JPH0238090Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a crankshaft lubrication device.

[Prior art]

FIG. 2 shows a conventional lubricating device for a crankshaft in a two-stroke engine.

In this engine, the outer wall 1 of the crankcase 1
A hole 5 for an oil passage is bored from a toward the inner circumferential surface 4a of the bearing holding portion 4 of the crankcase 1 where the bearing 2 and oil seal 3 are held. Further, a union bolt 6 is fitted into the outer end opening 5a of the hole 5. In this engine, the union bolt 6 and an oil pump (not shown) are connected by an oil tube or the like, and oil is pumped from the oil pump to the union bolt 6 by the oil tube or the like.
The lubricant is supplied to the lower inner peripheral surface of the bearing holding portion 4 through the hole 5 to lubricate the crankshaft 7.

By the way, in the crankshaft lubricating device formed in this engine, as described above, although the crankshaft 7 is sufficiently lubricated by the oil pumped by the oil pump, an oil reservoir is formed in the crank chamber 8. As a result, there was a problem in that the space capacity within the crank chamber 8 was reduced. Furthermore, in this lubricating device, a long and narrow hole 5 had to be bored in the crankcase 1, making the machining work difficult.

On the other hand, FIG. 3 shows another lubricating device for a two-stroke engine. In this engine, a bearing holding portion 12 of a crankcase 11 is provided with a hole 14 that communicates an inner circumferential surface 12a of the holding portion 12 with a scavenging passage 13.

In this engine, the oil supplied together with the air-fuel mixture into the crank chamber 15 is
5 is supplied to the lower inner circumferential surface of the bearing holding portion 12 through the scavenging passage 13 and the hole 14, and the crankshaft 16 is lubricated by the supplied oil.

In the above-mentioned lubricating device, since the hole 14 extends in the axial direction of the cylinder, the hole 14 can be drilled at the same time as the cylinder block mounting bolt holes and the like are formed in the crankcase 11. However, as mentioned above, since the crankshaft 16 is lubricated by the oil mixed in the air-fuel mixture, the amount of oil supplied to the crankshaft 16 is generally small, and as a result, the durability of the bearing 17 is reduced. It was also a cause of mechanical noise.

[Purpose of invention]

In view of the above circumstances, the present invention aims to provide a crankshaft lubrication device that can appropriately lubricate the crankshaft without forming an oil pool in the crank chamber, and is also easy to machine. do.

[Structure of the idea]

In order to achieve the above object, in the present invention, a mixture passage is bored in the bearing holding part of the crankcase to communicate the inner peripheral surface of the bearing holding part with the scavenging passage, and the outer surface of the bearing holding part is An oil passage that communicates with the mixture passage and the mixture passage is bored approximately perpendicular to the mixture passage, and an oil pump is connected to the oil passage to forcefully feed oil, thereby lubricating the crankshaft. ing.

〔Example〕

Hereinafter, the present invention will be described with reference to an embodiment shown in the drawings.

FIG. 1 shows a two-stroke engine equipped with a crankshaft lubrication device according to the present invention.

In this engine, the bearing holding portion 22 of the crankcase 21 has an inner circumferential surface 22 of the holding portion 22.
A mixture passage 24 is provided which communicates the scavenging passage 23 with the scavenging passage 23. Further, in this engine, an oil passage 25 is arranged so as to be substantially perpendicular to the mixture passage 24 from the outer surface 22b of the bearing holding portion 22.
is formed. Further, a union bolt 26 is fitted into the outer end opening 25a of the oil passage 25. In this engine, the union bolt 26 and an oil pump (not shown) are connected by an oil tube or the like.
Here, as is clear from the figure, the mixture passage 24 extends along the axial direction of the cylinder, in other words, substantially perpendicular to the dividing plane between the crankcase 21 and the cylinder block. Therefore, the air-fuel mixture passage 24 can be bored at the same time as the cylinder block mounting bolt holes are formed in the crankcase 21.

Further, since the oil supply passage 25 extending substantially orthogonally to the mixture passage 24 is relatively short as shown in the figure, it can be easily drilled.

In the crankshaft lubrication device for a two-stroke engine configured in this way, oil pumped by the oil pump is fed into the mixture passage 24 via the aforementioned oil tube (not shown), union bolt 26 and oil passage 25. is supplied to On the other hand, in this engine, a part of the air-fuel mixture that is primarily compressed in the crank chamber 27 is transferred to the scavenging passage 23.
The mixture flows into the air-fuel mixture passage 24 through the air-fuel mixture.

Therefore, in this crankshaft lubrication device,
The oil supplied from the oil passage 25 into the mixture passage 24 is diluted by the mixture and supplied to lubricate the crankshaft 28.

[Effect of idea]

As explained above, according to the crankshaft lubrication device according to the present invention, the oil pumped by the oil pump is diluted by the air-fuel mixture flowing in from the scavenging passage and then supplied to the crankshaft. Therefore, even if a sufficient amount of oil is supplied to lubricate the crankshaft, no oil pool will be formed in the crank chamber, and it is also necessary to drill a long, thin hole in the crankcase during machining. Since there is no material, machining is easy.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a two-stroke engine equipped with a crankshaft lubrication device according to the present invention, and FIGS. 2 and 3 are two-stroke engines equipped with a conventional crankshaft lubrication device.
FIG. 2 is a vertical cross-sectional view of main parts of a cycle engine. 21...Crankcase, 22...Bearing holding portion, 22a...Inner peripheral surface, 22b...Outer surface,
23...Scavenging passage, 24...Mixture passage, 25...
...Oil passage, 26...Union bolt, 27...
...Crank chamber, 28...Crankshaft.

Claims (1)

[Scope of claim for utility model registration] The oil in the oil tank is pumped to the bearing holding part of the crankcase,
A crankshaft lubricating device configured to lubricate a crankshaft, comprising: a mixture passage bored in a bearing holding part of the crankcase and communicating an inner circumferential surface of the bearing holding part with a scavenging passage; The bearing holding part is provided with an oil passage that is bored substantially orthogonally to the mixture passage and communicates the outer surface of the bearing holding part with the mixture passage, and an oil pump is connected to the oil passage. A crankshaft lubricating device characterized by: