DE102014207631A1 - Camshaft adjuster with additional positive connection between torque transmitting parts - Google Patents

Abstract

The invention a camshaft adjuster for an internal combustion engine having a first part 10, 21, 30, 41, 80 and a second part 24, 44, 71, wherein both parts 10, 21, 24, 30, 41, 44, 71, 80 frictionally with each other are connected and whose frictional connection is provided to transmit a torque between the two parts 10, 21, 24, 30, 41, 44, 71, 80. In order to improve the frictional connection, it is proposed that the first part 10, 21, 30, 41, 80 have a surface 19, 34, 89 with shaped elements 14, 37, counterforming elements in a mating surface 18, 38, by the shaped elements 14, 37, 45 of the second part 24, 44, 71 are impressed due to the non-positive connection. As a result, the torque to be transmitted is increased by increasing the coefficient of friction in the bolt assembly, is easy to implement and can be optionally applied depending on the load case.

Description

Field of the invention

The invention relates to a camshaft adjuster for an internal combustion engine with a first part and a second part, wherein both parts are non-positively connected with each other and whose frictional connection is provided to transmit a torque between the two parts.

Background of the invention

Camshaft adjusters are used to occupy the camshaft with respect to the crankshaft with a variable phase in order to control the gas valves of an internal combustion engine so more advantageous. For camshaft adjusters, there is a wide variation spectrum, which is lifted to the type of actuator. A phaser can work on a hydraulic or electromechanical basis.

In all types of camshaft adjusters, there are parts that pass the torque transmitted from the crankshaft to the camshaft via a frictional connection. Force-fit connections are typically realized by means of a screwed-together clamping connection, in particular cover screws, wherein the clamping connection is typically also used for the cohesion of the camshaft adjuster housing. Therefore, the size of the torque to be transmitted by the strength of the positive connection, or the tightening torque of the mounting screws depends.

Out DE 10 2011 004 070 A1 is a three-shaft adjusting known, which comes in internal combustion engines for adjusting phase angles, primarily for adjusting the opening and closing times of the gas exchange valves used. In this case, the adjuster housing is formed by a drive ring gear and a stop ring, which are both connected to one another via a screw. The positive connection of the screw is additionally supported by a radial rear grip of the drive ring gear through the stop ring.

Such solutions have met the requirements so far, however, require future variable speed, and in particular with camshaft adjusters, a higher cost efficiency and ease of manufacture. In the cited prior art, both positive engagement and traction is used to ensure a torque transmission. This requires appropriate precision and the associated resources for implementation. Often, in order to produce the necessary clamping force, the tightening torque must be introduced into the screw. The screw is twisted. The torsional moment must be supported by suitable means on other components. Torsional torque and clamping force generate high stress in the cover screw. Consequently, the components must be dimensioned accordingly, whereby an increased space requirement and additional weight is implied. Added to this is the risk of hydrogen embrittlement.

Object of the invention

The invention has for its object to provide a camshaft adjuster, which can rely on a clamping compound, which minimizes the disadvantages of the prior art without affecting the genus typical properties of a camshaft adjuster.

Description of the invention

The object is achieved with a camshaft adjuster of the type mentioned above in that the first part has a surface with molded elements, counterforming elements being impressed in a mating surface of the second part due to the frictional connection by the shaped elements. The first part thus has a shaping effect on the second part, which accordingly has a passive function. During the establishment of the frictional connection, which is accomplished, for example, by a screw connection of the first to the second part, the molded on the first surface molding element imprints a counter-molding element in the opposite surface of the second part. In this way, the second part must not be prefabricated, as far as the positive connection with the first part is concerned. Instead, during the establishment of a frictional connection, that is, in a clamping, a positive engagement by plastic deformation of the second part is actively prepared. In this way, a non-positive connection of the first and the second part is coupled to a positive connection of the first and the second part.

The connected first and second part form a clamping connection, optionally with other parts of the adjuster housing and / or the camshaft adjuster. For example, it may be a Deckelschraubenklemmverband.

In an advantageous embodiment, the first part is a drive wheel, in particular a drive ring gear or a drive pulley, and the second part is a housing ring. Depending on the application, or the camshaft adjuster type, the surface and the associated mating surface can be attached to corresponding definable parts be formed of the respective camshaft adjuster. It is not important whether the torque should be transmitted from the first part to the second part or vice versa.

In the context of the invention is understood by a ring gear, for example, a drive ring gear, a wheel or ring with an internal or external toothing, wherein the wheel or the ring comprises an interior. In other words, a ring gear or a drive ring gear according to the invention does not necessarily have an internal toothing, but decisive is their property to include an interior.

In an advantageous embodiment, the surface of the first part is at least 50 HV harder than the counter surface of the second part. This may advantageously be a microforming, which is produced by the molding element and the counter-molding element. The difference in the degree of hardness of the surface and the counter surface causes a correspondingly strong impression of the counter-form element, which in turn leads to an improved form-fitting. Preferably, when establishing the frictional connection, that is, upon application of the clamping force of the cover screws, the shaped elements press into the softer mating surface in order to impress the corresponding mating elements there. In this case, the desired form fit forms the adhesion.

The first and second parts may also be identified with other parts of the phaser that are to form a compound and transmit torque.

In an advantageous embodiment, at least one of the mold elements forms a survey with a height of 0.1 to 1 millimeter. At this height, the positive locking has already reached such a strength that a significantly lower torsional moment must be used in the fastening screws, but still the same holding effect is achieved. Thus, the sizing of the required clamping screws was significantly reduced while maintaining the strength of the composite.

In an advantageous embodiment, the form elements form at least in part a knurl. With a knurling, it is an annular surface, which imprints into the counter surface. In this way, the positive connection is ensured in all directions along the contact surface between the surface and the counter surface. Material from the mating surface enters the knurling and produces the desired positive fit.

In the case of the aforementioned elevations and / or a knurling, it is advantageous if the surface portion of the elevations and / or the knurls is less than 50%, whereby the material of the counter surface is given sufficient space to penetrate into the space of the knurled form element.

In an advantageous embodiment, the mold elements are produced by prototyping, forming and / or machining. Thus, there is a very wide production range, from which in the production of the surface or the associated form elements, can be benefited. The mold elements may have been produced, for example, during a casting or injection process (prototyping). In addition, for example, forming techniques, in particular cold forming, can be used to form the shaped elements on the surface (reshaping). Alternatively or additionally, a machining operation may form the molding element or it may be specified or otherwise improved by a machining operation.

In an advantageous embodiment, the mating surface is formed of a sintered material. Sintered materials are extremely inexpensive to produce, at the same time the hardness of the sintered part can be influenced depending on the material used and the sintering technique.

In an advantageous embodiment, the mold elements are microscopic elevations formed by laser roughening, preferably with a height of 0.001 to 0.1 millimeter. The desired, additional form-fitting is achieved not only in the first place by the said height of the elevations formed by laser roughening, but secondarily also by their number. In the case of a large-scale treatment, it is quite possible to produce a considerable number of microscopic-form elements, which in total lead to a very good micro-positive fit.

In an advantageous embodiment, the surface is harder than the counter surface by at least 10 HV due to laser roughening. This results in the advantage that the first part and the second part can be made of the same material, both consequently having the same hardness. Instead of now performing a cure, such as induction hardening or the like, a laser roughening may take place instead, which additionally only generates an additional hardness of 10 HV at the surface of the first part. In this way, an advantageous difference in hardness of 10 HV between the first and the second part is produced and can advantageously also combined with the formation of the mold elements on the surface of the first part become. This does not exclude that other curing processes on the first part or its surface are also carried out in order to further increase the hardness difference.

In an advantageous embodiment, the elevations formed by laser roughening are arranged around at least one screw opening. This ensures that the clamping force transmitted by the screw head is ensured directly on the raised portions, which represent the microscopic form elements, and the corresponding microscopic counterforming elements can be advantageously formed on the counter surface.

In an advantageous embodiment, the surface and / or the mating surface, but in particular the mold elements, form reservoirs which allow a material flow to be directed in a specific direction. In this way, a toothing of the first part with the second part is much better to produce.

Further advantageous embodiments and development of the invention are specified in the description of the figures and / or the subclaims.

In the following the invention will be further described and explained with reference to the embodiments given in the figures.

Brief description of the drawings

Show it:

1A a drive disk wheel with form elements of a first embodiment in a perspective view,

1B the drive pulley off 1A in a cutaway view,

2A a detail of a camshaft adjuster of a first embodiment,

2 B an enlarged view of a terminal composite 2A .

3A a drive pulley of a second embodiment in a perspective view,

3B the drive pulley off 3A in a cutaway view,

4A a sectional view of a camshaft adjuster of a second embodiment,

4B an enlarged view of the terminal composite 4A .

5 a section through a designed as Kettenhohlrad drive ring gear of a third embodiment,

6 a section through a camshaft adjuster of the third embodiment with the Kettenhohlrad the 5 .

7 the Kettenhohlrad 5 in a perspective view, and

8th a drive pulley to the third embodiment of the 6 ,

Detailed description of the drawings

1A and 1B show a drive pulley 10 , which improves the adhesion to the housing ring 24 who in 2A is shown, a plurality of form elements 14 having circumferentially spaced from each other on the surface 19 are formed. The form elements 14 have a conical recess 13 on, which is bordered by an annular elevation, so a knurling. Furthermore, the disc-shaped part of the drive disc wheel 10 five holes 15 on, which are each provided for a clamping screw.

The drive pulley 10 is the first part according to the invention. Radially inside of the body 12 has the drive pulley 10 an internal toothing 11 which is provided for coupling to the wave generator, not shown. From the main body 12 radially outward is the disk-shaped part 16 away, the area also 19 with the form elements 14 formed.

2A and 2 B show a camshaft adjuster, in particular parts of the Verstellgetriebes within the housing, wherein it can be seen that the drive pulley 10 through the screws 27 to the housing ring 24 is clamped, wherein the housing ring 24 according to the invention acts as a second part and the drive pulley 10 as a first part. In the clamping compound is also the drive ring gear 21 with the external teeth 22 involved, but with the additional positive connection between the housing ring 24 and the drive pulley 10 , or between the opposing surface 18 and the area 19 , is trained.

The form element 14 is on the counter surface 18 pressed, with material in the conical recess 13 entry. As a result, the screw can 27 smaller dimensions, although the clamping bandage has the same stability as in pure traction with correspondingly larger sized screw.

Advantageously, there is between the counter surface 18 and the area 19 a hardness difference of at least 50 HV (Vickers hardness), whereby the required tightening torque in the manufacture of the composite is advantageously reduced without compromising its stability.

The form element 14 , and accordingly also the counter-form element, may be an increase in relation to the respective area of 1 Have millimeter, which has been made to the adhesion a substantial positive engagement.

Advantageously, in the first embodiment, a corresponding formschlussgestützter composite between the drive sprocket designed as a sprocket 21 and the housing ring 24 be formed. This may additionally or alternatively to the already formschlussverstärkten adhesion between the drive pulley 10 and the housing ring 24 happen.

Advantageously, the housing ring 24 designed as a sintered part, which leads to a cost reduction and an advantageously definable hardness of the counter surface.

3A and 3B show a drive pulley 30 , a total of five holes 35 in the area 34 on the disc-shaped part 36 having. Otherwise, the drive pulley has 30 an internal toothing 31 at the base body 32 on, as synonymous with the drive pulley 10 of the 1A the case is. According to the invention, the drive pulley 30 the first part in the second embodiment.

The holes 35 have axially on one side as an annular survey 37 executed form element 37 on, which is in the immediate vicinity of the hole 35 located.

4A and 4B show a camshaft adjuster housing in a sectional view with an included, partially imaged corrugated transmission.

The drive ring gear 41 forms together with the drive pulley 30 and the two wheels in between 30 . 41 arranged housing ring 44 a clamping bandage, by means of the screw 47 is held together positively and positively.

The drive takes place via a chain that controls the torque of the crankshaft on the external teeth 42 and thus on the drive ring gear 41 transfers.

The wave generator 48 is axially through the lid 40 covered, which is also part of the said clamping association. The torque is from the drive ring gear 41 over the housing ring 44 on the drive pulley 30 transferred, which by means of its internal toothing 31 to external teeth 45 can make the desired intervention. The external toothing 45 is mounted on a deformable, oval component, so that the corresponding phase to the cylindrical part 49 the driven wheel 46 can be produced.

In 4B it can be seen that the annular elevation 37 as a form element 37 in the opposite surface 38 has penetrated and there pronounces a Gegenformelement. The expression is extremely effective here, especially as the annular elevation 37 in close proximity to the screw 47 is arranged. Thus, the greatest possible positive connection is produced, which can be achieved by means of a clamping screw. Because the annular elevation 37 also around the screw 47 Around a positive connection for all possible directions of movement in the connection plane can be made evenly.

Also between the drive ring gear 41 and the housing ring 44 the adhesion can be improved in addition to a positive connection according to the invention. This can be done alternatively or optionally.

5 shows a section through a camshaft adjuster, which by means of a laser treatment with an additional positive connection between the drive ring gear 71 and the associated drive pulley has been provided. The driven wheel 66 is in the sectional view together with the drive ring gear 71 and its external teeth 72 displayed.

6 shows the camshaft adjuster housing with clamping compound and a wave generator contained therein 68 , In the third embodiment of 6 are two drive wheels 80 . 71 provided, wherein the drive ring gear 71 via a form fit according to the invention with the drive disk wheel 80 connected is. According to the invention, the drive pulley 80 the first part and the drive ring gear the second part. The wave gear works in the same way as in the second embodiment, but with no housing ring 44 is available. The softer component represents the drive ring gear 71 which is preferably made of a sintered material. Moldings may now be preferred on the drive pulley 80 be formed to a mating surface on the drive ring gear 71 to shape.

7 shows the drive ring gear made of a sintered material 71 which recesses 73 has, at the bottoms of a bore 74 having an internal thread. The internal thread of the holes 74 corresponds to the external thread of the screws 67 , whereby the clamping connection is produced and the counter surface 75 can be used for the expression of Gegenformelementen.

8th shows the drive pulley 80 of the third embodiment, wherein the screw openings 85 on the surface 89 with a roughened elevation 87 are surrounded. The holes 85 alternate in the circumferential direction with the holes 83 alternately, with the holes 83 Form outlet openings for the oil used as a lubricant.

In the neighborhood of the recesses 73 The clamping bandage forms on the surface 75 several Gegenformelemente to the roughened elevations 87 off, if the clamping bandage by means of screws 43 is assembled.

It is advantageous that even the drive pulley 80 can be made of a sintered material, wherein the different hardness by laser treatment of the surface 89 and only in the area of roughened surveys 87 , Alternatively, of course, a larger difference in hardness can be produced by the drive pulley 80 is made for example of a hardened molded part or forging.

Advantageously, the roughened elevations form 87 a laser structure that has a height between 0.001 to 0.01 millimeters. Here, the area proportion of roughened surveys 87 between 10 and 100% of the area 89 turn off. Such roughening by means of a laser can be caused, for example, by a continuous or pulsed laser, which can advantageously be directed onto or applied to almost any surface of a drive wheel, in particular drive ring gear or drive disk wheel. The form elements 87 can therefore be produced by pulse or continuous lasers, for example, under a rotation of the component to be machined in spiral, annular or radial-linear shape. An application-specific form is easy to achieve.

In summary, the invention relates to a camshaft adjuster for an internal combustion engine with a first part 10 . 21 . 30 . 41 . 80 and a second part 24 . 44 . 71 , where both parts 10 . 21 . 24 . 30 . 41 . 44 . 71 . 80 are positively connected with each other and their non-positive connection is provided to a torque between the two parts 10 . 21 . 24 . 30 . 41 . 44 . 71 . 80 transferred to. To improve the positive connection, it is proposed that the first part 10 . 21 . 30 . 41 . 80 an area 19 . 34 . 89 with form elements 14 . 37 having, wherein by the form elements 14 . 37 Counterforming elements in a counter surface 18 . 38 . 45 of the second part 24 . 44 . 71 are impressed due to the non-positive connection. As a result, the torque to be transmitted is increased by increasing the coefficient of friction in the bolt assembly, is easy to implement and can be optionally applied depending on the load case.

LIST OF REFERENCE NUMBERS

10

 Drive pulley / first part

11

 internal gearing

12

 body

13

 Spherical recess

14

 forming element

15

 drilling

16

 disc-shaped part

17

 annular elevation

18

 counter surface

19

 area

20

 cover

21

 Drive ring gear / first part

22

 external teeth

23

 internal gearing

24

 Housing ring / second part

25

 external teeth

26

 disc-shaped part

27

 screw

28

 wave generator

29

 cylindrical part of the drive pulley

30

 Drive pulley / first part

31

 internal gearing

32

 body

34

 area

35

 drilling

36

 disc-shaped part

37

 annular elevation

38

 counter surface

40

 cover

41

 Drive ring gear / first part

42

 external teeth

43

 internal gearing

43

 screw

44

 Housing ring / second part

45

 external teeth

46

 output gear

47

 screw

48

 wave generator

49

 cylindrical part of the output gear

60

 cover

63

 internal gearing

66

 output gear

67

 screw

68

 wave generator

69

 cylindrical part of the output gear

71

 Drive ring gear / second part

72

 external teeth

72

 body

73

 recess

74

 Bore with internal thread

75

 counter surface

80

 Drive ring gear / first part

81

 internal gearing

82

 body

83

 drilling

85

 screw opening

86

 disc-shaped part

87

 roughened elevations

89

 area

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 102011004070 A1 [0004]

Claims (10)

Camshaft adjuster for an internal combustion engine with a first part ( 10 . 21 . 30 . 41 . 80 ) and a second part ( 24 . 44 . 71 ), both parts ( 10 . 21 . 24 . 30 . 41 . 44 . 71 . 80 ) are frictionally connected to each other and whose non-positive connection is provided to a torque between the two parts ( 10 . 21 . 24 . 30 . 41 . 44 . 71 . 80 ), characterized in that the first part ( 10 . 21 . 30 . 41 . 80 ) an area ( 19 . 34 . 89 ) with form elements ( 14 . 37 . 87 ), wherein by the form elements ( 14 . 37 . 87 ) Gegenformelemente in a mating surface ( 18 . 38 . 45 ) of the second part ( 24 . 44 . 71 ) are impressed due to the non-positive connection. Camshaft adjuster according to claim 1, wherein the first part ( 10 . 21 . 30 . 41 . 80 ) a drive wheel ( 10 . 21 . 30 . 41 . 80 ), in particular a drive ring gear ( 10 . 30 . 80 ) or a drive pulley ( 21 . 41 . 80 ) and the second part ( 24 . 44 ) a housing ring ( 24 . 44 ). Camshaft adjuster according to one of the preceding claims, wherein the surface ( 19 . 34 . 89 ) of the first part ( 10 . 21 . 30 . 41 . 80 ) at least 50 HV is harder than the counter surface ( 18 . 38 . 75 ) of the second part ( 24 . 44 . 71 ). Camshaft adjuster according to one of the preceding claims, wherein at least one of the molded elements ( 14 . 37 ) forms a survey with a height of 0.1 to 1 mm. Camshaft adjuster according to one of the preceding claims, wherein the shaped elements ( 14 . 37 . 87 ) at least in part a knurling ( 17 . 37 . 87 ) train. Camshaft adjuster according to one of the preceding claims, wherein the shaped elements ( 14 . 37 ) are produced by prototyping, forming and / or machining. Camshaft adjuster according to one of the preceding claims, wherein the mating surface ( 18 . 38 . 75 ) is formed of a sintered material. Camshaft adjuster according to one of claims 1 to 3, wherein the molded elements ( 87 ) microscopic elevations formed by laser roughening ( 87 ), preferably with a height of 0.001 to 0.1 mm. Camshaft adjuster according to claim 8, wherein the surface ( 89 ) is at least 10 HV harder than the counter surface due to laser roughening ( 75 ). Camshaft adjuster according to one of claims 8 or 9, wherein the surveys formed by laser roughening ( 87 ) around at least one screw opening ( 85 ) are arranged around.

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