JP2020159342A - Oil pump drive structure for internal combustion engine - Google Patents

Abstract

To improve flexibility of positional shapes of an oil pump drive transmission mechanism and its cover part and easily manufacture a swelling part that forms the cover part in an internal combustion engine in which a crank chamber, etc. becomes a negative pressure chamber.SOLUTION: In an oil pump drive structure for an internal combustion engine including a crank case 40 in which a crank chamber 40a becoming a negative pressure chamber is partitioned from a transmission chamber 50 by a partition wall 40b, an oil pump 100 disposed in the transmission chamber side and a pump drive shaft 92 connected to a transmission drive part 91 of an oil pump drive transmission mechanism 90 rotated in cooperation with a crank shaft, a transmission space 106 communicated with the crank chamber side via a gap part 105 of the partition wall is provided in a swelling part 107 swelling to the transmission chamber side, and a transmission driven part 93 disposed in the transmission space is provided in the pump drive shaft. The transmission driven part is connected to the transmission drive part via the gap part, and a cover member 108 forming the transmission space separately from the partition wall is mounted to the partition wall to surround the gap part from the transmission chamber side so as to constitute the swelling part.SELECTED DRAWING: Figure 5

Description

The present invention relates to an oil pump drive structure of an internal combustion engine provided with a crank chamber serving as a negative pressure chamber.

In an in-line 4-cylinder internal combustion engine in which the crank chamber or the like is a negative pressure chamber, the oil pump drive of the internal combustion engine is formed by bulging the partition wall on the lower surface of the clutch chamber for the cover portion for accommodating the oil pump drive transmission mechanism. The structure is shown, for example, in Patent Document 1 below.
By the way, in what is shown in Patent Document 1 below, the cover portion of the oil pump drive transmission mechanism is formed by a bulging portion in which a part of a partition wall integrated with the crankcase is bulged downward.
When forming a bulging portion of this shape with a mold, it is necessary to provide a draft for removing the mold, so that the number of man-hours for processing bosses and the like provided on the bulging portion increases, and an oil pump is driven to secure clearance. The position and shape of the transmission mechanism may be restricted.

Japanese Patent No. 5847152 (FIGS. 4 to 7)

In view of the above prior art, the present invention improves the degree of freedom in the position and shape of the oil pump drive transmission mechanism and its cover portion of an internal combustion engine in which a crank chamber or the like is a negative pressure chamber, and forms the cover portion. An object of the present invention is to provide an oil pump drive structure of an internal combustion engine having a structure in which a bulging portion is easy to manufacture.

In order to solve the above problems, according to the present invention,
An internal combustion engine having the crankcase in which a crank chamber in which the crankshaft is housed and becomes a negative pressure chamber and a transmission room in which the transmission shaft is housed are partitioned by a partition wall integrally provided in the crankcase. An oil pump arranged on the transmission chamber side and driven by the crankshaft to pump oil to each part of the internal combustion engine, and a transmission drive unit of an oil pump drive transmission mechanism that rotates in conjunction with the rotation of the crankshaft. In an oil pump drive structure of an internal combustion engine having a pump drive shaft connected to and transmitting rotation to the oil pump rotor shaft of the oil pump.
The crankcase is provided with a transmission space that communicates with the crank chamber side through a gap portion provided in the partition wall in the bulging portion that bulges from the crank chamber side to the transmission chamber side.
The pump drive shaft is provided with a transmission driven portion of the oil pump drive transmission mechanism arranged in the transmission space, and the transmission driven portion is connected to the transmission drive portion through the gap portion.
An internal combustion engine characterized in that a cover member that forms the transmission space separately from the partition wall is attached to the partition wall from the transmission chamber side so as to surround the gap portion to form the bulging portion. Oil pump drive structure is provided.

According to the oil pump drive structure of the internal combustion engine of the present invention.
The pump drive shaft that transmits power from the crankcase side to the transmission room side, which is partitioned by the partition wall, is arranged over both compartments by penetrating the cover member that is separate from the crankcase. A structure that is easy to manufacture because the bulging part that forms the transmission space where the transmission driven part of the mechanism is arranged is composed of a separate cover member, which suppresses the complicated shape of the crankcase and restrictions such as die cutting. It becomes.

According to a preferred embodiment of the invention
The pump drive shaft is rotatably supported by a drive shaft bearing portion provided on the cover member.
The drive shaft bearing portion is provided with an oil supply hole.
The refueling hole is connected to a refueling path provided in the crankcase.
Therefore, in addition to the provision of refueling holes to improve the lubrication performance of the pump drive shaft and the improvement of airtightness between the crank chamber side and the transmission chamber side.
A cover member that forms a bulging part is provided separately from the partition wall, and by forming a refueling structure in the drive shaft bearing part provided on the cover member, the bulging part has a refueling hole as compared with the case where it is integrated with the crankcase. Processing etc. becomes easy.

According to a preferred embodiment of the invention
The transmission drive unit of the oil pump drive transmission mechanism is a pump drive sprocket, the transmission drive unit is a pump drive sprocket, and the pump drive sprocket and the pump drive sprocket are connected by a pump drive chain.
Therefore, the oil pump drive transmission mechanism can be constructed at low cost, and the degree of freedom in arranging the pump drive shaft is improved.

According to a preferred embodiment of the invention
The oil pump includes a scavenging pump.
An oil suction pipe is provided in which one end is connected to the suction side of the scavenging pump and the other end is connected to the lower part of the cover member.
Therefore, by sucking the oil accumulated in the cover member by the scavenging pump, the oil stirring resistance of the transmission driven portion of the oil pump drive transmission mechanism can be suppressed.

According to a preferred embodiment of the invention
The cover member is divided into a first cover member and a second cover member, and the first cover member is inside a drive shaft bearing portion that rotatably supports the pump drive shaft and the inside of the first cover member. The second cover member has a boss portion of the drive shaft bearing portion that protrudes, an upper opening portion at the upper end connected to the periphery of the gap portion, and a lower opening portion at the lower end. It is connected so as to match the lower opening and has an oil suction pipe connection at the lower part that communicates with the upper opening.
Therefore, when the cover member is molded by a mold, it is divided into a first cover member and a second cover member, and the first cover member has an upper opening and a lower opening, so that the inside of the first cover member is inside. Even if there is a protruding boss portion, the mold can be divided into two upper and lower parts and pulled out from the upper opening and the lower opening, respectively, so that a structure that is easy to manufacture can be obtained.

According to a preferred embodiment of the invention
The oil pump is provided on one side of the cover member.
The oil pump rotor shaft and the pump drive shaft are coaxially connected so as not to rotate relative to each other.
A water pump having a water pump shaft coaxially driven by the pump drive shaft is fitted and provided in a fitting port provided on the other side of the cover member.
Therefore, the oil pump and the water pump can be driven with a small number of parts, and the assembling property of the water pump is improved.

According to the oil pump drive structure of the internal combustion engine of the present invention.
The pump drive shaft that transmits power from the crankcase side to the transmission room side, which is partitioned by the partition wall, is arranged over both compartments by penetrating the cover member that is separate from the crankcase. A structure that is easy to manufacture because the bulging part that forms the transmission space where the transmission driven part of the mechanism is arranged is composed of a separate cover member, which suppresses the complicated shape of the crankcase and restrictions such as die cutting. It becomes.

It is a left side view of the motorcycle which is a saddle-type vehicle equipped with the internal combustion engine which concerns on one Embodiment of this invention. It is a right side view of the internal combustion engine in FIG. It is sectional drawing of the power unit by the arrow III-III in FIG. It is a vertical sectional view of the crankcase from the main shaft in FIG. 2 to the pump drive shaft coaxial with the water pump shaft, as viewed in the same direction. FIG. 4 is a vertical cross-sectional view taken along the pump drive shaft of the lower case according to the VV arrow in FIG. FIG. 5 is a left side sectional view of the scavenging pump by looking at the VI-VI arrow in FIG. FIG. 5 is a cross-sectional view of the right side surface of the drive shaft bearing portion of the cover member as viewed from the arrow of VII-VII in FIG. It is sectional drawing of the cover member which forms the bulging part shown in FIG. FIG. 8 is a perspective view of the first cover member as viewed by IX arrow. It is a perspective view of the first cover member by the X arrow view in FIG. It is a perspective view of the 2nd cover member by the XI arrow view in FIG.

Hereinafter, an embodiment according to the present invention will be described with reference to the drawings.
FIG. 1 is a left side view of a motorcycle 1 which is a saddle-mounted vehicle equipped with an internal combustion engine 4 according to an embodiment of the present invention.
In the scope of claims and the description of the specification, the front-back, left-right, up-down directions shall be in accordance with the usual standard that the straight-ahead direction of the motorcycle 1 according to the present embodiment is forward, and in the drawings, FR refers to the front. UP is upward, LH is left, and RH is right.

The body frame 2 of the saddle-mounted motorcycle 1 is divided into left and right from the head pipe 20, and the main frames 21 and 21 extend rearward, and the rear center frame portions 21a and 21a are bent downward.
In addition, the down frames 22 and 22 extend diagonally downward from the head pipe 20.
The seat rail 23 extends diagonally upward from the front to the upper bent portion of the center frame portions 21a and 21a of the main frames 21 and 21.

The front wheel 11 is pivotally supported at the lower end of the front fork 10 which is steerably supported by the head pipe 20, and the steering wheel 12 is connected to the front fork 10 via a steering shaft (not shown) extending upward.

Further, a rear fork 13 whose front end is pivotally supported by a pivot shaft 13a extends rearward to the center frame portion 21a, and a rear wheel 14 pivotally supported at the rear end is provided so as to swing up and down.
A link mechanism 15 is provided between the lower edge of the rear fork 13 and the lower end of the center frame portion 21a, and a rear cushion 16 is interposed between a part of the link mechanism 15 and the upper portion of the center frame portion 21a. Has been done.

The power unit 3 mounted on the body frame 2 of the motorcycle 1 is configured by integrally housing the transmission mechanism 5 in the rear part of the crankcase 40 of the internal combustion engine 4. The power unit 3 is on the front side of the main frame 21. It is suspended on the down frame 22 and the main frame 21 of.
A fuel tank 17 is erected on the main frame 21 above the power unit 3, and a seat 18 is supported by a seat rail 23 behind the fuel tank 17.

The internal combustion engine 4 is a water-cooled in-line 4-cylinder 4-stroke cycle internal combustion engine, and is mounted on the motorcycle 1 with its crankshaft 41 directed in the vehicle width direction (left-right direction).
FIG. 2 shows the right side surface of the internal combustion engine 4 in FIG.
As shown in FIG. 2, the crankcase 40 is vertically divided with the crankshaft 41 pivotally supported, and the cylinder block 42 and the cylinder head 43 are stacked in order on the upper case 40A to some extent. It is erected at an angle to the front and is fastened with stud bolts (not shown). The cylinder head cover 44 is placed on the cylinder head 43.
On the other hand, the oil pan 36 is attached under the lower case 40B.
In front of the internal combustion engine 4, a radiator 75 that expands in the left-right vehicle width direction is arranged in a forward-tilted posture along the front of the forward-tilted cylinder block 42 and the cylinder head 43.

As shown in FIG. 1, an intake pipe 60 extends upward from a cylinder head 43 tilted forward of the internal combustion engine 4, and is connected to an air cleaner 62 via a throttle body 61.
Further, the four exhaust pipes 65 extending forward from the cylinder head 43 and extending downward are gathered at a rearward bend, and extend rearward below the crankcase 40 via the catalyst device 66 to the rear wheels 14. It is connected to the muffler 67 arranged along the right side of the.

The counter shaft 52 of the transmission mechanism 5, which is the output shaft of the power unit 3, penetrates the left bearing wall and projects to the left, and the output sprocket 53 is fitted to the left end portion thereof. The output sprocket 53 and the rear wheels The drive chain 55 is wound around the driven sprocket 54 fitted to the rear axle of 14, and the output of the power unit 3 is transmitted to the rear wheels 14 via the drive chain 55 to drive the motorcycle 1.

As shown in FIG. 2, a water pump 70 for circulating cooling water is provided on the right side surface of the crankcase 40 of the internal combustion engine 4 as described above, below the transmission mechanism 5.
The water pump 70 includes a water pump shaft 72 and an impeller 70a housed in a pump body fitted on the right side of the crankcase 40, and the impeller 70a is covered from the outside by a pump cover 71.

FIG. 3 is a cross-sectional development view of the power unit 3 viewed from the arrow III-III in FIG.
As shown in FIG. 3, the transmission mechanism 5 housed in the transmission chamber 50 at the rear of the crankcase 40 includes a main shaft 51 and a counter shaft 52 arranged in parallel with the crankshaft 41, as described above. The counter shaft 52 serves as the output shaft of the power unit 3, and the output sprocket 53 is mounted on the counter shaft 52 with its left end protruding through the crankcase 40.

Each journal wall 45 of the upper case 40A and the lower case 40B supports the journal portion 41a of the crankshaft 41 so as to be sandwiched from above and below via the main bearing 45a, and the crankshaft 41 is rotatably shafted in the crank chamber 40a. Support.
Since the internal combustion engine 4 is an in-line 4-cylinder in which four cylinders 46 are arranged in series and integrally formed, the crankshaft 41 has five journal portions 41a, and the upper and lower cases 40A and the lower case 40B are above and below. The crankshaft 41 is rotatably supported by five journal walls 45 each.

The upper case 40A and the lower case 40B are integrally fastened with bolts so that their split surfaces are aligned with each other.
Between the adjacent journal portions 41a of the crankshaft 41, the left and right sides are sandwiched between the web portions 41b, and the crankpin 41c is integrally formed and is located in the crank chamber 40a.
A piston 47 is fitted to the four cylinders 46 of the cylinder block 42 integrally fastened to the upper case 40A so as to be slidable back and forth, and the piston 47 is connected to the crank pin 41c of the crankshaft 41 via a connecting rod 48. Cylinder.

In the cylinder head 43, for each cylinder 46, a combustion chamber 30 formed facing the piston 47 and an intake port 33 that opens into the combustion chamber 30 and is opened and closed by a pair of intake valves 31 extend rearward. An exhaust port 34 opened and closed by a pair of exhaust valves 32 extends forward, and a spark plug 35 facing the combustion chamber 30 is attached. FIG. 3 shows a front exhaust valve 32 and an exhaust port 34.
A throttle body 61 is connected to the intake pipe 60 on the upstream side of the intake port 33, and an air cleaner 62 is connected to the upstream side of the throttle body 61. An exhaust pipe 65 is connected to the downstream opening of the exhaust port 34. (See Fig. 1)

Each intake valve 31 and each exhaust valve 32 are opened and closed and driven in synchronization with the rotation of the crankshaft 41 by the intake cam shaft 37i and the exhaust cam shaft 37e rotatably supported by the cylinder head 43.
Therefore, the cam shafts 37i and 37e are between the cam driven sprockets 41d and the cam driven sprockets 38i and 38e, in which the cam driven sprockets 38i and 38e are fitted at the right end and are fitted near the right end of the crankshaft 41. The timing chain 39 is hung on the sprocket (see FIG. 3), and is rotationally driven at half the rotation speed of the crankshaft 41. Note that FIG. 3 shows the exhaust side.
Cam chain chambers 42a and 43a for arranging the timing chain 39 are formed at the right ends of the cylinder block 42 and the cylinder head 43 (see FIG. 3).
On the other hand, as shown in FIG. 3, an AC generator 49 is provided at the left end of the crankshaft 41 protruding to the left from the leftmost journal wall 32 (X) forming the left wall of the crankcase 40. ..

A transmission mechanism 5 is arranged in the transmission chamber 50 behind the crank chamber 40a accommodating the crank shaft 41 in the crankcase 40, and the main shaft 51 and the counter shaft 52 serving as the transmission shaft are accommodated. ..
The crankcase 40a and the transmission chamber 50 are partitioned by a partition wall 40b integrally provided on the crankcase 40.
The transmission mechanism 5 is a gear transmission that is always meshed, and the main shaft 51 is rotatably supported on the upper case 40A via a bearing 56 at an obliquely upward position behind the crank shaft 41, and the crank shaft 41 The counter shaft 52 is rotatably supported via the bearing 57 between the split surfaces of the upper case 40A and the lower case 40B at the rear, and is mounted on the main shaft 51 and the counter shaft 52 parallel to the crank shaft 41, respectively. The speed change gear groups 51g and 52g mesh with each other in pairs, and the gears that are spline-fitted to the shaft and serve as shifters are moved by a speed change operation mechanism (not shown) to shift gears.
That is, the transmission chamber 50 is defined over the upper case 40A and the lower case 40B.

A multi-plate clutch 8 is provided at the right end 51a of the main shaft 51, and a primary driven gear 81 supported so as to rotate together with the clutch outer 8a of the clutch 8 and a second web counting from the right of the crankshaft 41. The primary drive gear 41e formed in the portion 41b meshes with each other to form a primary deceleration mechanism.
The clutch inner 8b, which is the output side of the clutch 8, is spline-fitted to the main shaft 51, so that the rotation of the crankshaft 41 is transferred to the main shaft 51 of the transmission mechanism 5 via the primary reduction mechanisms 41e and 81 and the clutch 8. Be transmitted.

The clutch 8 is covered with a clutch cover 82 on the outside, that is, on the right side of the upper case and the lower case 40B, and the clutch cover 82 is hermetically connected to the right wall of the upper case 40A and the lower case 40B. It forms the clutch chamber 80.
Further, since the primary drive gear 41e in the crank chamber 40a and the primary driven gear 81 in the clutch chamber 80 are in a meshing relationship, the crank chamber 40a and the clutch chamber 80 form a communicative space.

The rotational power of the crank shaft 41 is transmitted to the clutch 8 via the primary drive gear 41e on the crank shaft 41 side and the primary driven gear 81 on the clutch 8 side, and the clutch 8 is in the process of gear switching of the transmission mechanism 5. Does not cut off the rotational power of the crank shaft 41 and transmit it to the transmission mechanism 5, but when the gear switching of the transmission mechanism 5 is completed and the rotational power is connected, the rotational power of the crank shaft 41 is transmitted to the transmission mechanism 5. It is configured in.

A pump-driven sprocket on the primary driven gear 81 (in the present invention) located between the bearing 56 for the main shaft 51 of the upper case 40A and the primary driven gear 81 so as to rotate with the primary driven gear 81 concentrically with the main shaft 51. "Transmission drive unit") 91 is installed.
The pump drive sprocket 91 is provided on the coaxial core on the main shaft 51 of the transmission mechanism 5, but is located in the clutch chamber 80 on the right side of the bearing 56 for the main shaft 51, and is located in the negative pressure chamber described later. Will be located.

FIG. 4 is a vertical cross-sectional view of the crankcase 40 from the main shaft 51 in FIG. 2 to the water pump shaft 72 and the pump drive shaft 92 having the coaxial center X as viewed in the same direction.
As shown in FIG. 4, a pump driven sprocket 91 provided concentrically with the main shaft 51 and a pump driven sprocket provided on the pump drive shaft 92 supported in the lower case 40B below the main shaft 51 ( A pump drive chain 94 is hung from the "transmission driven portion") 93 in the present invention.

The oil pump drive transmission mechanism 90 according to the present invention is configured by the pump drive sprocket 91, the pump drive chain 94, and the pump driven sprocket 93, and the oil pump drive transmission mechanism 90 rotates in conjunction with the rotation of the crankshaft 41. The pump drive sprocket 91 and the pump driven sprocket 93 are connected via the pump drive chain 94, and the pump drive shaft 92 is rotated.
The pump drive shaft 92 transmits rotation to the oil pump rotor shaft 103 of the oil pump 100, which will be described later (see FIG. 5).
The oil pump drive transmission mechanism 90 of the present invention may be configured by a combination of a pump drive gear as a transmission drive unit and a pump driven gear as a transmission driven mechanism, instead of those of the above embodiments.

In the present embodiment, the transmission drive unit of the oil pump drive transmission mechanism 90 is a pump drive sprocket 91, the transmission driven unit is a pump driven sprocket 93, and the pump drive sprocket 91 and the pump driven sprocket 93 are connected by a pump drive chain 94. Since they are connected, the oil pump drive transmission mechanism 90 can be constructed at low cost, and the degree of freedom in arranging the pump drive shaft 92 is improved.

FIG. 5 is a vertical cross-sectional view taken along the pump drive shaft 92 of the lower case 40B as viewed by the arrow VV in FIG.
As shown in FIG. 5, the partition wall 40b which is the lower surface of the crank chamber 40a and separates the transmission chamber 50 is arranged on the transmission chamber 50 side and is driven by the crankshaft 41 to pump oil to each part of the internal combustion engine 4. The oil pump 100 is installed.
The oil pump 100 includes a feed pump 100A that sucks oil from an oil pan 36 below the transmission chamber 50 through an oil suction conduit 101 to lubricate and cool each part of the internal combustion engine 4, and a crank chamber 40a. A scavenging pump 100B that positively discharges the return oil from the internal combustion engine 80 and the clutch chamber 80 to the oil pan 36 is provided on the same oil pump rotor shaft 103.
In the present embodiment, the feed pump 100A is composed of one system by the central rotor 104C, and the scavenging pump 100B is composed of two systems by the left rotor 104L and the right rotor 104R arranged on the left and right sides of the central rotor 104C.

Since the scavenging pump 100B sucks oil from the crank chamber 40a and the clutch chamber 80, the crank chamber 40a and the clutch chamber 80 are used as negative pressure chambers, and the pumping loss of the crank chamber 40a is reduced. ..
As described above, the crank chamber 40a and the clutch chamber 80 are communicated with each other because the primary drive gear 41e in the crank chamber 40a and the primary driven gear 81 in the clutch chamber 80 are in a meshing relationship, and one negative pressure space is formed. Form.

FIG. 6 is a left side sectional view of the scavenging pump 100B as viewed from the arrow VI-VI in FIG.
The oil A in the crank chamber 40a, which is a negative pressure chamber, is sucked out by the scavenging pump 100B, discharged as positive pressure oil B into the transmission chamber 50, which is a positive pressure chamber, and dropped and stored in the lower oil pan 36. Will be done. With reference to FIG. 3, the oil flowing down the two cylinders 46 on the right side is mainly caused by the right rotor 104R of the scavenging pump 100B on the right side, and the oil flowing down below the two cylinders 46 on the left side is mainly used. The left rotor 104L of the left scavenging pump 100B discharges the oil to the transmission chamber 50 side.

On the other hand, referring to FIG. 3, the cam drive sprocket 41d, the timing chain 39, the cam chain chambers 42a and 43a containing the intake cam driven sprocket 38i and the exhaust cam driven sprocket 38e, the intake cam shaft 37i and the exhaust cam shaft 37e, etc. The valve mechanism chamber 37, which houses the valve mechanism system of the above, is separated from the crank chamber 40a by the journal wall 45 (Y) at the right end to form a positive pressure chamber, and the transmission chamber 50 is also a crank chamber 40a by the partition wall 40b. The positive pressure chamber is separated from the clutch chamber 80, and the negative pressure chamber is limited to the crank chamber 40a and the clutch chamber 80.
Therefore, compared to the conventional structure in which the cam chain chamber or the valve operating mechanism chamber is also a negative pressure chamber, the space where the negative pressure is applied is suppressed to be small, the suction efficiency by the scavenging pump 100B is improved, and the scavenging pump 100B is improved. The increase in size is suppressed.

As shown in FIG. 5, the partition wall 40b is provided with a gap 105 so as to communicate the crank chamber 40a side, which is a negative pressure chamber, and the transmission chamber 50 side, which is a positive pressure chamber. A transmission space 106, which is a negative pressure chamber communicating with the crank chamber 40a side via the crank chamber 40a, is provided in a bulging portion 107 that bulges from the crank chamber 40a side to the transmission chamber 50 side.
The bulging portion 107 is configured such that a cover member 108 that forms a transmission space 106 separately from the partition wall 40b is attached to the partition wall 40b from the transmission chamber 50 side so as to surround the gap portion 105.

The pump drive shaft 92 is rotatably supported by inserting a drive shaft bearing portion 109 provided on the side wall 108a on one side (left side) of the cover member 108, and is rotatably supported, and the oil pump drive transmission is arranged in the transmission space 106. The pump driven sprocket 93 of the mechanism 90 is attached.
The pump-driven sprocket 93 passes through the gap 105 and is connected to the pump-driven sprocket 91 via the pump-driven chain 94.
Therefore, the oil pump drive transmission mechanism 90 in the present invention including the pump drive sprocket 91, the pump drive chain 94, and the pump driven sprocket 93 is arranged in the negative pressure space.

The transmission room 50 side of the pump drive shaft 92 through which the drive shaft bearing portion 109 is inserted, that is, the left side, is connected to the oil pump rotor shaft 103 at a coaxial center X so as not to rotate relative to each other. It is driven to rotate.
Further, a fitting port 110 having a coaxial center X with the drive shaft bearing portion 109 is provided on the side wall 108b on the side opposite to the drive shaft bearing portion 109 of the cover member 108, that is, on the other side (right side), and the fitting port 110 is provided with a fitting port 110. The water pump 70 is fitted, and the water pump shaft 72 is connected to the pump drive shaft 92 at a coaxial center X so as not to rotate relative to each other.

As described above, the crankcase 40 is a pump drive shaft 92 that transmits power from the crankcase 40a side (including the clutch chamber 80), which is a negative pressure chamber partitioned by the partition wall 40b, to the transmission chamber 50 side in the positive pressure space. Since it was arranged over both compartments by penetrating the cover member 108, which is a separate body from the above, the bulging portion 107 forming the transmission space 106 in which the pump driven sprocket 93 of the oil pump drive transmission mechanism 90 is arranged is a partition wall. It is composed of a cover member 108 that is separate from the 40b, and has a structure that is easy to manufacture because the shape of the crankcase 40 is complicated and restrictions such as die cutting are suppressed.

FIG. 7 is a cross-sectional view of the right side of the drive bearing portion 109 of the cover member 108 as viewed from the arrow VII-VII in FIG.
The pump drive shaft 92 is rotatably supported by a drive shaft bearing portion 109 provided on the side wall 108a on one side (left side) of the cover member 108, and the drive shaft bearing portion 109 is provided with an oil supply hole 111. The oil supply hole 111 is connected to the oil supply passage 112 provided in the crankcase 40, and can receive the oil supply from the feed pump 100A via the oil supply passage on the upstream side (not shown).
Since the oil supply hole 111 is provided in this way, the lubrication performance of the pump drive shaft 92 is improved, and the airtightness between the crank chamber 40a side of the negative pressure chamber and the transmission chamber 50 side of the positive pressure chamber is airtight. Is improved by oil.
Further, the cover member 108 forming the bulging portion 107 is provided separately from the partition wall 40b, and the bulging portion 107 is formed in the crankcase 40 by forming the oil supply structure in the drive shaft bearing portion 109 provided in the cover member 108. The structure is such that the refueling hole 111 can be easily processed as compared with the case where it is integrally formed with.

With reference to FIG. 5, oil from the crank chamber 40a and the clutch chamber 80 flows down into the bulging portion 107 formed by the cover member 108, that is, into the transmission space 106 through the gap portion 105 of the partition wall 40b. However, an oil suction pipe 113 having one end connected to the suction side 100Ba of the scavenging pump 100B is provided with the other end connected to the lower portion 108c of the cover member 108.
Therefore, the oil accumulated in the transmission space 106 in the cover member 108 is sucked by the scavenging pump 100B through the oil suction pipe 113, and the pump driven sprocket 93 of the oil pump drive transmission mechanism 90 is accumulated in the transmission space 106. The oil agitation resistance generated by agitating the oil is suppressed.

FIG. 8 shows a cross-sectional view of the cover member 108 forming the bulging portion 107 shown in FIG.
The cover member 108 is substantially vertically divided into a first cover member 108A and a second cover member 108B.
The first cover member 108A has an upper upper opening 108Aa connected to the periphery of the gap 105 of the partition wall 40b and a lower opening 108Ab at the lower end, and the above-mentioned transmission space 106 is formed therein. The side wall 108a on one side (left side) has a drive shaft bearing portion 109 that rotatably supports the pump drive shaft 92, and a boss portion 109a of the drive shaft bearing portion 109 that projects inward of the first cover member 108A. The side wall 108b on the other side (right side) is provided with a fitting port 110 into which the water pump 70 is fitted in the coaxial center X with the drive shaft bearing portion 109.
The second cover member 108B is fastened to the first cover member 108A so that its upper opening 108Ba coincides with the lower opening 108Ab of the first cover member 108A, and a part of the transmission space 107 is formed inside. It has an oil suction pipe connection 108Bb at the bottom that communicates with the upper opening 108Ba.

FIG. 9 is a perspective view of the first cover member 108A roughly viewed by IX in FIG. 8, and FIG. 10 is a perspective view of the first cover member 108A roughly viewed by arrow X in FIG.
Further, FIG. 11 is a perspective view of the second cover member 108B, which is generally seen by arrow XI in FIG.
The second cover member 108B shown in FIG. 11 is fastened to the first cover member 108A while matching its upper opening 108Ba with the lower opening 108Ab of the first cover member 108A shown in FIG. Therefore, a bulging portion 107 having a transmission space 106 internally formed by the cover member 108 is formed.

Due to the structure of such a cover member 108, when the cover member 108 is molded by a mold, it is divided into a first cover member 108A and a second cover member 108B, and the first cover member 108A has an upper opening 108Aa. Due to the presence of the lower opening 108Ab, even if there is a boss portion 109a protruding inside the first cover member 108A, the mold can be divided into upper and lower parts and pulled out from the upper opening 108Aa and the lower opening 108Ab, respectively. It has a structure that is easy to manufacture.

Looking at the internal combustion engine 4 of the present embodiment, as shown in FIG. 5, the oil pump 100 is provided on one side (left side) of the cover member 108, and the oil pump rotor shaft 103 of the oil pump 100 is , Water that is connected to the pump drive shaft 92 at the coaxial center X so as not to rotate relative to each other and is driven by the pump drive shaft 92 at the coaxial center X at the fitting port 110 provided on the other side (right side) of the cover member 108. A water pump 70 having a pump shaft 72 is fitted and provided.
Therefore, the oil pump 100 and the water pump 70 can be driven with a small number of parts, and a structure that improves the assembling property of the water pump 70 is obtained.

Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and various other aspects can be changed within the scope of the gist of the present invention. For example, the power unit and internal combustion engine of the present invention are not limited to motorcycles, and may be widely applied to other types of saddle-mounted vehicles.
For convenience of explanation, the left-right arrangement of the device has been described according to the illustrated embodiment, but the present invention is not limited to this, and the left-right arrangement may be reversed.

1 ... motorcycle, 2 ... body frame, 3 ... power unit, 4 ... internal combustion engine, 5 ... transmission mechanism, 8 ... clutch, 30 ... combustion chamber, 36 ... oil pan, 37 ... valve mechanism chamber, 40 ... crankcase, 40a ... Crankcase, 40b ... Bulkhead, 40A ... Upper case, 40B ... Lower case, 41 ... Crankcase, 41e ... Primary drive gear, 42 ... Cylinder block, 42a, 43a ... Cam chain chamber, 43 ... Cylinder head, 45 … Journal wall, 46… cylinder, 47… piston, 51… main shaft, 52… counter shaft, 70… water pump, 72… water pump shaft, 80… clutch chamber, 81… primary driven gear, 82… clutch cover, 90… Oil pump drive transmission mechanism, 91 ... pump drive sprocket ("transmission drive unit" in the present invention), 92 ... pump drive shaft, 93 ... pump driven sprocket ("transmission driven unit" in the present invention), 94 ... pump drive chain, 100 ... oil pump, 100A ... feed pump, 100B ... sprocket pump, 100Ba ... suction side, 103 ... oil pump rotor shaft, 105 ... gap, 106 ... transmission space, 107 ... bulge, 108 ... cover member, 108A ... 1st cover member, 108Aa ... upper opening, 108Ab ... lower opening, 108B ... second cover member, 108Ba ... upper opening, 108Bb ... oil suction pipe connection, 109 ... drive shaft bearing, 109a ... boss, 110 … Mating port, 111… Refueling hole, 112… Refueling path, 113… Oil suction pipe, X… Coaxial core

Claims (6)

The crankcase (40a) in which the crankshaft (41) is housed and becomes a negative pressure chamber and the transmission room (50) in which the transmission shafts (51,52) are housed are integrally provided in the crankcase (40). An internal combustion engine (4) having the crankcase (40) partitioned by a partition wall (40b).
An oil pump (100) arranged on the transmission chamber (50) side and driven by the crankshaft (41) to pump oil to each part of the internal combustion engine (4).
It is connected to the transmission drive unit (91) of the oil pump drive transmission mechanism (90) that rotates in conjunction with the rotation of the crankshaft (41), and rotates to the oil pump rotor shaft (103) of the oil pump (100). In an oil pump drive structure of an internal combustion engine having a pump drive shaft (92) to transmit
The crankcase (40) provides a transmission space (106) communicating with the crankcase (40a) side through a gap (105) provided in the partition wall (40b) from the crankcase (40a) side. Prepared in the bulging portion (107) that bulges toward the transmission chamber (50).
The pump drive shaft (92) is provided with a transmission driven portion (93) of the oil pump drive transmission mechanism (90) arranged in the transmission space (106), and the transmission driven portion (93) is described. It is connected to the transmission drive unit (91) through the gap portion (105).
The partition wall (40b) so that the cover member (108), which is separate from the partition wall (40b) and forms the transmission space (106), surrounds the gap portion (105) from the transmission chamber (50) side. An oil pump drive structure for an internal combustion engine, characterized in that the bulge (107) is formed by being attached to an internal combustion engine. The pump drive shaft (92) is rotatably supported by a drive shaft bearing portion (109) provided on the cover member (108).
The drive shaft bearing portion (109) is provided with a lubrication hole (111).
The oil pump drive structure for an internal combustion engine according to claim 1, wherein the oil supply hole (111) is connected to an oil supply passage (112) provided in the crankcase (40). The transmission drive unit (91) of the oil pump drive transmission mechanism (90) is a pump drive sprocket (91), and the transmission driven unit (93) is a pump driven sprocket (93) with the pump drive sprocket (91). The oil pump drive structure for an internal combustion engine according to claim 1 or 2, wherein the pump driven sprocket (93) is connected to the pump drive chain (94). The oil pump (100) includes a scavenging pump (100B).
An oil suction pipe (113) is provided so that one end is connected to the suction side (100Ba) of the scavenging pump (100B) and the other end is connected to the lower portion (108c) of the cover member (108). The oil pump drive structure of an internal combustion engine according to any one of claims 1 to 3. The cover member (108) is divided into a first cover member (108A) and a second cover member (108B).
The first cover member (108A) includes a drive shaft bearing portion (109) that rotatably supports the pump drive shaft (92) and the drive shaft bearing portion that projects inward of the first cover member (108A). It has a boss portion (109a) of (109), an upper upper opening (108Aa) connected to the periphery of the gap (105), and a lower opening (108Ab) at the lower end.
The second cover member (108B) is connected so that its upper opening (108Ba) matches the lower opening (108Ab), and is connected to the lower part for an oil suction pipe (108Bb) communicating with the upper opening (108Ba). The oil pump drive structure of the internal combustion engine according to claim 4. The oil pump (100) is provided on one side of the cover member (108).
The oil pump rotor shaft (103) and the pump drive shaft (92) are connected by a coaxial center (X) so as not to rotate relative to each other.
A water pump (70) having a water pump shaft (72) driven by the pump drive shaft (92) at a coaxial center (X) at a fitting port (110) provided on the other side of the cover member (108). The oil pump drive structure of the internal combustion engine according to any one of claims 1 to 5, wherein the) is fitted and provided.

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