JPH04121402A - Direct acting type oil pressure rush adjuster - Google Patents

Abstract

PURPOSE:To accumulate air only in a space in the vicinity of an oil feed hole which is enclosed with a bulkhead, and dissolve suction of air in the high pressure chamber of an oil pressure unit by providing the bulkhead extending downward in an auxiliary reservoir so as to enclose the oil feed hole from just the upper part of the oil feed hole. CONSTITUTION:An oil pressure rush adjuster is composed of a backet (X) and a rush adjuster oil pressure unit (Y) which is stored therein and interposed between an cam 100 and the shaft end part of a valve 101. In the oil pressure unit (Y), an auxiliary reservoir 2 which communicates with a main reservoir 7 is formed around the main reservoir 7 which is isolated by the circumference wall surface of a plunger 4, and working oil is supplied therein through the oil feed hole 3 of the backet (X). In such constitution, a bulkhead 1 extending downward is provided in the auxiliary reservoir 2 so as to surround the oil feed hole 3 directly from above the oil feed hole 3. It is thus possible to eliminate suction of air in a high pressure chamber 6 regardless of change of the ambient temperature in environment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement of a direct-acting hydraulic lash adjuster in which a hydraulic unit of the lash adjuster is built into a bucket.

[Conventional technology]

A valve train in an internal combustion engine is generally susceptible to wear and thermal expansion, and the valve wJ gap changes during operation, which adversely affects output and noise. Therefore, hydraulic lash adjusters have come to be used to appropriately correct this gap.

Among these, for the purpose of reducing the weight of internal combustion engine equipment, a hydraulic lash adjuster as shown in Figure 7 is also used in a direct-acting valve mechanism in which the cam directly hits the end of the valve shaft. ing.

This hydraulic lash adjuster is composed of a bucket X and a lash adjuster hydraulic unit Y housed inside the bucket, and is interposed between the cam (100) and the shaft end of the valve (101). Among them, the hydraulic unit Y of the lash adjuster includes a bottomed cylindrical plunger (4) having an oil hole (40) at the bottom, and a ring that is slidably mounted on the outer periphery of the plunger (4). A similarly bottomed cylindrical body (5) forming a high pressure chamber (6) therebetween, and the high pressure chamber (6)
), which urges the body (5) toward its closed surface; and an elastic body (60) which is also provided in the high pressure chamber (6) and controls opening and closing of the oil hole (40). Check valve (
61), a valve spring (62) that holds the check valve (61), and a check valve cage (63). This hydraulic unit Y is the bucket
The face disk (8) of the bucket
A main reservoir (7) for oil sump is located between the X plane and the hollow part of the plunger (4), and an overflow recess (70 ) forms an auxiliary reservoir (2) that communicates with the reservoir, and hydraulic oil is supplied thereto through the oil feed hole (9) of the cylinder head and the oil feed hole (3) of the bucket X. On the other hand, the cam (100) is in contact with the face disk (8) of the bucket X, and the shaft end of the valve (101) is in contact with the closing surface of the body (5).
is connected to the valve (101) via the hydraulic lash adjuster.
) The shaft end is directly driven.

This type of hydraulic lash adjuster has an elastic effect due to volume compression and leakdown to the outside that occurs in the hydraulic oil itself when pressure is applied to the hydraulic oil filled in the high pressure chamber (6), and the pressure is further added. The system utilizes the rigidity effect of the hydraulic oil that occurs when the volume compression no longer progresses, and also uses the elastic body (60) inserted into the high pressure chamber (6) to stretch when the pressure is released. By generating a repulsive force, a correction operation is performed to reduce the gap in the valve mechanism caused by thermal deformation or the like to zero.

[Problem that the invention seeks to solve]

However, in the above-mentioned direct-acting hydraulic lash adjuster, the hydraulic fluid repeatedly expands and contracts due to changes in the surrounding environment temperature.
A problem has been that the hydraulic oil in the sub-reservoir (2) leaks from the oil supply hole (3).

That is, when the temperature rises, the hydraulic oil expands, and as shown in Figure 8(a)
As shown in the figure, the hydraulic oil leaks from the oil supply hole (3) due to the expansion.Next, when the temperature drops due to cooling, etc. due to the stoppage of the internal combustion engine, the hydraulic oil contracts and the hydraulic oil leaks from the oil supply hole (3). As shown in FIG. 2, air corresponding to this contracted volume enters the sub-reservoir (2) through the oil supply hole (3).

Furthermore, once air enters the sub-reservoir (2), the relationship between the expansion rates of hydraulic oil and air is hydraulic oil - air, so leakage of hydraulic oil due to temperature changes will increase, resulting in There is a problem in that air is sucked into the high pressure chamber (6) of the hydraulic unit Y, causing the lifter to no longer function as a lifter.

The present invention was devised in view of the above-mentioned problems of the prior art, and as described above, even if there are changes in the surrounding environmental temperature, the present invention is a direct-acting hydraulic lash system that does not draw air into the high-pressure chamber. It is intended to provide an adjuster.

[Means for solving problems]

Therefore, the direct-acting hydraulic lash adjuster of the present invention has a secondary reservoir (2) as shown in FIGS. 1(a) and (b).
The basic feature is that a partition wall (1) is provided inside the oil supply hole (3) and extends downward from just above the oil supply hole (3) so as to surround the oil supply hole (3).

[For production]

According to the above configuration, due to a change in the surrounding environmental temperature, air entering from the oil supply hole (3) is removed from the oil supply hole surrounded by the partition wall (1), as shown in FIGS. (3) It will be kept in a nearby space, and until the space is filled with air, the hydraulic oil and air will be replaced only in this space. On the other hand, after this space is filled with air, as shown in FIG. Since no air enters, air is prevented from entering the high pressure chamber (6).

〔Example〕

Hereinafter, specific embodiments of the present invention will be described based on the accompanying drawings.

FIG. 2(a) shows a valve mechanism installed in an internal combustion engine, in which a hydraulic lash adjuster consisting of a bucket X and a hydraulic unit Y is connected to a cam (10
This is a direct-acting valve mechanism that is interposed between the valve (101) and the valve (101).

The hydraulic unit Y includes a bottomed cylindrical plunger (4) having an oil hole (40) at the bottom, and a high-pressure chamber disposed between the plunger (4) and the bottom. (
6), and a main reservoir (7) formed in the plunger (4) and communicating with the high pressure chamber (6) via the oil hole (40). It also includes an elastic body (60) interposed in the low/high pressure chamber (6), a check valve (61) that controls the opening and closing of the oil hole (40), a check valve spring, a valve cage (63), etc. .

Furthermore, the bucket
A secondary reservoir (2) communicates with the primary reservoir (7) by
is formed by the septum sleeve (20). An oil supply hole (3) is bored in the peripheral wall surface of the bucket X to introduce hydraulic oil supplied from an oil feed hole (not shown) on the cylinder head side into the sub-reservoir (2).

On the other hand, in this embodiment, a partition wall (10) having an angular cross-section and extending downward from just above the oil supply hole (3) to surround the oil supply hole (3) is provided in the sub-reservoir (2). There is. When this partition wall (10) is viewed from the same figure (b) showing the cross section AA in the same figure, it is formed in a U-shape so as to surround the oil supply hole (3).

Therefore, in this direct-acting hydraulic lash adjuster, the hydraulic oil expands when the temperature rises due to changes in the surrounding environmental temperature, and the expansion leaks from the oil supply hole (3). Further, when the temperature drops, the hydraulic oil contracts, and air corresponding to the contracted volume enters from the oil supply hole (3), but this air is absorbed by the partition wall (1).
It will accumulate in the space surrounded by 0). In this way, the hydraulic oil in the space is gradually replaced with air in response to changes in the surrounding environmental temperature, but once this space is filled with air, the oil supply hole ( 3) Only air leaks, and as a result, air can be prevented from being sucked into the high pressure chamber (6).

In addition, in this embodiment, the valve clamping angle K, the internal combustion engine mounting angle e
And due to the maximum inclination angle Ω during running, the bucket
The leakage of hydraulic oil from the oil supply hole (3) continues until the oil level reaches the lowest part of the oil supply hole (3). At this time, if the oil level is located below the lower end of the partition wall (10), air will enter into the upper part of the sub-reservoir (2). The effect of preventing air from entering the space is lost.

Therefore, in this embodiment, the vertical height H of the partition wall (10) is
If A is made larger than the oil level equivalent length A of the partition wall (10) when tilted, the oil level will not fall below the lower end of the wall (10) even when the bucket X is tilted.

The length A corresponding to the oil level at this time of inclination is, as is clear from the drawing, the length B from the top of the partition wall (10) to the oil supply hole (3) position, the distance W (10), and the gap C between the bucket X. and the designed bucket inclination angle α.

That is, A=B+C-tanα However, the bucket inclination angle α is determined from the valve angle K, the internal combustion engine mounting angle e, and the maximum inclination angle Ω during running as follows.

α=(K/2)+e+Ω And since H>A, H>B+C-tanα It is necessary to meet the following conditions.

On the other hand, when the slope is opposite to the above, the oil supply hole (3)
Since it faces upward, it is difficult for air to enter, and there is no need to particularly consider the conditions in such a state.

Considering the above conditions in a concrete example, for example, B: 5 m, C near mm spacing (10), valve clamping angle: 20°, engine mounting angle e: 15° traveling. When the maximum inclination angle Q = 15°.

α=(K/2)+e+ρ=40°,”, A=B+C-tanct=5+7・t
an40=10.87 Therefore, if the vertical height H of the bulkhead (10) is made larger than 10.87 m, the design prevents hydraulic oil from leaking from the oil supply hole (3) even when the bucket X is tilted. do not have.

Figures 4 (a) (b), 5 (a) (b) and 6 (a) (b) show partition walls (11) (12) (13) in the sub-reservoir (2) of bucket FIG. 3 is an explanatory cross-sectional view showing other embodiments of the present invention provided with the following.

〔Effect of the invention〕

As detailed above, according to the present invention, in the sub-reservoir,
Since there is a partition wall that extends downward from just above the oil supply hole to surround this oil supply hole, air that enters due to the expansion and contraction of hydraulic oil and air due to temperature changes in the surrounding environment is surrounded by this partition wall. After the space is filled with air, only air will leak from the oil supply hole when the temperature rises, and as a result, no air will enter above the sub-reservoir. This prevents air from being sucked into the high pressure chamber of the hydraulic unit of the hydraulic lash adjuster. Therefore, this hydraulic lash adjuster is prevented from reducing the rigidity of the hydraulic fluid under pressure load due to air suction.

[Brief explanation of drawings]

FIGS. 1(a), (b), (c), and (d) are explanatory diagrams showing the configuration of a direct-acting hydraulic lash adjuster of the present invention, and FIG. 2(a) is a longitudinal cross-section showing the configuration of an embodiment of the present invention. Figure, same figure (
b) is a cross-sectional view taken along the line A-A in FIG. (b) is a sectional view showing another embodiment of the present invention, FIGS. 5(a) and (b) are sectional views showing still another embodiment, and FIGS. 6(a) and (b) are another embodiment. 7 is a sectional view showing an example of the configuration of a direct-acting valve mechanism equipped with a hydraulic lash adjuster, and FIG.
FIGS. 2A and 2B are explanatory diagrams showing the cause of air intrusion into the sub-reservoir in a conventional direct-acting hydraulic lash adjuster. In the figure, (1) (10) (11) (12) (13) is the partition wall, (2) is the sub-reservoir, (3) is the oil supply hole, (4) is the plunger, (5) is the body, (6) is a hyperbaric chamber, (7)
(8) is the main reservoir, (8) is the face disk, (9) is the oil feed hole, (100) is the cam, and (101) is the valve. Diagram (a) Temperature change rise diagram (b) Decrease (C) (d) Shin diagram °KY樗

Claims (2)

[Claims] (1) A hydraulic unit for the lash adjuster is built into the bucket, and a sub-reservoir is installed around the hydraulic unit inside the bucket to supply hydraulic oil to the main reservoir on the hydraulic unit side. In the direct-acting hydraulic lash adjuster, in which an oil supply hole for injecting hydraulic oil from the outside is provided on the circumferential surface of the bucket, a partition wall extending downward from directly above the oil supply hole to surround the oil supply hole is provided in the sub-reservoir. A direct-acting hydraulic locking adjuster. (2) In the direct acting type hydraulic lash adjuster described in the preceding paragraph, the height in the vertical direction of the bulkhead is the height H determined based on the following formula. Hydraulic lash adjuster. H>B+C・tan α However, B: Length from the top of the bulkhead to the oil supply hole position C: Gap between the bulkhead and the inner circumferential surface of the bucket α: Designed maximum tilt angle of the bucket