WO1993019285A1

WO1993019285A1 - Tappet with hydraulic valve clearance compensation

Info

Publication number: WO1993019285A1
Application number: PCT/EP1993/000650
Authority: WO
Inventors: Harald Elendt; Michael Haas; Franz Dellermann
Original assignee: Ina Wälzlager Schaeffler Kg
Priority date: 1992-03-24
Filing date: 1993-03-18
Publication date: 1993-09-30
Also published as: DE4209442A1

Abstract

A tappet (1) with hydraulic valve clearance compensation has a ring-shaped space (16) and a clearance compensating element (15). In order to obtain a particularly stable, leak-proof tappet that is further protected against undesirably sucking air in, ribs (17) with oil throughbores (19, 20) are arranged in an oil storage chamber (16).

Description

description

Tappet with hydraulic valve clearance compensation

The invention relates to a tappet with hydraulic valve clearance compensation, which is arranged in a receiving bore of a cylinder head of an internal combustion engine and against whose end face which is designed as a base, a control cam of a camshaft runs, whereby between a hollow cylindrical wall of the tappet, in which an inlet bore is provided , and a concentric to the hollow cylindrical wall arranged guide sleeve, an annular space is provided.

Such a plunger is known from EP-PS 00 30 780. The ribs shown there only have a stiffening function. An oil channel is guided through at least one of these ribs and allows the hydraulic oil required to compensate for play to reach a central oil reservoir. A first oil reservoir or a device by means of which this tappet is designed to be particularly leak-proof are not provided. Furthermore, the direct inlet opening into the central oil reservoir, which is close to the floor, that is to say at the highest point, can result in undesired air getting into the play compensation element, which in turn can only escape through an oil channel.

The invention is therefore based on the object of providing a tappet with hydraulic valve lash compensation, in which the disadvantages described at the outset are eliminated, the valve lash compensation device being particularly reliable, stable and protected against undesired suction of air.

According to the invention, this object is achieved according to the characterizing part of claim 1 in that the annular space is divided into individual chambers by ribs, in which transition bores are provided. is divided, the transfer bores leading from one chamber to the next. These transition holes on the one hand make it possible to dispense with a labyrinth-like leak protection of the first space against leaking oil, and on the other hand the tappet listed here is designed to be particularly leak-proof. The above-mentioned ribs give the entire construction a very good rigidity, despite the low material and manufacturing costs.

Further embodiments according to the invention are the subject of subclaims 2 to 5 and are described in more detail below.

It is apparent from claim 2 that the transition bores are provided in the ribs in the vicinity of the base and / or in an annular wall opposite the base and arranged on the end face of the hollow cylindrical wall. This claim specifies possibilities for an advantageous arrangement of the transition bores. If these are arranged, for example, in the vicinity of the floor, the respective highest-lying chamber cannot run out when the ram is inclined, ie. that is, a certain oil level is maintained in this chamber. An undesired intake of air into the play compensation element is thus avoided.

The claim 3 describes that the inlet bore in the hollow cylindrical wall to a connecting bore in the interior of the guide sleeve offset in the circumferential direction by a small angle, and is arranged separated by at least one rib. This claim relates to one of the advantageous possible combinations of the arrangement of the inlet bore and the bore. If the inlet bore in the hollow cylindrical wall to the connecting bore is separated by at least one rib through the guide sleeve, it is ensured that air is prevented from being sucked in at various inclined positions of the tappet, especially since the tappet is eccentric with respect to the control cam the axial line of the plunger is set in a rotational movement, and thus its possibly unfavorable position is eliminated.

Claim 4 describes that the inlet bore in the hollow cylindrical wall is in the vicinity of the ring wall. The deep one Inlet hole ensures that the oil pressure from an unspecified oil supply is always at the inlet hole.

It is apparent from claim 5 that the ring wall consists of an additional part which is inserted into the inside of the plunger and snapped onto the inside of the hollow cylindrical wall. This variant represents an alternative embodiment to the plungers shown previously. The sheet metal part shown here can be easily manufactured and assembled.

A solution is also conceivable for all tappet variants presented here and included in the scope of protection of this invention, in which the play compensation element runs directly in a guide made of aluminum material.

The use of the tappet described here should not be limited to the valve train of internal combustion engines. All areas in which it is necessary to compensate for play due to thermal expansion or wear are conceivable.

The scope of protection of this invention relates not only to the individual features claimed. There are also possible combinations of individual claim features with what is disclosed in the information on advantages and in the exemplary embodiment. Furthermore, the scope of protection of the invention should not be limited to the plungers described here. Also conceivable are those whose housings including the base consist, for example, of a lightweight material such as aluminum, it then being conceivable to additionally coat the base.

Embodiments of the invention are shown in the figures and are described in more detail below. Show it:

1 shows a longitudinal section through a plunger in the installed state;

FIG. 2 shows a partial view of a longitudinal section through a plunger shown enlarged;

Figure 3 shows a cross section along line III-III in Figure 2; Figure 4 is a schematic representation of the formation of the plunger with a rib;

FIG. 5 shows a schematic illustration of the design of the ram with two ribs,

Figure 6 is a schematic representation of the formation of the tappet with four ribs and

Figure 7 shows a further embodiment of the plunger.

FIG. 1 shows a tappet 1 according to the invention. This consists of a hollow cylindrical tappet housing 2. The tappet housing 2 is preferably made of a lightweight material, such as a high-strength, extrudable and / or forged aluminum alloy. However, conventional materials are also conceivable here.

A bottom 3 closes the plunger 1 at one of its axial end regions 4. A control cam 5 moves the plunger 1 with its flank 6 in the axial direction. The plunger housing 2 also consists of a hollow cylindrical wall 7. At least one inlet bore 8 is provided in the hollow cylindrical wall 7. This inlet bore 8 is located in the vicinity of an annular wall 11, which starts from an inner side 9 of the wall 7 and extends annularly into the plunger interior 10. This annular wall 11 is arranged on a side opposite the base 3.

Starting from the ring wall 11, a guide sleeve 12 extends concentrically to the hollow cylindrical wall 7 in the direction of the bottom 3. This guide sleeve 12 has a further connection bore 13. This connection bore 13 serves to supply oil to a bore 14 in the bore 14 Guide sleeve 12 located game compensation element 15. The operation of the plunger 1 described here with the game compensation element 15 is not discussed in detail here, as this is already well known to the experts. A space 16 is formed between the hollow cylindrical wall 7 and the annular wall 11, which serves to store oil for the actual play compensation. The space 16 mentioned above is divided into individual chambers 18 by ribs 17. These chambers 18 are advantageously connected to one another by top or bottom transfer bores 19, 20. A concentrically arranged sleeve 22 extending from an underside 21 of the base 3 extends into the above-mentioned bore 14 of the guide sleeve 12. The underside 23 of the sleeve 22 is additionally fixed in position by caulking 24 in the ring wall 11.

The bottom 3 advantageously consists of a steel with a coefficient of thermal expansion similar to that of aluminum. However, it can also consist of a wear-resistant material steel or of another material. In the exemplary embodiment described here, the connection of the base 3 to the tappet housing 2 is advantageously carried out by soldering, gluing, welding, high-pressure pressing or friction welding or combinations thereof. Further connection options can be found in the description of FIG. 2.

The outer surface 25 of the hollow cylindrical wall 7 can be additionally coated to increase its wear resistance. Such coating processes are conceivable here, such as chrome plating, hard coating, nickel plating or the application of carbon layers.

Furthermore, it can be provided to design the concentrically arranged sleeve 22 as a separate tube part and to connect it to the base 3 by a welded connection or the like. Another solution provides for the sleeve 22 to be provided with a flange-like attachment (not described in more detail). This approach extends parallel to the bottom 3 in the direction of the hollow cylindrical wall 7. The actual bottom 3 is then attached to this approach.

A partial longitudinal section through an enlarged plunger 1 can be seen from FIG. The floor 3, in this case made of steel, although other wear-resistant or coated materials are also conceivable, has a structured outer surface 26. The In contrast to the one shown in FIG. 1, the hollow cylindrical wall 7 is provided with an extension 27. This approach 27 is anroll ert on the bottom 3. Thus, a very good seal of the space 16 against escaping oil and an excellent position of the bottom 3 against the entire plunger housing 2 is achieved.

The actual play compensation element 15 is in turn arranged concentrically in the ram interior 10. This design, as well as that shown in Figure 1, has the advantage of up to 40% less weight compared to conventional, well-known plungers.

Due to the subdivision of the space 16 into individual chambers 18, as well as through the constructive measures described here and also in FIG. The choice of the number and strength of the ribs 17 can be varied depending on the particular application. Additional sealing measures of the space 16 against escaping oil are omitted here due to the annular wall 11 extending from the wall 7.

Furthermore, it can be seen from FIG. 2 that, as shown in FIG. 1, a sleeve 22 extends from the underside 21 of the base 3, concentrically arranged and projecting into the plunger interior 10. This guides the play compensation element 15 on the one hand, and on the other hand stabilizes the entire tappet housing 2 when forces are exerted on the hollow cylindrical wall 7, which are transmitted to the base 3.

FIG. 3 shows a cross section along the section lines III-III of FIG. 2. In this case, eight ribs 17 distributed around the circumference were provided. These have top or bottom transition bores 19, 20. In this case only top crossing bores 19 are shown. The inlet bore 8 is arranged in the circumferential direction between two ribs 17 and the hollow cylindrical wall 7. The ribs 17 are supported on the guide sleeve 12. The sleeve 22 of the base 3 (not shown) is pressed into the bore 14 of the guide sleeve 12. The sleeve 22 can, but need not, be pressed in for the cases described here.

The advantages of some of the possibilities for designing the space 16 with u-distributed ribs 17 and transition bores 19, 20 and the inlet bore 8 and the connecting bore 13 are described.

A schematic representation of the design of the plunger 1 with a rib 17 can be seen from FIG. A vent hole 28, here marked with a star, may be located in the hollow cylindrical wall 7. This vent hole 28 allows escape of any unwanted air that may be in the space 16. On the one hand, this air can get into the space 16 when the plunger 1 is filled with oil. On the other hand, it cannot be ruled out in real engine operation that air is sucked into the space 16 via the inlet bore 8. If this air now passes through the space 16 and the connection bore 13 into the play compensation element 15, which is not described in any more detail, there may be foaming with the oil located there. The resulting undesirable compressibility of the foamed oil reduces the play-compensating function of the entire plunger 1. The vent hole 28 described here is also conceivable for other plungers 1, as well as for not shown.

The special advantages of the leakage protection of the plunger 1 are discussed below. It can be assumed that the space 16 of the plunger 1 is sufficiently filled with oil. If, when the tappet 1 is in an inclined position, which is also conceivable for installation in V-engines and others, the vent hole 28 is the highest point, the oil runs onto a side 29 opposite the vent hole 28. The rib 17 prevents that all the oil collects on page 29. This leaves a sufficient amount of oil for suction through the lash adjuster 15 through the connection bore 13. The connection bore 13 is mounted near the ring wall 11 which cannot be removed here. As the air now has the tendency to escape upwards, oil is safely sucked into the play compensation element. Further variants of the inclination are not explained at this point, since the person skilled in the art can easily understand this himself. FIG. 5 shows a schematic representation of the design of the plunger 1 with two ribs 17. These ribs 17 are each provided with an overflow bore 19 at the top. When the space 16 is filled through the inlet bore 8, the space 16 between the two ribs 17 is filled first. If the oil level now reaches the transfer bore 19, oil reaches the remaining space 16. The connecting bore 13 is arranged in the case described here on the side opposite the inlet bore 8. Furthermore, at least one vent hole 28 (not shown here) can be provided.

If, for example, the connecting bore 13 is the imaginary highest point, the oil level still extends to this connecting bore 13, since the ram 1 is prevented from running dry by the ribs 17 located below.

6 shows a schematic representation of the design of the plunger 1 with four ribs 17. When the space 16 between the two ribs 17 is filled with oil through the inlet bore 8, the air therein is pressed into the next space 16 through the overflow bore 19 located above. After-flowing oil presses the air from the second space 16 into the third space 16 (clockwise) when the first space 16 is filled. If oil now arrives in the third space 16, the air rises there, as is known, and oil is pressed through the transition bore 20 below into a fourth space 16. No air thus enters the fourth space 16 through the transition bore 20 located at this point, in which the connecting bore 13 for filling the play compensation element 15 (not shown here) is located. A vent hole 28 may be provided. This allows the air in the fourth space 16 due to fluctuating oil level and other influences to escape unhindered.

There are countless other possible variations between the number, thickness and arrangement of the ribs 17 with the transfer bores 19, 20 for the arrangement and design of the inlet bore 8 and the connecting bore 13. FIG. 7 shows a further plunger 1. In contrast to the plungers shown above, its ring wall 11 consists of an additional part which is inserted into the plunger interior 10 and snapped into the hollow cylindrical wall 7. In the example shown here, the plunger housing 2 is shown completely made of a material such as aluminum. The floor 3 can be provided with an additional layer to increase its wear resistance.

Claims

1. tappet (1) with hydraulic valve lash adjuster, which is arranged in a receiving bore (30) of a cylinder head of an internal combustion engine and against whose end face (3), a control cam (5) of a camshaft runs, whereby between a hollow cylindrical wall (7) the plunger (1), in which an inlet bore (8) is provided, and a guide sleeve (12) arranged concentrically to the hollow cylindrical wall (7), an annular space (16) is provided, characterized in that the annular space (16 ) is divided into individual chambers (18) by ribs (17) in which transfer bores (19, 20) are provided, the transfer bores (19, 20) leading from one chamber (18) to the next, are trained.

2. Tappet according to claim 1, characterized in that the transition bores (19, 20) in the ribs (17) in the vicinity of the bottom (3) and / or one opposite the bottom (3), on the end face of the hollow cylindrical wall ( 7) arranged ring wall (11) are provided.

3. Tappet according to claim 1, characterized in that the inlet bore (8) in the hollow cylindrical wall (7) to a connecting hole (13) in the interior of the guide sleeve (12) in the circumferential direction offset by a small angle and by at least one Rib is arranged separately.

4. Tappet according to claim 1, characterized in that the inlet bore (8) in the hollow cylindrical wall (7) is in the vicinity of the ring wall (11).

5. Tappet according to claim 1, characterized in that the ring wall (11) from an additional, in the inside (10) of the tappet (1) inserted and on the inside (9) of the hollow cylindrical wall (7) snapped ge Part exists.