JPS595820A - Oil pan structure - Google Patents

Abstract

PURPOSE:To improve a starting performance at a low temperature, by providing a buffle at an area between an oil pan and a crankcase, and a lead valve at the underside of buffle, in an engine to be installed with an inclination. CONSTITUTION:A buffle 10 is provided at an area between an oil pan 4 and a crankcase 1, and at the underside thereof a lead valve 11 is provided, which is opened by the actuation of pulsating pressure in the crankcase 1 and transfers an oil into the oil pan 4. A partition wall 12 has a passage 13 formed at one side thereof for communicating with the lead valve 11 and an oil chamber 14 formed at the other side thereof for collecting an oil therein overflowed from the passage 13. During the engine operation, the level of oil in the crankcase 1 is lowered for causing balance shafts 5, 6 and a crankweb 8 to reduce their agitating and upward scratching of oil. While an engine remains in recess, this condition is maintained as it is, and whereby facilitating to start an engine at a lower temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention particularly relates to an oil pan structure for an engine equipped with a two-shaft balancer that is mounted at an angle because the height of the engine mounting portion is regulated.

In this type of engine, for example, as shown in Fig. 1, a crankcase 1, a cylinder head 2 at the top, a rocker cover 3 with a valve mechanism, and an oil pan 4 at the bottom of the crankcase are installed in an inclined manner. . 4-stroke, 2-cylinder] A two-axis balancer used to cancel out the primary excitation force caused by the reciprocating mass of pistons, etc. in carrots.
5.6 are disposed on both sides of the crankshaft 7 in the crankcase 1, that is, above and below the crankshaft 7.

Therefore, lubricating oil is stored not only in the oil pan 4 but also in the lower part of the crankcase 1, and the lower balance shaft 6 is almost completely submerged in this oil, and the crankshaft 7 1 and <. Further, the oil that has lubricated the valve mechanism inside the rocker cover 3 falls down the oil return passage 9 under its own weight and returns to the inside of the crankcase 1;
Since the outlet of the rocker cover 3 is blocked by the oil scraped up by the balancer shaft 6 and the web 8 of the crankshaft 7, a large amount of oil accumulates inside the rocker cover 3, causing problems such as oil blowing.

In view of these circumstances, the present invention lowers the oil level on the crankcase side during engine operation to reduce oil agitation and scraping up by the balancer shaft and crank web, and maintains this state even when the engine is stopped and the vehicle is parked. The purpose of the present invention is to provide an oil pan structure that improves startability at low temperatures and prevents various problems on slopes.

For this purpose, the oil pan structure according to the present invention focuses on the fact that pulsating pressure due to the reciprocating movement of the piston exists in the crankcase, and partitions the oil pan from the crankcase with a baffle having a reed valve. uses pulsating pressure in the crankcase to move the oil there to the oil pan side after the baffle, and in the oil pan, an oil chamber is provided for the passage communicating with the reed valve by a partition wall,
While the vehicle is parked, oil is stored in this oil chamber to maintain the oil level in the crankcase at a low level.

Incidentally, as a prior art related to the present invention, for example,
- There is a publication No. 114305, which is aimed at engines mounted vertically, and has a check piece installed between the crankcase and oil pan. This prevents the backflow of oil from the oil pan side of the oil pan, and the objective, function and effect are different from the present invention, and the structure is only partially similar.

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In this configuration, a baffle 10 is provided between the oil pan 4 and the crankcase 1 to partition the two, and a reed valve 11 is installed at the bottom of the baffle 10 to prevent pulsation in the crankcase 1 caused by the reciprocating movement of the piston. Installed to open only in case of positive pressure.

In addition, inside the oil pan 4 partitioned by the baffle 10,
A partition wall 12 is erected from the bottom along the baffle 10 to a predetermined height, and a reed valve 1 is installed on one side of the partition wall 12.
1 and an oil chamber 14 is formed on the other side, and when the reed valve 11 is opened, the oil pan 4 is opened.
The oil guided to the side overflows the passage 13 and is stored in the oil chamber 14.

In this way, since the lubricating oil accumulates in the oil chamber 14, a strain 15 is provided in the oil chamber 14 when the oil is pumped up by the oil pump.

Furthermore, when the reed valve 11 opens, the blow-by gas in the crankcase is also guided to the oil pan 4 side and accumulates in the upper part of the oil pan 4, so the blow-by gas flows from the upper part of the oil pan 4 to the oil separator 16 of the rocker cover 3. gas passage 1
1 is set consecutively.

Because of this configuration, during engine operation, positive and negative pulsating pressure is generated in the crankcase 1 due to the reciprocating movement of the piston, and when the pulsating pressure is positive, the reed valve 11 opens and the crankcase 1 is Transfer the oil to the oil pan side. Therefore, the oil that enters the oil pan 4 from the strainer valve 11 rises in the passage 13, overflows from there, and accumulates in the oil chamber 14. It is pumped up and supplied to various parts for lubrication. On the other hand, the oil returned to the crankcase 1 through the oil return passage 9 etc. after lubrication is transferred to the oil pan 4 by the above-mentioned pump action.
In this way, the oil passes through the crankcase 1 without accumulating and circulates, and as a result, the oil level in the crankcase 1 and oil pan 4 reaches the solid line in the figure. Therefore, it is at a lower position than the reed valve 11 in the crankcase 1, and the balancer shaft 6 at the lowest position is slightly submerged in the oil, leaving a mark.

Next, when the engine is stopped and the vehicle is parked, the oil level in the oil pan 4 is in the state shown by the dashed line B in the figure, and the reed valve 11 is
is in a closed state, but in addition to the fact that the sealing performance of the reed valve is not always sufficient, pressure due to the weight of the oil on the oil pan 4 side acts, so the oil on the oil pan 4 side closes the reed valve. It leaks from the gap 11 and flows back to the crankcase 1 side. Here, reed valve 11
communicates only to the passage 13, and since this passage 13 is partitioned off from the oil chamber 14 by the high partition wall 12, the oil only leaks approximately from the passage 13. Therefore, the oil level in the crankcase 1 in this case is maintained at a position that is slightly higher than during the engine operation, as indicated by the dashed line B in the figure.

As is clear from the above description, according to the present invention, in an engine that is mounted tilted and further has a balancer shaft 6 disposed below the crankshaft 7, the pulsating pressure generated in the crankcase 1 is utilized during engine operation. to drain the oil and
Since the curved surface is kept low, stirring resistance and oil scraping of the web 8 of the crankshaft 7 and the balancer shaft 6 are significantly reduced, and problems associated with this are reduced. Even when the engine is stopped and parked, the oil level in the crankcase 1 is only slightly higher than when the engine is running, so the stirring resistance of the balancer shaft 6 when restarting is small, making it easier to start in low humidity such as in winter. Improves sex. Further, when the engine is further tilted such as when parking on an uphill slope, backflow of oil to the rocker cover 3 and excessive oil rising into the combustion chamber can be prevented. Since the oil is collected at a sufficient height in the oil chamber 14, the strainer 15 is prevented from being exposed and the oil can be reliably pumped up.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view schematically showing a conventional oil pan structure.
FIG. 2 is a sectional view showing an embodiment of the oil pan structure according to the present invention. 1... Crank case, 2... Cylinder head, 3
...rocker cover, 4...oil pan, 5,6...
・Balancer shaft, 7... Crankshaft, 8... Web,
9...Oil return passage, 10...Baffle, 11.
... Reed valve, 12 ... Partition wall, 13 ... Passage,
14...Oil chamber, 15...Strainer, 16...
・Oil separator, 11... blow-by gas passage. Patent applicant Fuji Heavy Industries Co., Ltd. Representative Patent Attorney Jundo Kobashi Patent Attorney Susumu Murai

Claims (1)

[Claims] For engines mounted at an angle, a baffle is installed between the oil pan and the crankcase to separate the oil pan, and a reed valve is installed at the bottom of the baffle to open with pulsating pressure in the crankcase and send the oil to the oil pan. A partition wall is erected from the lower part of the oil pan along the baffle, and a passage communicating with the reed valve is formed on one side of the partition wall, and the use thereof is to collect oil that overflows through the passage. An oil pan structure characterized by the formation of an oil chamber.