JPS6153533B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic lifter disposed in a valve train of an internal combustion engine, and more particularly, to a hydraulic lifter having a mechanism for preventing hydraulic oil in a reservoir of the hydraulic lifter from flowing out. .

The hydraulic lifter is used during the operation of the internal combustion engine valve mechanism.
Valve clearance is always maintained at a predetermined value, ensuring stable operation of the valve mechanism without being affected by changes in ambient temperature. Various types of hydraulic lifters have been developed to provide such functions, one of which uses silicone oil that has better low-temperature properties than engine oil and has a high compression ratio, and is In order to be able to follow the large volume change in the pressure chamber when the engine starts,
A hydraulic lifter is provided having a passage communicating the reservoir with the atmosphere. In a hydraulic lifter that communicates the reservoir with the atmosphere, changes in pressure caused by changes in volume of the reservoir caused by the operating stroke of the Fulcrum or changes in ambient temperature may adversely affect the sealing means for the sealed oil. It is widely used because it does not give However, the hydraulic lifter having such advantages is difficult to use when the hydraulic lifter is removed from the valve mechanism and stored, or when it is supplied as a spare part.
There is a risk that the passage connecting the reservoir and the atmosphere may cause the sealed oil to leak to the outside. This leakage of sealed oil prevents normal operation of the hydraulic lifter when it is incorporated into a valve mechanism, and causes noise in the well-known internal combustion engine and a reduction in its output.

The present invention was developed with attention to the above-mentioned points, and an object of the present invention is to provide a hydraulic lifter having a mechanism for preventing the hydraulic oil in the reservoir from flowing out.

Embodiments of the invention will be described with reference to the accompanying drawings.

The hydraulic lifter 1 has a cylindrical body 3 having a bottom wall 2, and a plunger 4 is disposed within the body 3 so as to be able to reciprocate. A fulcrum 5 is provided at the upper part of the plunger 4, and a check valve 6 is arranged at the lower part thereof. The plunger 4 has a reservoir chamber 7 therein, and a pressure chamber 9 is located between the bottom wall 8 of the plunger 4 and the bottom wall 2 of the body 3.
is defined. Communication between the reservoir chamber 7 and the pressure chamber 9 is controlled by a check valve 6. The plunger 4 receives the biasing force of the first spring 10 via the retainer 11 and is biased in one direction, but its movement is restricted by a ring 12 fixed to the upper part of the inner wall of the body 3. In addition, the plunger 4 is a Fulcrum 5 that cooperates with the Rocker arm.
Due to the downward movement of the body 3, it descends with a leak clearance 13, but this movement is caused by the stopper 1 provided on the lower inner wall of the body 3.
4.

A check valve 6 for controlling the opening and closing of a central aperture 15 in the bottom wall 8 of the plunger 4 has a ball valve 17 within the retainer 11 that is biased by a second spring 16. The ball valve 17 is always urged by the second spring 16 and closes the central opening 15.

Passages 18 and 19 are formed in the fulcrum 5, and the passage 18 is connected to the upper passage 2 of the plunger 4.
0 through a passage 21. That is, when the plunger 4 descends from a state where the upper part of the plunger 4 is in contact with the ring 12 and communication between both passages 20 and 21 is cut off, the ring 1
2 and the upper part of the plunger 4 are in a non-contact state, and the outside and the reservoir chamber 7 are in communication via the passages 20, 21, 18, and 19.

The ring 12 is press-fitted into the inner wall of the body 3, and a sealing material made of synthetic rubber or the like is fixed to the inner circumferential surface and the lower wall surface which abuts the upper part of the plunger 4. The part of the plunger 4 that comes into contact with the ring 12 is a stepped portion 22 provided on the plunger 4, and an annular space 23 is formed below this stepped portion 22 between the inner wall surface of the body 3 and the outer wall surface of the plunger 4. I'll do what I do. This annular space 23 communicates with the passage 20 and passes through the leak clearance 13 to the pressure chamber 9.
It functions to return silicone oil, ie, working oil, flowing back from the reservoir chamber 7 to the reservoir chamber 7. An annular space 24 is also provided between the inner peripheral wall of the ring 12 and the outer peripheral surface of the Fulcrum 5.

As shown in FIG. 1, when no external force acts on the Fulcrum 5, the biasing force of the first spring 10 pushes the plunger 4, and the stepped portion 22 comes into contact with the sealing material of the ring 12, both annular spaces 23 , 24 are completely cut off from communication. That is, both passages 20,
The communication with 21 is cut off. For this reason,
When the hydraulic lifter is removed from the internal combustion engine or is being transported as shown in FIG.
is completely isolated from the atmosphere, there is no leakage of the hydraulic oil sealed in the reservoir chamber, and when the hydraulic lifter is attached to the valve operating mechanism of an internal combustion engine and the Fulcrum is pushed down, the specified operation can be obtained.

In the example shown in FIG. 2, the fulcrum 5 slides into a central through hole 25 provided in a portion of the plunger 4 extending outward from the body 3, and has a passage 18 that can communicate with a passage 19. stem part 2 with
It has 6. The stepped portion 27 of the Fulcrum 5 can be seated on the upper end of the plunger 4. A retainer 28 is fixed to the lower outer peripheral wall of the stem portion 26, and a window 29 is provided in the center of the inner peripheral wall of the reservoir chamber 7.
A cup body 30 having a
A third spring 31 is disposed between the retainer 28 and the retainer 28 . When no external force acts on the Fulcrum 5, the biasing force of the third spring 31 acting on the stem portion 26 via the retainer 28 moves the Fulcrum 5 to the position shown by the imaginary line in FIG. As a result, the passage 18 of the stem portion 26 comes into contact with the inner circumferential wall surface of the central through hole 25, and communication between the passage 19 and the passage 18 is cut off. The state shown by the imaginary line in FIG. 2 corresponds to the state in which the hydraulic lifter 1 is removed from the valve mechanism or stored as a spare part, but in these states, the hydraulic oil in the reservoir chamber 7 is not released to the outside. There is no leakage. In this way, the predetermined function as a hydraulic lifter can be maintained at all times. When using, please add the third part to Fulcrum 5.
A downward force is applied to resist the biasing force of the spring 31, and the stepped portion 27 of the Fulcrum 5 is seated on the upper end of the plunger 4, as shown by the solid line in FIG. In such a state, if the Fulcrum 5 and the Rotsuker arm are made to work together, the Fulcrum 5 and the plunger 4 will move in response to the movement of the Rotsuker arm.
Because the passages 19 and 18 are in communication with each other, the reservoir chamber 7 can be maintained at atmospheric pressure at all times.

In the example shown in FIG. 3, the fulcrum 5 is provided with a bore 32 that opens into the reservoir chamber 7, and a retainer 34 having a central passage 33 is fixed to the bore 32.
Between the tip of the bore 32 and the retainer 34, a third
A valve body 36 is disposed which normally comes into contact with the retainer 34 under the biasing force of a spring 35 . Valve body 36
has an opening 37 and a ball 39 whose one end receives the biasing force of a fourth spring 38 seated on the retainer 34 to keep the opening 37 normally closed. The biasing forces of the third and fourth springs 35 and 38 cause the valve body 36 to come into light contact with the retainer 34, and the reservoir chamber 7
The hydraulic oil is selected so as not to leak out from between the valve body 36 and the retainer 34. Fulcrum 5
A passage 40 is formed in the bore 3 .
It is in communication with the upper part of the retainer 34 of No. 2. As shown in FIG. 3, when the reservoir chamber 7 is maintained at atmospheric pressure, the ball 39 closes the opening 37 under the urging force of the fourth spring 38.
Further, the valve body 36 receives the biasing force of the third spring 35 to bring the valve body 36 into contact with the retainer 34 . Therefore, there is no communication relationship between the reservoir chamber 7 and the atmosphere, and therefore, there is no leakage of the working oil from the reservoir chamber 7. This state corresponds to the state when the hydraulic lifter 1 is removed from the valve mechanism or when it is stored as a spare part.In such a state, there is no leakage of hydraulic oil from the hydraulic lifter, and the hydraulic lifter is operated again. Even if the hydraulic lifter is installed in the valve mechanism, the hydraulic lifter can always achieve the specified function. On the other hand, during use etc.
When the reservoir chamber 7 enters a negative pressure state, the ball 37 moves downward and the atmosphere is introduced into the reservoir chamber 7 from the passage 40 through the opening 37. Also, reservoir chamber 7
When the pressure becomes higher than atmospheric pressure, the valve body 36 is pushed up,
A gap is created between the valve body 36 and the retainer 34, and the reservoir chamber 7 communicates with the atmosphere via the gap and the passage 40. In this way, the reservoir chamber 7 is always maintained at atmospheric pressure.

The hydraulic lifter 1 shown in FIG. 4 has a bore 32 in its fulcrum 5, which communicates with the atmosphere via a passage 40. The spiral stem 47 is
A guide 48 fixed in the bore 32 and a hole 49 in the fulcrum 5 hold the fulcrum 5 so that it can move up and down reliably. An O-ring 50 is arranged at the bottom of the stem 47, and a seat 51 is formed below it. On the other hand, there is a retainer 5 inside the plunger 4.
2 is fixed, and a third spring 53 is arranged between the seat 51 and the retainer 52 to press the stem 47 upward. When the stem 47 is in the position shown in FIG. This is closed, and the other opening 56 of the passage 54 is in contact with the inner wall surface of the guide 48 . In the position of FIG. 4, where the third spring 53 presses the stem 47 upward, the O-ring 50
8 and the stem 47. Thus,
The reservoir chamber 7 and the atmosphere are completely isolated from each other.
In use, the rocker arm pushes the upper end of the stem 47 and pushes the stem 47 down so that the upper end of the stem 47 is along the top wall of the Fulcrum 5. In this pressed down state, one opening 55 is connected to the passage 40.
The opening 56 communicates with the atmosphere through the opening 56, and the other opening 56 is open to the reservoir chamber 7. In this way, the atmosphere and the reservoir chamber 7 are in communication, and the reservoir chamber 7 is always maintained at atmospheric pressure. When the hydraulic lifter 1 is removed from the valve mechanism or stored as a spare part, it is in the state shown in FIG. 4, so no hydraulic oil flows out from the reservoir chamber, as described above.

As is clear from the above, in the present invention, when the hydraulic lifter is removed from the valve mechanism, that is, in a free state, communication between the reservoir chamber and the atmosphere is cut off. Therefore, the hydraulic oil in the reservoir chamber does not leak out to the outside, and the hydraulic lifter can always operate with a predetermined function.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a hydraulic lifter as an example of the present invention, FIG. 2 is a sectional view of another example of a hydraulic lifter, and FIG.
The figure is a sectional view of another example of the hydraulic lifter, and FIG. 4 is a sectional view of still another example of the hydraulic lifter. In the figure, 1... Hydraulic lifter, 3... Body, 4... Plunger, 5... Fulcrum, 6... Check valve, 7... Reservoir chamber, 9... Pressure chamber, 10... Spring, 18, 19, 20, 40, 54... Passage. .

Claims (1)

[Claims] 1. A plunger having a reservoir chamber and a fulcrum is reciprocably disposed within the body,
In the hydraulic lifter, the plunger and the body form a pressure chamber that can communicate with the reservoir chamber via a check valve, the plunger receives a biasing force of a spring, and the reservoir chamber communicates with the atmosphere, A hydraulic lifter characterized in that, when no external force is applied, the fulcrum assumes the highest position and a communication path between the reservoir chamber and the atmosphere is cut off.