JP3133994B2 - Engine oil storage device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil storage device for an engine, and more particularly to an oil pan mounting structure for storing lubricating oil.

[Related Art] A four-stroke engine for a motorcycle includes an oil pan that stores lubricating oil at the bottom of a crankcase. Conventionally, this type of oil pan is formed of an aluminum die-cast product or a sheet metal press-formed product, and is formed in a dish shape with an open upper surface. The oil pan has a flange-shaped mating surface at the peripheral edge of the opening that abuts against the bottom surface of the crankcase, and the mating surface is fixed to the bottom surface of the crankcase via a plurality of bolts.

[Problems to be Solved by the Invention] However, in this oil pan, although the area of the bottom plate facing the bottom surface of the crankcase is large, the entire oil pan including the bottom plate is formed to be thin.
In particular, the rigidity of the bottom plate having a large area is reduced.

Therefore, when engine vibration is transmitted to the oil pan,
There is a problem that the bottom plate of the oil pan is easily vibrated and noise is generated.

The present invention has been made in view of the above circumstances, and it is possible to reduce noise by preventing vibration of the bottom plate of an oil pan, and furthermore, it is possible to omit a seal for a bolt penetrating portion and to deform the bottom plate. It is an object of the present invention to provide an oil storage device for an engine, which can prevent the occurrence of the oil strainer and can use a common bolt for fixing the oil strainer and the oil pan to the case.

[Means for Solving the Problems] In order to achieve the above object, the present invention is to fix an aluminum die-cast oil pan having a bottom plate facing the bottom to a bottom of a case in which an oil passage is opened. It is premised on an engine oil storage device in which an oil strainer connected to the oil passage is accommodated inside an oil pan.

And, on the bottom plate of the oil pan, a hollow cylindrical boss portion protruding upward from the vicinity of the oil strainer is integrally formed, and a bolt is inserted into the inside of the boss from below the oil pan, By forming a support part interposed between the upper end of the boss part and the bottom part of the case at the top of the oil strainer, and inserting the bolt insertion end through the support part and screwing it into the bottom part of the case, The bottom plate of the oil pan is connected to the bottom of the case.

[Operation] According to such a configuration, since the bottom plate of the oil pan is coupled to the bottom of the case via the bolt, the rigidity of the bottom plate is increased accordingly. Therefore, even if the vibration of the engine is transmitted to the oil pan, the vibration of the bottom plate of the oil pan can be prevented.

Also, the bolts that connect the bottom plate of the oil pan to the case are isolated from the inside of the oil pan by passing through the boss that projects upward from the bottom plate of the oil pan.
The lubricating oil stored in the oil pan does not enter the penetrating portion of the bolt, and a special seal for preventing oil leakage from the penetrating portion of the bolt is not required.

Furthermore, when the bolts are tightened, the boss is interposed between the bottom plate of the oil pan and the bottom of the case,
Deformation of the bottom plate due to excessive tightening of the bolts can be prevented.

In addition, since the bottom plate of the oil pan is coupled to the bottom of the case via the oil strainer, the mounting portion of the bottom plate of the oil pan and the oil strainer to the bottom of the case can be shared. At the same time, since the bottom plate of the oil pan and the oil strainer are fixed to the case with common bolts, a dedicated bolt for fixing the bottom plate is not required, and the number of parts can be reduced accordingly.

Embodiment A first embodiment of the present invention will be described below with reference to FIGS. 1 to 4 applied to a motorcycle.

The motorcycle shown in FIG. 4 includes a double cradle-shaped frame 1. Between the pair of left and right main pipes 2 and the down tube 3 constituting the frame 1,
An air-cooled 4-cycle 4-cylinder engine 4 is mounted.

As shown in FIG. 3, the crankcase 5 of the engine 4
Is divided into an upper case 5a and a lower case 5b, and a crankshaft 5c is housed inside the crankcase 5. A transmission case 6 for accommodating a gear transmission (not shown) is formed integrally with a rear portion of the crankcase 5.

A cylinder block 7 and a cylinder head 8 are connected to the upper front end of the crankcase 5. The cylinder block 7 and the cylinder head 8 are inclined slightly forward with respect to the vertical line, and four intake ports 9 extending upward are provided on the rear surface of the cylinder head 8.
A downdraft type carburetor 10 is connected to each intake port 9. These vaporizers 10 are housed between the left and right main pipes 2.

On the bottom of the crankcase 5 and the transmission case 6,
An oil pan 15 for storing lubricating oil is attached. The oil pan 15 is formed of an aluminum die-cast product, and has a dish shape having an opening 16 on the upper surface as shown in FIGS.

That is, the oil pan 15 has a large bottom plate 17 having a large area facing the bottom surfaces of the crankcase 5 and the transmission case 6.
And the right and left and right side plates 18 rising from the periphery of the bottom plate 17
Are integrally formed, and the upper edge of the side plate 18 forms an opening 16. The bottom plate 17 and the side plate 18 of the oil pan 15 are formed to be thin for weight reduction, and the upper edge of the side plate 18, that is, the peripheral portion of the opening 16 is abutted against the bottom surface of the crankcase 5 and the transmission case 6. It has a flat mating surface 19. A plurality of bolt holes 20 are formed in the mating surface 19 at intervals in the circumferential direction of the opening 16, and the oil pan 15 is connected to the crankcase 5 by bolts (not shown) passed through the bolt holes 20. An oil passage 22 connected to an oil pump (not shown) is opened at the center of the bottom surface of the lower case 5b, which is fixed to the bottom surface of the transmission case 6 and the bottom surface of the transmission case 6. An oil strainer 23 for pumping lubricating oil stored in the oil pan 15 is attached to an open end of the oil passage 22. The oil strainer 23 includes a strainer main body 24 extending downward from the bottom surface of the lower case 5b.
A suction passage 25 is formed inside the strainer main body 24, and the suction passage 25 is connected to the oil passage 22.

As shown in FIG. 1 and FIG.
A mounting seat 26 is formed at the upper end of the mounting plate. The mounting seat 26 is fastened to the boss portion 27 of the lower case 5b via a bolt 28, whereby the strainer body 24
Are fixed to the crankcase 5.

At the lower end of the suction passage 25 of the strainer body 24, a large-diameter suction port 30 is formed close to the bottom plate 17 of the oil pan 15. The suction port 30 is covered with a wire net 31 for filtering foreign substances in the lubricating oil. The wire netting 31 is fixed to the suction port 30 via a strainer cover 32, and the strainer cover 32 is attached to the bottom plate 17 of the oil pan 15.
Is almost in the center.

Therefore, the lubricating oil sucked from the suction port 30 of the oil strainer 23 is sent out to the gear transmission and the oil filter 33 via the oil pump, and the lubricating oil passing through the oil filter 33 is discharged to the crankshaft 5c and the cylinder head 5c. 8 is supplied to the valve operating mechanism.

As shown in FIG. 1, the bottom plate 17 of the oil pan 15 has a cylindrical boss 35. The boss 35 is
The bottom plate 17 protrudes integrally upward from the inner surface of the bottom plate 17 toward the bottom surface of the lower case 5b. The boss portion 35 is adjacent to the oil strainer 23, and the upper end surface of the boss portion 35 is abutted on a receiving seat 36 extending downward from the bottom surface of the lower case 5b.

The boss 35 has an insertion hole 37 extending in the axial direction.
The insertion hole 37 is opened at the upper end surfaces of the bottom plate 17 and the boss 35, and a bolt 38 is inserted into the insertion hole 37 from below the oil pan 15. The insertion end of the bolt 38 is screwed into a screw hole 39 of the receiving seat 36.

For this reason, the bottom plate 17 of the oil pan 15 is fastened and fixed to the lower case 5b in the vicinity of the oil strainer 23, and a rubber-like elastic body is provided between the bottom plate 17 and the strainer cover 32 of the oil strainer 23. The damper 40 is sandwiched in a compressed state.

Reference numeral 41 in FIG. 1 denotes a drain bolt for discharging lubricating oil.

According to such a configuration, the bottom plate 17 of the oil pan 15 is
Since it is directly tightened and fixed to the lower case 5b of the crankcase 5 through the bolt 38, the bottom plate 17 having a large area
Rigidity increases.

Therefore, even if the vibration of the engine 4 is transmitted to the oil pan 15, the bottom plate 17 of the oil pan 15 becomes difficult to vibrate,
Noise from the oil pan 15 can be reduced.

Further, according to the above configuration, the bolt 38 that couples the bottom plate 17 of the oil pan 15 to the lower case 5b is
Is inserted through a boss 35 projecting upward from the boss 35, and the upper end surface of the boss 35 is
The bolt 38 and this bolt
The insertion hole 37 through which the 38 passes can be isolated from the inside of the oil pan 15.

Therefore, the lubricating oil stored in the oil pan 15 does not enter the penetrating portion of the bolt 38, and the bolt 38
A special seal for preventing oil leakage from the penetrating portion is not required. Therefore, the number of parts can be reduced, the cost can be reduced, and the troublesome work of installing the seal can be omitted.

When the bolt 38 is tightened, the oil pan
Since the boss 35 is interposed between the bottom plate 17 of 15 and the receiving seat 36 of the lower case 5b, the bottom plate
17 can be prevented beforehand.

In addition, in the case of the present embodiment, since the damper 40 is sandwiched between the bottom plate 17 of the oil pan 15 and the oil strainer 23, the vibration of the bottom plate 17 can be absorbed by the damper 40. For this reason, noise from the oil pan 15 can be more reliably prevented, and quiet operation is possible.

The present invention is not limited to the first embodiment, and FIG. 5 shows a second embodiment of the present invention.

In the second embodiment, as the strainer main body 24 of the oil strainer 23 moves downward, the oil pan 15 is inclined toward a position away from the center of the bottom plate 17 of the oil pan 15. At the upper end of the strainer body 24, a pair of support portions
51a and 51b are formed. These support portions 51a, 51b are abutted against the boss portion 27 of the lower case 5b, and are fixed to the boss portion 27 via bolts 28a, 28b, respectively.

At the center of the bottom plate 17 of the oil pan 15, a cylindrical boss 52 extending upward is projected. The upper end surface of the boss portion 52 is abutted against the lower surface of one support portion 51a of the strainer main body 24, and the support portion 51a is sandwiched between the boss portion 27. The boss portion 52 has an insertion hole 53 extending in the axial direction. The insertion hole 53 is opened at the upper end surfaces of the bottom plate 17 and the boss portion 52, and a bolt 28a for fixing the one support portion 51a to the boss portion 27 is inserted into the insertion hole 53. Therefore, the bolt 28a is screwed into the boss 27 of the lower case 5b from below the oil pan 15 through the insertion hole 53 and one of the support portions 51a.

Therefore, the bottom plate 17 of the oil pan 15 and the strainer body
The one support portion 51a of 24 is fastened and fixed to the lower case 5b by one common bolt 28a.

According to the configuration of the second embodiment, the bottom plate of the oil pan 15
17 is the lower case 5 of the crankcase 5 through the bolt 28a.
The rigidity of the bottom plate 17 having this large area is increased because the bottom plate 17 is fastened to b. Therefore, even if the vibration of the engine 4 is transmitted to the oil pan 15, the bottom plate of the oil pan 15
17 becomes less likely to vibrate, and noise from the oil pan 15 can be reduced.

Further, since the bolt 28a penetrates through the central portion of the bottom plate 17, the portion of the bottom plate 17 having the lowest rigidity can be connected to the crankcase 5, which is convenient for suppressing vibration of the bottom plate 17. Become.

At the same time, the bolt 28a is connected to the boss 52 and the strainer body 24 that project upward from the bottom plate 17 of the oil pan 15.
And the upper end surface of the boss 52 abuts against the one support 51, so that the bolt 28a is inserted through the insertion hole 53 through which the bolt 28a passes.
Can be isolated from the inside of the oil pan 15.

Therefore, the lubricating oil stored in the oil pan 15 does not enter the penetrating portion of the bolt 28a,
A special seal for preventing oil leakage from the penetrating portion of 8a is not required.

In addition, according to the above configuration, the mounting portion of the bottom plate 15 of the oil pan 15 and the oil strainer 23 to the lower case 5b is shared, so that a dedicated receiving seat for receiving the boss 52 of the oil pan 15 from the lower case 5b. Can be omitted,
A dedicated bolt for fixing the bottom plate 17 of the oil pan 15 can be omitted. Therefore, in addition to the fact that the seal is not required, the number of parts can be reduced, the cost can be reduced, and the troublesome work of incorporating the seal can be omitted.

Further, when the bolt 28a is tightened, the boss 52 is interposed between the bottom plate 17 of the oil pan 15 and one of the support portions 51a of the strainer main body 24. There is an advantage that it can be prevented beforehand.

Incidentally, the mounting structure of the oil pan according to the present invention is 4
The present invention is not limited to the cycle engine, and can be implemented in a rotary engine, for example. In the case of the rotary engine, the housing accommodating the rotor corresponds to the case.

[Effects of the Invention] According to the present invention described in detail above, even if the vibration of the engine is transmitted to the oil pan, the bottom plate of the oil pan is unlikely to vibrate, so that the noise from the oil pan can be reduced. Quiet operation becomes possible.

Moreover, since the bolts for fixing the bottom plate of the oil pan and the case are isolated from the inside of the oil pan by the boss portion, the lubricating oil stored in the oil pan does not enter the penetrating portion of the bolt, and therefore, This eliminates the need for a special seal for preventing oil leakage from the bolt penetration portion. Therefore, the number of parts can be reduced, the cost can be reduced, and the troublesome work of installing the seal can be omitted.

Further, when the bolt is tightened, the boss portion is interposed between the bottom plate of the oil pan and the case, so that deformation of the bottom plate due to excessive tightening of the bolt can be prevented.

In addition, since the oil pan bottom plate and the oil strainer are attached to the bottom of the case in common,
A dedicated seat for receiving the boss of the oil pan from the case can be omitted. At the same time, since the bottom plate of the oil pan and the oil strainer are fixed to the case with common bolts, there is no need for a dedicated bolt for fixing the bottom plate, which also has the advantage of contributing to a reduction in the number of parts.

[Brief description of the drawings]

1 to 4 show a first embodiment of the present invention. FIG. 1 is a sectional view of an oil pan, FIG. 2 is a bottom view of the oil pan, and FIG. FIG. 4 is a side view of a motorcycle, and FIG. 5 is a cross-sectional view of an oil pan according to a second embodiment of the present invention. 5 ... Case (crankcase), 15 ... Oil pan, 17 ... Bottom plate, 22 ... Oil passage, 23 ... Oil strainer, 28a, 38 ... Bolt, 35,52 ... Boss, 51a ... Support.

Claims (1)

(57) [Claims] An oil passage is provided at a bottom of a case where the oil passage is opened.
In an engine in which an aluminum die-cast oil pan having a bottom plate facing the bottom is fixed and an oil strainer connected to the oil passage is accommodated inside the oil pan, a bottom plate of the oil pan is provided from the vicinity of the oil strainer. An upwardly projecting hollow cylindrical boss is integrally formed, a bolt is inserted into the boss from below the oil pan, and the upper end of the boss and the bottom of the case are placed above the oil strainer. A bottom portion of the oil pan is coupled to the bottom of the case by forming a support portion interposed between the bottom portion and the bottom end of the case by screwing the insertion end of the bolt through the support portion and screwing the bottom end of the case. Engine oil storage device.