DE102007020527A1 - Camshaft adjustment mechanism has inner rotor with thread fixed to camshaft by screw - Google Patents

Abstract

A camshaft adjustment mechanism (1) alters the valve timing on a piston engine. The camshaft adjustment (1) has an inner rotor (3) that is fixed to the camshaft (9) by a screw. Each component (20, 21) has a thread (20, 21). The longitudinal axis (21a) of the respective thread (20, 21) coincides with the axis of rotation (22) of the respective component (3, 9).

Description

Field of the invention

The The invention relates to a camshaft adjuster with the control times of gas exchange valves of an internal combustion engine variably adjustable are. Such camshaft adjusters are used to the Phase angle between a crankshaft and a camshaft one Internal combustion engine variably adjustable in a defined angular range to design. For this purpose, a drive element is provided, which, for example, a chain, belt or Gear drive is in drive connection with the crankshaft. Of Furthermore, the camshaft adjuster comprises an output element, which rotatably connected to the camshaft of the internal combustion engine is. Between the drive element and the output element is a Actuator formed over the the phase position of the output element relative to the drive element, and thus the camshaft relative to Crankshaft, can be selectively changed or maintained.

Of the Actuator can, for example, as a hydraulic or electromechanical Be configured actuator.

A camshaft adjuster with an electromechanical actuator is for example from the US 6,523,512 B2 known. This embodiment has a sprocket, which is in driving connection with the crankshaft by means of a chain drive. Integral with the sprocket, a first bevel gear is formed, the camshaft side facing a second bevel gear. Between the two bevel gears a swash plate is arranged, which is provided in the axial direction on both sides in each case with a circumferential bevel gear teeth in the circumferential direction. One of the two bevel gear teeth of the swash plate engages the first bevel gear in a defined angular interval, while the other of the two bevel gear teeth of the swash plate engages in the second bevel gear. At least one of the two bevel gear teeth in the swash plate has a tooth number difference to the bevel gear, in which engages. The swash plate is positioned at an angle of attack on an adjusting shaft, wherein the adjusting shaft can be driven by an electric motor. By regulating the speed of the adjusting shaft, the relative phase angle of the sprocket relative to the camshaft selectively selectively changed or maintained.

The Output element is either in this embodiment by means of a central screw or several eccentrically arranged Screws bolted to the camshaft. The use of a central screw or more eccentrically arranged screws has an increased Installation costs result. The number of mounting components is relatively high and additionally introduced by the screws Mass adversely affects the response of the internal combustion engine and the fuel consumption.

From the US 6,363,896 B1 is a camshaft adjuster with a hydraulic actuator in vane-type construction known. The camshaft phaser comprises an outer rotor (drive element) and an inner rotor (output element). The outer rotor has recesses which are pressure-tightly sealed by the outer rotor, the inner rotor arranged concentrically therewith and two side walls. Wings are formed on the inner rotor, with each wing extending into each of the recesses and dividing them into two oppositely acting pressure chambers.

The outer one Rotor is in driving connection with a sprocket the crankshaft of the internal combustion engine. The inner rotor is by means of a central bolt extending through a central bore of the inner rotor extends, rotatably connected to the camshaft.

through a central valve which is located within the central bore is, pressure medium can optionally to the various pressure chambers directed or removed from these. The central valve comprises a valve housing and an axially displaceable therein Spool. In this embodiment, the central screw hollow executed, which at the same time the function fulfilled the valve housing. For this purpose are in the outer circumferential surface of the central screw connections introduced in the form of holes which communicate with annular grooves, formed on the inner circumferential surface of the central bore are.

additionally to the above-mentioned disadvantages with respect to an electromechanical Camshaft adjuster occurs in this embodiment the problem on that the accuracy requirements to the central screw / that Valve body with respect to the fit of the connections is relatively high to the annular grooves. Already small deviations can control the pressure fluid flow from the central valve in the adjusters noticeably influence. As a result, the response suffers of the pretender. The screw connection determines the position of the valve housing. An alignment of the connections to the annular grooves on not be made.

From the US 5,566,651 is known a camshaft adjuster in axial piston design. In this embodiment, both the drive element and the output element is provided with a helical toothing. An axially displaceable piston separates two opposing pressure chambers and is also provided with two helical gears. In this case, a helical toothing of the piston engages in the helical toothing of the drive element and the other helical toothing of the piston in the helical toothing of the driven element. Thus, the phase position of the output elements to the drive element and thus the camshaft to the crankshaft can be selectively varied or maintained by targeted pressure medium or emptying the pressure chambers.

The Output element of the in this embodiment by means of a Central screw rotatably connected to the camshaft.

Summary of the invention

Of the Invention is therefore the object of these disadvantages to avoid and thus to create a camshaft adjuster, wherein reduces the number of components to be mounted, the assembly even relieved and the moving mass of the camshaft adjuster should be reduced. In addition, should be in hydraulic Camshaft adjusters with a central valve solution the Connection of the connections of the central valve to the hydraulic system the camshaft adjuster facilitates and less error prone be designed.

In a first embodiment of a camshaft adjuster with a drive element, which means for driving through a Having crankshaft, and a rotatably connected to a camshaft Output element, wherein a phase angle of the output element within an angular range to the drive element is variable, is the problem according to the invention solved by the output element has a first thread whose longitudinal axis coincides with an axis of rotation of the output element.

In a further embodiment of a camshaft adjuster with a drive element, an output element and a camshaft, wherein the drive element is in drive connection with a crankshaft stands, wherein the output member rotatably with a camshaft is connected and wherein a phase angle of the output element within an angular range to the drive element is variable, is the problem according to the invention solved by the output element has a first thread, the camshaft a complementary to the first thread second thread has and the non-rotatable connection between the camshaft and driven element as a screw connection by means of the first and second threads is trained.

In In these embodiments, the output element has a Thread on, whose longitudinal axis with the axis of rotation of the output element coincides. This thread can, for example, as an internal thread be formed and with a mounted on the camshaft, complementary external threads cooperate in such a way that the output element are screwed directly onto the camshaft can, with no other fasteners, such as Central screws or eccentrically arranged screws needed become. Also conceivable are solutions in which the output element with an external thread and the camshaft with a complementary Internal thread are provided.

By forming the connection producing threads on the Connecting components eliminates the need for more Connecting elements, such as screws. This reduces the number of components to be assembled and thus the assembly facilitated. Furthermore, eliminates the mass of standing The technology required screws, reducing the moving mass of the camshaft adjuster is reduced.

One Another advantage is the fact that in hydraulic camshaft adjusters a central valve within a central bore of the rotor in any Position can be arranged without causing consideration taken on the threaded connection between the valve housing output member camshaft must be, since in the embodiments according to the invention the valve body is separate from the threaded bandage. Consequently it is possible to use the connections of the control valve to position exactly to the adjacent construction of the output element. It is also possible the valve body completely omit and the control piston of the control valve directly in a To arrange central bore of the output element.

In an advantageous embodiment of the invention is provided that the first thread as internal thread within a central opening of the output element is formed.

In This embodiment has the camshaft on the axial End, on which the camshaft adjuster is attached, an external thread on. This end portion of the camshaft engages in the central opening of the output element and the inner rotor can by means of the first Thread, without further fasteners, directly on the second thread be screwed on and fixed. This is done by a relative Rotary movement of the output element to the camshaft about the common Rotary axis reached.

Alternatively, it can be provided that the output element has a cylindrical portion and the first thread is formed as an external thread on the cylindrical portion.

In this embodiment is the axial end of the camshaft, at which the camshaft adjuster is fastened, at least partially hollow executed. Inside this hollow executed Section, the camshaft is provided with an internal thread. The cylindrical portion of the driven element is during the assembly in the hollow portion of the camshaft introduced and the connection between the two components over the two threads by means of a relative rotational movement of the output element made to the camshaft about the common axis of rotation.

In an advantageous embodiment of the invention is provided that the first thread in the screwing a first centering is upstream. Furthermore, it can be provided that the second Thread downstream in the screwing a second centering is, wherein the second centering element of the first centering element is adjusted.

at The centering may be, for example, each one act cylindrical surface. In this case is at one the two components have a cylindrical inner surface formed, which with a formed on the other component, complementary to the first inner circumferential surface, Outer shell surface cooperates such that thereby set the radial position of the output element to the camshaft is. Also conceivable are centering elements which differ from the cylindrical shape, for example, penetrated by longitudinal grooves are.

In an advantageous embodiment of the invention is provided that the axial extent of the first centering element larger formed as the axial extent of the second centering element is. By such a configuration of the axial extensions of the Centering elements ensures that a traction between these produced at the end of the screwing and thus the strength of the screw connection between the output element and Camshaft is enlarged.

In a development of the first embodiment may be provided be that the first thread has a first threaded portion with a first pitch and a second threaded portion with one of the first slope has different second slope.

In an advantageous development of the second embodiment can be provided that the one of the threads a first threaded portion with a first pitch and a second threaded portion with a different from the first slope second slope having. It can further be provided that the slope of the the other thread in the screwing facing threaded portion coincides with the pitch of the other thread, wherein Slope of the other thread over the entire length is constant.

By the training equal slope in both threads is a lightweight Screwing the output element ensures on the camshaft. Of the second adjoining the first threaded section Thread section of different pitch increases during of the screwing the strength of the connection between the Output element and the camshaft.

Brief description of the drawings

Further Features of the invention will become apparent from the following description and from the drawings, in which embodiments of the Invention are shown in simplified form. Show it:

1 a longitudinal section through a camshaft adjuster according to the invention,

2 a cross section through the in 1 shown camshaft adjuster along the line II-II,

3 a longitudinal section through a further embodiment of a camshaft adjuster according to the invention.

Detailed description the drawing

The invention will now be described by way of example with reference to a hydraulic camshaft adjuster 1 explained in vane-cell construction. The 1 and 2 show a camshaft adjuster according to the invention 1 an internal combustion engine. The camshaft adjuster 1 consists essentially of an outer rotor (drive element) 2 and a concentrically arranged inner rotor (driven element) 3 , A drive wheel 4 is non-rotatable with the outer rotor 2 connected and formed in the illustrated embodiment as a sprocket. About the drive wheel 4 is the outer rotor 2 in drive connection with a crankshaft, not shown. The inner rotor 3 is non-rotatable with a camshaft 9 connected.

Embodiments are also conceivable in which the outer rotor 2 rotatably with the camshaft 9 connected and the inner rotor 3 is in drive connection with a crankshaft, not shown. In this case, the inner rotor 3 the drive selement and the outer rotor 2 the output element.

The outer rotor 2 is rotatable on the inner rotor 3 mounted, wherein on the inner circumferential surface of the outer rotor 2 in the illustrated embodiment, five circumferentially spaced recesses 5 are provided. The recesses 5 be in the radial direction of the outer rotor 2 and the inner rotor 3 , in the circumferential direction of two side walls 6 of the outer rotor 2 and in the axial direction through first and second side covers 7 . 8th limited. Each of the recesses 5 is sealed pressure-tight in this way.

The two side covers 7 . 8th by means of screws 8a rotatably with the outer rotor 2 connected.

On the outer circumferential surface of the inner rotor 3 are axially extending vane grooves 10 formed, with in each wing groove 10 a radially extending wing 11 is arranged. In every recess 5 a wing extends 11 , where the wings 11 in the radial direction on the outer rotor 2 and in the axial direction on the side covers 7 . 8th issue. Every wing 11 divided a recess 5 in two opposing pressure chambers 12 . 13 , Alternatively, embodiments are conceivable in which the wings 11 in one piece with the inner rotor 3 are formed.

By means of first and second pressure medium lines 16 . 17 can the first and second pressure chambers 12 . 13 via a control valve 14 be connected to a pressure medium pump, not shown, or a tank, also not shown. As a result, an actuator is formed which causes a relative rotation of the outer rotor 2 opposite the inner rotor 3 allows. Be the first pressure chambers 12 with the pressure medium pump and the second pressure chambers 13 Connected to the tank, the first pressure chambers expand 12 at the expense of the second pressure chambers 13 out. This results in a displacement of the wings 11 in the circumferential direction, in the arrow 18 illustrated direction. By moving the wings 11 becomes the inner rotor 3 relative to the outer rotor 2 twisted. A rotation in the opposite direction can be achieved by reversing the pressure medium flows.

From the relative rotation of the inner rotor 3 relative to the outer rotor 2 , as a result of the supply and discharge of pressure medium to and from the pressure chambers 12 . 13 , results in a phase shift between the camshaft 9 and crankshaft. By targeted introduction and discharge of pressure medium in the pressure chambers 12 . 13 Thus, the timing of the gas exchange valves of the internal combustion engine can be selectively varied or optionally held.

The pressure medium lines 16 . 17 are executed in the illustrated embodiment as a substantially radially arranged bores extending from a central opening 19 of the inner rotor 3 extend to the outer circumferential surface. Inside the central opening 19 is a control valve in the illustrated embodiment 14 arranged over which the pressure chambers 12 . 13 can be selectively connected to the pressure medium pump or the tank. Another option is inside the central opening 19 instead of the control valve 14 to arrange a pressure medium distributor, the pressure medium lines 16 . 17 connects via pressure medium channels and annular grooves with the terminals of an externally mounted control valve.

In the illustrated embodiment, within the central opening 19 only a control piston 15 arranged, which is displaceable in the axial direction by means of a magnet, not shown. The control piston 15 cooperates with through the pressure medium lines 16 . 17 trained control edges together and thus controls the pressure fluid flow to and from the pressure chambers 12 . 13 , It is also conceivable between the control piston 15 and the central opening 19 to insert a separate valve housing into which the control piston 15 to be led. Because this valve housing is not in the screw connection camshaft 9 - inner rotor 3 stands, it can be arbitrarily within the central opening 19 be positioned.

Inside the central opening 19 of the inner rotor 3 is a first thread 20 , in the form of an internal thread, on the camshaft 9 formed facing side. In addition, a second thread 21 in the form of an external thread on the inner rotor 3 facing side of the camshaft 9 educated. The first and the second thread 20 . 21 are complementary to each other, with their longitudinal axes 21a with the rotation axis 22 of the respective component coincides. During assembly, the inner rotor becomes 3 with the help of the two threads 20 . 21 on the camshaft 9 screwed.

In the central opening 19 of the inner rotor 3 is a first centering element 23 the first thread 20 upstream. Furthermore, on the camshaft 9 a second centering element 24 formed, starting from the axial end of the camshaft 9 the second thread 21 is downstream. Using the two centering elements 23 . 24 becomes the radial position of the inner rotor 3 relative to the camshaft 9 established.

The second centering element 24 on the one hand by the second thread 21 and on the other hand by a radial collar 25 limited. The Radial Union 25 is designed such that by investing the ers th centering element 23 at this Radialbund 25 the axial position of the inner rotor 3 relative to the camshaft 9 is fixed.

To the strength of the screw connection between inner rotor 3 and the camshaft 9 For example, one of the two threads can increase 20 . 21 have two threaded sections. One of the two threaded sections has the same thread pitch as the complementary thread 20 . 21 of the other component 3 . 9 on. Advantageously, this threaded portion is arranged facing the other component. The other threaded portion has a different thread pitch.

Alternatively or additionally, it may be provided that the axial extent a _{1 of} the first centering element 23 is made larger than the axial extent a _{2 of} the second centering 24 ,

By these measures, in addition to the screw connection, a further frictional connection between the inner rotor 3 in the camshaft 9 made and thus the strength of the screw can be increased.

3 shows a further embodiment of a camshaft adjuster according to the invention 1 , In contrast to the first embodiment, the inner rotor 3 an axial extension in the form of a cylindrical portion 26 is formed on the outer circumferential surface of the first thread 20 is trained. The camshaft 9 is in this embodiment on the camshaft 9 facing axial end at least partially hollow, wherein the second thread 21 is formed inside the hollow end as an internal thread.

In an advantageous development of the invention, it is provided here that the outer diameter of the extension corresponds to the inner diameter of the hollow end of the camshaft 9 adapted, which makes the first thread 20 subsequent section of the extension as the first centering element 23 serves. Thus, a radial centering of the inner rotor 3 to the camshaft 9 reached.

Also conceivable is the use of the invention in other hydraulic camshaft adjuster types, for example Axialkolbenverstellern. Furthermore, the invention can also be used in electromechanical camshaft adjusters. In these types of adjusters, the phase angle between the crankshaft and the camshaft 9 be varied by means of a three-shaft gear, for example, a swash plate gear, Innenexzentergetriebes, Doppelinnenexzentergetriebes, wave gear, planetary gear or by means of pivoting arms. In this case, one of the two shafts is in driving connection with the crankshaft, another shaft is non-rotatable with the camshaft 9 connected via a third shaft and torque of an electromechanical drive, such as an electric motor or brakes, in the camshaft adjuster 1 be fed. The non-rotatable connection between the camshaft fixed shaft of the three-shaft transmission and the camshaft can be analogous to that in the 1 to 3 illustrated embodiment are produced by means of a screw, wherein the thread directly to the components to be connected (camshaft 9 , Output element 3 ) are formed and the longitudinal axes of the threads coincide with the axis of rotation of the components.

1

Phaser

2

outer rotor

3

inner rotor

4

drive wheel

5

recesses

6

Side wall

7

first side cover

8th

second side cover

8a

screw

9

camshaft

10

vane

11

wing

12

first pressure chamber

13

second pressure chamber

14

control valve

15

spool

16

first Pressure medium line

17

second Pressure medium line

18

arrow

19

central opening

20

first thread

21

second thread

21a

longitudinal axis

22

axis of rotation

23

first centering

24

second centering

25

radial collar

26

cylindrical section

a ₁

axial extension

a ₂

axial extension

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

• - US 6523512 B2 [0003]
• - US 6363896 B1 [0005]
• US 5566651 [0009]

Claims (10)

Camshaft adjuster ( 1 ) with a drive element ( 2 ), which has means for driving through a crankshaft and • a non-rotatable with a camshaft ( 9 ) connectable output element ( 3 ), Wherein a phase angle of the output element ( 3 ) within an angular range to the drive element ( 2 ) is variable, characterized in that • the output element ( 3 ) a first thread ( 20 ), whose longitudinal axis ( 21a ) with a rotation axis ( 21b ) of the output element ( 3 ) coincides. Camshaft adjuster ( 1 ) with a drive element ( 2 ), an output element ( 3 ) and a camshaft ( 9 ), Wherein the drive element ( 2 ) is in drive connection with a crankshaft, wherein the output element ( 3 ) rotatably with a camshaft ( 9 ) and wherein a phase angle of the output element ( 3 ) within an angular range to the drive element ( 2 ) is variable, characterized in that • the output element ( 3 ) a first thread ( 20 ), the camshaft ( 9 ) to the first thread ( 20 ) complementary second thread ( 21 ) and • the non-rotatable connection between the camshaft ( 9 ) and output element ( 3 ) as a screw connection by means of the first and the second thread ( 20 . 21 ) is trained. Camshaft adjuster ( 1 ) according to one of claims 1 or 2, characterized in that the first thread ( 20 ) as internal thread within a central opening ( 22 ) of the output element ( 3 ) is trained. Camshaft adjuster ( 1 ) according to one of claims 1 or 2, characterized in that the output element ( 3 ) a cylindrical section ( 26 ) and the first thread ( 20 ) as an external thread on the cylindrical portion ( 26 ) is trained. Camshaft adjuster ( 1 ) according to one of claims 1 or 2, characterized in that the first thread ( 20 ) in the screwing-in direction a first centering element ( 23 ) is upstream. Camshaft adjuster ( 1 ) according to claim 5, characterized in that the second thread ( 21 ) in the screwing a second centering element ( 24 ), wherein the second centering element ( 24 ) the first centering element ( 23 ) is adjusted. Camshaft adjuster ( 1 ) according to claim 5, characterized in that the axial extent (a ₁ ) of the first centering element ( 23 ) greater than the axial extent (a ₂ ) of the second centering element ( 24 ) is trained. Camshaft adjuster ( 1 ) according to claim 1, characterized in that the first thread ( 20 ) has a first threaded portion having a first pitch and a second threaded portion having a second pitch different from the first pitch. Camshaft adjuster ( 1 ) according to claim 2, characterized in that one of the threads ( 20 21 ) has a first threaded portion having a first pitch and a second threaded portion having a second pitch different from the first pitch. Camshaft adjuster ( 1 ) according to claim 9, characterized in that the pitch of the other thread ( 20 . 21 ) in the screwing facing threaded portion with the pitch of the other thread ( 20 . 21 ), wherein the pitch of the other thread ( 20 . 21 ) is constant over the entire length.