DE102014110674A1 - Method for adjusting an axial clearance between two components of a camshaft - Google Patents

Abstract

The present invention relates to a method for adjusting an axial clearance between components of a camshaft and such a camshaft, wherein the camshaft has a fundamental shaft extending through the components and wherein the components have respective sliding surfaces which can slide against each other to form an axial play. According to the invention, the method has at least the following steps:
Coating at least one of the sliding surfaces with a detachable coating;
- Assembling the camshaft with at least the first and the second component, which are axially joined together without play;
- Commissioning of the camshaft, wherein the coating at least partially dissolves and
- Formation of axial play with the thickness of the dissolved part of the coating.

Description

The present invention relates to a method for adjusting an axial clearance between components of a camshaft, wherein the camshaft has a fundamental shaft extending through the components and wherein the components have respective sliding surfaces which can slide against each other to form an axial play.

STATE OF THE ART

Camshafts are received for rotatable assembly in a cylinder head or, for example, in a hood module which is arranged together with one or two camshafts on a cylinder head of the internal combustion engine. For rotatably supporting the camshafts are often plain bearings, which are designed as radial bearings. The components of the camshaft may cam elements, bearing rings, adjusting elements, drive wheels or, for the purposes of the present invention, the components of the camshaft may also include bearing blocks that are received on the fundamental and may be isolated or the bearing blocks are in conjunction with the hood module and form part of the hood module.

The bearing blocks can thus be part of the receiving body for rotatably receiving the camshaft, or the bearing blocks are to be individually arranged on the camshaft, and for rotatably receiving the camshaft on the receiving body, the bearing blocks can finally be mounted in the assembled assembly together with the camshaft on the receiving body, for example a screw connection.

For axial guidance of the camshaft, at least one component serves for supporting against a further component on the camshaft, for example a cam element against a bearing block. For correct operation of the camshaft axial play of the camshaft must be adjusted, whereby the setting of a required axial play is associated with difficulties when, for example, cam elements are placed on the fundamental shaft of the camshaft. The setting of the cam elements on the fundamental shaft is carried out under application of a high setting force, especially when the setting of the cam elements takes place with the prior formation of a rolling profile on the fundamental shaft. The adjustment of the axial play must take place under very high forces in this rolling and setting process, which is consequently associated with assembly problems.

Depending on the design of the camshaft, it may also be necessary to set an axial clearance between two rotating components of the camshaft. For example, adjusting cam elements are known, which comprise at least a first and at least one second cam element, which can be adjusted on the fundamental shaft of the camshaft over a limited angular range to each other. An axial clearance between the two adjacent cam elements must be set accordingly. If the cam elements which are applied resting on the fundamental shaft are set by a rolling and setting method as described above by the application of high forces, the difficulty arises of precisely setting the axial clearance between the cam elements. In particular, when the components adjoin one another, a subsequent machining of the lateral sliding surfaces is no longer possible.

Exemplary shows the DE 20 2006 018 359 U1 a camshaft with multiple components such as cam elements, drive wheel, sensor ring, pump cams or the like. In particular, bearing blocks are accommodated on the camshaft. If the camshaft is to be assembled with a rolling and setting method by placing the components of the camshaft on the fundamental shaft, then the axial accuracy of the setting position of the cam element must be correspondingly high. In particular, a high accuracy is required between the cam elements and the bearing blocks, since the cam elements have axially aligned sliding surfaces, which slide on opposite axial sliding surfaces on the bearing blocks and thus axially support the camshaft.

The DE 103 03 601 A1 shows a camshaft having a plurality of components, which are designed as cam elements and seated in a package assembly on the fundamental shaft of the camshaft. Here, two fixedly connected to an outer shaft cam elements enclose a rotatable cam member which is connected to an inner shaft. The gaps between the cam elements must have a small bearing clearance, and if the outer cam elements are pressed onto the outer shaft in the longitudinal compression by a rolling-setting method, the difficulty is to adjust the relatively small axial clearance.

DISCLOSURE OF THE INVENTION

The object of the invention is the development of a method for easy adjustment of an axial play between components of a camshaft, wherein the components can preferably be placed on the fundamental shaft by a roller burnishing method.

This object is achieved on the basis of a method for adjusting an axial clearance according to the preamble of claim 1 and starting from a camshaft according to the preamble of claim 7 with the respective characterizing features. Advantageous developments of the invention are specified in the dependent claims.

• – Beschichten wenigstens einer der Gleitflächen mit einer lösbaren Beschichtung;
• – Zusammenbau der Nockenwelle mit wenigstens einer ersten und einer zweiten Komponente, die axial spielfrei aneinandergefügt werden;
• – Inbetriebnahme der Nockenwelle, wobei sich die Beschichtung wenigstens teilweise auflöst und
• – Bildung des Axialspiels mit der Dicke des aufgelösten Teils der Beschichtung.

The method according to the invention has at least the following steps:

• Coating at least one of the sliding surfaces with a detachable coating;
• - Assembly of the camshaft with at least a first and a second component, which are joined axially backlash-free;
• - Commissioning of the camshaft, wherein the coating at least partially dissolves and
• - Formation of axial play with the thickness of the dissolved part of the coating.

The inventive method allows a simplified setting of the components on the fundamental wave with the roll-setting method, and adjoining components can be joined together without play by a "block set", without having to pay attention to an axial play. For example, two or three components can be assembled in blocks by pressing the components together using the roller burnishing method. As a result, an axial stop can be formed, for example, by a first component for a second component, so that the components, for example cam elements adjacent to a bearing block, can be joined with high forces occurring during the rolling and setting process.

If the camshaft is then put into operation, the coating dissolves partially or completely, and the bearing clearance generated corresponds to the former thickness of the coating or the part thereof. The coating is at least so hard that it can withstand the axial forces that arise when attaching the components together. For the purposes of the present invention, the coating does not necessarily adhere to the sliding surface and can also be present, for example, in the form of a substantially inherently dimensionally stable disk or the like.

Advantageously, the coating can be dissolved by an abrasion process by the sliding surface opposite the coating, ie a further component, when the camshaft is put into operation. The coating can also be oil-soluble and / or heat-soluble, so that the coating is dissolved by oil, in particular oil for lubricating the camshaft, or by heat, when the camshaft is put into operation.

According to an advantageous embodiment, the coating can be formed from a bonded coating or from an oil-soluble paper pulp. The coating, for example the lubricating varnish or the paper pulp, can be applied over the whole area to the lateral sliding surface of the component, wherein advantageously the coating can also be applied only to a limited extent to a partial region, in particular locally limited on the sliding surface. For example, a plurality of subregions may be provided which are formed selectively or at least locally limited to segments of the circular sliding surface by the coating.

The inventive method provides for the commissioning of the camshaft to dissolve the coating and to form the axial play, and the commissioning of the camshaft, for example, can be made only in arrangement on a cylinder head of an internal combustion engine, ie in the later operating environment. For example, the coating can be dissolved by an ordinary startup of the camshaft or a camshaft module, in which the camshaft is received. Alternatively, even before the actual commissioning of the camshaft they are put into operation on an inlet level, especially when coating materials are used which are not later to get into the oil circuit of the internal combustion engine. Advantageously, however, the coating can be formed by a substance which causes no damage by the solid solution in the oil during operation of an internal combustion engine. The finely dissolving constituents of the coating can be deposited, for example, via filter systems in the internal combustion engine.

Under a commissioning can be understood in the present context, the use of the camshaft in the intended environment or on an inlet. However, the commissioning of the camshaft can already be seen in the fact that the camshaft, for example, is subjected to a cleaning or preservation process by which the coating can also already be partially or completely dissolved. In the present case, commissioning means any further action on the camshaft after assembly of the components, by means of which the coating can be at least partially dissolved.

For example, the shows DE 10 2009 009 664 A1 a principle of transport protection based on a dissolvable material, and the camshaft is put into operation, so triggers the substance forms to form the transport safety device, and the substance of the transport safety device can be deposited over the oil.

The method according to the invention provides for such a substance to form a coating which allows an axial play, wherein likewise the substance of the coating can be dissolved for example by wear, by heat or by chemical decomposition.

The invention further relates to a camshaft having a fundamental shaft and having at least two components through which the fundamental shaft extends and wherein the components have respective sliding surfaces which can slide against each other to form an axial play, and it is a coating on at least one of Sliding surfaces provided, which is solvable by commissioning the camshaft.

In this case, a first component and / or a second component can be formed co-rotating with the camshaft and the components can be formed, for example, by a cam element or by a bearing ring. Furthermore, a first component may be formed co-rotating with the camshaft and a second component may be formed by a non-co-rotating bearing block for supporting the camshaft. This results in a sliding movement of the two sliding surfaces on each other, so that, for example, the side surface of a rotating cam element slides on a side surface of the bearing block. For example, the coating may be applied to one of these side surfaces.

Alternatively, the components between which the axial play is to be formed may also be formed only by cam elements, for example in association with a Verstellnockenpaketes. Verstellnockenpakete can be adjusted against each other, for example, via an outer shaft and an inner shaft received concentrically in the outer shaft, wherein the lateral sliding surfaces of the cam elements can hold a coating according to the invention. If the adjusting cam package is brought into operation by adjusting movements of the cam elements to each other, the coating can dissolve in the manner described above, and a required axial play is established, although the cam elements were initially set to block with the inclusion of the coating and, for example, initially only sluggish moves to each other can be.

According to a further aspect of the invention, the coating may be present on the cam elements and close a gap to an adjacent component, perform a sealing function to prevent the ingress of grinding dust between or under the cam elements during grinding of the cam elements.

The coating may for example be made detachable by abrasion from the sliding surface of the component or the coating may be oil-soluble and / or heat-soluble. It is also possible that the coating is formed of a bonded coating or of an oil-soluble paper pulp.

The coating may be, for example, thicknesses of a few micrometers, for example two micrometers to, for example, 500 micrometers. If a higher axial clearance is required, for example, two sliding surfaces sliding on each other can have respective coatings, so that an axial play of up to one millimeter or more can be produced.

PREFERRED EMBODIMENTS OF THE INVENTION

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

1 a first embodiment of a camshaft, which can be formed using a coating with the method according to the invention with an axial play,

2 the embodiment of the camshaft according to 1 , wherein two coatings are provided and

3 a further embodiment of a camshaft with a Verstellnockenpaket.

The 1 and 2 show two embodiments of a camshaft 1 , and the camshaft 1 can be mounted on the inventive method, by between individual components 11 . 12 the camshaft 1 a required axial clearance is adjustable in a simple manner.

The camshaft 1 has a fundamental wave 10 on, which is shown in sections. On the fundamental wave 10 are three components 11 . 12 recorded, and the components 11 . 12 adjoin one another.

The outer components 11 are exemplary by cam elements 18 formed, and the middle component 12 forms a bearing block 21 , and about the bearing block 21 can the camshaft 1 rotatable in a cylinder head or for example one Camshaft module can be added. For this purpose, several bearing blocks 21 over the entire length of the fundamental 10 can be provided, moreover, more than two cam elements 18 on the fundamental wave 10 to be ordered.

For mounting the components 11 . 12 can the cam elements 18 via a roller burnishing method on the outside of the fundamental 10 be placed, and in the known Rollier-Setz-method is applying a generally large axial force, the cam elements 18 pushed to the place of setting. Around the components shown 11 . 12 on the fundamental wave 10 to add, so can the first cam element 18 on the fundamental wave 10 then the component becomes 12 , namely the bearing block 21 , to the fundamental wave 10 deferred and thereby the further cam element 18 via the rolling and setting method on the fundamental 10 placed. When placing the second cam element 18 Can this against the bearing block 21 and against the first cam element 18 be pushed on block, leaving all three components 11 and 12 directly adjacent to each other or even axially slightly biased.

In 1 is a coating 17 shown, for example, on the lateral sliding surface 14 of the cam element 18 has been applied. In the same way, the coating 17 also on the sliding surface 15 of the bearing block 21 be upset.

In 2 Both have joints between the cam elements 18 and the bearing block 21 a coating 17 on, so that in an axial play of three components 11 and 12 also two coatings 17 can be included.

Will the camshaft 1 put into operation by the fundamental wave 10 is rotated while the bearing block 21 does not rotate, so the coating can 17 for example, wear off and dissolve completely. Alternatively to abrasive removal of the coating 17 It may also dissolve in or through oil, decompose by chemical reactions or be dissolved by thermal action. Because the coating 17 an axial thickness on the sliding surface 14 or 15 This thickness forms the later axial play according to the present invention. In the later, permanent operation of the camshaft 1 is the coating 17 has been removed by a dissolution, so that the corresponding bearing clearance remains set.

3 shows a further embodiment of a camshaft 1 with a fundamental wave 10 that is an outside wave 22 and an inner shaft 23 includes. The inner shaft 23 is in the tubular outer shaft 22 introduced and can be twisted in this. About a cross pin 24 is a cam element 20 with the inner shaft 23 rotatable, with more cam elements 19 on the outside 22 firmly seated and the cam element 20 enclose on both sides. In this case, the cam elements 19 in a known manner via the rolling-setting method on the outer shaft 22 be put on.

In the joint between the cam element 20 that with the inner shaft 23 is rotatable and the cam elements 19 there is a coating 17 , The coating 17 is for example on the sliding surface 14 of the cam element 19 or on the sliding surface 16 of the cam element 20 been applied before the cam elements 19 . 20 were added in a package arrangement. For example, only one coating is shown 17 , which also continue on both sides of the cam element 20 can be provided. In doing so, the coatings must 17 not necessarily be formed the same thickness and they may, for example, between different components have a different thickness.

Will the camshaft 1 put into operation, so in operation, the middle cam element 20 between the two outer cam elements 19 twisted over an angle segment. If the coating dissolves either due to wear or oil or another chemical reaction, a desired axial play arises between the cam elements 19 and 20 as this coating 17 this is removed.

The invention is not limited in its execution to the above-mentioned preferred embodiment. Rather, a number of variants is conceivable, which makes use of the illustrated solution even with fundamentally different types of use. All of the claims, the description or the drawings resulting features and / or advantages, including structural details or spatial arrangements may be essential to the invention both in itself and in various combinations.

LIST OF REFERENCE NUMBERS

1

 camshaft

10

 fundamental wave

11

 component

12

 component

13

 component

14

 sliding surface

15

 sliding surface

16

 sliding surface

17

 coating

18

 cam member

19

 cam member

20

 cam member

21

 bearing block

22

 outer shaft

23

 inner shaft

24

 cross pin

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 202006018359 U1 [0006]
• DE 10303601 A1 [0007]
• DE 102009009664 A1 [0017]

Claims (12)

Method for adjusting an axial clearance between components ( 11 . 12 . 13 ) a camshaft ( 1 ), wherein the camshaft ( 1 ) a fundamental wave ( 10 ) characterized by the components ( 11 . 12 . 13 ) and wherein the components ( 11 . 12 . 13 ) respective sliding surfaces ( 14 . 15 . 16 ), which can slide against each other to form an axial clearance, the method comprising at least the following steps: coating at least one of the sliding surfaces ( 14 . 15 . 16 ) with a detachable coating ( 17 ); - assembly of the camshaft ( 1 ) with at least a first and a second component ( 11 . 12 . 13 ), which are joined together axially backlash-free; - Commissioning of the camshaft ( 1 ), whereby the coating ( 17 ) at least partially dissolves and - forming the axial play with the thickness of the dissolved part of the coating ( 17 ). Method according to claim 1, characterized in that the coating ( 17 ) by an abrasion process by the coating ( 17 ) opposite sliding surface ( 14 . 15 . 16 ) is resolved when the camshaft ( 1 ) is put into operation. Method according to claim 1 or 2, characterized in that the coating ( 17 ) is oil-soluble and / or heat-soluble, so that the coating ( 17 ) by an oil, in particular for lubrication of the camshaft ( 1 ), or is dissolved by heat, when the camshaft ( 1 ) is put into operation. Method according to one of claims 1 to 3, characterized in that the coating ( 17 ) is formed from a lubricating varnish or from an oil-soluble paper pulp. Method according to one of the preceding claims, characterized in that the coating ( 17 ) limited to a partial area, in particular locally limited on the sliding surface ( 14 . 15 . 16 ) is applied. Method according to one of the preceding claims, characterized in that the commissioning of the camshaft ( 1 ) is made in arrangement on a cylinder head of an internal combustion engine. Camshaft ( 1 ) with a fundamental wave ( 10 ) and with at least two components ( 11 . 12 . 13 ), through which the fundamental wave ( 10 ) and wherein the components ( 11 . 12 . 13 ) respective sliding surfaces ( 14 . 15 . 16 ), which can slide against each other to form an axial play, characterized in that at least one of the sliding surfaces ( 14 . 15 . 16 ) a coating ( 17 ) by commissioning the camshaft ( 1 ) is solvable. Camshaft ( 1 ) according to claim 7, characterized in that a first component ( 11 ) and / or a second component ( 13 ) with the camshaft ( 1 ) is formed co-rotating and by a cam member ( 18 . 19 . 20 ) or is formed by a bearing ring. Camshaft according to claim 7 or 8, characterized in that a first component ( 11 ) with the camshaft ( 1 ) is formed co-rotating and that a second component ( 12 ) by a non-rotating bearing block ( 21 ) for the bearing of the camshaft ( 1 ) is formed. Camshaft according to one of claims 7 to 9, characterized in that the components ( 11 . 13 ) by cam elements ( 19 . 20 ) are formed, which form a Verstellnockenpaket. Camshaft according to one of claims 7 to 10, characterized in that the coating ( 17 ) by abrasion from the sliding surface ( 14 . 15 . 16 ) of the component ( 11 . 12 . 13 ) is detachably formed. Camshaft according to one of claims 7 to 11, characterized in that the coating ( 17 ) is dissolvable by a chemical reaction, in particular that the coating ( 17 ) is oil-soluble and / or heat-soluble and / or that the coating ( 17 ) is formed of a lubricating varnish or of an oil-soluble paper pulp.

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