt type continuously variable transmission that is supported by the transmission case and disposed between the crankshaft of the engine and the rear wheel.
[0002]
[Prior art]
Conventionally, in such a motorcycle power unit, the engine is configured as a single cylinder type (see, for example, JP-A-4-163287).
[0003]
[Problems to be solved by the invention]
The present invention has a large design freedom in which the direction of the cylinder can be freely selected without being interfered with the transmission case, while the engine is configured in a two-cylinder type in order to enhance the output. It is an object of the present invention to provide a motorcycle power unit capable of easily producing and assembling a cylinder block.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a power unit connected to a vehicle body frame, and extends rearward from one side of the left and right direction of the crankcase of the engine with a crankshaft arranged in the left and right direction of the vehicle body. A transmission case and a belt type continuously variable transmission supported by the transmission case and disposed between a crankshaft and a rear wheel of the engine, wherein the crankcase is connected to an intermediate portion in the axial direction of the crankshaft. divided by the division plane passing through, the transmission and the first crankcase half positioned in the transmission case side, therewith together constitute at the second crankcase half body located opposite, the first crankcase half thereof The case is connected continuously, and the block mounting surface formed on the outer peripheral surface of the crankcase The cylinder block having parallel to two cylinders, as well as joined by six stud bolts are arranged so as to surround the two cylinders, the two stud bolts of the central of those six stud bolts and the central place on a vertical imaginary plane passing through between the two cylinders, constitute the crankshaft integral only two points of right and left ends of the crank shaft, supported on the crankcase The dividing surface is offset with respect to a central position between the two cylinders so that the dividing surface does not pass through the two stud bolts in the center. Features.
[0005]
According to this first feature, it is possible to minimize the number of parts of the assembly of the crankcase and the transmission case and facilitate casting while configuring the engine as a parallel two-cylinder and increasing the output. it can. In addition, on the outer peripheral surface of the crankcase, the formation area of the block mounting surface that joins the cylinder block without interfering with the transmission case is wide. As a result, various power units corresponding to various motorcycles having different formats can be easily obtained. Further, the structure of the crankshaft can be simplified by integrating the crankshaft, and the journals are formed only at the two left and right end portions of the integrated crankshaft, so that the first and second crankcases are formed. Simultaneously with the joining of the half bodies, the crankshaft can be supported and the assemblability is good.
[0006]
In addition to the first feature, the present invention has a second feature in that the two cylinders are arranged substantially horizontally with their heads facing the front of the vehicle body.
[0007]
According to the second feature, the center of gravity of the power unit can be lowered. Moreover, since a large space can be secured above the engine, a power unit suitable for a motor tasker in which a luggage compartment is disposed above the engine can be obtained.
[0008]
Furthermore, in addition to the first or second feature, the present invention forms a timing transmission chamber outside the cylinder located on the side opposite to the transmission case. The timing transmission chamber includes the crankshaft and the cylinders. A third feature is that a timing transmission device for connecting a valve camshaft disposed on the head of the motor is accommodated.
[0009]
According to the third feature, when arranging the timing transmission device, the journal interval at both ends of the crankshaft is kept to a minimum, and the overhang amount at the output end of the crankshaft connected to the transmission is also minimized. Can keep.
[0010]
Furthermore, according to the present invention, in addition to any one of the first to third features, a fourth aspect is that the axis of the cylinder located on the mission case side is aligned with or close to the rotation center plane of the rear wheel. It is characterized by.
[0011]
According to the fourth feature, when the power unit is mounted on the vehicle body, the right and left weight balance of the power unit with respect to the rear wheel can be achieved, which can contribute to improvement in maneuverability.
[0012]
Furthermore, the present invention, in addition to any one of the first to fourth features, includes an inner transmission case half integrally connected to the first crankcase half, and an inner transmission case half. A fifth feature is that the outer mission case half adjacent to the outside is joined and configured, and the dividing surface is offset toward the inner mission case half from the center position between the two center cylinders. To do.
[0013]
According to the fifth feature, despite the fact that the inner transmission case half is integrally formed with the first crankcase half, the width of the combined body of the first crankcase half and the inner transmission case half, Since the lateral width of the second crankcase half is equal or approximate, the molding depth and the machining depth are not biased toward one of the combined body and the second crankcase half. Casting and cutting can be easily performed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below based on one embodiment of the present invention shown in the accompanying drawings.
[0015]
1 is a side view of a motor tasker equipped with the power unit of the present invention, FIG. 2 is a plan view of the power unit, FIG. 3 is an enlarged vertical sectional view of FIG. 3 in FIG. 2, and FIG. 5 is a sectional view taken along line 5-5 in FIG. 3, and FIG. 6 is a sectional view taken along line 6-6 in FIG.
[0016]
In the description, front and rear and left and right are based on the body of the motor tasker.
[0017]
First, in FIG. 1, a front fork 4 that supports a front wheel 3 f is steerably connected to a front end of a body frame 2 of the motor tasker 1, and a steering handle 5 is attached to a steering stem of the front fork 4. A power unit 6 supporting the rear wheel 3r is connected to the middle portion of the vehicle body frame 2 via a swing link 7 so as to be swingable up and down, and a rear cushion 8 is connected to each rear end portion of the power unit 6 and the vehicle body frame 2. Are attached at both ends. A step 11, a seat 12 and a carrier 13 are provided on a vehicle body outer plate 10 covering the vehicle body frame 2, and a container 14 is formed in the vehicle body outer plate 10 immediately below the seat 13.
[0018]
As shown in FIGS. 2 to 4, the power unit 6 includes a four-cycle two-cylinder engine 15 and a transmission 16 that transmits the power of the engine 15 to the rear wheel 3 r, and the transmission 16 includes the engine 15. The crankcase 17 is housed in a mission case 18 extending rearward from the left end portion, and the rear wheel 3r is pivotally supported on the rear end portion of the mission case 18.
[0019]
The engine 15 includes an integrated crankshaft 20 that is disposed with its axis line in the left-right direction, a crankcase 17 that supports the crankshaft 20, a cylinder block 21 that is joined to the outer peripheral surface of the crankcase 17, A cylinder head 22 joined to the upper surface of the cylinder block 21 and a carburetor 23 (see FIG. 1) attached to the outer surface of the cylinder head 22 are provided. The cylinder block 21 is provided with _two cylinders 24 ₁ and 24 ₂ juxtaposed in the left and right, and correspondingly, the crankshaft 20 is also formed with _two crank portions 25 ₁ and 25 ₂ arranged in the left and right, Pistons 26 ₁ and 26 ₂ fitted to the cylinders 24 ₁ and 24 ₂ are connected to corresponding crank portions 25 ₁ and 25 ₂ via connecting rods 27 ₁ and 27 ₂ . The crankshaft 20 has journals 28 ₁ , 28 ₂ only at two positions adjacent to the outside of both crank portions 25 ₁ , 25 ₂ , and these journals 28 ₁ , 28 ₂ are bearing members 29 ₁ , 29. ₂ to be supported by the crankcase 17. That is, the intermediate shaft portion 20a connecting the _two crank portions 25 ₁ and 25 ₂ of the crankshaft 20 is not supported by the crankcase 17, and is more than the journals 28 ₁ and 28 _{2 in} order to ensure the bending rigidity thereof. Formed in large diameter.
[0020]
The crankcase 17 is divided by a vertical dividing surface 30 that is offset toward the mission case 18 from the center position between the _two cylinders 24 ₁ , 24 ₂ , and the first crankcase half located on the mission case 18 side. 17 ₁ and a second crankcase half 17 ₂ located on the opposite side. The mission case 18 is divided by an inner transmission case half 18 ₁ on the crankcase 17 side and an outer mission case half 18 ₂ located on the opposite side, which are divided by a division plane 31 parallel to the division plane 30. The inner transmission case half 18 ₁ and the first crankcase half 17 ₁ that are configured are integrally formed by casting.
[0021]
The first and second crankcase halves 17 ₁ and 17 ₂ are joined to each other at their peripheral portions by a plurality of bolts (not shown), and the inner and outer transmission case halves 18 ₁ and 18 ₂ are joined together. Are joined to each other by a plurality of bolts 32 at their peripheral portions.
[0022]
As described above, the assembly of the crankcase 17 and the transmission case 18 includes the first crankcase half 17 ₁ and the inner transmission case half 18 ₁ , the second crankcase half 17 ₂ , and the outer transmission case half. Since the body 18 ₂ is divided into three parts, the number of parts of the assembly can be minimized and casting of each part can be facilitated.
[0023]
Further, the integrated crankshaft 20 is formed with journals 28 ₁ , 28 ₂ supported by the first and second crankcase halves 17 ₁ , 17 ₂ only at two points at both ends thereof. Although the shaft 20 is integrated, the crankshaft 20 can be supported simultaneously with the joining of the two crankcase halves 17 ₁ , 17 ₂ , and the assemblability is good.
[0024]
Further, as clearly shown in FIG. 2, the split surface 30 between the first crankcase half 17 ₁ integrated with the inner transmission case half 18 ₁ and the second crankcase half 17 ₂ has two left and right cylinders. 24 _1, since it is arranged offset to the inside transmission case half 18 ₁ side from the center position between the 24 _2, the width of the first crankcase half 17 ₁ and the inner transmission case half 18 ₁ conjugate S ₁ And the lateral width S _{2 of} the second crankcase half 17 ₂ are equal to or approximate to each other. Therefore, the molding depth and the working depth are biased deeply toward one of the above-mentioned combined body and the second crankcase half 17 _2. Therefore, each casting and cutting can be easily performed.
[0025]
By the way, the power unit 6 is arranged so that the axis Y of the cylinder 24 ₁ on the mission case 18 side coincides with or is close to the rotation center plane C of the rear wheel 3r. If it does in this way, the right-and-left weight balance of the power unit 6 with respect to the rear-wheel 3r can be aimed at, and the improvement of maneuverability can be aimed at.
[0026]
As shown in FIGS. 3, 5 and 6, a block mounting surface 35 is formed on the outer peripheral surface of the crankcase 17, particularly in the illustrated example, on the front surface thereof so as to surround the _two cylinders 24 ₁ and 24 _2. Six stud bolts 36, 36... To be arranged are planted. These stud bolts 36, 36... Are inserted into six bolt holes 37, 37... Penetrating the cylinder block 21 and the cylinder head 22, and nuts 38, 38. Both the block 21 and the cylinder head 22 are joined to the crankcase 17. In this way, the cylinder block 21 is disposed substantially horizontally with the head facing forward. Thus, the center two stud bolts 36, 36 of the six stud bolts 36, 36... Pass through the center between the _two cylinders 24 ₁ , 24 ₂ as shown in FIG. Therefore, the split surface 30 of the crankcase 17 that is offset toward the mission case 18 as described above does not pass through the two stud bolts 36 and 36 at the center. .
[0027]
Thus, since the block mounting surface 35 is formed on the outer peripheral surface of the crankcase 17, the formation area can be secured widely without interfering with the transmission case 18, and therefore the cylinder block 21 with respect to the crankcase 17 can be secured. The mounting angle can be freely selected in design, and various power units 6 corresponding to various motorcycles having different types can be easily obtained.
[0028]
In particular, as shown in the illustrated example, when the cylinder block 21 is joined to the block mounting surface 35 formed on the front surface of the crankcase 17 and is disposed substantially horizontally, the center of gravity of the power unit 6 can be lowered. it can. In addition, since a large space can be secured above the engine 15, in the motor tasker 1, a large container 14 that can store a helmet or the like can be formed above the engine 15.
[0029]
3 and 4 again, the second crankcase half 17 ₂ , the cylinder block 21 and the cylinder head 22 are formed with a timing transmission chamber 40 adjacent to the outside of the cylinder 24 ₂ opposite to the transmission case 18, The timing transmission chamber 40 includes a drive sprocket 41 fixed to the crankshaft 20, a driven sprocket 43 fixed to a valve camshaft 42 supported by the cylinder head 22, and a chain 44 wound around the sprockets 42 and 43. A timing transmission device 45 is provided. A head cover 46 that covers the valve operating device including the valve operating cam shaft 42 is joined to the front surface of the cylinder head 22.
[0030]
In this way, the distance between the left and right journals 28 ₁ , 28 ₂ of the crankshaft 20 is kept to a minimum, and the overhang amount at the output end of the crankshaft 20 to which the transmission 16 is connected is also kept to a minimum. The timing transmission device 45 can be easily arranged.
[0031]
The second outer wall of the crankcase half 17 ₂ provided openings 47 for opening the timing transmission chamber 40, the rotor 49 of the generator 48 to the right end of the crank shaft 20 which projects outside the opening 47 There is fixed, the stator 50 of which is secured to the inner wall of the side caps 51 which are bonded to _two second crankcase half 17 to close the opening 47. The crankshaft 20 is rotatably provided with a large-diameter gear 52 driven from a starter motor (not shown) between the timing transmission 45 and the generator 48. The large-diameter gear 52 and the rotor 49, an overrunning clutch 53 is interposed.
[0032]
The transmission 16 has a variable diameter type drive pulley 54 attached to the output end of the crankshaft 20 and a variable diameter type attached to an intermediate transmission shaft 59 supported on the rear end of the inner transmission case half 18 _1. Of the driven pulley 55 and a belt 57 wound around the driven and driven pulleys 54, 55. The driving pulley 54 has a centrifugal speed change that increases the diameter of the pulley as the rotational speed of the crankshaft 20 increases. A mechanism 56 is provided, and a centrifugal clutch 58 that is connected to the driven pulley 55 and the intermediate transmission shaft 59 according to an increase in the rotational speed of the driven pulley 55 is interposed.
[0033]
A partition wall 60 defining a deceleration chamber 61 is joined to the inner wall of the rear end portion of the inner transmission case half body 18 ₁ , and the intermediate transmission shaft 59 is also supported by the partition wall 60. Also this is the partition wall 60 and the inner transmission case half 18 ₁ rear drive shaft 63 is supported, gear reduction device 62 for connecting the intermediate transmission shaft 59 and the rear drive shaft 63 is disposed in the speed reduction chamber 61 The The rear wheel 3r is detachably splined to the outer end of the rear wheel drive shaft 63.
[0034]
Thus, during the operation of the engine 15, the power from the crankshaft 20 to the drive pulley 54, the belt 57, the driven pulley 55, the centrifugal clutch 58, the intermediate transmission shaft 59, the gear reduction device 62, and the rear wheel drive shaft 63 sequentially. Then, it is transmitted to the rear wheel 3r and driven. At that time, the engine 15 can exert high output with the _two cylinders 24 ₁ and 24 ₂ .
[0035]
A cooling fan 64 is integrally formed on the outer surface of the drive pulley 54, and a cooling air intake 65 facing the cooling fan 64 is provided on the side wall of the outer transmission case half 18 _2. An air cleaner 66 is provided in the cooling air intake 65. Installed. When the cooling fan 64 rotates, the outside air filtered by the air cleaner 66 is introduced into the transmission case 18 from the cooling air intake 65, cools each part of the transmission 16, and is discharged from a discharge port (not shown).
[0036]
The present invention is not limited to the embodiments described above, and various design changes can be made without departing from the scope of the invention.
[0037]
【The invention's effect】
As described above, according to the first feature of the present invention, the crankcase is divided by the dividing surface passing through the intermediate portion in the axial direction of the crankshaft, and the first crankcase half located on the transmission case side and the opposite thereof. The transmission case is integrally connected to the first crankcase half, and the block mounting surface formed on the outer periphery of the crankcase is arranged in the left-right direction of the vehicle body. Since the cylinder block having two cylinders in parallel is joined, the engine is configured with two parallel cylinders, and the output is increased while minimizing the number of parts of the crankcase and transmission case assembly and casting. Simplification can be achieved. In addition, on the outer peripheral surface of the crankcase, the formation area of the block mounting surface that joins the cylinder block without interfering with the transmission case is wide. As a result, various power units corresponding to various motorcycles having different formats can be easily obtained. And even if the engine is a parallel 2-cylinder, the journals supported by the crankcase are formed only at the two left and right ends of the crankshaft that is configured as an integral type, so that the structure of the crankshaft can be simplified. In addition, since the crankshaft can be supported simultaneously with the joining of the first and second crankcase halves, the assemblability can be improved.
[0038]
Further, according to the second feature of the present invention, since both cylinders are disposed substantially horizontally with their heads directed toward the front of the vehicle body, the center of gravity of the power unit can be lowered, and the cylinder is wide above the engine. Space can be reserved, and therefore a power unit suitable for a motor tasker that places a luggage compartment above the engine can be provided.
[0039]
Furthermore, according to the third feature of the present invention, a timing transmission chamber is formed outside the cylinder located on the opposite side of the transmission case, and the crank transmission shaft and the head of each cylinder are disposed in the timing transmission chamber. The timing transmission that connects the camshaft to the valve camshaft is housed, so that the journal spacing at both ends of the crankshaft is kept to a minimum, and the amount of overhang at the output end of the crankshaft is also minimized. It is possible to easily arrange the timing transmission device while maintaining the above.
[0040]
Furthermore, according to the fourth feature of the present invention, since the axis of the cylinder located on the transmission case side coincides with or is close to the rotation center plane of the rear wheel, when the power unit is mounted on the vehicle body, the power unit for the rear wheel The right and left weight balance can be achieved, which can contribute to the improvement of maneuverability.
[0041]
Furthermore, according to the fifth aspect of the present invention, when the first crankcase half and the inner transmission case half are joined and the second crankcase half is cast and cut, the forming depth and the working depth are the above-mentioned. There is no bias toward one of the combined body and the second crankcase half, and the manufacturability is improved.
[Brief description of the drawings]
FIG. 1 is a side view of a motor tasker equipped with a power unit of the present invention.
FIG. 2 is a plan view of the power unit.
3 is an enlarged vertical sectional view of FIG. 3 part of FIG.
FIG. 4 is an enlarged vertical sectional view of FIG. 4 part of FIG.
5 is a cross-sectional view taken along line 5-5 of FIG.
6 is a cross-sectional view taken along line 6-6 in FIG.
[Explanation of symbols]
1 ... Motorcycle
2 .... body frame 3r ... rear wheel 6 ... power unit 15 ... engine 16 ... transmission 17 ... crank case 17 ₁ ... first crankcase half 17 ₂ .. the second crankcase half 18 ... transmission case 18 ₁ ... inner transmission case half 18 ₂ ... outer transmission case half 20 ... crankshaft 21 ... cylinder block 24 ₁ ... cylinder 24 ₂ - · Cylinder 28 ₁ · · Journal 28 ₂ · · Journal 30 · Dividing surface 35 · Block mounting surface 40 · Timing transmission chamber 42 · Valve camshaft 45 · · · Timing transmission device C · · · ..Rotation center plane Y of rear wheel ... Axis of cylinder 24 ₁

Claims (5)

A power unit (6) coupled to the body frame (2),
An engine (15) having a crankshaft (20) disposed in the left-right direction of the vehicle body, a transmission case (18) extending rearward from one side of the crankcase (17) of the engine (15), and the transmission case ( 18) comprising a belt-type continuously variable transmission (16) supported between 18 and the crankshaft (20) of the engine (15) and the rear wheel (3r),
A first crankcase half (17 ₁ ) located on the side of the transmission case (18), the crankcase (17) being divided by a dividing surface (30) passing through the axial intermediate portion of the crankshaft (20). If, at the same together constitute de second crankcase half located on the opposite side (17 _2), continuously provided first crankcase half its (17 ₁₎ to said transmission case (18) together,
A cylinder block (21) having _two cylinders (24 ₁ , 24 ₂ ) arranged in parallel in the left-right direction of the vehicle body is mounted on a block mounting surface (35) formed on the outer peripheral surface of the crankcase (17). The six stud bolts (36) arranged so as to surround the _two cylinders (24 ₁ , 24 ₂ ) are joined together, and the center two stud bolts (of the six stud bolts (36)) ( 36) is arranged on a vertical virtual plane passing through the center between the _two cylinders (24 ₁ , 24 ₂ ),
Constitutes the crank shaft (20) into an integrated, forming the two points of the right and left ends of the crank shaft (20) only, wherein the journal is supported in the crankcase (17) (28 _1, 28 ₂₎ And
The dividing surface (30) is located at a central position between the _two cylinders (24 ₁ , 24 ₂ ) so that the dividing surface (30) does not pass through the two stud bolts (36) in the center. A motorcycle power unit characterized by being offset. In the motorcycle power unit according to claim 1,
A power unit for a motorcycle, wherein both the cylinders (24 ₁ , 24 ₂ ) are arranged substantially horizontally with their heads facing the front of the vehicle body. In the motorcycle power unit according to claim 1 or 2,
A timing transmission chamber (40) is formed outside the cylinder (24 ₂ ) located on the opposite side of the transmission case (18), and the crankshaft (20) and each of the timing transmission chambers (40) are provided in the timing transmission chamber (40). A motorcycle power unit comprising a timing transmission device (45) for connecting a valve camshaft (42) disposed on a head of a cylinder (24 ₁ , 24 ₂ ). In the motorcycle power unit according to any one of claims 1 to 3,
The cylinder (24) located on the mission case (18) side ₁ ) Axis line (Y) coincides with or is close to the rotation center plane (C) of the rear wheel (3r). In the motorcycle power unit according to any one of claims 1 to 4,
The transmission case (18) is connected to the first crankcase half (17). ₁ ) Inner transmission case half (18) ₁ ) And its inner mission case half (18 ₁ ) Outer mission case halves adjacent to the outside (18) ₂ ), And the dividing surface (30) is formed by the two central cylinders (24 ₁ , 24 ₂ ) From the center position between the inner transmission case half (18 ₁ Motorcycle power, characterized by being offset to the side) -Unit.

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