JPH0213687Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an oil passage for an internal combustion engine valve train that uses the inside of a hollow camshaft as an axial oil passage, and is particularly applicable to a valve train with a latch adjuster. Regarding the structure of a hollow camshaft.

BACKGROUND ART A device that uses a hydraulic lash adjuster in the valve train of an internal combustion engine and supplies lubricating oil to the hydraulic lash adjuster through an axial oil passage inside a hollow camshaft has been known for some time. ing. In these devices, if there are many air bubbles in the lubricating oil supplied to the hydraulic lash adjuster, the hydraulic lifter will cause lift loss (sinking) and cause the valve to make a clicking sound. After centrifuging the lubricating oil in the hollow camshaft, it is supplied to the hydraulic latch adjuster (for example,
Utility Model Publication No. 57-95408, Japanese Patent Publication No. 58-5416, Japanese Patent Publication No. 58-5416
59-39911).

Problems to be Solved by the Invention However, in this method of centrifugal separation within a hollow shaft, oil with a higher bubble rate gathers in the radial direction inside the hollow shaft due to the centrifugal force, and this oil collects on the cam surface, If oil with many bubbles is supplied to the lash adjuster without flowing out to the journal surface, a problem arises in that lift loss causes valve clicking noise as described above.

In order to remove the air after centrifugation, it is possible to make a hole in the center of the downstream end of the hollow camshaft, but this poses the problem of oil also coming out through this hole, so it is not necessary to provide such a hole. It is necessary to supply oil with a low bubble rate to the lash adjuster.

Therefore, the present invention supplies high-quality oil with a low bubble rate to the lash adjuster instead of providing an air bleed, thereby preventing the occurrence of valve knocking noise due to lift loss of the lash adjuster. The purpose is to

Means for Solving the Problems In order to achieve this objective, in the oil passage using the hollow camshaft of the present invention, a hollow camshaft having an outflow hole for supplying oil to the cam surface, journal surface, and latch adjuster is used. of,
Outflow holes other than the outflow holes that supply oil to the lash adjuster are provided with pipes that project inward of the hollow camshaft.

Effect In such an oil passage, as mentioned above, due to centrifugal separation, oil with a high bubble rate exists in the radial center of the hollow shaft, and oil with a low bubble rate exists toward the radial outer circumference. but,
Since oil is supplied to the cam surface and journal surface by flowing out from a pipe protruding inward of the hollow shaft, oil with a high bubble rate is supplied. Then, oil with a low bubble rate is supplied to the lash adjuster from the outer peripheral side of the oil passage in the hollow shaft, that is, from the outflow hole without passing through the pipe, and air intrusion into the lash adjuster is suppressed. Therefore, lift loss of the lash adjuster due to air bubbles is prevented, and the occurrence of valve tapping noise is prevented.

Embodiments Hereinafter, preferred embodiments of an oil passage using a hollow camshaft of the present invention will be described with reference to the drawings.

FIG. 1 schematically shows a first embodiment of the present invention, and FIG. 2 shows an oil supply path to a hollow camshaft of the engine. Oil accumulated in an oil pan 1 is sent from a strainer 2 to a hollow camshaft 6 through an oil pump 3, an oil filter 4, and a main gear rally 5. The inside of the hollow camshaft 6 is used as an oil passage 7 extending in the axial direction, and has a cam surface 8, a journal surface 9, and outflow holes 11, 12, 13 for supplying oil to a hydraulic lash adjuster 10. It is provided.

Among these outflow holes 11, 12, 13, the outflow holes other than the outflow hole 13 to the lash adjuster 10, that is, the outflow holes 11, 12 that communicate with the cam surface 8 and the journal surface 9, are connected to the oil passage of the hollow camshaft 6. 7. Pipes 14 and 15 projecting inward are provided. The pipes 14 and 15 extend toward the center in the radial direction of the cross section of the oil passage 7, and in this embodiment, the protruding lengths of the pipes 14 and 15 are set to be approximately the same.

These pipes 14 and 15 are designed to prevent them from falling off due to centrifugal force and vibrations generated when the hollow camshaft rotates six times. For example, as shown in FIG.
6. A hole 18 with a recess 17 is provided, and the tapered part 1
6, insert a ring 20 made of soft metal, press the ring 20 with a punch 21, and press the outer circumferential surface of the ring 20 against the recess 17 to fix the pipe 19. It is done by twisting. Further, as shown in FIG. 4, the pipe 22 may be fixed with a screw bolt 23. In this method, after the screw bolt 23 is turned and tightened, an impact force is applied to the screw bolt 23 to crush the thread, thereby making the fixation more complete. Furthermore, as shown in FIG. 5, the pipe 24 itself has a threaded portion 25 and a hexagonal hole 26.
It is also possible to provide a screw and screw it in. It may be fixed by any other suitable means.

Further, regarding the pipe provided in the outflow hole and its fixing method, as an applied example, it may be as shown in FIG. 6. FIG. 6 shows the cam 27. In this example, a stepped hole is made in the hollow camshaft 6, a pipe 29 having an elongated hole 28 for oil outflow is inserted, and the pipe 29 is fixed with a ring 30.

In the oil passage configured in this way,
The oil in the oil passage 7 in the hollow shaft 6 is supplied to the hollow camshaft 6 which rotates at 1/2 the engine speed.
Due to rotation, centrifugal force is applied. Due to the centrifugal separation effect, oil with a higher bubble rate gathers toward the center in the radial direction of the oil passage 7, and the bubble rate decreases toward the periphery. Therefore, the distribution of bubble rate is
As shown in the figure, the oil passage 7 has a chevron shape in the radial direction.

Since the pipes 14 and 15 are provided in the outflow holes 11 and 12 for this bubble rate distribution, the oil outflow positions from the oil passage 7 are B and C with respect to the cam surface 8 and the journal surface 9 in FIG. point, and point A for the lash adjuster 10. Therefore, oil with a relatively large number of bubbles flows out onto the cam surface 8 and the journal surface 9, and the lash adjuster 1
0 is supplied with high quality oil with few bubbles.
Therefore, air bubbles are prevented from entering the lash adjuster 10, lift loss is suppressed, and the occurrence of valve knocking noise is suppressed.

Next, FIG. 8 shows a second embodiment of the present invention. In this embodiment, the pipe 31 provided in the outflow hole 11 communicating with the cam surface 8 is set to have a longer protrusion length than the pipe 32 provided in the outflow hole 12 communicating with the journal surface 9. With this setting, as shown in FIG. 9, the lash adjuster 10
The outflow point A to the journal surface 9, the outflow point B to the cam surface 8, and the outflow point C to the cam surface 8 are as shown in the figure. The air escape is difficult in the journal part, but since the cam surface 8 is exposed to the atmosphere, the air escape is sufficient.
By changing the bubble ratio of the supplied oil as shown in the figure, the appropriate amount of oil will be supplied to each part as a result. Other configurations and operations are similar to those of the first embodiment.

Next, FIG. 10 shows a third embodiment of the present invention. In this embodiment, contrary to the second embodiment,
A pipe 33 leading to the journal surface 9 is set to have a longer protrusion length than a pipe 34 leading to the cam surface 8. This is a case where lubrication on the cam surface 8 is given higher priority than on the journal surface 9. However, oil is supplied to the journal surface 9 from point B as shown in FIG. Therefore, the bearing part 35 of the journal has an air bleed hole 3 facing upward.
6 is provided. In this case as well, the best oil is supplied to the lash adjuster 10. Other configurations and operations are similar to those of the first embodiment.

Effects of the invention As explained above, according to the invention, oil from the part of the hollow camshaft oil passage with the lowest bubble ratio can be supplied to the lash adjuster. It is possible to suppress the inclusion of air bubbles, prevent lift loss due to the inclusion of air bubbles, and thereby prevent the occurrence of valve tapping sounds.

Furthermore, in addition to preventing the generation of hammering sounds, the smooth operation of the lash adjuster can be ensured by preventing air bubbles from entering, so that the gap absorption function of the valve train by the lash adjuster can be improved.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an oil passage using a hollow camshaft according to the first embodiment of the present invention, Fig. 2 is a perspective view of an engine showing the oil supply system to the hollow camshaft, and Fig. 3 is a method of fixing the pipe. FIG. 4 is a partial cross-sectional view of a hollow camshaft showing another example of a method for fixing a pipe, and FIG. 5 is a partial cross-sectional view of a hollow camshaft showing another embodiment of a method of fixing a pipe. 6 is a sectional view of the cam portion of the hollow camshaft showing another embodiment of the pipe and the method of fixing the pipe; FIG. 7 is the bubble ratio of the oil passage in the hollow camshaft in the device of FIG. 1. 8 is a sectional view of an oil passage using a hollow camshaft according to the second embodiment of the present invention, and FIG. 9 is a bubble rate distribution diagram of the oil passage in the hollow camshaft in the apparatus of FIG. FIG. 10 is a sectional view of an oil passage using a hollow camshaft according to a third embodiment of the present invention, and FIG. 11 is a bubble rate distribution diagram of the oil passage in the hollow camshaft in the apparatus of FIG. 6...Hollow camshaft, 7...Oil passage,
8...Cam surface, 9...Journal surface, 10...Lush adjuster, 11, 12, 13...Outflow hole, 14, 15, 19, 22, 24, 29, 3
1, 32, 33, 34...pipe, A, B, C...
...Outflow point.

Claims (1)

[Claims for Utility Model Registration] (1) A hollow camshaft with an outflow hole that uses the inside of the hollow camshaft as an axial oil passage and supplies the oil in the oil passage to the cam surface, journal surface, and lash adjuster. An oil passage using a hollow camshaft, characterized in that, in the camshaft, a pipe protruding inward of the hollow camshaft is provided in each of the outflow holes other than the outflow holes that supply oil to the lash adjuster. (2) The hollow camshaft according to claim 1, which is registered as a utility model, wherein the length of the pipe protruding inward from the hollow camshaft is such that the pipe of the outflow hole communicating with the cam surface is longer than the pipe of the outflow hole communicating with the journal surface. Oil passage using. (3) The hollow camshaft according to claim 1, which has been registered as a utility model, wherein the length of the pipe protruding inward from the hollow camshaft is such that the pipe of the outflow hole communicating with the journal surface is longer than the pipe of the outflow hole communicating with the cam surface. Oil passage using. (4) An oil passage using a hollow camshaft according to claim 1, in which the pipe is prevented from falling off.