DE102021200219A1 - sliding cam assembly - Google Patents

Abstract

Sliding cam arrangement, comprising a support shaft (1) with a support shaft longitudinal axis (L) and at least one non-rotatable and axially displaceable slide cam (2) accommodated on the support shaft (1), wherein the slide cam 2 has an opening (24) for receiving the support shaft (1). which is equipped with an inner slide spline (241) comprising slide spline teeth (2411) and the support shaft (1) is equipped with an outer slide spline (11) comprising slide spline teeth (111), wherein the slide cam assembly is equipped with a latching device (3). which is set up to releasably fix the sliding cam (2) in a first axial position and at least one second axial position, the latching device comprising at least one sliding tooth (242) of the inner sliding toothing (241) which is wider than adjacent sliding toothing teeth (2411).

Description

The present invention relates to a slide cam assembly according to the preamble of claim 1.

Sliding cam assemblies of the aforementioned type are, for example, from DE 10 2004 011 586 A1 , DE 10 2011 084 043 A1 and DE 10 2009 005 731 A1 known.

the DE 10 2004 011 586 A1 describes, for example, a slide cam assembly with a latch for the slide cam. The locking device consists of a locking element arranged in the camshaft bearing, which engages in locking grooves machined into the cam carrier. In the case of a cam carrier with two cams, each of which has two cam tracks, two axially adjacent locking grooves are required in the cam carrier, in which the locking element engages.

the DE 10 2011 084 043 A1 describes a slide cam assembly with a locking device. For the sliding cam arrangement, it is provided here that the direction of the force component or the resulting force component of the locking device or devices is selected such that the backlash between the base shaft and the sliding cam in the end region of the base circle phase is eliminated as seen in the direction of rotation.

the DE 10 2009 005 731 A1 describes a sliding cam arrangement with a detent device in which it is provided that the bore is a through bore in which two spring-loaded detent balls are arranged.

With a detachable axial fixation of the sliding cam relative to the support shaft by means of a locking device, in particular by means of a ball-spring mechanism, only a part can be implemented as an axial force component due to the force of the spring in relation to the locking contour. In order to achieve the desired holding force, the spring force should be correspondingly high, which in turn leads to high contact forces or pressures and thus to wear on the locking contour and/or ball.

This is where the present invention comes in and sets itself the task of providing an improved sliding cam arrangement that overcomes the disadvantages outlined above, or at least brings about improvements. In particular, a sliding cam arrangement is to be provided whose latching device is less subject to wear and/or a reduction in the contact forces or pressures to a level of material durability while ensuring the same holding function. In this context, material durability means the permissible surface pressure for the respective material. In other words, what stresses can the material withstand. The permissible surface pressure / stress depends in particular on the material parameter, the yield point and the tensile strength.

According to the invention, this object is achieved by a sliding cam arrangement having the characterizing features of claim 1. Due to the fact that the locking device comprises at least one sliding tooth of the inner sliding toothing which is wider than the adjacent sliding toothing teeth, an improved sliding cam arrangement can be provided, in particular a sliding cam arrangement whose locking device is less subject to wear and/or in which the pressures are reduced to a level of material durability while ensuring the same holding function can.

In an advantageous embodiment of the present invention, it can be provided that the latching device comprises at least one recess for receiving the widened sliding toothing between adjacent sliding toothing teeth of the outer sliding toothing. The recess can also be designed as a missing sliding gear tooth or missing sliding gear teeth in this area.

In a further advantageous embodiment of the present invention, it can be provided that the sliding cam arrangement comprises at least one further sliding tooth of the inner sliding toothing which is wider than adjacent sliding toothing teeth. Such a further broadened sliding tooth can be part of a further latching device, but also part of a further guide.

In a further advantageous embodiment of the present invention, it can be provided that the sliding cam arrangement comprises at least one further recess between adjacent sliding toothing teeth of the outer sliding toothing for receiving an enlarged sliding toothing tooth. Such a further recess can be part of a further latching device, but also part of a further guide.

In a further advantageous embodiment of the present invention can be provided that the number and / or their angular offset of the widened sliding teeth and / or the recesses based on the field of application Sliding cam arrangement, in particular the engine concept, is selected. The number of further additional recesses is preferably dependent on the respective engine concept. For example, in the case of a 4-cylinder engine with variable valve lift switching, it is advantageous in terms of production technology that the recesses in the support shaft are evenly distributed or the teeth in the sliding cam are widened. In the case of a 3-cylinder engine, there are then three recesses with an offset of 120°. In principle, the number and distribution depends on the application and the engine and valve lift changeover concept, in particular 3/4/5/6 cylinder engines, 2, 3, 4, 5, 6 cylinders with valve changeover.

In a further advantageous embodiment of the present invention, it can be provided that the widened sliding toothing tooth or teeth run parallel to the longitudinal axis of the support shaft.

In a further advantageous embodiment of the present invention, it can be provided that the latching device comprises a latching element/spring combination.

In a further advantageous embodiment of the present invention, it can be provided that the latching element/spring combination comprises a spring and a ball as the latching element. A ball as a locking element is particularly advantageous. The ball can advantageously slide or roll on a correspondingly shaped surface of the widened sliding tooth. Only a very small amount of wear is to be expected.

In a further advantageous embodiment of the present invention, it can be provided that the locking element and the spring of the locking element-spring combination are accommodated in a radially aligned opening in the support shaft. Correspondingly, the latching element can be pressed into the opening against the spring force and the sliding cam can be displaced on the support shaft.

In a further advantageous embodiment of the present invention, it can be provided that the sliding cam arrangement is equipped with a plurality of radially aligned openings for locking element-spring combinations, with the openings each being introduced rotated by the ignition angle, for example by 90° offset for a 4-cylinder engine , 120° offset for a 3-cylinder engine, for an in-line 6-cylinder engine 60° offset, for a 5-cylinder engine 72° offset, etc. This can preferably mean that the same widened sliding toothing can always be used for the detent of all sliding cams . A 180° offset of radially aligned openings for locking element-spring combinations in a 4-cylinder engine with cylinder deactivation on two cylinders is also conceivable.

In a further advantageous embodiment of the present invention, it can be provided that the widened sliding tooth has a surface facing the support shaft. This surface essentially serves as a support for the latching element and can be optimized for the intended use by appropriate design. As a result, the properties of the locking device, in particular with regard to low wear and/or reduction of the pressures to a level of material wearability while ensuring the same holding function, can be further improved.

In a further advantageous embodiment of the present invention, it can be provided that the surface of the widened sliding tooth is adapted to the adjacent contour of the locking element, in particular the ball. As a result, the properties of the latching device, in particular with regard to the low degree of locking and/or reduction of the pressures to a level of material wearability while ensuring the same holding function, can be further improved.

• - einen ersten Bereich (I) mit abfallender Oberfläche,
• - einen zweiten Bereich (II) mit ebener Oberfläche,
• - einen dritten Bereich (III) mit ansteigender Oberfläche,
• - einen vierten Bereich (IV) mit ebener Oberfläche,
• - einen fünften Bereich (V) mit abfallender Oberfläche,
• - einen sechsten Bereich (VI) mit ebener Oberfläche, sowie
• - einen siebten Bereich (VII) mit ansteigender Oberfläche aufweist.

In a further advantageous embodiment of the present invention, it can be provided that the widened sliding tooth, in particular the surface of the sliding tooth facing the support shaft, in the axial direction relative to the longitudinal axis of the support shaft

• - a first area (I) with a sloping surface,
• - a second area (II) with a flat surface,
• - a third region (III) with a rising surface,
• - a fourth area (IV) with a flat surface,
• - a fifth area (V) with a sloping surface,
• - a sixth area (VI) with a flat surface, as well as
• - has a seventh region (VII) with a rising surface.

In particular, the latching contour outlined above enables the sliding cam to be releasably fixed, optionally at a first or second axial position, and a corresponding displacement by pressing the latching element against the spring force into the opening.

• 1 eine erfindungsgemäße Nockenwellenanordnung in einer perspektivischen Ansicht;
• 2 eine erfindungsgemäße Nockenwellenanordnung in einer seitlich geschnittenen Ansicht mit dem Schiebenocken in einer ersten axialen Position;
• 2a eine erfindungsgemäße Nockenwellenanordnung in einer seitlich geschnittenen Ansicht mit dem Schiebenocken in einer Position zwischen der ersten axialen Position und der zweiten axialen Position;
• 2b eine erfindungsgemäße Nockenwellenanordnung in einer seitlich geschnittenen Ansicht mit dem Schiebenocken in einer zweiten axialen Position;
• 3 eine perspektivische Ansicht auf die Innenverzahnung des Schiebenockens;
• 4 ein Schnitt X-X gemäß 2a;
• 5 eine vergrößerte Darstellung «Detail X» gemäß 4;
• 6 eine perspektivische Darstellung der Tragwelle;
• 7 eine Querschnittdarstellung des Verschiebenockens mit vier verbreiterten Schiebeverzahnungszähnen;
• 8 eine Querschnittdarstellung des Verschiebenockens mit einem verbreiterten Schiebeverzahnungszahn.

Further features and advantages of the present invention become clear from the following description of preferred exemplary embodiments with reference to the attached figures. show in it

• 1 a camshaft assembly according to the invention in a perspective view;
• 2 a camshaft assembly according to the invention in a side sectional view with the sliding cam in a first axial position;
• 2a a camshaft assembly according to the invention in a side sectional view with the shift cam in a position between the first axial position and the second axial position;
• 2 B a camshaft assembly according to the invention in a side sectional view with the sliding cam in a second axial position;
• 3 a perspective view of the internal teeth of the sliding cam;
• 4 a cut XX according to 2a ;
• 5 an enlarged view according to «Detail X» 4 ;
• 6 a perspective view of the support shaft;
• 7 a cross-sectional view of the shift cam with four widened shift gear teeth;
• 8th a cross-sectional view of the shift cam with an enlarged shift gear tooth.

R

Rastierungskontur

L

Tragwellenlängsachse

1

Tragwelle

2

Schiebenocken

3

Rastvorrichtung

11

(äußere) Schiebeverzahnung der Tragwelle

12 (a-c)

Aussparung

21

erste Nockenanordnung

22

zweite Nockenanordnung

23

Schaltkulisse

24

Öffnung

32

Feder

33

Rastelement, insbesondere Kugel

34

Öffnung

111

Schiebeverzahnungszahn (der Schiebeverzahnung der Tragwelle)

211

erster Nocken

212

zweiter Nocken

221

erster Nocken

222

zweiter Nocken

241

(innere) Schiebeverzahnung des Schiebennockens

242 (a-c)

verbreiterter Schiebeverzahnungszahn

2411

(angrenzender) Schiebeverzahnungszahn

2421

Oberfläche des verbreiterten Schiebeverzahnungszahns

In particular, the following reference symbols are used in the figures:

R

detent contour

L

Longitudinal axis of the supporting shaft

1

supporting shaft

2

sliding cam

3

locking device

11

(Outer) sliding toothing of the support shaft

12 (ac)

recess

21

first cam arrangement

22

second cam arrangement

23

shift gate

24

opening

32

Feather

33

Latching element, in particular ball

34

opening

111

Sliding spline tooth (of the sliding spline of the support shaft)

211

first cam

212

second cam

221

first cam

222

second cam

241

(inner) sliding teeth of the sliding cam

242 (ac)

widened sliding tooth

2411

(adjacent) sliding spline tooth

2421

Surface of the widened sliding spline tooth

First, reference is made to FIG.

A sliding cam arrangement essentially comprises a support shaft 1 with at least one sliding cam 2. The sliding cam 2 is held on the support shaft 1 in a rotationally fixed but axially displaceable manner. For this purpose it can be provided, for example, that the sliding cam 2 has an opening 24 for receiving the support shaft 1, which is equipped with an inner sliding toothing 241 and the supporting shaft 1 is also equipped with an outer sliding toothing 11. The sliding cam 2 has a first cam arrangement 21 with a first cam 211 and at least one second cam 212 . The cams 211 and 212 differ in terms of their cam contour, which can also be implemented in that the cams have different phase positions. The sliding cam 2 can also be equipped with at least one additional, second cam arrangement 22 . The second cam arrangement 22 can in turn be equipped with a first cam 221 and at least one second cam 222 . The cams 221 and 222 differ in terms of their cam contour, which can also be implemented in that the cams have different phase positions. Furthermore, the sliding cam 2 has a shift gate 23 . An actuator pin (not shown) can intervene here and carry out the correspondingly desired axial displacement of the sliding cam 2 so that the first cam 211 or the at least second cam 212 selectively controls the associated gas exchange valve of an internal combustion engine (not shown). How a slide cam assembly works and how they work together play with gas exchange valves of an internal combustion engine is sufficiently known to a person skilled in the art, so that no detailed explanation is required here.

The sliding cam arrangement is also equipped with a latching device 3 which is set up to releasably fix the sliding cam 2 on the support shaft 1 in a first axial position and at least one second axial position. The two axial positions and the intermediate position are particularly in the 2 until 2 B shown.

The locking device essentially comprises at least one sliding tooth 242 of the inner sliding toothing 241 that is widened compared to the adjacent sliding toothing teeth 2411 surface 2421 facing the support shaft 1, which is to be described in more detail.

Both the at least one widened sliding gear tooth 242, the at least one recess 12, and the sliding gear teeth 111 or 2411 as such run in the axial direction, in particular parallel to the longitudinal axis L of the support shaft. The recess 12 can also be used as a missing sliding gear tooth or missing sliding gear teeth in it be designed area.

Furthermore, the latching device comprises a latching element-spring combination 32 and 33 on the support shaft side. The latching element can preferably be designed as a ball. Other shapes are also conceivable, such as a cylindrical roller. However, the following examples refer to a ball as the locking element.

Spring 32 and ball 33 are received in a radially oriented opening 34 in the support shaft and urge ball 33 against surface 2421 of enlarged sliding spline tooth 242.

The surface 2421 of the widened sliding toothing tooth 242 facing the support shaft 1 advantageously has a curvature in the circumferential direction which largely corresponds, preferably corresponds, to the spherical curvature of the ball 33 . In particular, this results in a widened sliding tooth 242, in particular surface 2421, as an optimized counter-contour of the locking element, in particular ball 33. This results in “almost” a surface pressure, in particular surface pressure, between the locking element, in particular ball 33, and the widened sliding tooth 242 , in particular the surface 2421. The running-in wear that is present enables an optimized counter-contour, in particular the surface 2421, to the locking element, in particular the ball 33 of the locking element-spring combination, in the case of a widened sliding toothing. The optimized counter-contour, in particular surface 2421, can also be machined.

• - Erster Bereich I: abfallende Oberfläche 2421
• - Zweiter Bereich II: ebene Oberfläche 2421
• - Dritter Bereich III: ansteigende Oberfläche 2421
• - Vierter Bereich IV: ebene Oberfläche 2421
• - Fünfter Bereich V: abfallende Oberfläche 2421
• - Sechster Bereich VI: ebene Oberfläche 2421
• - Siebter Bereich VII: ansteigende Oberfläche 2421.

The widened sliding gear tooth 242, in particular the surface 2421 of the widened sliding gear tooth 242, can have, for example, seven regions in the axial direction. In a longitudinal sectional view, these can be seen as locking contour R. The locking contour R has a wavy shape in cross section. In the axial direction, the following characteristics of the areas with the longitudinal axis L of the support shaft as a reference result:

• - First area I: sloping surface 2421
• - Second area II: flat surface 2421
• - Third area III: rising surface 2421
• - Fourth area IV: flat surface 2421
• - Fifth area V: sloping surface 2421
• - Sixth area VI: flat surface 2421
• - Seventh area VII: rising surface 2421.

In this context, sloping means that the surface 2421 moves away from the longitudinal axis of the support shaft. In this context, rising means that the surface 2421 turns toward the longitudinal axis of the support shaft. The flat areas can also be infinitesimally small, so to speak merely as a turning point between the adjacent rising or falling areas. The individual areas preferably merge seamlessly into one another.

In the radial direction, the fourth area protrudes further in the direction of the longitudinal axis L of the supporting shaft than the second area and the sixth area. The fourth area is, so to speak, a raised area compared to the second area and the sixth area. Accordingly, when the sliding cam 2 is axially displaced, the ball 33 always slides over the fourth area, i.e. it is pressed in the direction of the support shaft 1 in order to choose between the first and third area or the fifth and seventh area. The sliding cam 2 is thus releasably fixed axially by the prestressing of the spring 32 or its exertion on the ball 33 . For more details, e.g point to the DE 10 2017 219 287 A1 to get expelled.

As in the 4 until 7 As can be seen, more than one, in particular four, sliding cam teeth 242 to 242c of the inner sliding toothing 241 which are wider than the adjacent sliding toothing teeth 2411 are provided. Corresponding to this, four recesses 12 to 12c are provided between adjacent sliding teeth of the outer sliding teeth 11 .

In particular, it can be provided that the sliding cam arrangement is equipped with a plurality of radially aligned openings 34 for latching element-spring combinations, with the openings being introduced rotated by the ignition angle, for example by 90° offset for a 4-cylinder engine, 120° offset for a 3-cylinder engine, for an in-line 6-cylinder engine 60° offset, for a 5-cylinder engine 72° offset, etc. This can preferably mean that the same widened locking tooth (sliding toothing) can always be used for locking all sliding cams. A 180° offset of radially aligned openings for locking element-spring combinations in a 4-cylinder engine with cylinder deactivation on two cylinders is also conceivable.

Alternatively, as for example in 8th shown, only one widened sliding tooth 242 and correspondingly a recess 12 can also be provided.

The surface 2421 of the widened sliding tooth 242 can preferably be adapted to the adjacent contour of the locking element, in particular the ball.

In summary, there is an advantageous guide for the locking device, in particular for the locking element, in particular a widening of the contact area to minimize running-in wear and/or a reduction in the pressures to a level of material wearability while ensuring the same holding function. In the 2 until 2 B it can be seen accordingly how the widened sliding tooth 242 is or are being displaced in the recess or recesses 12 .

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was 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.

Patent Literature Cited

• DE 102004011586 A1 [0002, 0003]
• DE 102011084043 A1 [0002, 0004]
• DE 102009005731 A1 [0002, 0005]
• DE 102017219287 A1 [0033]

Claims (13)

Sliding cam arrangement, comprising a support shaft (1) with a support shaft longitudinal axis (L) and at least one non-rotatable and axially displaceable slide cam (2) accommodated on the support shaft (1), wherein - the slide cam (2) has an opening (24) for receiving the support shaft ( 1) which is equipped with an inner slide spline (241) comprising slide spline teeth (2411) and the support shaft (1) is equipped with an outer slide spline (11) comprising slide spline teeth (111), wherein - the slide cam assembly having a latching device (3) which is set up to releasably fix the sliding cam (2) in a first axial position and at least one second axial position, characterized in that the latching device has at least one sliding tooth (242) of the includes inner sliding teeth (241). sliding cam arrangement claim 1 , characterized in that the detent device comprises at least one recess (12) for receiving the widened sliding gear tooth (242) between adjacent sliding gear teeth (111) of the outer sliding gear (11). Sliding cam arrangement according to at least one of the preceding claims, characterized in that the sliding cam arrangement comprises at least one further sliding tooth (242a-c) of the inner sliding toothing (241) which is wider than adjacent sliding toothing teeth (2411). Sliding cam arrangement according to at least one of the preceding claims, characterized in that the sliding cam arrangement comprises at least one further recess (12a-c) between adjacent sliding splines (111) of the outer sliding spline (11) for receiving an enlarged sliding spline tooth (242a-c). Sliding cam arrangement according to at least one of the preceding claims, characterized in that the number of widened sliding teeth (242 and 242a - c) and/or the associated recesses (12, 12a - c) is selected on the basis of the field of application of the sliding cam arrangement. Sliding cam arrangement according to at least one of the preceding claims, characterized in that the widened sliding toothing tooth or teeth (242) run parallel to the longitudinal axis (L) of the support shaft. Sliding cam arrangement according to at least one of the preceding claims, characterized in that the latching device comprises a latching element/spring combination (32, 33). Sliding cam arrangement according to at least one of the preceding claims, characterized in that the latching element-spring combination comprises a spring (32) and a ball (33) as latching element. Sliding cam arrangement according to at least one of the preceding claims, characterized in that the latching element (33) and the spring of the latching element-spring combination are accommodated in a radially aligned opening (34) in the support shaft (1). Sliding cam arrangement according to at least one of the preceding claims, characterized in that the sliding cam arrangement is equipped with a plurality of radially aligned openings (34) for latching element-spring combinations, the openings (34) each being introduced rotated by the firing angle. Sliding cam arrangement according to at least one of the preceding claims, characterized in that the widened sliding tooth (242) of the locking device has a surface (2421) facing the support shaft (1). Sliding cam arrangement according to at least one of the preceding claims, characterized in that the surface (2421) of the widened sliding toothing tooth (242) is adapted to the adjacent contour of the latching element (33), in particular the ball. Sliding cam arrangement according to at least one of the preceding claims, characterized in that the widened sliding tooth (242), in particular the surface (2421) of the sliding tooth (242) facing the support shaft, in the axial direction in relation to the longitudinal axis (L) of the support shaft - a first area (I ) with a sloping surface, - a second region (II) with a flat surface, - a third region (III) with a rising surface, - a fourth region (IV) with a flat surface, - a fifth region (V) with a sloping surface, - a sixth area (VI) with a flat surface, and - has a seventh region (VII) with a rising surface.

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