DE9206480U1 - Bucket tappets with hydraulic valve clearance compensation - Google Patents

Description

INA Rolling Bearings Schaeffler KG, Industriestr. 1-3

8522 Herzogenaurach

ANR 17 17 332

2359-11-EN

Bucket tappets with hydraulic valve clearance compensation

The innovation relates to a bucket tappet with hydraulic valve clearance compensation, which is arranged in a receiving bore of a cylinder head of an internal combustion engine, consisting of a hollow cylindrical housing closed by a base, in which a clearance compensation element with a pressure piston is arranged concentrically, which is connected via an oil transfer arranged in the underside of the base to an annular first oil storage chamber radially surrounding the clearance compensation element, wherein the pressure piston slides axially movably on an outer surface of a hollow cylindrical guide sleeve, which, starting from the underside of the base, projects into the interior of the bucket tappet and delimits a second oil storage chamber for the direct supply of the clearance compensation element.

Such a bucket tappet is disclosed in US-PS 44 70 381.

This generic bucket tappet has a lens-shaped recess for the oil to pass from the first annular oil reservoir into the second oil reservoir for the direct supply of the clearance compensation element. The lens-shaped recess has a cross-section such that, when the guide sleeve rests against the base of the bucket tappet, a sufficient supply of oil to the second fluid reservoir is ensured.

The disadvantage of the bucket tappet described here is that this above-mentioned depression weakens the strength of the bottom of the tappet due to its necessary, relatively large-volume design. This is particularly important for bucket tappets with a bottom made of a

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Lightweight material and/or in variants with a thin base and/or in relatively brittle or hardening materials as a further contribution to minimising the weight of the bucket tappet, since in these solutions the recess must not extend too far into the base. 5

Since the extent of the depression in the direction of the thickness of the base is thus limited, the depression with its cross section must cover a not insignificant area of the contact surface of the guide sleeve on the base of the bucket tappet in order to ensure the required transfer cross section of oil from the first oil reservoir into the second oil reservoir.

Another disadvantage is that increased tensions in the ground occur if the depression is in the plane of force of a cam acting on the ground. In this case, an increased surface pressure can also be detected between the contact surface of the guide sleeve on the underside of the ground. In the worst case, there is a risk of the guide sleeve tipping into the depression due to the reduced contact surface of the guide sleeve on the underside of the ground.

The innovation is based on the task of creating a bucket tappet of the type described at the beginning, in which the disadvantages indicated are eliminated and in particular a sufficient oil supply to the second oil storage space is realized without significantly reducing the strength of the base.

This object is achieved according to claim 1 in that the oil transfer has at least two recesses leading from the first oil storage chamber to the second oil storage chamber.

This design of the recesses, which is easy to manage in terms of manufacturing technology, would prevent the tipping of the guide sleeve into the recess described above by a middle section thus formed, but would still ensure the cross-section for the oil to pass over. This also means a reduction

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the deformation of the soil and a minimization of the tensile stresses occurring in a depression.

According to claim 2, it is provided that the recesses are formed in a groove-like manner directly next to one another, so that a web runs between adjacent recesses.

These recesses can also have a dome-shaped, lens-shaped or cuboid-shaped geometry, although other designs are also conceivable. The shape of the design is easy to produce and guarantees the desired overflow cross-section.

Claim 3 provides that the recesses are arranged parallel to one another and are designed with substantially equal dimensions.

This design minimizes the costs for the tools and ensures easy-to-manage production. The scope of protection of this innovation should also include solutions in which the recesses are not arranged parallel to one another and/or have different dimensions or designs. With the above-mentioned parallel arrangement and similar design, it is also advantageous to use only one design of the base for guide sleeves of clearance compensation elements with different diameters, but it must be ensured that the respective recesses extend sufficiently into the first and second oil storage chambers.

According to claim 4, it is advantageous that the recesses extend in the radial direction.
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This guarantees minimal stress on the floor while ensuring a secure cross-section for the oil to pass through the depressions.

Claim 5 describes that the recesses preferably have a depth that does not exceed half the wall thickness of the base.

This training ensures, as described in the previous paragraph, that the

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Loads on the base, especially when it is made of a thin-walled lightweight material, should be kept as low as possible. Other numbers of recesses in accordance with the new design are also conceivable, for example a three- or multi-fold design with any distribution around the circumference of the contact surface of the guide sleeve on the underside of the base, depending on the respective boundary conditions such as leakage safety, overflow cross-section and others.

The innovation equally affects bucket tappets with an oil supply from the outside and bucket tappets that are closed off from the outside and act hydraulically independently. The innovation is not only limited to the features of the claims. There are also possibilities for combining individual features of the claim with what is disclosed in the advantages and the design example.
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Embodiments of the invention are shown in the drawing and are described in more detail below. They show:

Figure 1 shows an axial section through a bucket tappet according to the innovation,

Figure 2 shows a partial section along the line H-II of Figure I ₁

Figure 3 shows another section similar to that shown in Figure 2 and

Figure 4 shows an additional partial section similar to that shown in Figure 2.

Figure 1 shows an axial section through a bucket tappet 1 according to the invention. This is guided with an outer surface 2 of a skirt 3 of a hollow cylindrical housing 4 in an axially movable manner in a receiving bore (not shown) of a cylinder head of an internal combustion engine. A play compensation element 9 with a pressure piston 10 is arranged concentrically in the hollow cylindrical housing 4 and is connected to a first, annular oil reservoir 5 via two recesses 6 in the underside 7 of a base 8, the pressure

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piston 10 slides axially movably on an outer surface 11 of a hollow cylindrical guide sleeve 12. This guide sleeve 12 protrudes from the underside 7 of the base 8 into the interior 13 of the bucket tappet 1, is arranged concentrically on the underside 7 of the base 8 and encloses a second oil reservoir 14 for the direct supply of the clearance compensation element 9 with oil.

The oil thus passes from the first oil storage chamber 5 into the second oil storage chamber 14 via two innovative recesses 6.
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The further structure and mode of operation of the bucket tappet 1 described here will not be discussed here, as this is sufficiently known to the experts.

Figure 2 shows a partial section along the line H-II of Figure 1. Two recesses 6 in accordance with the innovation are shown in the underside 7 of the base 8. These recesses 6 have groove-shaped cross sections and are parallel and have the same dimensions.

The above-mentioned depressions 6 protrude with partial areas of their cross-section from the first, annular oil storage chamber 5 to the second oil storage chamber 14 and cover a partial area of the contact surface 15 of the guide sleeve 12.

Figure 3 shows another partial section similar to that shown in Figure 2. This shows the possibility of using play compensation elements 9 with different diameters of their guide sleeve 12 when the recesses 6 in the underside 7 of the base 8 have the same design and/or when the base 8 has the same design. The further construction corresponds to that described in Figure 2.

Figure 4 shows an additional partial section similar to that shown in Figure 2. While the recess 6 in the underside 7 of the base 8 has the same design as the recesses 6 shown previously, they extend in the radial direction.

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Reference number list

1 Tappet 2 Outer surface 3 Shirt 4 Housing 5 Oil storage room 6 Deepenings 7 bottom 8th Floor 9 Play compensation element 10 Pressure piston 11 Outer surface 12 Guide sleeve 13 Tappet inner 14 Oil storage room 15 Contact area 16 web 17 Oil spill

Claims (5)

INA Wälzlager Schaeffler KG, Industriestr. 1-3 8522 Herzogenaurach ANR 17 17 332 2359-11-DE Claims 1. Bucket tappet (1) with hydraulic valve clearance compensation, which is arranged in a receiving bore of a cylinder head of an internal combustion engine, consisting of a hollow cylindrical housing (4) closed by a base (8), in which a clearance compensation element (9) with a pressure piston (10) is arranged concentrically, which is connected via an oil passage (17) arranged in the underside (7) of the base (8) to an annular first oil storage chamber (5) radially surrounding the clearance compensation element (9), wherein the pressure piston (10) slides axially movably on an outer surface (11) of a hollow cylindrical guide sleeve (12) which, from the underside (7) of the base (8), projects into the interior (13) of the bucket tappet (1) and delimits a second oil reservoir (14) for the direct supply of the play compensation element (9), characterized in that the oil transfer (17) has at least two depressions (6) leading from the first oil reservoir (5) to the second oil reservoir (14). 2. Tappet according to claim 1, characterized in that the recesses (6) are formed in the shape of a groove directly next to one another, so that a web (16) runs between adjacent recesses (6). 3. Tappet according to claim 1 or 2, characterized in that the recesses (6) are arranged parallel to one another and are designed with substantially the same dimensions. 4. Bucket tappet according to one of claims 1 to 3, characterized in that the recesses (6) extend in the radial direction. 2359-11-EN 2 5. Tappet according to one of claims 1 to 4, characterized in that the recesses (6) preferably have a depth which does not exceed half the wall thickness of the base (8).