EP3478954B1 - Camshaft holder having bearing caps bored with an oil passage - Google Patents

Description

The invention relates to a camshaft holder intended to be fixed to a cylinder head of an internal combustion engine of a motor vehicle and a set of a cylinder head and a camshaft holder mounted on and secured to the cylinder head, the interface of the camshaft holder resting against an interface of the cylinder head.

The camshaft holder according to the invention comprises bearing caps pierced with an oil passage and the shaft holder is mounted in a single assembly on the cylinder head of the internal combustion engine.

A camshaft holder receives at least one camshaft. The camshaft is guided in rotation by means of at least two bearings, each bearing being formed by an internal cylindrical bearing secured to the periphery of the camshaft housed between two half-bearings.

The camshaft holder comprises a base supporting a succession of half-bearings, that is to say four half-bearings when there are four bearings. These half-bearings of the base are associated respectively with a half-bearing present on one of several successive bearing caps, that is to say four bearing caps in the case of four bearings.

Each bearing cap therefore has on one side a complementary half-span of a half-span of the base and each half-span of the bearing caps is removably secured to the half-span of the base, advantageously by two elements fastening through each bearing cap. Each association of a half-span of the base with a half-span of the bearing cap forms an advantageously circular bearing receiving an internal cylindrical bearing secured to the periphery of the camshaft by forming a bearing.

One face of the camshaft holder has at its periphery an interface intended to be in contact with an interface of the cylinder head. The connection between the two interfaces respectively for the camshaft holder and the cylinder head is effected by fastening elements regularly distributed around the cylinder head and the camshaft holder.

There are various cylinder head assembly architectures with at least one camshaft holder. For example, it is known a cylinder head associated with a camshaft holder lower and to an upper camshaft holder. There can also be a camshaft holder with a single bearing cap.

Frequently, a camshaft holder and its camshaft line are machined when the camshaft holder is already mounted on the cylinder head. This requires a time for mounting the camshaft holder on the cylinder head and then the line of camshafts in the camshaft holder.

In addition, for the lubrication of the camshaft and the bearings, it is no longer possible to pass through the camshaft due to the presence of variable distributions of the cam lift type and the fact that the Machining a longitudinal channel for a high pressure oil circuit on the camshaft holder is very difficult to perform in the case of a pressure foundry.

For example, the document CN-A-101956625 describes a lubrication structure for a cylinder head comprising a cylinder head body, a camshaft front bearing cap, a camshaft intermediate bearing cap and a camshaft rear bearing cap, a ring camshaft formed inside each bearing cap. An opening for the lubricating oil is made in the cap of the front bearing of the camshaft and an opening for the lubricating oil is made in the cap of the rear bearing of the camshaft. This orifice is not, however, integrated into the cylinder head, the bearing cap covering a lower half-span which, for its part, is housed in the body of the cylinder head.

Consequently, the problem underlying the invention is, on the one hand, to design a camshaft holder whose attachment to a cylinder head is simplified while having increased precision in mounting in the cylinder head and, on the other hand, to provide a high pressure lubrication circuit which is compatible with a variable distribution.

To achieve this objective, there is provided according to the invention a camshaft holder intended to be fixed to a cylinder head of an internal combustion engine of a motor vehicle, one face of the camshaft holder having at its periphery an interface intended for be in contact with an interface of the cylinder head, the camshaft holder accommodating at least one camshaft, the camshaft being inserted between a base of the camshaft holder comprising a succession of half-bearings and caps bearing each carrying on one side a half-span complementary to a half-span of the base, each half-span of the bearing caps being detachably secured to a half-span of the base, characterized in that the caps are secured to the camshaft holder projecting from the face presenting the interface, each bearing cap having a passage for lubricating oil.

The technical effect is to obtain a shaft holder mounted completely with bearing caps and camshaft, this independently of a cylinder head. The shaft carrier is in a semi-finished state, that is to say that it only remains to make adjustments, on the one hand, of the lubrication oil passages with elements such as wells present in the cylinder head and, on the other hand, shaft holder and cylinder head interfaces. Such a shaft holder can be mounted at a supplier and sent as a whole to the car manufacturer, who will make the final adjustments.

In addition, the fact of incorporating the lubricating oil passages in the bearing caps makes it possible to make the shaft carrier compatible with different types of motor, in particular motors with variable distribution. To do this, the bearing caps cover the shaft holder on its face intended to be secured to the cylinder head and not on the opposite face of the shaft holder as is conventionally the case in the prior art.

Advantageously, the passage of lubricating oil from each bearing cap passes through the bearing cap right through the side of the bearing cap carrying the half-bearing towards an opposite face projecting towards the outside of the camshaft carrier. of the face presenting the interface.

Advantageously, the passage of lubricating oil is extended by an oil duct on the opposite face projecting towards the outside of the camshaft carrier from the face presenting the interface. For each bearing cap, it is this oil conduit which is intended to penetrate most deeply into the cylinder head, for example being received in a respective well for each oil conduit arranged in the cylinder head.

Advantageously, the location of the oil passages on the bearing caps differs according to the position of the bearing cap in the camshaft holder. This may be the case in particular for the first and last bearing caps of a succession of bearing caps in the length of the shaft holder.

Advantageously, the camshaft carrier houses at least two camshafts, the half-bearings of the base and of the associated bearing caps following in the longitudinal direction of the camshaft carrier, the bearing caps associated with a first shaft. with cams being symmetrical to the bearing caps of a second camshaft with respect to the median longitudinal direction of the camshaft holder.

Advantageously, an auxiliary interface is provided which completes the interface at the periphery of the camshaft holder, the auxiliary interface forming a U interposed between said at least two camshafts of the camshaft holder with a symmetry with respect to the median longitudinal direction of the camshaft holder. The auxiliary interface defines an internal box able to receive elements associated with the internal combustion engine such as a fuel injection system.

Advantageously, the half-bearings of the bearing caps are secured by at least two fastening elements respectively to a half-span of the base to form an internal cylindrical bearing secured to the periphery of said at least one camshaft.

The invention also relates to an assembly of a cylinder head and a camshaft holder mounted on the cylinder head, the interface of the camshaft holder resting against an interface of the cylinder head, fastening elements passing through the interfaces of the camshaft holder and cylinder head, characterized in that the camshaft holder is as previously described, the bearing caps being portions of the camshaft holder most internal to the cylinder head.

Advantageously, the portions of the cylinder head facing the bearing caps have wells aligned respectively with a passage of lubricating oil or, when the passage of lubricating oil is extended by an oil duct, the wells receive in their interior respectively an oil conduit.

The invention finally relates to a method of manufacturing such an assembly of a cylinder head and a camshaft holder comprising the step of machining the camshaft holder and bearing caps with mounting of said at least a camshaft in the camshaft holder prior to mounting the camshaft holder on the cylinder head, the bearing caps being in a semi-finished state after this machining, this step being followed by the machining step the interface of the camshaft holder with the cylinder head and bearing caps, the bearing caps being integral with the camshaft holder.

The manufacturing process according to the invention therefore breaks down into two main stages, namely machining and assembly of the shaft holder independently of its positioning on the cylinder head, then positioning of the shaft holder forming a whole on and in the cylinder head with final machining of the parts in contact with the shaft holder and the cylinder head.

The fact that the adjustments concerning the bearing caps are made with the bearing caps secured to the shaft carrier allows better precision of the elements of the shaft carrier in interface with the cylinder head. With the bearing caps positioned between the rest of the shaft holder and the cylinder head, the oil circuit is internal to the cylinder head and shaft holder assembly, which could not be the case with the bearing caps positioned on the other side of the shaft holder than that applied to the cylinder head, therefore outside the cylinder head, as proposed in the document CN-A-101956625 .

• la figure 1 est une représentation schématique d'une vue en perspective d'un porte-arbre à cames selon la présente invention, le porte-arbre à cames étant équipé de chapeaux de palier faisant saillie de sa face destinée à former l'interface avec la culasse et les chapeaux de palier étant munis d'un passage d'huile de lubrification,
• la figure 2 est une représentation schématique d'une vue en perspective selon la présente invention d'une culasse présentant des chapeaux de palier d'un porte-arbre à cames selon la présente invention, le reste du porte-arbre à cames autre que les chapeaux de palier ayant été occulté à cette figure afin de rendre visible l'intégration des chapeaux de palier dans la culasse.

Other characteristics, aims and advantages of the present invention will appear on reading the detailed description which follows and with regard to the appended drawings given by way of nonlimiting examples and in which:

• the figure 1 is a schematic representation of a perspective view of a camshaft holder according to the present invention, the camshaft holder being fitted with bearing caps projecting from its face intended to form the interface with the cylinder head and the bearing caps being provided with a lubricating oil passage,
• the figure 2 is a schematic representation of a perspective view according to the present invention of a cylinder head having bearing caps of a camshaft holder according to the present invention, the rest of the camshaft holder other than the bearing caps having been obscured in this figure in order to make visible the integration of the bearing caps in the cylinder head.

It should be borne in mind that the figures are given by way of examples and are not limitative of the invention. They constitute schematic representations of principle intended to facilitate understanding of the invention and are not necessarily at the scale of practical applications. In particular, the dimensions of the various elements illustrated are not representative of reality.

In what follows, reference is made to all the figures taken in combination. When reference is made to one or more specific figures, these figures are to be taken in combination with the other figures for the recognition of the designated numerical references.

Referring to all the figures, the present invention relates to a camshaft holder 1 intended to be fixed to a cylinder head 2 of an internal combustion engine of a motor vehicle.

The figure 1 shows a camshaft holder 1 and the figure 2 shows a cylinder head 2 of a motor vehicle with bearing caps 6 forming part of the camshaft holder 1. It should be noted that the figure 2 does not correspond to reality, since, according to the invention, the bearing caps 6 are applied to the cylinder head 2 with the rest of the camshaft holder 1, this rest not being illustrated in the figure 2 to make the bearing caps 6 visible. In the context of the invention, it is the camshaft carrier 1 with all its elements and in particular its bearing caps 6 secured to the camshaft carrier 1 which is mounted on the cylinder head 2.

Referring to all the figures, one face of the camshaft holder 1 has at its periphery an interface 3 intended to be in contact with an interface 4 of the cylinder head 2. The camshaft holder 1 accommodates at least one trees cam, figure 1 two camshafts, the camshaft being inserted between a base or framework of the camshaft carrier 1 comprising a succession of half-bearings 5. The camshaft carrier 1 also comprises bearing caps 6 each bearing on one side with a complementary half-bearing and facing a half-bearing 5 of the base, these bearing caps 6 being removable from the shaft holder 1 with cams.

Each half-bearing of the bearing caps 6 is removably secured to a half-bearing 5 of the base, forming an advantageously circular bearing receiving the internal cylindrical bearing secured to the periphery of the camshaft.

According to the invention, the bearing caps 6 are secured to the camshaft carrier 1 by projecting from the face having the interface 3, each bearing cap 6 having a passage 7 for lubricating oil. According to the state of the art, it is common for the camshaft carrier 1 to have the bearing caps 6 on its face opposite to that secured to the cylinder head 2. The present invention provides the reverse configuration for which the bearing caps 6 are arranged on the face of the camshaft carrier 1 applied against the cylinder head 2. The lubricating oil is advantageously under high pressure.

The half-bearing surfaces of the bearing caps 6 can be secured by at least two fixing elements respectively to a half-bearing 5 of the base to form a internal cylindrical bearing secured to the periphery of said at least one camshaft. In the figures there are shown four bearings for the camshaft, which is not limiting.

The passage 7 of lubricating oil crosses the bearing cap 6 by a flat face intended to contact the cylinder head 2 and supporting the half-bearing by opening on the half-bearing. The lubrication oil passages 7 in the bearing caps 6 are hidden at the figure 1 by a respective oil duct 8 but oil passages 7 can be better seen at the figure 2 under reference 7 for some bearing caps 6.

The passage 7 for lubricating oil from each bearing cap 6 passes through the bearing cap 6 right through the side of the bearing cap 6 carrying the half-bearing towards an opposite face projecting towards the outside of the shaft carrier 1 with cams on the face having the interface 3. The passage 7 for lubricating oil therefore extends substantially perpendicular to the junction plane of the cylinder head 2 and of the camshaft carrier 1 or with a small angle of inclination relative to the direction perpendicular to this junction plane.

The passage 7 for lubricating oil can be extended by an oil pipe 8 on the opposite face projecting towards the outside of the camshaft carrier 1 from the face having the interface 3. Each oil pipe 8 is intended to enter a well 10 arranged in the cylinder head 2 as shown in the figure 2 for two wells 10 but there is a well for each line 8 of oil.

There can be several types of bearing caps 6 differing by their oil duct 8 and / or the positioning of the oil passage 7 on the bearing cap 6. All the bearing caps 6 can have, on the opposite face making projecting outwards from the camshaft holder 1, the opening of the oil passage 7 centered or slightly offset towards the outside of the camshaft holder 1 on this face.

Thus, the location of the oil passages 7 and / or the dimensions of the oil duct 8 on the bearing caps 6 may differ depending on the position of the bearing cap 6 in the camshaft holder 1. For example, a camshaft holder 1 can carry four bearing caps 6 per camshaft which can succeed one another in the length of the camshaft holder 1.

Without being limiting, when there is a single camshaft, the first bearing cap 6 of the succession may have a wider passage than those of other bearing caps 6 and the last bearing cap 6 may have an oil duct 8 more inclined than the other bearing caps 6, the intermediate bearing caps 6 being substantially similar.

Still without this being limiting, when there are two camshafts, the first bearing caps 6 of the two successions for the two camshafts may have a wider passage than those of the other bearing caps 6. Only the last cap bearing 6 of a camshaft can have an oil duct 8 more inclined than the other bearing caps 6, the intermediate bearing caps 6 being substantially similar for the two successions. Other configurations are of course also possible.

Thus, the camshaft holder 1 can accommodate at least two camshafts. For each camshaft, the half-bearings 5 of the base and of the associated bearing caps 6 can follow one another in the longitudinal direction of the camshaft holder 1. The half-bearings 5 associated with a first camshaft can be symmetrical to the half-bearings 5 of a second camshaft with respect to the median longitudinal direction of the camshaft holder 1. This can be valid for all the oil passages 7 and oil lines except for the oil line 8 of the last oil cap of a succession of a camshaft which can be more inclined than its screw. opposite the succession of the other camshaft.

An auxiliary interface 3a can be provided supplementing the interface 3 at the periphery of the camshaft holder 1, the auxiliary interface 3a forming a U interposed between said at least two camshafts of the camshaft holder 1 by presenting a symmetry with respect to the median longitudinal direction of the camshaft holder 1.

The auxiliary interface 3a in U can form an advantageously sealed box or made sealed for fuel injectors in the internal combustion engine housed in the cylinder head 2 or other auxiliary elements of the engine. The auxiliary interface 3a is applied against an auxiliary interface 4a carried by the cylinder head 2.

The invention also relates to an assembly of a cylinder head 2 and of a camshaft carrier 1 mounted on the cylinder head 2, the interface 3 of the camshaft carrier 1 resting against an interface 4 of the cylinder head 2, fastening elements passing through the interfaces 3, 4 of the camshaft holder 1 and of the cylinder head 2. According to the invention, the camshaft holder 1 is such as previously described, the bearing caps 6 being portions of the shaft holder 1 with cams most internal to the cylinder head 2.

Advantageously, the portions of the cylinder head 2 facing the bearing caps 6 have wells 10 aligned respectively with a passage 7 for lubricating oil or, when the passage 7 for lubricating oil is extended by a conduit 8 of oil, the wells 10 receive in their interior respectively a conduit 8 of oil.

The invention also relates to a method of manufacturing an assembly of a cylinder head 2 and a camshaft carrier 1 as previously described. The method comprises a step of machining the camshaft holder 1 and bearing caps 6 with mounting of said at least one camshaft in the camshaft holder 1 before mounting the camshaft holder 1 on the cylinder head 2.

The bearing caps 6 as well as the camshaft carrier 1 are in a semi-finished state after this machining. The step of machining the camshaft holder 1 is followed by a step of machining the interface 3 of the camshaft holder 1 with the cylinder head 2 and the passage 7 for oil in the bearing caps 6 , the bearing caps 6 being integral with the shaft holder 1 with cams.

By semi-finished state, it is understood a state where the machining of the camshaft holder 1 has been carried out and that only the machining operations remain to adjust the camshaft holder 1 to the cylinder head 2, that is to say that is to say mainly of the interface 3 and of the bearing caps 6 in particular of the oil conduits 8 having to penetrate into a respective well 10 arranged in the cylinder head 2.

The invention is in no way limited to the embodiments described and illustrated which have been given only by way of examples.

Claims (10)

1. A camshaft holder (1) intended to be attached to a cylinder head (2) of an internal combustion engine of a motor vehicle, one face of the camshaft holder (1) having at its periphery an interface (3) intended to be in contact with an interface (4) of the cylinder head (2), the camshaft holder (1) housing at least one camshaft, the camshaft being inserted between a base of the camshaft holder (1) including a series of half-seats (5) and bearing caps (6) each supporting on one side a complementary half-seat of a half-seat (5) of the base, each half-seat of the bearing caps (6) being removably secured to a half-seat (5) of the base, characterized in that the bearing caps (6) are secured to the camshaft holder (1) by protruding from the face having the interface (3), each bearing cap (6) having a passage (7) for lubricating oil.
2. The camshaft holder (1) according to Claim 1, in which the passage (7) for lubricating oil of each bearing cap (6) passes through the bearing cap (6) on the side of the bearing cap (6) supporting the half-seat towards an opposite face protruding towards the exterior of the camshaft holder (1) of the face presenting the interface (3).
3. The camshaft holder (1) according to Claim 2, in which the passage (7) for lubricating oil is extended by an oil duct (8) on the opposite face protruding towards the exterior of the camshaft holder (1) of the face presenting the interface (3).
4. The camshaft holder (1) according to any one of Claims 1 to 3, in which the location of the oil passages (7) on the bearing caps (6) differs according to the position of the bearing cap (6) in the camshaft holder (1) .
5. The camshaft holder (1) according to any one of the preceding claims, which houses at least two camshafts, the half-seats (5) of the base and of the associated bearing caps (6) following one another in longitudinal direction of the camshaft holder (1), the bearing caps (7) associated with a first camshaft being symmetrical to the bearing caps (7) of a second camshaft with respect to the median longitudinal direction of the camshaft holder (1).
6. The camshaft holder (1) according to the preceding claim, in which there is provided an auxiliary interface (3a) completing the interface (3) at the periphery of the camshaft holder (1), the auxiliary interface (3a) forming a U inserting itself between said at least two camshafts of the camshaft holder (1) by presenting a symmetry with respect to the median longitudinal direction of the camshaft holder (1).
7. The camshaft holder (1) according to any one of the preceding claims, in which the half-seats of the bearing caps (6) are secured by at least two attachment elements respectively to a half-seat (5) of the base for forming an internal cylindrical seat integral with the periphery of said at least one camshaft.
8. An assembly of a cylinder head (2) and of a camshaft holder (1) mounted on the cylinder head (2), the interface (3) of the camshaft holder (1) resting against an interface (4) of the cylinder head (2), securing elements passing through the interfaces (3, 4) of the camshaft holder (1) and of the cylinder head (2), characterized in that the camshaft holder (1) is in accordance with any one of the preceding claims, the bearing caps (6) being portions of the camshaft holder (1) the most internal to the cylinder head (2).
9. The assembly according to Claim 8, in which the portions of the cylinder head (2) opposite the bearing caps (6) have wells (10) aligned respectively with a passage (7) for lubricating oil or, when the passage (7) for lubricating oil is extended by an oil duct (8), the wells (10) receive in their interior respectively an oil duct (8).
10. A method for the production of an assembly of a cylinder head (2) and of a camshaft holder (1) according to any one of Claims 8 or 9, including the step of machining the camshaft holder (1) and bearing caps (6) with mounting of said at least one camshaft in the camshaft holder (1) prior to the mounting of the camshaft holder (1) on the cylinder head (2), the bearing caps (6) being in a semi-finished state after this machining, this step being followed by the step of machining of the interface (3) of the camshaft holder (1) with the cylinder head (2) and bearing caps (6), the bearing caps (6) being integral with the camshaft holder (1).

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