JPH0545766Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an oil supply device for a crank pin in an internal combustion engine.

<Prior Art> As shown in FIG. 4, which shows a cross section of a crankshaft side end support portion representing a conventional crankpin oil supply device, a crankshaft 1 of an internal combustion engine is supported by a crankcase 2. There is a certain gap S at the side end of the cover 3 of the crankcase 2.
It is rotatably held with the An oil reservoir 4 is formed between the side end surface 1a of the crankshaft 1 and the cover 3, and the crankshaft 1 is provided with an oil passage 5 communicating with the crank pin side. The crank pin is supplied with oil by supplying pressure oil to the oil reservoir 4 and passing the oil through the oil passage 5.

<Problems to be solved by the invention> In the oil supply device described above, if the gap S between the side end of the crankshaft 1 and the cover 3 is too large, pressure oil will flow from the gap S and sufficient pressure oil will not be in the oil passage 5. The supply will run out. Also, if the gap S is too small,
The rotation of the crankshaft 1 becomes heavy, and particularly in the case of a hand-cranked internal combustion engine, starting performance becomes poor and output loss occurs. If a load is applied to the crankshaft 1 and the crankshaft 1 is deformed, seizure may occur. In this way, the dimension of the gap S must be maintained with high precision, but since the crankshaft 1 and the cover 3 are assembled using multiple parts such as bearings, the crankshaft 1 and the cover 3 must be
Positioning accuracy control has become extremely difficult. In some cases, an elastic body is attached to the inside of the cover 3, and the inner periphery of the elastic body holds the outer periphery of the side end of the crankshaft 1 to facilitate positioning accuracy control between the crankshaft 1 and the cover 3. but,
The use of an elastic body is limited to those in which the crankshaft 1 has a small diameter.

This invention was developed in view of the above situation, and it is possible to maintain an appropriate gap between the crankshaft and the crankcase side through easy positioning accuracy control, and is suitable for crank pin lubrication in internal combustion engines that is not limited by the diameter of the crankshaft. The object of the present invention is to provide a device that facilitates ensuring sealing between the crankshaft and crankcase, properly lubricating the crank pin, and prevents output loss of the crankshaft.

<Means for Solving the Problems> The structure of the present invention to achieve the above object is to form an oil reservoir between the side end surface of the crankshaft and the crankcase side, and from the side end surface to the inside of the crankshaft. An oil supply device that supplies pressurized oil from an oil reservoir to a crank pin through a provided oil passage, the outer peripheral surface of which is movably fitted into a fitting hole formed on the crankcase side in an oil-tight manner. a ring-shaped seal having a hole opening in the oil passage formed at the bottom, and whose bottom surface is closely locked to the side end surface of the crankshaft by the pressure of the pressure oil when pressure oil is supplied to the oil reservoir; It is characterized by comprising a member.

<Operation> By supplying pressurized oil to the oil reservoir, the sealing member, which is movable and fitted in an oil-tight state into the fitting hole formed on the crankcase side, is moved to the crankshaft side by the pressure of the pressurized oil. The seal member is closely fixed to the end face and rotates together with the crankshaft with an appropriate gap. The pressure oil presses the seal member against the crankshaft and is sent from the hole in the seal member to the crank pin through the oil passage.

<Example> Fig. 1 shows a cross section of a crankshaft side end support showing a crank pin oil supply device according to an embodiment of the present invention, Fig. 2 shows an enlarged state of the arrowed part in Fig. 1, and Fig. The figure shows a cross section showing the crankshaft support structure.

In Fig. 3, 11 is the crankshaft;
The crankshaft 11 is rotatably supported by a crankcase 13 via a main bearing 12. A crank pin 14 is formed in the crankshaft 11, and a side end 1 is formed inside the crankshaft 11.
An oil passage 15 is formed from 1a to the crank pin 14. On the other hand, as shown in FIG. 1, the crankcase 13 at the side end 11a of the crankshaft 11 has
A cover 17 forming an oil reservoir 16 between the cover 17 and the cover 17 is fixed with bolts 19 via a bush 18. A ring-shaped sealing member 20 is loosely fitted into the fitting hole 17a formed in the cover 17 with the outer peripheral surface of the fitting hole 17a having a gap C (3/100 to 9/100 mm) (see FIG. 2). The seal member 20 is provided with a hole 20a that opens to the oil passage 15. The amount of the gap C is such that the seal member 20 can slide inside the fitting hole 17a and the pressure oil in the oil reservoir 16 will not leak. By supplying pressure oil to the oil reservoir 16, the bottom surface 20b of the seal member 20 is brought into contact with the side end surface 11b of the crankshaft 11 due to the pressure P of the pressure oil.
The seal member 20 rotates together with the crankshaft 11 while maintaining a gap C between the cover 17 and the crankshaft 11.

In the above configuration, during engine operation, the sliding portion of the crank pin 14 is supplied with lubricating oil separated by the lubricating oil system of the engine as pressure oil through the oil reservoir 16, the hole 20a of the seal member 20, and the oil passage 15. At this time, the bottom surface 20b of the seal member 20 is closely locked to the side end surface 11b of the crankshaft 11 due to the pressure P from the oil reservoir 16, and the
The side end portion 11a of the cover 1 is rotatably held by the cover 17 with a gap C through the seal member 20 while maintaining an appropriate sealing property. That is, since there is a gap C between the cover 17 and the seal member 20, the seal member 20 is free to move in the axial direction and radial direction of the crankshaft 11, and relative assembly errors of each member are avoided. is absorbed, and the crankshaft 11 always remains freely rotatable with respect to the cover 17.

<Effects of the invention> In the crank pin oil supply device for an internal combustion engine of the present invention, the sealing member is fitted to the crankcase side so that it can move freely in the axial and radial directions of the crankshaft, making it easy to control positioning accuracy. A proper clearance can be secured between the crankshaft and the crankcase side, and the crankshaft can be used from small to large diameter crankshafts.
As a result, even if there is a certain degree of relative assembly error between the members, the sealing performance between the crankshaft and the crankcase can be maintained properly, and the crank pin can easily be properly lubricated. Furthermore, since the friction torque of the crankshaft is always minimal, loss of output of the crankshaft is prevented.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a crankshaft side end support showing a crankpin oil supply device according to an embodiment of the present invention, FIG. 2 is an enlarged view of the arrowed part in FIG. 1,
FIG. 3 is a sectional view showing a crankshaft support structure, and FIG. 4 is a sectional view of a crankshaft side end support portion showing a conventional crankpin oil supply device. In the drawing, 11 is a crankshaft, 11a is a side end, 11b is a side end surface, 13 is a crankcase,
14 is a crank pin, 15 is an oil passage, 16 is an oil sump,
17 is a cover, 20 is a sealing member, 20a is a hole,
20b is the bottom surface, and C is the gap.

Claims (1)

[Scope of utility model registration request] An oil supply device that forms an oil reservoir between a side end surface of a crankshaft and a crankcase side, and supplies pressurized oil from the oil reservoir to a crank pin from the side end surface through an oil passage provided inside the crankshaft, The outer circumferential surface is movably and oil-tightly fitted into a fitting hole formed on the crankcase side, and a hole opening into the oil passage is formed in the lower part, and pressure oil is supplied to the oil reservoir. 1. A crankpin oil supply device for an internal combustion engine, comprising a ring-shaped seal member whose bottom surface is closely locked to a side end surface of the crankshaft by the pressure of the pressure oil when supplied.