DE102016219915A1 - The wave gear - Google Patents

Abstract

A wave gear, in particular in an electric camshaft adjuster, has an inner ring (9) with a non-circular outer contour. Next, the wave gear on an overload clutch (4), wherein a coupling component of the overload clutch (4) through the inner ring (9) is formed.

Description

The invention relates to a suitable for use as a control gear, in particular in an internal combustion engine, wave gear.

From the DE 10 2004 033 522 A1 is known a phaser with electric drive, which has an overload clutch. The overload clutch is arranged between an electric motor and an adjusting mechanism. The adjusting gear is a three-shaft gear.

Further wave gear drives, which are intended for use in a motor vehicle, are for example from DE 10 2004 009 128 A1 , from the DE 10 2013 220 220 A1 as well as from the DE 10 2014 202 060 A1 known. Also in these cases are gearboxes of electric camshaft adjusters.

The invention has for its object to provide a comparison with the prior art evolved, suitable for a camshaft adjuster wave gear with a particularly compact, claim appropriate structure.

This object is achieved by a wave gear with the features of claim 1. A wave generator of the wave gear has, in a known per se basic concept an inner ring with a non-circular, in particular elliptical, outer contour. This inner ring forms according to the invention a coupling component of an overload clutch of the wave gear. The inner ring thus has as a component of the wave generator and as a component of the overload clutch a multiple function, which in comparison to conventional actuators, to which an overload clutch is connected, a particularly compact structure, in particular in the axial direction of the wave gear, can be realized.

A harmonic drive has an inherent elastic toothed transmission component. In the case of the wave gear according to the invention, this may be a flexible component of any geometry. For example, the flexible transmission component may have a simple ring shape, that is, be designed as a flex ring. Likewise, the flexible transmission component may be a component having a substantially cylindrical toothed portion, on which a radially outwardly or inwardly directed flange is formed. In the case of a radially outwardly directed flange this is also referred to as a collar and the entire flexible transmission element as a collar sleeve. On the other hand, if the flange of the gear element is directed radially inwards, then the gear element as a whole describes a pot shape. Regardless of the geometric design of the flexible toothed transmission element, this is deformed during operation of the corrugated transmission by the wave generator, wherein the deformation of the elastic transmission element causing inner ring is a self-rigid transmission element.

The invention is based on the consideration that different operating states of an internal combustion engine are possible in which torque peaks occur in an electric camshaft adjuster. This may be the case, for example, when components of the camshaft adjuster which are pivotable relative to one another strike one another in a stop position.

It has been shown that a particularly effective limitation of mechanical loads within the electric camshaft adjuster can be achieved by an electric motor, which drives an adjusting shaft of a corrugated transmission of the electric camshaft adjuster, can be decoupled from the wave generator of the wave gear. Instead of an integration of an overload clutch in the corrugated transmission actuating electric motor or an interposition of such overload clutch between the electric motor and the wave gear overload clutch is integrated according to the invention in the wave gear, wherein the inner ring of the wave generator is a transmission-side coupling component, while another coupling component of the overload clutch for the rotationally fixed connection with a servomotor, namely electric motor, is provided. The servomotor can either be rigidly coupled via a damping element or a compensating coupling, in particular Oldham coupling, with the coupling component rotatably.

The overload clutch of the wave gear is formed according to various possible designs as latching clutch, in particular as a ball detent clutch. In this case, latching elements, in particular balls, can be displaced either in the radial direction or in the axial direction of the inner ring.

Alternatively, the overload clutch has a spring detent ring, with which it is likewise embodied as a latching clutch, but does not have separate detent elements which are approximately spherical or pin-shaped. The spring detent ring is preferably designed as a sheet-metal ring and has a plurality of metal lips, which are each elastically yielding in the radial direction of the spring detent. These metal lips are preferably designed to engage directly in locking contours on the inner circumference of the inner ring of the wave generator. At the same time, the sheet metal ring, which acts as a coupling component of the overload clutch, be rotatably coupled to a component of Oldham coupling or even one Component of an Oldham coupling form. According to a possible design, the metal lips of the spring detent are formed as in the circumferential direction extending spring tongues. At the same time, further, radially inwardly extending tongues of the spring detent ring are preferably designed to cooperate with an Oldham disc of a compensating coupling.

Instead of a latching overload clutch and a trained as a friction clutch overload clutch in the harmonic drive is used. A torque transmitting and at the same time limiting surfaces of a friction clutch can be arranged on an end face of the inner ring or on its inner circumferential surface. Likewise, designs with a combined positive and frictional engagement of the overload clutch can be produced.

Regardless of the operating principle of the overload clutch, the inner ring of the wave generator can be designed either as a bearing ring of a sliding bearing or as a bearing ring of a rolling bearing. In the case of a rolling bearing this has either balls or other rolling elements, such as rollers or needles, on.

The wave gear is particularly suitable for use as a control gear in an internal combustion engine. This may be, for example, a control gear of an electric camshaft adjuster or a control gear of a device for varying the compression ratio of a reciprocating engine.

• 1 den Drehmomentfluss in einem elektrischen Nockenwellenversteller,
• 2 in einem Diagramm die Funktion einer Überlastkupplung in einem elektrischen Nockenwellenversteller,
• 3 bis 5 verschiedene Bauformen von Wellgetrieben für elektrischen Nockenwellenversteller mit rastender Überlastkupplung, nämlich Kugelrastkupplung,
• 6 ein Wellgetriebe mit als Rutschkupplung gestalteter Überlastkupplung,
• 7 ein Wellgetriebe mit einer Überlastkupplung, welche mehrere stiftförmige Rastelemente aufweist,
• 8 ein Detail aus der Anordnung nach 7,
• 9 ein Wellgetriebe mit als Federlippenkupplung ausgebildeter Überlastkupplung,
• 10 ein Detail der Anordnung nach 9,
• 11 und 12 ein Wellgetriebe mit einer Überlastkupplung, welcher einen Blechring als Kupplungskomponente aufweist,
• 13 und 14 eine Gleitlagervariante eines Wellgenerators eines Wellgetriebes,
• 15 und 16 eine weitere Ausführungsform einer Überlastkupplung mit als Blechring ausgebildeter Kupplungskomponente,
• 17 den Blechring der Anordnung nach den 15 und 16.

Several embodiments of the invention will be explained in more detail with reference to a drawing. Here show, partly in a schematic representation:

• 1 the torque flow in an electric phaser,
• 2 in a diagram, the function of an overload clutch in an electric camshaft adjuster,
• 3 to 5 various designs of corrugated gears for electric camshaft adjuster with latching overload clutch, namely ball detent clutch,
• 6 a wave gear with designed as a slip clutch overload clutch,
• 7 a wave gear with an overload clutch, which has a plurality of pin-shaped latching elements,
• 8th a detail from the arrangement after 7 .
• 9 a wave gear with trained as spring lip clutch overload clutch,
• 10 a detail of the arrangement 9 .
• 11 and 12 a wave gear with an overload clutch, which has a sheet metal ring as a coupling component,
• 13 and 14 a slide bearing variant of a wave generator of a wave gear,
• 15 and 16 a further embodiment of an overload clutch formed as a sheet metal ring coupling component,
• 17 the sheet metal ring of the arrangement according to 15 and 16 ,

A total with the reference numeral 1 characterized electrical camshaft adjuster, with regard to its principal function is referred to the cited prior art, comprises a trained as a corrugated transmission actuating gear 2 as well as an electric motor 3 , The electric motor 3 is with the wave gear 2 via an overload clutch 4 which deviates from the schematic representation according to FIG 1 in the wave gear 2 is integrated. In the wave gear 2 it is a three-shaft gear, wherein an input shaft is a housing-fixed component of the wave gear 2 represents and rotates within an internal combustion engine in a conventional manner with half the crankshaft speed. On the output side of the wave gear this is connected to a camshaft, not shown. An output side torque is in 1 denoted M1, an associated speed D1. When operating the camshaft adjuster 1 It can be on the output side of the wave gear 2 come to a stop between different parts, what in 1 is symbolized by an output-side clamping. Such a stop on the output side of the corrugated transmission 2 can lead to torque peaks, which on the input side of the wave gear 2 react. A through the electric motor 3 generated torque is in 1 with M2, an associated speed denoted by D2.

In 2 is the behavior of the corrugated transmission 2 , in particular its overload clutch 4 , illustrated in the case of a torque peak and compared with the behavior of a conventional camshaft adjuster without overload clutch. This is dependent on the angle α one designated 5, the wave gear 2 actuating adjusting shaft, which by the electric motor 3 is driven, one in the adjusting shaft 5 acting torque M outlined.

It is assumed that in the adjusting shaft 5 initially a moderate torque M acts. Due to an output-side stop, that is, a stop on the part of the output shaft designated 6 of the wave gear 2 . the torque M increases in the adjusting shaft 5 and thus also in the overload clutch 4 at. This increase is at a triggering moment m_k the overload clutch 4 stopped, with the overload clutch 4 engages again at a reduced torque. The reduced torque level, which in 2 is marked by a dashed line, is by a slip torque of the overload clutch 4 given. With this slip torque will continue power from the electric motor 3 in the wave gear 2 fed. If, on the other hand, no overload clutch were present, then, as in 2 is indicated by a solid line in the adjustment 5 acting torque M over the release torque m_k increase, which increases the risk of damage to parts of the corrugated transmission 2 could mean.

• In den Ausgestaltungen nach den 3 bis 5 ist die Überlastkupplung 4 jeweils als rastende Überlastkupplung, nämlich Kugelrastkupplung, ausgebildet. Erkennbar ist in allen Fällen ein mit 7 bezeichneter Wellgenerator des Wellgetriebes 2, welcher ein Wälzlager 8, nämlich Kugellager, aufweist. Ein mit 9 bezeichneter Innenring des Wälzlagers 8 weist eine nicht kreisrunde, elliptische Außenkontur auf. Auf dem Innenring 9 rollen Kugeln als Wälzkörper 10 ab. Die Kugeln 10 sind in einem Kä11 geführt und kontaktieren einen nachgiebigen Außenring 12, welcher ebenfalls dem Wellgenerator 7 zuzurechnen ist. Der Außenring 12 passt sich permanent der nicht kreisförmigen Kontur des Innenrings 9 an. Durch den Außenring 12 wird ein in den 3 bis 5 nicht dargestelltes nachgiebiges Getriebeelement des Wellgetriebes 2 partiell gegen ein in sich starres Getriebeelement des Wellgetriebes 2 gedrückt. Zwischen dem elastischen und dem in sich starren Getriebeelement ist damit ein Drehmoment übertragbar.

In the following, various design options of the overload clutch 4 explains:

• In the embodiments according to the 3 to 5 is the overload clutch 4 each designed as a latching overload clutch, namely ball detent clutch. It can be seen in all cases a designated 7 wave generator of the wave gear 2 , which is a rolling bearing 8th , namely ball bearings, has. An inner ring, designated 9, of the rolling bearing 8th has a non-circular, elliptical outer contour. On the inner ring 9 Roll balls as rolling elements 10 from. The balls 10 are in a Ka 11 guided and contact a compliant outer ring 12 , which also the wave generator 7 attributable to. The outer ring 12 Adjusts permanently to the non-circular contour of the inner ring 9 at. Through the outer ring 12 will be one in the 3 to 5 not shown yielding transmission element of the wave gear 2 partially against a self-rigid transmission element of the wave gear 2 pressed. A torque can thus be transmitted between the elastic and the inherently rigid transmission element.

To overload the wave gear 2 to prevent is the inner ring 9 as a coupling component of the overload clutch 4 educated. Here, the inner ring acts 9 with a further coupling component, namely a coupling carrier 13 , together. The coupling carrier 13 in turn is via a compensating coupling 14 , namely Oldham coupling, with the adjusting shaft 5 coupled.

Between the coupling components 9 . 13 the overload clutch 4 are in the designs after the 3 to 5 roll 15 arranged as a ratchet body. In the designs after the 3 and 4 is every ball 15 by a separate spring 16 spring-loaded, which is in a recess in the inner ring 9 ( 3 ) or in the coupling carrier 13 ( 4 ) is located. By the springs 16 are all balls 15 in the radial direction of the inner ring 9 and thus spring-loaded the entire wave gear.

In contrast, in the embodiment are after 5 the balls 15 between end faces of the inner ring 9 and the coupling carrier 13 , For springing in this case is a plate spring 17 provided, which in the axial direction of the inner ring 9 acts and through a circlip 18 is secured.

In the execution example after 6 is the overload clutch 4 designed as a friction clutch. This loads a clutch spring 19 the inner ring 9 with a force in the axial direction, being on the clutch spring 19 facing away from the inner ring 9 a friction lining 20 with the inner ring 9 connected is. The friction lining 20 contacts a friction disc 21 , which firmly with the coupling carrier 13 connected is.

The 7 and 8th show a design of overload clutch 4 , which combines a form-fitting effect with frictional engagement. These are pens 22 provided as a locking body, which in addition by frictional engagement with the inner ring 9 Act. Comparable with the design 4 are the pins 22 each by a spring 16 , which are in a bag in the coupling carrier 13 is located, spring-loaded. Axial displacements between the coupling carrier 13 and the inner ring 9 be through an axial lock 23 prevented.

In the embodiment of the 9 and 10 is the overload clutch 4 designed as a spring lip clutch. This overload clutch 4 acts in the axial direction of the coupling components 9 . 13 , with plastic lips 24 of the coupling carrier 13 with locking contours on the inner ring 9 interact. For axial securing are in this case snap-action lugs 25 to the coupling carrier 13 molded, which in an annular shoulder on the compensating coupling 14 remote end face of the inner ring 9 intervention.

In the in the 11 and 12 illustrated overload clutch 4 it is also a spring lip clutch, which in contrast to the design after the 9 and 10 is effective in the radial direction. As with the inner ring 9 cooperating coupling component 13 is in this case a fixed with a component of the compensating coupling 14 connected, formed as a spring detent sheet metal ring 26 provided, which a variety of metal lips 27 has, in each case in latching contours of the inner ring 9 intervention. Additional locking body, such as in the form of balls or pins, are not required in this case.

The 13 and 14 show an alternative design of storage within the wave generator 7 , It is a plain bearing 28 , which in each of the previously described designs, the rolling bearing 8th can replace. The inner ring 9 is here designed as an elliptical sliding bearing ring, which contacts the designated 29 flexible transmission element and this forces in an elliptical shape. The externally toothed flexible transmission element 29 meshes with an internal toothing of a designated 30, inherently rigid transmission element, that is ring gear. Also in the design after the 13 and 14 represents the inner ring 9 a coupling component of the overload clutch 4 represents.

The 15 to 17 show one with an inner ring 9 cooperating coupling component 13 which in this respect have similarities with the embodiment of the 11 and 12 has, as it is designed as a one-piece sheet metal part. The inner ring 9 is in the embodiment of the 15 to 17 designed as a rolling bearing inner ring; this could also be a plain bearing inner ring, as in the 13 and 14 outlined.

The trained as a metal ring coupling component 13 , which is also referred to as a spring detent, has a plurality of spring tongues 31 as locking elements. Furthermore, engagement elements 32 at the coupling component 13 recognizable, which is a torque transmission between an Oldham disc and the coupling component 13 allow simultaneous compensation of radial misalignment.

LIST OF REFERENCE NUMBERS

1

electric camshaft adjuster

2

The wave gear

3

electric motor

4

Overload clutch

5

adjusting

6

output shaft

7

wave generator

8th

roller bearing

9

Inner ring, coupling component

10

rolling elements

11

Cage

12

outer ring

13

Coupling carrier, coupling component

14

Flexible coupling

15

Ball, detent body

16

feather

17

Belleville spring

18

circlip

19

clutch spring

20

friction lining

21

friction

22

Pen, detent body

23

axial safety

24

Plastic lip

25

snap lug

26

Sheet metal ring, spring detent ring, coupling component

27

sheet metal lip

28

bearings

29

flexible transmission element

30

in itself rigid transmission element

31

spring tongue

32

engaging member

α

angle

D1, D2

rotation speed

M1, M2

torque

m_k

release force

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 102004033522 A1 [0002]
• DE 102004009128 A1 [0003]
• DE 102013220220 A1 [0003]
• DE 102014202060 A1 [0003]

Claims (10)

Well gear, with a wave generator (7), which has an inner ring (9) with a non-circular outer contour, and with an overload clutch (4), wherein a coupling component of the overload clutch (4) through the inner ring (9) is formed. Wave gear after Claim 1 , characterized in that the overload clutch (4) is designed as a latching clutch. Wave gear after Claim 2 , characterized in that the overload clutch (4) is designed as ball detent coupling. Wave gear after Claim 2 , characterized in that the overload clutch (4) has a with the inner ring (9) cooperating spring detent ring (26). Wave gear after Claim 4 , characterized in that the spring detent ring (26) is designed as a sheet metal ring and has a plurality of elastically yielding in the radial direction sheet metal lips (27). Wave gear after Claim 5 , characterized in that the metal lips (26) as in the circumferential direction of the spring detent ring (26) extending spring tongues (31) are formed. Wave gear after Claim 1 , characterized in that the overload clutch (4) is designed as a friction clutch. Wave gear after one of Claims 1 to 7 , characterized in that the wave generator (7) comprises a roller bearing (8). Wave gear after one of Claims 1 to 7 , characterized in that the wave generator (7) has a sliding bearing (28). Using a wave gear after Claim 1 in a control gear of an internal combustion engine, in particular in an electric camshaft adjuster.

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