WO2015172985A1

WO2015172985A1 - Bearing bracket for mounting a camshaft

Info

Publication number: WO2015172985A1
Application number: PCT/EP2015/058679
Authority: WO
Inventors: Jürgen MEUSEL; Walter Schimmer
Original assignee: Thyssenkrupp Presta Teccenter Ag
Priority date: 2014-05-16
Filing date: 2015-04-22
Publication date: 2015-11-19
Also published as: DE102014106925A1; DE102014106925B4

Abstract

The present invention relates to a bearing bracket (1) for mounting a camshaft for the valve train of an internal combustion engine, having a main body (10) made from a main material, wherein at least one shaft leadthrough (11) for guiding through the at least one camshaft is made in the main material. According to the invention, a ring body (12) is provided which is substantially enclosed in the main material of the main body (10) and encloses the shaft leadthrough (11).

Description

Bearing bridge for the bearing of a camshaft

Description

The present invention relates to a bearing bracket for supporting a camshaft for the valve train of an internal combustion engine, comprising a base body made of a base material, wherein at least one shaft passage for passing the at least one camshaft is introduced into the base material.

STATE OF THE ART

For example, DE 10 2012 007 334 A1 shows a bearing bracket for mounting a camshaft for the valve train of an internal combustion engine, and the bearing bridge has a base body made of plastic, and in the plastic shaft passages are introduced, are inserted into the bearing rings. In the bearing rings camshafts can be rotatably mounted, so that the bearing bridges can be carried out with minimal weight, and the bearing rings can be made of a material that forms an optimal sliding partner for the camshaft. By appropriate selection of the bearing rings, therefore, an optimal bearing material can be provided. However, it can be disadvantageous here that, because of different coefficients of thermal expansion, the bearing rings can migrate out of the shaft passages, or the bearing rings can otherwise be released from the plastic and, for example, rotate with the camshaft.

Furthermore, bearing brackets for supporting a camshaft for the valve train of an internal combustion engine are known, and the main body of the bearing bridge has an aluminum material. By contrast, camshafts are often made of a steel material and there are significant differences in the case of a basic body made of aluminum and in the case of camshafts made of a steel material Expansion coefficient. In this case, it can come to a greater increase in the shaft passage in the base material of the body at a heating, while the camshaft does not increase in diameter with the same degree. For example, in a temperature range of -40 ° C to + 140 ° C, the bearing gap between the base material of the body in the shaft passage and the camshaft can greatly increase. This results in the hot run of the engine with a large bearing gap to the requirement of increased flow rate through the oil pump to maintain the hydrodynamic lubrication effect in the plain bearing between the shaft passage in the base material of the body and the camshaft.

If steel materials are used to form the bearing bridges, such a material selection leads to a high weight of the bearing bridges, which should be avoided.

Also known are cast bearing rings made of steel material, and the bearings thus form a friction pair between the camshaft and the bearing ring made of steel material, which is not necessarily optimal. The bearings can thus consist of two materials in shell construction with the disadvantage of steel-steel friction pair, also increase the cross sections of the bearing heights to achieve the component strength, which should be avoided in principle. Desirable is a friction pair for supporting the camshaft in the bearing bridge, which includes a steel material and an aluminum material.

DISCLOSURE OF THE INVENTION

The object of the invention is the development of a bearing bridge for supporting a camshaft for the valve train of an internal combustion engine, in which the bearing gap remains the same over a wide temperature range to form a bearing of the camshaft, and wherein the bearing bridge should be executed as low as possible. Furthermore, to be achieved in a simple manner, an advantageous material pairing in the storage of the camshaft.

This object is based on a bearing bridge for mounting a camshaft for the valve train of an internal combustion engine according to the preamble of claim 1 in conjunction with the characterizing features. Advantageous developments of the invention are specified in the dependent claims.

The invention includes the technical teaching that an annular body is provided, which is essentially enclosed in the base material of the base body and which encloses the shaft passage.

The essence of the invention is that the base material for providing the main body of the bearing bridge can continue to serve for the formation of the sliding mating camshaft, although a foreign body, namely the annular body which surrounds the shaft passage is enclosed in the main body of the bearing bridge. In this case, the ring body should enclose the shaft passage so that the inside of the ring body, the base material of the body is still present. The ring body thus forms a kind of reinforcement, and heats up the bearing bridge, the ring body can prevent the shaft passage increases disproportionately due to the thermal expansion of the base material. The ring body can be enclosed substantially by the base material of the body, which is not required that the ring body must always be completely enclosed. However, the substantial enclosure of the ring body requires an enclosure of at least 50%, preferably of at least 70% and more preferably of at least 85% of the surface of the ring body. In particular, in the inner side of the annular body, a certain enclosure of the annular body with the base material should be present to provide sufficient strength of the journal formed with the shaft passage in the main bearing for the bearing of the camshaft. For example, the ring body does not have to be completely enclosed in the lateral direction, or the ring body projects laterally beyond the base body.

With particular advantage, the material of the annular body may have a smaller thermal expansion coefficient than the base material of the main body. For example, the coefficient of thermal expansion of the ring body may coincide with the thermal expansion coefficient of the ring body Material from the camshaft. In particular, the material of the annular body may also be suitable for the formation of camshafts and bearing rings, in particular, the material of the annular body may coincide with the material of a camshaft, which may be stored in the shaft passage of the bearing bridge.

According to a first particularly preferred embodiment of the bearing bridge according to the invention, the material of the annular body may be formed porous and wherein the base material is at least partially infiltrated into the porous material of the annular body. For example, the base material of the base body can be made of aluminum, and if the base body is produced in a casting process, aluminum can penetrate into the porous ring body, forming a so-called infiltration. This results in a reinforcing acting ring which surrounds the shaft passage in the bearing bridge, and which is enclosed at least radially outward and radially inward with the aluminum casting material and connected thereto. The expansion coefficient of the porous material is analogous or similar to the coefficient of expansion of steel material, for example, a camshaft.

The result is a bearing bridge with a closed structure of the body, in which at least one ring body can be accommodated, and despite a possible friction pairing with the camshaft with the base material, in particular with aluminum, there is an expansion coefficient of the material area around the shaft passage around, with the coefficient of expansion of steel material for the camshaft coincides or is substantially similar to this.

With further advantage, the infiltrated base material in the ring body can increase the component strength, wherein the porous material can be formed, for example, from ceramic and / or from iron-sintered metal. The stable bearing gap over the temperature profile of the bearing bridge in arrangement on a cylinder head of an internal combustion engine can therefore be combined with the reduction of oil pump performance and an advantageous friction pair of aluminum-steel. Furthermore, the component strength of the bearing bridge can be increased by the ring body.

According to a further embodiment of the invention, the annular body may be formed by a steel ring or by a ceramic ring, which is preferably non-porous and therefore not formed for infiltration of the base material. In this case, the steel ring may be substantially enclosed by the base material of the base body and in particular encapsulated. For example, the steel ring may have a U-shaped cross-section, similar to a spool, wherein the base leg of the U-shape between the two parallel side legs inwardly into the shaft passage in, without forming the running surface of the bearing in which the camshaft is mounted , Finally, the base material can also enclose the steel ring on the inside, so that even when using a steel ring, the sliding bearing is formed by the base material of the base body. In the same way, a ring of a ceramic material can be used.

For the formation of the ring body and other body can be used advantageously. For example, the annular body can be produced by an annularly wound sheet metal, preferably a perforated sheet, or by a coiled wire with an arbitrary cross section. Or the ring body is formed by a plurality of stacked into a package and sheets, in particular perforated plates, with an annular cross-section, for example, prepared by a stamping process, are provided. These can for example be welded together, in particular via an outside seam, which connects the sheets together. The outer circumference of the ring body does not necessarily have to be round, irrespective of the design. be rotationally symmetric.

As a steel ring is presently understood any ring made of an iron base material, which may be performed in different material configurations. For example, the steel ring may comprise a sintered material, a cast material or a ferrous material in general. With further advantage, the steel ring may have holes which are substantially penetrated by the base material of the base body. The holes can be introduced laterally and / or in the base leg of the U-shaped steel ring.

According to a further advantageous embodiment for forming the bearing bridge according to the invention, the base body can be produced by a metal die casting method, wherein the ring body is encapsulated by means of an insertion through the base material. The insertion of the ring body can for example be made in a mold, in particular in a metal die casting mold. If the base material is injected into the die, then the ring body, for example embodied as a porous ring body or as a steel ring, can be encapsulated with the base material.

With particular advantage, the base material of the base body may comprise aluminum. This can be created with the bearing bridge a sliding bearing for a camshaft, which allows the material pairing aluminum-steel, when the camshaft is made of a steel material. This results in particularly advantageous running properties, wherein other materials can also be used to form the body. According to a further advantageous aspect of the invention, the annular body may have at least one radial passage through which an oil supply to the running surface of the shaft passage can be created. For example, the radial passage can be brought into coincidence with a channel in the main body, via which an oil supply of the sliding bearing is made possible.

The bearing bridge may have two shaft passages, for example for two parallel camshafts, and each shaft passage may be associated with a ring body. Consequently, the bearing bridge may comprise two annular bodies. In particular, the bearing bridge may be configured for placement on a hood body to form a camshaft module. In this case, the bearing bridge can also be integrally formed with a housing or a frame of the hood body and the same material. PREFERRED EMBODIMENTS OF THE INVENTION

Further, measures improving the invention will be described in more detail below together with the description of preferred embodiments of the invention with reference to FIGS. It shows:

Figure 1 is a perspective view of a bearing bridge and an enlarged view of a cut-through shaft passage in the bearing bridge and

Figure 2 shows another embodiment of a bearing bridge with more

Features of the present invention, wherein a ring body is formed as a steel ring, which is shown in a cut portion of a shaft passage in the bearing bridge.

Figure 1 shows a first embodiment of a bearing bridge 1 with the features of the present invention. The bearing bridge 1 can be integrated in a hood module for arrangement on a cylinder head or the bearing bridge 1 can be mounted directly on a cylinder head of an internal combustion engine. For this purpose, the bearing bridge 1 mounting dome 17 through which, for example, screw can be passed. By way of example, the bearing bridge 1 is designed with two shaft passages 11, and with the bearing bridge 1, two camshafts can be mounted running parallel to one another. The camshafts can be stored in succession by a plurality of bearing bridges 1 in an arrangement, wherein the shaft passages 1 1 of the respective bearing bridges 1 are aligned with each other.

The bearing bridge 1 consists essentially of a base body 10, which is formed of a base material, and the base material has, for example, aluminum. Due to the structure of the base body 10 shown, it can be manufactured with the base material in a metal die casting process. Subsequently, the mounting domes 17, other contact surfaces 18, which may serve as a connection surface for oil supply, for example, and the shaft passages 1 1 are machined with the running surfaces 16. As shown in the enlarged view of the cut surface in the shaft passage 1 1, the main body 10 has an enclosed therein annular body 12. The annular body 12 is bordered in the region of the shaft passage 11 so that the material of the main body 10 substantially encloses the annular body 12. In particular, the running surface 16 is not formed by the inner region of the ring body 12 itself, but by the base material of the base body 10, since this also encloses the ring body 12 on the inside. The ring body 12 is thus completely enclosed according to the embodiment shown by the base material of the body and has a larger inner diameter than the diameter of the shaft passage 1 1 in the main body 10th

The ring body 12 is shown with a porous structure indicated, and the porous material of the ring body 12 can be infiltrated with the base material, in particular during the casting process. Thereby, the ring body 12 attains an increased strength, and in particular, the ring body 12 can have a material having a thermal expansion coefficient smaller than the expansion coefficient of the base material. If the bearing bridge 1 heats up, there is no significant increase in the diameter of the shaft passage 11 and if a camshaft is mounted in the shaft passage 11, the bearing clearance in the plain bearing formed does not increase or does not increase significantly. At the same time, however, the tread 16 is obtained from the base material of the base body 10, so for example made of aluminum.

Figure 2 shows another embodiment of a bearing bracket 1 for supporting a camshaft for the valve train of an internal combustion engine, wherein the bearing bridge 1 is only partially shown, and the bearing bridge 1 also has mounting domes 17 and a contact surface 18. By way of the contact surface 18, for example, an oil supply of the sliding bearing formed with the shaft passage 1 1 may be effected by introducing into the base body 10 an oil passage 19 which opens into the contact surface 18 facing downwards. As a result, an oil supply of the shaft passage 1 1 via a radial passage 15, which must be incorporated in the ring body 12, as described in more detail below. The embodiment shows an annular body 12 in the form of a steel ring 13. The steel ring 13 has a circumferential U-shaped profile and has a plurality of holes 14 in both the side regions and in the base leg of the U-shape. If the steel ring 13 is inserted in the casting mold of the main body 10 in the casting mold, then the steel ring 13 can be completely encapsulated with the base material of the main body 10. In particular, the base material of the main body 10 may also extend through the holes 14, so that a positive fit of the steel ring 13 is secured in the base body 10. Also, this embodiment shows a shaft passage 1 1 with a tread 16, which is formed by the base material of the base body 10, so for example made of aluminum. This is made possible by the annular body 12 having an inner diameter which is greater than the diameter of the shaft passage 11.

The steel ring 13 is made of a material having a coefficient of thermal expansion, which is smaller than the coefficient of thermal expansion of the base material to form the base body 10. When the bearing bridge 1 warms up, it is ensured by the steel ring 13 that the shaft passage 1 1 with the Tread 16 in diameter is not significantly increased, in particular, the increase in the diameter of the tread 16 may have the same value as the growth of a camshaft of a steel material, when heated. As a result, the bearing clearance of the plain bearing of the camshaft formed with the shaft passage 1 1 remains essentially the same over a wide temperature range. Furthermore, the sliding bearing with the shaft passage 1 1 have a pair of materials, which is formed of the materials aluminum-steel.

The invention is not limited in its execution to the above-mentioned preferred embodiments. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. All features resulting from the claims, the description or the drawings and / or Advantages, including constructional details, spatial arrangements, can be essential to the invention, both for themselves and in the most diverse combinations.

Designation of the bearing yoke Main body

Shaft passage

ring body

steel ring

hole

radial passage

tread

Montagedom

contact surface

oil passage

Claims

Patent claims

1 . Bearing bridge (1) for mounting a camshaft for the valve train of an internal combustion engine, comprising a base body (10) made of a base material, wherein in the base material at least one shaft passage (1 1) is introduced for passing the at least one camshaft,

characterized in that an annular body (12) is provided, which is substantially enclosed in the base material of the base body (10) and which surrounds the shaft passage (1 1).

Second bearing bridge (1) according to claim 1, characterized in that the material of the annular body (12) has a smaller thermal expansion coefficient than the base material.

3. Bearing bridge (1) according to claim 1 or 2, characterized in that the material of the annular body (12) is porous and wherein the base material is at least partially infiltrated in the porous material of the annular body (12).

4. bearing bridge (1) according to one of claims 1 to 3, characterized in that the material of the annular body (12) is suitable for the formation of camshaft bearing rings.

5. bearing bridge (1) according to claim 1, characterized in that the annular body

(12) is formed by a steel ring (13) or by a ceramic ring, which is substantially enclosed by the base material of the base body (10) and in particular encapsulated.

6. bearing bridge (1) according to claim 5, characterized in that the steel ring

(13) has holes (14) which are substantially penetrated by the base material of the base body (10).

7. bearing bridge (1) according to claim 5 or 6, characterized in that the steel ring (13) has a U-shaped cross-section, wherein the base leg of the U-shape inwardly in the shaft passage (1 1) points.

8. Bearing bridge (1) according to any one of the preceding claims, characterized in that the base body (10) is produced by a metal die-casting process, wherein the annular body (12) is surrounded by an insertion into a mold or a die casting through the base material.

9. bearing bridge (1) according to one of the preceding claims, characterized in that the base material of the base body (10) comprises aluminum.

10. Bearing bridge (1) according to one of the preceding claims, characterized in that the annular body (12) has at least one radial passage (15) through which an oil supply to the running surface (16) of the shaft passage (1 1) is created.

1 1. Bearing bridge (1) according to one of the preceding claims, comprising two shaft passages (1 1) with two associated ring bodies (12).

12. Bearing bridge (1) according to one of the preceding claims, designed for mounting on a hood body to form a camshaft module.