JPH0247561B2 - ATSUSOSHIKYUATSURIFUTA - Google Patents

Abstract

PURPOSE:To prevent an oil from flowing out of a reservoir at the time when the engines are stopped irrespective of whether the engines are arranged horizontally in opposite relationship with each other or at an angle of inclination by a method wherein annular passages for forming an oil flow-in passage and an oil flow-out passage, respectively, within the reservoir. CONSTITUTION:Upper and lower ring plates 25 and 26 which are laid one above the other to provide annular hollow sections therebetween are arranged within the reservoir 15 and a sealing plate 27 having a sealing projection is provided between both of the plates 25 and 26. The oil from an oil supply source makes nearly a round of the circular hollow section of the lower ring plate 25 and enters the reservoir 15. The annular hollow section of the upper ring plate 26 serves as the oil flow-out passage and the oil flows out of the reservoir after making nearly a round of the passage. Accordingly, there is no possibility that the oil in the reservoir 15 flows out and air enters a pressure chamber and therefore, the function of the lifter is maintained in a favorable condition at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hydraulic lifter, and more particularly to a pressure-feed hydraulic lifter installed in a valve train of an internal combustion engine.

Generally, in this type of hydraulic lifter, a cylinder with an open top is formed inside a lifter body that serves as a housing, and a plunger is slidably disposed within the cylinder so that it can reciprocate in the vertical direction. A hydraulic oil reservoir is formed within the plunger, and a pressure chamber is formed between the lower end surface of the plunger and the bottom of the cylinder.
The hydraulic oil pumped by the oil pump is supplied into the reservoir through an oil passage provided in the lifter body. When a conventional pressure-feeding hydraulic lifter having such a configuration is installed in a horizontally opposed engine or an inclined engine, there is a risk that working oil may flow out of the lifter from the reservoir when the engine is stopped. As a result, when the engine is started, air enters the pressure chamber inside the cylinder from the reservoir, making it impossible for the hydraulic lifter to reach the specified length (total height of the lifter), which tends to cause tappet sound. There was a problem.

SUMMARY OF THE INVENTION In view of the problems of the prior art described above, an object of the present invention is to prevent operating oil from flowing out from a reservoir when an engine is stopped.

In order to achieve the above object, the present invention has an upper and a lower ring plate each having an annular hollow part arranged in a vertically stacked manner in a reservoir, and a sealing protrusion that seals one part of each annular hollow part of the ring plate. interposed between both ring plates, the annular hollow part of the lower ring plate serves as an oil inflow passage to the reservoir, and the annular hollow part of the upper ring plate serves as an oil outflow passage from the reservoir. At the same time, an oil inflow passage is communicated with an oil supply source through a hole on one side of the seal protrusion, and a reservoir is communicated through a hole on the other side, and an oil outflow passage is communicated with the reservoir through a hole on one side of the seal protrusion. The hole on the other side communicates with the atmosphere.

As another technical means for achieving the purpose of the present invention described above, which is to prevent the operating oil from flowing out from the reservoir when the engine is stopped, a configuration in which the inflow/outlet is closed by valve operation may be considered. Valve operation is unstable because oil has to flow in and out against the biasing force of the spring that makes up the valve, and the valve itself becomes unstable due to acceleration of the engine valve system. Although there are problems such as the outflow-side valve creating resistance when starting the engine and preventing oil from flowing into the pressure chamber from the reservoir, such problems can be solved by following the configuration of the present invention.

Hereinafter, one embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a hydraulic lifter 10 installed in the valve train of an internal combustion engine.
The lifter body 11 has a cylinder 12 with an open top end formed therein, and an oil passage 13 communicating with an oil supply source on its outer periphery.
A plunger 14 is slidably disposed within the cylinder 12 of the lifter body 11 so as to reciprocate in the vertical direction. Hydraulic oil to be pumped into the oil passage 13 is supplied into a reservoir 15 formed inside the plunger 14 via a fluid passage in a ring plate, which will be described later. Sheet member 16
The upper end surface consisting of a concave spherical surface is not shown in the figure.
It is operatively connected to the push rod of the OHV valve system, and its lower end surface is fitted into the upper end opening of the plunger 14.

On the other hand, a pressure chamber 17 is formed within the cylinder 12 by the lower end surface of the plunger 14 . An oil passage 18 is provided at the center of the bottom of the plunger 14 so that the reservoir 15 and the pressure chamber 17 can communicate with each other. In addition, the pressure chamber 17 of the oil passage 18
A well-known ball check valve 19 is arranged on the chamber side, and the valve 19 controls the opening and closing of the oil passage 18 so as to only allow oil to flow from the reservoir 15 to the pressure chamber 17. The check valve 19 is constantly biased in the closing direction by the other end of the spring 21, one end of which is supported by the cap-shaped retainer 20. The pressure chamber 17 has the spring 2
A plunger return spring 22 with a load greater than 1 is tensioned, that is, the spring 22 causes the plunger 14 to move towards the lifter body 11.
is constantly biased upward against the Sheet member 16
The upward movement of the plunger 14 is restricted by the snap spring 23, thereby restricting the restoring force of the plunger return spring 22. Furthermore, an extremely small leak clearance 24 is formed between the inner peripheral surface of the lifter body 11 and the outer peripheral surface of the plunger 14, and this clearance 24 serves as a passage for oil leaking from the pressure chamber 17.

Now, in the upper part of the reservoir 15, a lower ring plate 25 (disclosed in FIGS. 2 and 3) having an annular hollow part and an upper ring plate 26 (disclosed in FIGS. 4 and 5) are arranged vertically. It is mounted on top of the The annular hollow part of the lower ring plate 25 serves as an oil inflow passage 25a to the reservoir 15, while the annular hollow part of the upper ring plate 26 serves as an oil outflow passage 26a from the reservoir 15. A seal plate 27 made of a gum member shown in FIGS. 6 and 7 is interposed between both ring plates 25 and 26, and cylindrical seal protrusions 27 project upward and downward from both sides of the seal plate 27 on the left side in the figure.
a, 27b are inflow and outflow passages 25a, 26a
The seal plate 27 is disposed inside and is sealed.
The inflow and outflow passages 25 are formed by the plate portion 27c of
a and 26a are separated and sealed from each other. The inner wall space 25b of the lower ring plate 25 is
It communicates with the inner wall space 26b of the upper ring plate 26 via the center hole 27d of the seal plate 27a. The lower ring plate 25 has a communication hole 25c communicating with the oil pump on one side of the seal projection 27a, and a communication hole 25d communicating with the reservoir 15 on the other side. Communication hole 2
Communication from 5c to the oil pump is via plunger 1.
This is done through the communication hole 14a and groove 14b formed in the oil passage 13 formed in the oil passage 13. On the other hand, in the upper ring plate 26, a communication hole 26c communicating with the reservoir 15 is formed on one side of the seal projection 27b, and a communication hole 26d communicating with the atmosphere is formed on the other side. The communication hole 26d communicates with the atmosphere through an oil passage 16a formed in the sheet member 16.

Next, the operation of the above configuration will be explained. The working oil pumped from the oil pump passes through the oil passage 13, the groove 14b, and the communication hole 14a to the communication hole 25 of the lower ring plate 25.
c, and further flows counterclockwise inside the inflow passage 25a as shown by the arrow in FIG.
d is supplied to the reservoir 15. On the other hand, the oil in the reservoir 15 similarly flows counterclockwise in the outflow passage 26a as shown by the arrow in FIG. 5 from the communication hole 26c, and is supplied to the communication hole 26d. is released from the lifter to the outside. Therefore, the hydraulic lifter 10 of the present invention
However, even when installed in a horizontally driven engine or an inclined engine, the problem of oil in the reservoir 15 flowing out and air getting mixed into the pressure chamber can be solved.

The hydraulic lifter 10 operates normally, and to explain its details, when a camshaft (not shown) starts rotating, the lifter body 11 is pushed upward in the figure, and the oil pressure in the pressure chamber 17 increases. , check valve 19 is in oil passage 1
Close 8. At this time, oil flows from inside the pressure chamber 17 into the reservoir 15 through the oil inflow passage 25a. Therefore, the plunger 14 sinks with respect to the lifter body 11 by the dimension a.

Next, when the camshaft rotates, the lifter body 11 moves downward in the figure, and the upward biasing force of the plunger return spring 22 pushes the plunger 14 upwards by a dimension a with respect to the lifter body 11. As a result, the oil pressure in the pressure chamber 17 decreases, and the check valve 19 opens the oil passage 18 against the urging force of the spring 21. At this time,
Since the oil in the reservoir 15 flows into the pressure chamber 17, the entire hydraulic lifter 10 returns to its original length. In this way, the normal hydraulic lifter 10 repeats expansion and contraction of the above-mentioned dimension a at all times during engine operation.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the hydraulic lifter according to the present invention, and FIG. 2 is a sectional view showing the lowering plate in FIG.
3 is a plan view of FIG. 2, FIG. 4 is a sectional view showing the upper ring plate in FIG. 1 (BB sectional view in FIG. 5), FIG. FIG. 4 is a plan view as viewed from C, FIG. 6 is a sectional view showing the seal plate in FIG. 1, and FIG. 7 is a plan view of FIG. 6. 10...Hydraulic lifter, 15...Reservoir, 25
...Lower ring plate, 25a...Inflow passage, 25c, 25d...Communication hole, 26...Upper ring plate, 26a...Outflow passage, 26
c, 26d...Communication hole, 27...Seal plate, 27
a, 27b... Seal protrusion.

Claims (1)

[Claims] 1. In a pressure-feeding hydraulic lifter installed in a valve train, upper and lower ring plates each having an annular hollow part are arranged vertically in a reservoir,
A seal plate having a seal protrusion that seals each of the annular hollow portions of the ring plate is interposed between the two plates, and the annular hollow portion of the lower ring plate serves as an oil inflow passage to the reservoir;
The annular hollow part of the upper ring plate forms an oil outflow passage from the reservoir, and the oil inflow passage is communicated with an oil supply source through a hole on one side of the seal protrusion, and communicated with an oil supply source through a hole on the other side. A pressure-feed hydraulic lifter, characterized in that the oil outflow passage is communicated with the reservoir through a hole on one side of the seal protrusion, and communicated with the atmosphere through a hole on the other side of the seal protrusion.