JPH0763119A - Crank case structure of engine - Google Patents

Abstract

PURPOSE:To provide the crank case structure of an engine by which the reduction of a total oil quantity and the miniaturization of an oil pan and an oil pump can be attempted. CONSTITUTION:Reinforcement means 61 are provided on the inner wall surface of the lower part of a crank case 32 in a direction which connects at right angles to the shaft direction of a crank shaft 45, and meanwhile, an oil pan 58 is provided at the lowest part of the crank case 32, and the rear end parts 62 of the reinforcement means 61 are pointed to the oil pan 58.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine crankcase structure.

[0002]

2. Description of the Related Art Some engine crankcases are provided with reinforcing means for the purpose of improving strength and rigidity.

FIG. 7 (a) is a view of the crankcase provided with the reinforcing means as seen from below, and FIG. 7 (b) is shown in FIG.
It is sectional drawing which follows the XX line of (a).

As shown in FIGS. 7 (a) and 7 (b), the crankcase 1 has ribs 2 as reinforcing means on the outer surface thereof in the axial direction (2a) of the crankshaft 3 and at right angles to the axial direction. It is provided in the direction (2b).

On the other hand, since the engine 4 has many sliding parts and rotating parts inside, oil is supplied to each part by using a lubricating device, and the frictional resistance of each part is reduced by the action of the oil.
The function of the engine 4 is fully exerted.

For example, as shown in FIG. 8, the oil flow of the dry sump type lubricating device is such that the oil stored in the oil tank 5 provided separately from the engine 4 is
The oil is supplied to the oil filter 8 provided in the engine 4 by the supply pump 7 through the oil supply hose 6. The oil filtered by the oil filter 8 is sent to each lubricating section in the engine 4 via the oil passage 9 and the like. After lubricating the lubricating parts in the engine 4, the oil naturally drops, or passes through the oil return passage 10 and the like to the oil pan 11
Accumulate in. The oil accumulated in the oil pan 11 is pumped up from the oil intake 12 immersed in the oil pan 11 by the pumping pump 13 and returned to the oil tank 5 via the oil return hose 14.

The arrangement position of the oil intake port is described in JP-A-2-1.
As shown in Japanese Patent No. 15507, the oil intake is often arranged directly below or in front of the crankshaft in order to avoid interference of the crank web provided on the crankshaft.

[0008]

However, the oil that naturally falls in the engine or should be accumulated in the oil pan via the oil return passage flows in the crankcase without ribs. Therefore, the oil intake may not be sufficiently immersed in the oil in the oil pan, and air may be sucked.

Further, due to the interference with the crank web and the air flow generated by the rotation of the crank web, the oil that should be stored in the oil pan comes to the rear of the oil intake port, and the oil intake port is also sufficiently immersed in the oil in the oil pan. Without doing so, there is a risk of inhaling air.

If the oil intake sucks air, the oil may not sufficiently reach the sliding parts and rotating parts inside the engine, and the sliding parts and rotating parts inside the engine may be seized. Intake of air occurs remarkably at high engine speeds.

In order to solve these problems, conventionally, the total amount of oil has been increased, and the capacity of the oil pan and the oil pump has been increased accordingly.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a crankcase structure for an engine which can reduce the total amount of oil and downsize the oil pan and the oil pump.

[0013]

In order to solve the above-mentioned problems, the crankcase structure of the engine according to the present invention has a shaft of a crankshaft on the inner wall surface of the lower part of the crankcase. While reinforcing means is provided in a direction orthogonal to the direction, an oil pan is provided at the lowest part of the crankcase, and a rear end portion of the reinforcing means is directed toward the oil pan.

Further, in order to solve the above-mentioned problems, as described in claim 2, the crankcase front side wall is formed so as to be close to the rotation orbit of the crank web, and above the oil pan. An oil intake port is provided in the wall, and a wall portion is provided behind the oil intake port so as to project upward.

[0015]

In the present invention having the above-mentioned structure, the reinforcing means is provided on the inner wall surface of the lower portion of the crankcase in a direction orthogonal to the axial direction of the crankshaft, while the oil pan is provided at the lowest portion of the crankcase to provide the reinforcement. While directing the rear end portion of the means to the oil pan, the crankcase front side wall is formed so as to follow along the rotation path of the crank web, while an oil intake port is provided above the oil pan. Since the wall portion is provided behind the oil intake port so as to project upward, the total amount of oil can be reduced and the oil pan and the oil pump can be downsized.

[0016]

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

FIG. 1 is a right side view showing an example of a motorcycle to which the present invention is applied.

In FIG. 1, the motorcycle 20 has a vehicle body frame 21, and a fuel tank 22 is provided above the vehicle body frame 21. In addition, the body frame 21
An engine 23 is mounted in the lower center part of the.

A head pipe 24 is provided in front of the vehicle body frame 21, and a steering mechanism 25 is provided on the head pipe 24. The steering mechanism 25 includes a front fork 2 that rotatably supports a front wheel 26.
7, a handlebar 28, etc. are provided, and the handlebar 28 steers the front wheel 26 rotatably left and right.

On the other hand, a swing arm 30 is pivotally mounted on a pivot shaft 29 provided under the center of the body frame 21 so as to swing around the pivot shaft 29, and a rear wheel 31 is rotated at the rear end of the swing arm 30. Freely supported.

2 is a vertical sectional view taken along the line AA of FIG. 1, and FIG. 3 is a horizontal sectional view taken along the line BB of FIG. 4 is a sectional view taken along the line CC of FIG.

1 to 4, the engine 23 mainly includes a crankcase 32, a cylinder block 33, a cylinder head 34, and a cylinder head cover 35.
The outer shape is composed of and.

The engine 23 is, for example, an air-cooled four-cycle parallel two-cylinder engine equipped with a dry sump type lubricating device, and as shown in FIG.
A double overhead camshaft (DOHC) type valve valve that opens and closes the valves 36 and 37 by providing two camshafts 38a and 38b for opening and closing the intake valve 36 and the exhaust valve 37 above the valves 36 and 37, respectively. The mechanism 39 is provided.

A camshaft 38a for opening and closing the intake valve 36
Are disposed, for example, on the rear side in the vehicle traveling direction of the motorcycle 20, and the exhaust valve 37 opening / closing camshaft 38b is disposed on the front side in the vehicle traveling direction at right angles to the vehicle traveling direction.

An intake passage 40 and an exhaust passage 41 are provided in the cylinder head 34. A carburetor 42a, which is an engine intake system 42, and an air cleaner 42b are connected to the intake passage 40. On the other hand, the exhaust passage 41
Is an exhaust pipe 43 which is an engine exhaust system 43.
a and the muffler 43b are connected. Further, an oil tank 44 is arranged behind the air cleaner 42b.

A crankshaft 45 is arranged in the crankcase 32 at right angles to the traveling direction of the motorcycle 20. A crank web 46 is formed on the crank shaft 45 for smooth rotation of the crank shaft 45.

The crankshaft 45 has a connecting rod 4
The large end 47a of 7 is connected. Also, the connecting rod 47
A piston 49 is connected to the small end portion 47 b of the piston via a piston pin 48. The piston 49 reciprocates in the cylinder liner 50 fitted in the cylinder block 33 in the vertical direction in the figure, and the reciprocating stroke is the connecting rod 47.
Is transmitted to the crankshaft 45 via the shaft to rotate the crankshaft 45.

A transmission case 51 is provided on the rear side of the crankcase 32. As shown in FIG. 3, a transmission mechanism 52, which is a primary speed reducer, is provided in the transmission case 51. The transmission mechanism 52 is provided with a counter shaft 54 to which the driving force from the crankshaft 45 is input via the clutch mechanism 53 and a drive shaft 55 that is a driving shaft that outputs the driving force to the rear wheels 31. The counter shaft 54 and the drive shaft 55 are provided with a plurality of mission gears 56 having different diameters, and the combination of these mission gears 56 is changed to perform primary deceleration.

As shown in FIG. 4, the crankcase 32 is divided into, for example, upper and lower parts, and the upper crankcase 3
2a and the lower crankcase 32b. Upper crankcase 32a and lower crankcase 32
Bearings 57 for the crankshaft 45, the counter shaft 54, and the drive shaft 55 are provided on the inner side of the split surface with respect to b.
5, 54, 55 are pivotally supported.

FIG. 5 is a plan view of the front side of the lower crankcase 32b, showing a state where the crankshaft 45 is removed. 6 is a sectional view taken along the line DD of FIG.

As shown in FIG. 4, FIG. 5 and FIG. 6, the crankshaft 4 is located at the lowest part of the lower crankcase 32b.
An oil pan 58 is provided near the middle of the counter shaft 54 and the counter shaft 54. The oil pan 58 is used for the engine 23.
After lubricating each of the lubricated parts, it has a role of temporarily storing engine lubricating oil that naturally falls or returns via an oil return passage 59 formed in the cylinder block 33.

On the outer wall surface on the front side of the lower crankcase 32b, an outer surface rib 60 serving as a reinforcing means is provided.
A plurality of them are provided in the axial direction of 5.

A plurality of inner ribs 61 as reinforcing means are provided on the inner wall surface on the front side of the lower crankcase 32b in a direction orthogonal to the axial direction of the crankshaft 45.
Further, the rear ends 62 of the inner ribs 61 are provided so as to face the oil pan 58.

The front wall of the lower crankcase 32b is formed so as to closely follow the rotation track 63 of the crank web 46.

At the upper part of the oil pan 58, the oil intake 6
4 are provided. A strainer 65 for filtering foreign matters in the oil is provided at the tip of the oil intake 64, and the strainer 65 is immersed in the oil stored in the oil pan 58.

As shown in FIGS. 4 and 6, a wall portion 66 projecting upward is provided on the bottom surface of the lower crankcase 32b behind the oil intake 64.

From the oil intake 64 toward the magneto chamber 67 provided on the right side of the engine 23, the oil pumping passage 6
8 is provided substantially horizontally, for example. The downstream side of the oil pumping passage 68 is connected to an oil pumping pump 69 provided in the magneto chamber 67. Oil pump 6
From 9, the oil return hose 71 is connected to the oil tank 44 via the oil discharge passage 70.

The magneto chamber 67 is covered with a magneto cover 72. An oil supply pump 73 is provided at a position corresponding to the right side of the oil pumping pump 69 in the magneto cover 72.
Is provided. The oil tank 44 is connected to the oil supply pump 73 via an oil supply hose 74 and an oil supply passage 75. An oil communication path (not shown) is extended from the oil supply pump 73 and an oil filter 76 is provided.
And an oil passage 77 and the like extending from the oil filter 76 to a sliding portion and a rotating portion inside the engine 23.

The central shafts 69a and 73a of the oil pumping pump 69 and the oil supply pump 73 are connected and interlocked with each other. A pump driven sprocket 78 is provided on a central shaft 69a of the oil suction pump 69, and the pump driven sprocket 78 is connected to a pump drive sprocket 80 via a pump drive chain 79. The pump drive sprocket 80 is provided at the right end of the crankshaft 45.
Then, the rotation of the crankshaft 45 operates the oil suction pump 69 and the oil supply pump 73.

Next, the operation of this embodiment will be described.

In the oil flow of the lubrication system for the engine 23 applied to this embodiment, first, the oil stored in the oil tank 44 is driven by the engine 23 via the oil supply hose 74 and the oil supply passage 75. The oil is fed to the oil filter 76 by the oil supply pump 73 that operates at. After being filtered by the oil filter 76, the oil is sent to the lubricating parts such as the sliding part and the rotating part inside the engine 23 via the oil passage 77 and the like.

The oil that has lubricated the lubricated parts in the engine 23 naturally drops or collects at the bottom of the lower crankcase 32b via the oil return passage 59 and the like. At this time, on the inner wall surface on the front side of the lower crankcase 32b, a plurality of inner surface ribs 61, which are reinforcing means, are arranged in the direction orthogonal to the axial direction of the crankshaft 45, and the rear end portions 62 of the inner surface ribs 61 are formed by the oil. Since the inner ribs 61 are provided so as to face the pan 58, the inner ribs 61 serve as oil guides, and the oil does not flow in the crankcase 32 and is reliably guided to the oil pan 58 by the inner ribs 61.

The oil that has dropped to the bottom of the lower crankcase 32b is, as shown in FIG.
6 is pushed backward by the air flow generated by the rotation of 6, but the lower crankcase 32b behind the oil intake 64
An oil sump 81 is formed on the oil pan 58 by being blocked by the upwardly projecting wall portion 66 provided on the bottom surface.

The oil accumulated in the oil sump 81 flows from the strainer 65 and the oil intake 64 to the engine 23.
Oil pumping passage 6 by the pumping pump that operates with the driving force of
8 is pumped up and returned to the oil tank 44 from the oil discharge passage 70 through the oil return hose 71.

An inner rib 61 provided on the bottom surface of the lower crankcase 32b and a wall portion 66 behind the oil intake 64.
As a result, the oil sump 81 is formed on the oil pan 58, so that the oil intake port 64 is sufficiently immersed in the oil sump 81 and air is not sucked in. Since the oil intake port 64 does not suck air, the oil is sufficiently distributed to the sliding portion and the rotating portion inside the engine 23, and there is no fear that the sliding portion and the rotating portion inside the engine 23 will be seized. As a result, the total amount of oil can be reduced, and the oil pan 58 and the oil pumps 69 and 73 can be reduced in size accordingly.

[0046]

As described above, according to the crankcase structure for an engine according to the present invention, the inner wall surface of the lower part of the crankcase is provided with the reinforcing means in the direction orthogonal to the axial direction of the crankshaft, while the crank is used. An oil pan is provided at the lowest part of the case, the rear end of the reinforcing means is directed to the oil pan, and the front wall of the crankcase is formed so as to be close to the rotation path of the crank web. Since the oil intake is provided above the pan and the wall is provided at the rear of the oil intake so as to project upward, the oil intake is sufficiently immersed in the oil in the oil pan and does not suck air. , Enough oil is distributed to the sliding parts and rotating parts inside the engine,
As a result, it is possible to reduce the total amount of oil and downsize the oil pan and the oil pump.

[Brief description of drawings]

FIG. 1 is a right side view of a motorcycle showing an embodiment of a crankcase structure for an engine according to the present invention.

FIG. 2 is a vertical sectional view taken along the line AA of FIG.

FIG. 3 is a horizontal sectional view taken along the line BB of FIG.

FIG. 4 is a sectional view taken along the line CC of FIG.

FIG. 5 is a plan view of the lower crankcase front side.

6 is a cross-sectional view taken along the line DD of FIG.

FIG. 7 (a) is a view of a conventional crankcase provided with a reinforcing means as seen from below, and FIG. 7 (b) is an X of (a).
-A sectional view taken along the line X.

FIG. 8 is a schematic view showing an oil flow of a dry sump type lubrication device.

[Explanation of symbols]

 20 Motorcycle 23 Engine 32 Crankcase 32a Upper Crankcase 32b Lower Crankcase 33 Cylinder Block 34 Cylinder Head 44 Oil Tank 45 Crankshaft 46 Crankweb 58 Oil Pan 60 External Rib (Reinforcing Means) 61 Inner Rib (Reinforcing Means) 62 Inner Surface Rear end of rib 63 Crank web rotation orbit 64 Oil intake 65 Strainer 66 Wall 68 Oil pumping passage 69 Oil pumping pump 73 Oil supply pump 81 Oil sump

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F01M 11/06 F 7604-3G

Claims (2)

[Claims] 1. A reinforcing means is provided on the inner wall surface of the lower part of the crankcase in a direction orthogonal to the axial direction of the crankshaft, and an oil pan is provided at the lowest part of the crankcase.
A crankcase structure for an engine, wherein a rear end portion of the reinforcing means is directed to the oil pan. 2. The front side wall of the crankcase is formed so as to closely follow the rotational trajectory of the crank web,
An engine crankcase structure, characterized in that an oil intake is provided above the oil pan, and a wall is provided behind the oil intake so as to project upward.