DE102007049072A1 - Phase adjuster for an internal combustion engine with an Oldham clutch - Google Patents

Abstract

The invention relates to a phase adjuster, in particular for an internal combustion engine, for adjusting the relative angular position of a camshaft (01) relative to a crankshaft, comprising an actuator (05) with an output shaft (19), an actuator (07) with an adjusting shaft (08 ), which is connected via an adjusting gear with the camshaft (01), and arranged between the output shaft (19) and adjusting shaft (08) Oldham coupling with an Oldham disc (12). The phase adjuster according to the invention is characterized in that the Oldham disc (12) of the Oldham coupling consists of plastic.

Description

Field of the invention

The The present invention relates to a phaser for adjustment a relative angular position of two waves according to the Preamble of claim 1.

Such Phases are especially for internal combustion engines for Adjusting the relative angular position of a camshaft opposite used a crankshaft and include an actuator with a Output shaft, an actuator with an adjusting, which over an adjusting gear is connected to the shaft to be adjusted, and a clutch disposed between the output shaft and the adjusting shaft.

phaser in internal combustion engines are preferably used to adjust the opening and Closing times of the gas exchange valves (camshaft adjuster) or as a phaser for actuator shafts at variable Valve trains. Phase adjusters are arranged in a shaft system. about the drive shaft - z. B. a Nockenwellenkettenrad - is Drive power supplied to the Wel lensystem, which means the output shaft - z. B. the camshaft - again is withdrawn. The phase adjuster serves as a link between the drive shaft and the shaft to be driven. He allows, in addition to couple mechanical power into the shaft system to drive power or remove from this. This can be done by the Drive wheel forced movement function of the shaft to be driven changed For example, a phase shift can be realized.

Phase adjusters can be subdivided into two main groups. The first main group include phaser with an actuator, ie a functional unit which engages in the mass flow or energy flow, which is for example formed hydraulically, electrically or mechanically, and rotates with gear elements of the camshaft adjuster. The second main group comprises phase adjusters with a separate actuator, ie a functional unit, in which the control output required for the control of the actuator control variable is formed from the controller output, and a separate actuator. The second main group has three types. The first design are phase adjuster with a co-rotating actuator and a co-rotating actuator, such as a high-ratio gear, the actuating shaft can be advanced by a co-rotating hydraulic motor or centrifugal motor and can be reset by means of a spring. The second design includes phasing with a co-rotating actuator and a stationary, motor-fixed actuator, such as an electric motor or an electric or mechanical brake. In the DE 100 38 354 A1 , of the DE 102 05 034 A1 and the EP 1 043 482 B2 such phase adjusters are used. The third design includes phasing with a directional combination of the solutions according to the first and second design, such as a motorized brake, in which a part of the braking power is used to tension a spring, which allows the return adjustment after switching off the brake. This design is used for example in the DE 102 24 446 A1 . WO 03 098010 . DE 103 24 845 A1 and DE 103 17 607 A1 used.

at Systems according to the second main group are actuators and actuator connected to each other by means of a control shaft. The Connection can be switchable or non-switchable, detachable or unsolvable, backlash-free or playful and soft or rigid. Independent of Design, the adjustment energy in the form of a provision by a drive or a braking power and taking advantage of Power losses of the shaft system (eg friction) or inertia or centrifugal forces. Braking can also be done full utilization or shared use of the frictional loss take the camshaft. A phaser can be with or without be equipped with a mechanical limitation of the adjustment. When Actuating mechanism or actuator come in a camshaft adjuster single or multi-stage three-shaft gear or multi-joint or Coupling gear of the following types are used: swash plate gear, Eccentric gear, planetary gear, shaft gear, cam gear, multi-link gear or coupling gear or combinations of the individual designs a multi-level execution.

in the State of the art, it is usually common camshaft, Arrange actuator and actuator in series. The actuator is this mostly on the camshaft by means of a central screw attached. The actuator is on the cylinder head, ie on the camshaft opposite side, attached. Due to the manufacturing tolerances creates a radial, undesirable axial offset between the output shaft of the actuator and the adjusting of the actuator.

A arranged between the output shaft and the adjusting shaft coupling should the torque from the actuator or the drive torque for the Transfer actuating gear and at the same time the axial offset compensate between output shaft and adjusting shaft.

From the DE 10 2004 041 751 A1 is a camshaft adjuster known in which the transmission of the drive torque of one of a Actuator driven actuating shaft via an intermediate clutch to a variable speed. The coupling comprises a first coupling half with a radial extension, which rests in the circumferential direction without play on a second coupling half and in the radial direction relative to the second coupling half is displaceable. In the DE 10 2004 041 751 A1 an embodiment is described in which the flow of force between the extension and the second coupling half via a circumferentially elastic element, such as a metal spring or a polymer tape takes place. In addition to elasticity in the circumferential direction, the elastic element can also provide for an axial elastic connection. As an alternative to using an elastic element, the extension itself can have its own elasticity, so that it itself forms the elastic element. By deformation of the elastic element small axial offsets between the actuating shaft of the actuator and Verstellgetriebewelle can be compensated. In addition, a low-noise function is ensured, even if alternating torques occur at the Verstellgetriebewelle. However, when using this known coupling, the central screw can not be mounted separately. In addition, the maximum possible axial offsets that can be compensated are limited. Another disadvantage is that due to deformations caused by misalignment and the resulting stresses can lead to the destruction of the elastic element.

From the DE 103 24 845 A1 For example, a valve timing control apparatus for an internal combustion engine is known. The angular position adjustment between crankshaft and camshaft is performed by a rotational phase control mechanism with an intermediate rotary member, which is adjusted by a braking mechanism with a hysteresis. The hysteresis brake comprises a hysteresis ring which has a retaining plate. The holding plate is connected to the intermediate rotary member. The intermediate rotary member or the holding plate is provided with a radial groove, while the holding plate or the intermediate rotary member has a projection which is slidably received in the groove to move the intermediate rotary member radially relative to the Hysteresering. As a result, an axial offset of the hysteresis brake can be compensated for the intermediate rotary member. The realized between hysteresis and intermediate intermediate coupling works on the well-known Oldham principle.

Oldham Couplings are well known in the art, so on an explanation of their basic construction and Functioning can be dispensed with at this point.

in the Prior art, it was customary so far, the Oldhamscheibe steel Oldham couplings. The usage of However, steel has the disadvantage that the coupling is only a relatively small Play, otherwise there will be problems in complying with the demanded low noise would come. Furthermore Steel has a high density and with it also a high mass moment of inertia. Last but not least, steel is also a comparatively expensive material.

The The object of the present invention is therefore a phase adjuster with an improved coupling, the clutch is characterized by a low-noise operation and the lowest possible moment of inertia should be awarded. For the clutch should be possible few components that are inexpensive to manufacture are used come. In addition, with the clutch comparatively large axial offsets between the output shaft of the Actuator and the adjusting of the actuator can be compensated.

to Solution of the problem of the invention serves a phaser according to the appended Claim 1. The phase adjuster according to the invention is characterized by the fact that the Oldham disc made of plastic consists.

One significant advantage of the solution according to the invention is that by using plastic for the Oldham disc a significant reduction in inertia can be achieved on the adjusting shaft, as compared to plastic to steel has a much lower density. Plastic possesses also very good damping properties, ensuring a low-noise function of the clutch is. Compared to conventional clutches, the Oldham discs use of steel, the inventive Coupling due to the good damping properties of Plastic have a much higher clearance, which is not ultimately leads to a reduction in manufacturing costs.

at an advantageous embodiment, the Oldham disc made of a thermoplastic material. Components made of thermoplastic materials can be manufactured and drawn extremely cheaply characterized by good performance properties.

Semicrystalline thermoplastics are suitable for the inventive design of the Oldham disk, especially reinforced polyamides. The latter have a high rigidity and strength, as well as an extreme impact resistance. This makes them extremely robust against mechanical stress. In addition, polyamides have very good sliding properties. As appropriate, for example, the use of glass fiber reinforced polyamide, such as PA 66 GF26 proved.

To a particularly preferred embodiment, the Oldham disc four each offset by 90 ° to each other slots or slots on. In addition, stand in this embodiment, the the Oldham disc facing ends of the output shaft and the adjusting shaft over two opposing bolts with the Slots or slots of the Oldham disc in conjunction. In this case, either the serving for connecting the output shaft Bolt or the bolt used to connect the adjusting shaft with a head.

to Fixing the bolts or execution of the bolts there There are three different design variants.

at the simplest variant are in the Oldham disc facing end faces of output shaft and adjusting shaft each introduced two opposite bores. In these holes, the bolts are inserted.

The second embodiment used to attach the Bolt separate connecting washers to the Oldham disc attached facing ends of the output shaft and the adjusting shaft are. The connecting discs each have two opposite Holes for fastening the bolts.

at a third embodiment is on the Oldham disc facing end of the output shaft arranged a drive element. The engagement with the slots or slots of Oldham disc serving bolts are in this embodiment as Extensions of the drive element formed.

all common embodiments described is the use simple, easy-to-manufacture components. Even the comparatively complex drive element of the third embodiment can be manufacture cost-effectively. For example, it can be sintered or as the Oldham disc also made of plastic become. The use of the drive element has an additional effect positive on the moment of inertia.

at a further advantageous embodiment, the Oldham disc adapted to the expected stress Wall thickness on. By adjusting the Oldham slice thickness to the particular application, a further optimization regarding the mass or inertia take place.

After all It has still proved to be advantageous if the Oldham disc is provided with ribbing. By the ribs can also with a relatively small wall thickness a high rigidity the Oldham disc can be realized, again with an optimization be achieved in terms of mass or inertia can.

Further Advantages, details and developments of the present invention result from the following description of preferred embodiments, with reference to the drawing. Show it:

1 a phaser according to the prior art in a simplified representation;

2 Components of a first embodiment of a clutch used in a phase shifter according to the invention in a schematic representation;

3 the assembled coupling according to 2 in a schematic sectional view;

4 a second embodiment of the coupling in a three-dimensional representation;

5 the clutch according to 4 in an exploded view.

1 shows a camshaft adjuster for an internal combustion engine according to the prior art in a simplified representation. The camshaft adjuster is used to adjust the relative angular position of a camshaft 01 opposite one with a drive wheel 03 in drive connection crankshaft. The camshaft adjuster includes an actuator 05 with an output shaft (not shown) and an actuator 07 with an adjusting shaft 08 , Between output shaft and adjusting shaft 08 a clutch (not shown) is arranged. As 1 it can be seen are the camshaft 01 , Actuator 07 and actuator 05 arranged in a row.

As an actuator 05 For example, an electric motor or a brake can be used. The actuator 05 is on the cylinder head 09 or another engine-fixed part of the internal combustion engine attached. As an actuator 07 For the most part, a gearbox with a high gear ratio is used. The actuator 07 is on the camshaft 01 attached via a central screw, not shown.

Due to the motor-fixed mounting of the actuator 05 and the camshaft-fixed mounting of the actuator 07 arises due to the manufacturing tolerances an axial offset between the output shaft of the Ak tuators 05 and the adjusting shaft 08 of the actuator 07 , Furthermore, the camshaft is subject to radial operating oscillations during operation of the internal combustion engine. This offset must be compensated by means of the coupling. The vibrations should not be transmitted to the actuator, which is also to be prevented by the coupling.

A first embodiment of a clutch used in the phase adjuster according to the invention is intended to be based on the 2 and 3 be explained. This shows 2 the individual components of the clutch and 3 the assembled coupling in a schematic representation.

The coupling comprises two connecting discs 11 and an Oldham disc 12 , In the Oldham disc 12 are four each offset by 90 ° to each other slots or slots 13 brought in. The Oldham disc 12 is made of plastic, preferably of a thermoplastic material, such as PA 66 GF26. The connecting discs 11 are similar in the illustrated embodiment. In the connecting discs 11 are each two holes 14 introduced, which for receiving bolts 15 . 16 serve. Bolts 15 . 16 differ in that the first bolts 15 are executed without a head and the second bolt 16 are provided with a head. One connecting disc each 11 is on the output shaft of the actuator 05 and the adjusting shaft 08 of the actuator 07 attached. The connecting discs 11 are over the bolts 15 . 16 with the Oldham disc 12 connected. This is where the bolts engage 15 . 16 in the slots or slots 13 the Oldham disc 12 one. The Oldham disc 12 has a central opening 17 through which the adjusting can be attached to the camshaft by means of the central screw. The transmission-side connecting disc 11 must have at least as large an opening for the passage of the central screw.

In 3 are two sectional views of each rotated by 90 ° coupling shown, so in Fig. a) the connection of the Oldham disc 12 with the connection disc 11 towards the output shaft of the actuator using the first bolt 15 and in Fig. b) the connection of the Oldham disc 12 with the adjusting shaft side connecting disc 11 using the second bolt 16 can be seen.

In the in 3 illustrated embodiment serve the first bolt 15 for connecting the output shaft of the actuator 05 arranged connection disc 11 with the Oldham disc 12 , The second bolt 16 connect the on the adjusting shaft 08 of the actuator 07 arranged connection disc 11 with the Oldham disc 12 , Because of that, the second bolt 16 run with head, is the Oldham disc 12 in this case axially to the connection disc 11 the adjusting shaft 08 bound. In other embodiments, the second bolts 16 also for coupling the connection disc 11 the output shaft of the actuator 05 with the Oldham disc 12 serve. The Oldham disc 12 would be in this case to the connection disc 11 tied to the output shaft. An between output shaft and adjusting shaft 08 present misalignment may be due to the play of the bolt 15 . 16 in the oblong holes or slits 13 the Oldham disc 12 be compensated.

In the execution of the actuator 07 to be fastened connection disc 11 It should be noted that the inner diameter of the connecting disc 11 must be chosen so large that the central screw can be performed. The on the output shaft of the actuator 05 to be fastened connection disc 11 does not have to allow the central screw to pass through and can therefore be optimized in terms of mass and inertia.

In the 4 and 5 a preferred embodiment of the invention is shown. The Oldham disc 12 is modified such that the slots provided for receiving the output shaft side connecting disk 13 down to the central opening 17 the Oldham disc 12 extend. Therefore, in this embodiment, instead of the connecting disk 11 also on the output shaft 19 of the actuator 05 arranged drive element 18 be used. The drive element 18 has extensions 20 on, like the bolts described above 15 the engagement in the slots or slots 13 the Oldham disc 12 serve. By using a comparatively small drive element, a further reduction of the mass moment of inertia can be achieved. Alternatively, the drive element 18 also be made in one piece with the output shaft.

At the in 4 and 5 shown embodiment, the Oldham disc 12 Ribbing on. Through these ribs, the mass of the Oldham disc 12 be further reduced while still achieving high rigidity.

The coupling can alternatively also without connecting discs 11 being constructed. In this case, those for fastening the bolts 15 . 16 serving bores in the end faces of the ends of the output shaft of the actuator 05 and adjusting shaft 08 of the actuator 07 directly introduced.

01

camshaft

02

03

drive wheel

04

05

actuator

06

07

actuator

08

adjusting

09

cylinder head

10

11

connection slices

12

Oldham disc

13

Elongated holes / slots in the Oldham disc

14

drilling in the connecting discs

15

first Bolt without head

16

second Bolt with head

17

central opening in Oldham disk

18

driving element

19

output shaft

20

extensions of the drive element

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 10038354 A1 [0004]
• - DE 10205034 A1 [0004]
• - EP 1043482 B2 [0004]
• - DE 10224446 A1 [0004]
• WO 03098010 [0004]
• - DE 10324845 A1 [0004, 0009]
• - DE 10317607 A1 [0004]
• DE 102004041751 A1 [0008, 0008]

Claims (16)

Phase adjuster for adjusting the relative angular position of two shafts, comprising an actuator ( 05 ) with an output shaft ( 19 ), an actuator ( 07 ) with an adjusting shaft ( 08 ), which is connected via an adjusting gear with one of the shafts, and between output shaft ( 19 ) and adjusting shaft ( 08 ) arranged clutch, characterized in that the clutch is an Oldham clutch whose Oldham disc ( 12 ) consists of plastic. Phase adjuster according to claim 1, characterized in that the shafts a camshaft ( 01 ) and a crankshaft of an internal combustion engine, wherein the adjusting mechanism via a central screw with the camshaft ( 01 ) connected is. Phase adjuster according to claim 1 or 2, characterized in that the actuator ( 05 ) is a drive or a braking device. Phase adjuster according to claim 3, characterized in that the actuator ( 05 ) is an electric motor. Phase adjuster according to one of claims 1 to 4, characterized in that the Oldham disc ( 12 ) consists of a thermoplastic material. Phase adjuster according to claim 5, characterized in that that the thermoplastic material is a semi-crystalline thermoplastic is. Phase adjuster according to Claim 6, characterized that the thermoplastic is polyamide. Phase adjuster according to claim 7, characterized that the thermoplastic is PA 66 GF26. Phase adjuster according to one of claims 1 to 8, characterized in that the Oldham disc ( 12 ) four each offset by 90 ° to each other slots or slots ( 13 ) that the Oldham disc ( 12 ) facing ends of the output shaft ( 19 ) and the adjusting shaft ( 08 ) via two opposing bolts ( 15 . 16 ) with the oblong holes or slots ( 13 ) the Oldham disc ( 12 ), wherein either the for connecting the output shaft ( 19 ) serving bolts ( 15 . 16 ) or for connecting the adjusting shaft ( 08 ) serving bolts ( 15 . 16 ) each have a head through which the Oldham disc ( 12 ) is axially fixed. Phase adjuster according to claim 9, characterized in that the output shaft ( 19 ) and the adjusting shaft ( 08 ) at her the Oldham disc ( 12 ) facing end faces each have two opposing bores, wherein in this bore the bolt ( 15 . 16 ) are used. Phase adjuster according to claim 9, characterized in that on the Oldham disc ( 12 ) facing ends of the output shaft ( 19 ) and the adjusting shaft ( 08 ) each a connecting disc ( 11 ), these connecting discs ( 11 ) each two opposing holes ( 14 ), in which bores ( 14 ) bolts ( 15 . 16 ) are used. Phase adjuster according to claim 9, characterized in that the output shaft ( 19 ) at her the Oldham disc ( 12 ) facing end a drive element ( 18 ), which engage for engagement with the slots ( 13 ) the Oldham disc ( 12 ) serving bolts ( 15 . 16 ) as extensions ( 20 ) of the drive element ( 18 ) are formed. Phase adjuster according to claim 12, characterized in that the extensions ( 20 ) in one piece on the drive element ( 18 ) are formed. Phase adjuster according to one of claims 1 to 13, characterized in that the Oldham disc ( 12 ) has a matched to the expected stress wall thickness. Phase adjuster according to one of claims 1 to 14, characterized in that the Oldham disc ( 12 ) Has ribbing. Phase adjuster according to one of claims 2 to 15, characterized in that the Oldham disc ( 12 ) a central opening ( 17 ), through which the assembly of the central screw on the camshaft ( 01 ) is possible.