JPH0634565Y2 - Engine crankshaft lubricating oil reduction structure - Google Patents

Description

[Detailed Description of the Invention] Purpose of the Invention (Industrial field of application) The present invention is designed to rotate between a cylinder block and a crank cap and to support the crank shaft by projecting from the rear wall of the crank cap. The present invention relates to a crankshaft lubricating oil reducing structure for reducing oil leaking from the sliding portion between a wall and a crank cap rear wall and a crankshaft to the outside of the rear wall to an oil pan.

(Prior Art) In an engine in which a crankshaft is rotatably supported between a cylinder block and an integrally-structured crankcap, the rear end of the crankshaft is configured to project from the cylinder block and the rear wall of the crankcap. Cage,
Oil supplied to the sliding portion between the rear wall of the cylinder block and the crank cap and the crankshaft leaks from the sliding portion to the outside of the rear wall. In order to reduce the leaked oil to the oil pan, a retainer that surrounds and seals the peripheral surface of the rear end of the crankshaft protrusion is fixedly attached to the cylinder block and the rear wall of the crank cap, and returns the leaked oil to the oil pan. A reduction chamber is formed for this. The leaked oil introduced into the return chamber is returned to the oil pan below the crank cap through an adjustment gap formed at the joint between the crank cap and the retainer on the lower peripheral edge side of the retainer.

(Problems to be solved by the invention) However, since the peripheral edge of the oil pan is joined to the lower peripheral edge of the retainer and a liquid gasket having high sealing performance is interposed at this joint, In some cases, the gasket may stick out from the joining portion and block the outlet side of the gap provided on the retainer side.
Therefore, there is a problem that the leaked oil collects in the reducing chamber and leaks from the oil seal portion between the crankshaft and the retainer.

Configuration of the Invention (Means for Solving Problems) Therefore, in the present invention, in the reduction chamber forming region of the rear wall of the crank cap that forms the reduction chamber together with the retainer, a region lower than the oil seal portion between the crankshaft and the retainer. A return passage that is open to the return chamber side and communicates with the oil pan side through the rear wall of the crank cap is provided below the oil seal portion.

(Operation) That is, the oil leaked from the sliding portion of the crankshaft and the rear wall of the crank cap and the rear wall of the cylinder block to the reduction chamber side is returned to the oil pan from the reduction passage,
Since the return passage opening to the return chamber is set below the oil seal portion between the crankshaft and the retainer, the liquid level of the oil stored in the return chamber is suppressed below the oil seal portion. Therefore, the oil in the return chamber is reliably returned to the oil pan without leaking from the oil seal portion to the outside. Moreover, since the conventional oil reduction gap is eliminated, the oil seal portion between the retainer and the oil pan can be brought closer to the engine center side, and the engine body and the oil pan can be made compact.

(Embodiment) An embodiment embodying the present invention will be described below with reference to FIGS.

A cylinder block 1 provided with a plurality of cylinder bores 1a (six in this embodiment) for guiding the reciprocating motion of a piston (not shown), and a crank cap 2 which is clamped and joined to the lower end of the cylinder block 1 are all integrally structured. Bearing recesses 6 are formed on the upper surfaces of the partition walls 3, the front wall 4 and the rear wall 5, which partition the plurality of crank chambers 2a on the crank cap 2 side corresponding to the cylinder bores 1a. Cylinder block 1
A similar bearing recess 7 is formed on the side of the cylinder block 1 corresponding to the bearing recess 6 on the side of the crank cap 2.
When the crank cap 2 and the crank cap 2 are fastened and joined together, the pair of upper and lower bearing recesses 7 and 6 correspond to the crank shaft 8 so that the crank shaft 8 can be rotatably supported. At this time, the crankshaft 8 is supported so that its rear end projects from the rear wall 9 of the cylinder block 1 and the rear wall 5 of the crank cap 2 as shown in FIG. A plain bearing 19 is interposed between them.

A fitting recess 9a is formed on the outer surface of the rear wall 9 of the cylinder block 1 so as to surround the bearing recess 7, and a fitting recess 5a also surrounds the bearing recess 6 on the outer surface of the rear wall 5 of the crank cap 2. Retainer 10 is fitted in the fitting recesses 5a and 9a.
Is tightly attached and fixed. When the cylinder block 1 and the crank cap 2 are fastened and joined, the retainers 10 are fastened and joined as shown in FIG. 3, and the retainer 10 and the circumferential surface of the protruding rear end portion 8a of the crankshaft 8 are oiled. The seal 12 is interposed. As a result, a reducing chamber 13 is formed between the rear wall 9 of the cylinder block 1 and the rear wall 5 of the crank cap 2 and the retainer 10.

In the rear wall 5 of the crank cap 2 that forms the return chamber 13, a return passage 14 that opens into the return chamber 13 is provided in a downward slope from the side of the return chamber 13 to the side of the crank chamber 2a, as shown in FIGS. As described above, the inlet 14a on the reducing chamber 13 side is lower than the oil seal 12,
Moreover, it is set outside the bolt holes 5b on the rear wall 5 side through which the pair of left and right bolts 15 for fastening and joining the cylinder block 1 and the crank cap 2 at the rear walls 5 and 9 are inserted. An outlet 14b is formed in the crank chamber 2a.

An oil pan 16 is fastened and joined to the lower end of the crank cap 2, and a joining edge 16a on the rear end side of the oil pan 16 is fastened and joined to the lower end of the retainer 10 via a liquid gasket 17.

Now, part of the oil supplied to the sliding portion between the rear wall 9 of the cylinder block 1 and the rear wall 5 of the crank cap 2 and the crankshaft 8 leaks to the reducing chamber 13 side, and inside the reducing chamber 13 Accumulate in. Since the return passage 14 having a downward slope from the return chamber 13 side to the crank chamber 2a side is set below the oil seal 12, the liquid level height of the oil accumulated in the return chamber 13 when the oil is at rest is equal to the return passage 14 It does not cross the entrance 14a. Therefore, the oil accumulated in the reduction chamber 13 is retained by the retainer.
The oil leaking from the oil seal portion between the crankshaft 8 and the crankshaft 8 does not leak to the outside, and the oil leaking into the return chamber 13 is returned to the oil pan 16 via the return passage 14. Return passage
Since the outlet 14b of 14 is open to the crank chamber 2a away from the joint between the lower side of the retainer 10 and the joint edge 16a of the oil pan 16, the protrusion of the liquid gasket 17 at this joint closes the outlet 14b. The oil in the return chamber 13 is certainly returned to the oil pan 16.

The return passage 14 that is not affected by the protrusion of the liquid gasket 17 does not require the conventional oil return groove provided at the joint portion between the rear wall 5 of the crank cap 2 and the retainer 10, and therefore the retainer 10 and the oil pan 16 are provided. It is possible to bring the oil seal portion of the engine closer to the center of the engine, and it is possible to make the engine body and the oil pan 16 compact.

In general, drilling a hole such as the return passage 14 in the wall on which the load is applied reduces the strength of the wall, but the hole is returned to the outer side between the bolt holes 5b most susceptible to the load applied to the crankshaft 8. By setting the passage 14, it is possible to minimize the reduction in strength of the rear wall 5 that receives the load on the crankshaft 8, and to secure the necessary yield strength performance.

Of course, the present invention is not limited to the above embodiment, and for example, as shown in FIG. 4, a slit-shaped reduction passage 18 from the reduction chamber forming region on the outer surface of the rear wall 5 of the crank cap 2 to the lower edge of the rear wall 5. An embodiment in which the cutout is formed is also possible, and the cutout formation position is set below the oil seal 12 and outside the bolt hole 5b, as in the above-described embodiment. As a result, an oil reducing action similar to that of the above-described embodiment is obtained, and unnecessary reduction in strength of the crank cap 2 is avoided.

Effect of the Invention As described in detail above, according to the present invention, the return passage that connects the return chamber and the oil pan is formed below the crank cap rear wall below the oil seal portion between the retainer that forms the return chamber and the crankshaft. Since it is installed, the oil in the reduction chamber can be reliably returned to the oil pan without leaking from the oil seal part to the outside, and the oil seal part of the retainer and the oil pan can be brought closer to the center part of the engine. It has an excellent effect that the main body and the oil pan can be made compact.

[Brief description of drawings]

1 to 3 show an embodiment embodying the present invention.
FIG. 2 is an exploded perspective view, FIG. 2 is a rear view of an essential part, FIG. 3 is a sectional view taken along line AA of FIG. 2, and FIG. 4 is a longitudinal sectional view of an essential part showing another example of the present invention. Cylinder block …… 1, crank cap …… 2, rear wall …… 5, crankshaft …… 8, protruding rear end …… 8
a, retainer …… 10, oil seal …… 12, reduction chamber …… 1
3, return passage …… 14,18, oil pan …… 16.

Claims (1)

[Scope of utility model registration request] 1. A crankshaft is supported by being rotatable between a cylinder block and a crankcap and protruding from a rear wall of the crankcap, and from a sliding portion of the crankshaft and the rear wall of the cylinder block and the crankcap. In an engine provided with a retainer that forms a reducing chamber that reduces the oil leaking to the outside to an oil pan below the crank cap, the upper end of the engine includes a reducing chamber forming region of the rear wall of the crank cap that forms the reducing chamber together with the retainer. A crankshaft lubricating oil reducing structure for an engine, wherein a reducing passage opening to a reducing chamber in a region lower than an oil seal portion between the crankshaft and the retainer and having a lower end communicating with an oil pan is formed through the rear wall of the crank cap.