JPH0355769Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an improvement of a hydraulic lifter in a valve operating system for an internal combustion engine that transmits a valve operating command from a cam to an intake/exhaust valve using hydraulic pressure and elastic force of an elastic member. .

Generally, a hydraulic lifter is supplied with hydraulic oil from an oil supply path provided in the engine block, but in order to maintain the normal operation of this hydraulic lifter, the hydraulic oil must always be kept clean and free from air. Efforts are being made to suppress this as much as possible. The present invention relates to this technical improvement.

Prior Art Fig. 3 shows a conventional example of a valve train having a hydraulic lifter, in which 1 is a rocker arm, 2 is a valve, and 3 is a valve train having a hydraulic lifter.
is a valve spring, 4 is a cam, and 5 is a hydraulic lifter. The details of the hydraulic lifter 5 are shown in FIG. 4, in which the body 51 has an open end 51a at the top and a closed end 51 at the bottom.
A hollow cylindrical body with a bottom and a hollow plunger 52 is fitted therein, and has a portion 52a extending outwardly from the body, and a push rod socket 53 is provided connected to the portion. There is. Hyperbaric chamber 54
is formed between the closed end 51b of the body 51 and the plunger 52, and an elastic body 55 is located within the high pressure chamber 54 to bias the plunger 52 outward from the body 51. Further, from the oil passage 6 shown in FIG.
c and the slit 53a provided on the end face of the push rod socket 53 to supply hydraulic oil to the oil reservoir chamber 56.
I try to guide myself inward. Further, a check valve 58 for controlling the opening and closing of the oil hole 57 between the oil reservoir chamber 56 and the high pressure chamber 54, and a check valve cage 59 for holding the check valve are provided in the high pressure chamber 54.

Problems to be Solved by the Invention In order to maintain normal operation of the hydraulic lifter 5, it is necessary to prevent dust from entering the hydraulic oil supplied to the hydraulic lifter from the oil supply path 6. If dirt is mixed in, there is a risk that this dirt will be caught between the check valve 58 and the check valve seat, causing an unexpected situation in which the operation of the plunger 52 will stop. Furthermore, if air is mixed into the hydraulic fluid, it will be introduced into the high pressure chamber 54, significantly reducing the rigidity of the chamber, resulting in an increase in valve lift loss. Furthermore, when the engine is stopped, as shown in FIG. 5, the hydraulic oil in the oil passage 6 flows back, and at the same time, the hydraulic oil in the hydraulic lifter 5 remains until it reaches the outer end 52a of the plunger 52. The rest will flow back. If the internal combustion engine is restarted under such conditions, there is a risk that air will be sucked in. This results in problems such as inducing noise generation when the valve is seated due to the resulting large valve lift loss.

Means for Solving the Problems The present invention has been made to solve these problems, and the push rod socket 53 is formed into a bottomed cylindrical shape with a downward opening, and the lower end of the opening is connected. An oil reservoir chamber 56 is provided inside the bottomed hollow plunger 52, and the push rod socket 53
By providing a structure in which an oil hole 53b, an oil passage 53d, and an oil groove 53c are provided in order from below on the outer periphery together with the slit 53a at the lower end, and an oil receiver 57 is provided above the push rod socket 53. ,
The hydraulic lifter itself has a filter function, and
Hydraulic oil is not supplied from outside the hydraulic lifter, and the hydraulic oil contained in the hydraulic lifter is used without leaking to the outside.

Operation In a configuration in which the high pressure chamber 54 and the oil reservoir chamber 56 are filled with sufficiently cleaned hydraulic oil in advance when the plunger 52 is displaced outward to the maximum extent, the operation in the high pressure chamber 54 when the plunger 52 contracts A portion of the oil passes between the outer periphery of the plunger and the inner periphery of the body, passes through the slit 53a provided between the plunger 52 and the push rod socket 53, and enters the oil reservoir chamber 56 therein.
Move to. The amount of oil corresponding to this amount of movement overflows from the outer end of the plunger containing the oil reservoir, passes between the outer periphery of the push rod socket 53 and the inner periphery of the body, and reaches the upper surface of the push rod socket. reach
At this time, if there is air mixed in the hydraulic oil, it will escape. When the plunger moves in the direction of expanding the high pressure chamber from this state, the hydraulic oil in the oil reservoir chamber enters the high pressure chamber through the opened check valve, and the hydraulic oil that overflows outside the oil reservoir chamber 56. Return to
In this way, it is possible to use the internal clean hydraulic oil without requiring an external supply of oil, and to release the entrained air into the atmosphere together with the overflowing oil during the operating cycle.

Further, since the space between the outer periphery of the push rod socket and the inner periphery of the body itself has a mechanical filter function, there is no need to provide a new filter.

Embodiment Figure 1 shows a hydraulic lifter that is an example of implementing the present invention.
Reference numeral 51 indicates a body, which is a bottomed hollow cylindrical body having an open end 51a at the upper part and a closed end 51b at the lower part, a plunger 52 is fitted in the hollow thereof, and has a part 52a extending outward from the body. A push rod socket 53 is provided connected to the section. The high pressure chamber 54 has an elastic body 55 formed between the closed end 51b of the body 51 and the plunger 52, which is located within the high pressure chamber 54 and urges the plunger 52 outward from the body 51. There is.

When the plunger 52 contracts from a state in which the high pressure chamber 54 and the oil reservoir chamber 56 are filled with hydraulic oil when the plunger 52 is displaced outward to the maximum extent, a portion of the hydraulic oil in the high pressure chamber reaches the plunger outer periphery 52a. It passes between the inner circumference 51c of the body and is led to the oil reservoir chamber 56 through a slit 53a provided at the lower end of the push rod socket 53. As a result, the pressure in the oil reservoir chamber 56 increases, and a portion of the hydraulic oil in the chamber overflows to the outside through the oil hole 53b provided above the push rod socket 53, causing the pressure in the oil reservoir chamber 56 to rise. Butt 5
Oil passage 53d and oil groove 53 provided on the outer periphery of 3
c, passes through a gap 53e between the inner circumference of the body and the outer circumference of the plunger, and reaches the oil pan 57 defined by the inner circumference of the body 51 and the upper surface of the push rod socket 53. At this time, if air is mixed in the oil reservoir chamber 56, when it reaches the oil receiver 57 together with some of the overflowing hydraulic oil, it will be dissipated into the atmosphere. 60 is push rod.

When the plunger 52 extends from this state, the high pressure chamber 54 expands and the pressure in this chamber and the oil reservoir chamber 56 becomes negative.
3c, the oil is led to the oil reservoir chamber 56 through the oil passage 53d and the oil hole 53b, and the oil reservoir chamber 56 and the high pressure chamber 54 are filled with oil.

As described above, when the plunger expands and contracts in accordance with the movement of the valve mechanism, hydraulic oil flows between the oil receiver 57, the oil reservoir chamber 56, and the high pressure chamber 54.

Since the oil receiver 57 is open outward, it always receives the lubricating oil inside the engine like a saucer.
Therefore, there is no risk that the hydraulic lifter will run out of oil. Furthermore, even if the oil thus received contains dirt, it is mechanically filtered when passing through the space 53e formed between the inner circumference of the body 51 and the outer circumference of the push rod socket 53. The hydraulic oil is in a clean state when it is introduced into the oil sump chamber.

Effects of the invention According to the invention, the hydraulic oil can be kept clean at all times due to the self-cleaning function of the hydraulic lifter, and since there is no external oil passage connected to the hydraulic lifter, there is no return of the built-in hydraulic oil to the outside. As a result, the required amount of oil can always be ensured, so there is no risk of air inhalation. Even if air is mixed in, the mixed air can be released into the atmosphere during the overflow process of the hydraulic oil from the oil sump chamber, so a hydraulic lifter that always maintains its rigidity can be used with high reliability.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one example of implementing the present invention;
3 is an explanatory diagram showing the arrangement of the hydraulic lifter, FIG. 4 is a sectional view showing a conventional example, and FIG. 5 is an explanatory diagram showing the arrangement thereof. The symbols in the drawings indicate the following members, respectively. 5...
Hydraulic lifter, 51...Body, 52...Plunger, 53...Push rod socket, 54...
High pressure chamber, 55...Elastic body, 56...Oil reservoir chamber, 57
...Oil pan, 58...Check valve, 59...
Check valve cage, 60...Push rod.

Claims (1)

[Scope of utility model registration request] A hollow cylindrical body 51 with a bottom, and a hollow plunger 52 with an oil hole at the bottom and slidably fitted into the body to form a high pressure chamber 54 between the inner surface of the bottom and the inner surface of the bottom. , an elastic body 55 provided in the high pressure chamber and urging the plunger to move away from the opening end of the body; a check valve 58 also provided in the high pressure chamber controlling opening and closing of the oil passage hole; A check valve cage 59 that holds a check valve, and a bottomed cylinder with a downward opening that is slidably fitted into the body and is located such that the lower end of the opening is connected to the open end of the plunger. push rod socket 53,
an oil reservoir 57 defined by the push rod receiving side surface of the push rod socket and the inner peripheral surface of the body; and an oil reservoir chamber 56 defined by the plunger and the push rod socket. The push rod socket has one or more slits 53a on the lower end surface, and one or more oil holes 53 communicating with the oil reservoir chamber on the upper side surface.
b, and the push rod socket is provided with an oil groove 53c on the side surface closer to the oil receiver than the oil hole.
A hydraulic lifter characterized in that an oil passage 53d connecting the oil hole and the oil groove is further provided on the outer periphery.