CAMSHAFT ADJUSTER AND METHOD FOR DETERMINING THE SETTING OF A CAMSHAFT ADJUSTER

Abstract

A camshaft adjuster for adjusting the phase angle between a crankshaft and a camshaft of an internal combustion engine comprises an actuator, in particular, an electric motor, and an adjustment module, which comprises a drive element, which can be driven by the crankshaft, and an output element, which can be rotated relative to the drive element to a limited extent and which is provided to be securely coupled to the camshaft, wherein a signal generator, which is arranged so as to be fixed in position on the internal combustion engine and which has an inductance, is inductively coupled to a measurement circuit, which is integrated into the adjustment module and which has at least one resonant circuit component having electrical properties that depend on the said phase angle.

Claims

1-10. (canceled)

11. A camshaft adjuster for adjusting the phase angle between a crankshaft and a camshaft of an internal combustion engine, said camshaft adjuster comprising an actuator and an adjustment module, which comprises a drive element, which can be driven by means of the crankshaft, as well as an output element, which can be rotated to a limited extent relative to said drive element and is securely coupled to the camshaft, wherein a signal generator, which has an inductance and is arranged so as to be fixed in position on the internal combustion engine, as well as a measurement circuit, which is inductively coupled to said signal generator and is integrated into the adjustment module and which has at least one resonant circuit component having electrical properties, which depend on the said phase angle.

12. The camshaft adjuster of claim 11, wherein a first inductance is provided as a resonant circuit component with electrical properties that depend on the phase angle.

13. The camshaft adjuster of claim 12, wherein a second inductance is connected in series to the first inductance, and the second inductance is not variable, and wherein only the second inductance is provided for coupling between the measurement circuit and the signal generator.

14. The camshaft adjuster of claim 11, wherein a first sub-component of the resonant circuit component is securely connected to the drive element; and a second sub-component of the resonant circuit component is securely connected to the output element.

15. The camshaft adjuster of claim 14, wherein one of the sub-components is designed as a current-carrying component; and the other sub-component, as a non-current carrying component.

16. The camshaft adjuster of claim 15, wherein the current-carrying sub-component is designed as a coil with three dimensional structure; and the non-current carrying sub-component, as an iron core, which dips into the coil and which can be pivoted relative to the coil.

17. The camshaft adjuster of claim 15, wherein the current-carrying sub-component is designed as a coil, which is implemented in the form of a printed circuit; and the non-current carrying sub-component, as a sheet metal ring, which is pivotable relative to the coil, arranged parallel to the coil, and has a width that varies in the circumferential direction.

18. The camshaft adjuster of claim 11, wherein an electric motor is provided as the actuator, and a stationary inductance is fixed on the housing of said electric motor.

19. The camshaft adjuster of claim 18, wherein the adjustment module is designed as a triple shaft transmission, and the resonant circuit component, which has variable properties, is disposed on the face of a transmission housing of the triple shaft transmission.

20. A method for measuring the setting of a camshaft adjuster, which is designed for adjusting the phase angle between a crankshaft and a camshaft of an internal combustion engine, said method comprising the following steps: supplying a stationary inductance, which is disposed so as to be fixed in position relative to the internal combustion engine, with a signal, coupling inductance signal with a measurement circuit, with said measurement circuit being totally formed by means of rotatable components of the camshaft adjuster, wherein the electrical properties of the measurement circuit depend on the setting of the camshaft adjuster; and, measuring a fed back signal, which depends on the setting of the camshaft adjuster, and which is picked up by means of the stationary inductance.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various embodiments are disclosed, by way of example only, with reference to the accompanying schematic drawings in which corresponding reference symbols indicate corresponding parts, in which:

[0019] FIG. 1 is a camshaft adjuster with an electric actuator and a device for measuring the phase angle between the crankshaft and the camshaft;

[0020] FIG. 2 illustrates various embodiments of an adjustable inductance shown in FIG. 1;

[0021] FIG. 3 illustrates a variant of a resonant circuit for the arrangement in FIG. 1;

[0022] FIG. 4 illustrates a variant of a resonant circuit for the arrangement in FIG. 1; and,

[0023] FIG. 5 illustrates a variant of a resonant circuit for the arrangement in FIG. 1.

DETAILED DESCRIPTION

[0024] At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements. It is to be understood that the claims are not limited to the disclosed aspects.

[0025] Furthermore, it is understood that this disclosure is not limited to the particular methodology, materials and modifications described and as such may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the claims.

[0026] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this disclosure pertains. It should be understood that any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the example embodiments.

[0027] It should be appreciated that the term substantially is synonymous with terms such as nearly, very nearly, about, approximately, around, bordering on, close to, essentially, in the neighborhood of, in the vicinity of, etc., and such terms may be used interchangeably as appearing in the specification and claims. It should be appreciated that the term proximate is synonymous with terms such as nearby, close, adjacent, neighboring, immediate, adjoining, etc., and such terms may be used interchangeably as appearing in the specification and claims. The term approximately is intended to mean values within ten percent of the specified value.

[0028] FIG. 1 shows a camshaft adjuster, which is marked in its entirety with the reference numeral 1; and with respect to its basic functionality reference is made, for example, to the German patent documents DE 10 2008 039 009 A1 and DE 10 2011 083 800 A1.

[0029] Camshaft adjuster 1 comprises actuator 2, i.e., an electric motor with stationary housing 3, and adjustment module 4, which is also called a variator, which is designed as a triple shaft transmission. A shaft, which is provided with the reference numeral 5, is securely connected to the motor shaft of electric motor 2 and to an adjustment shaft of adjustment module 4 or is identical to at least one of these motor shafts or transmission shafts. A toothed gear acts as drive element 6 of adjustment module 4, with said toothed gear being securely connected to transmission housing 7 of adjustment module 4. An output element, which is labeled 8 and which is part of adjustment module 4, is securely connected to a camshaft of an internal combustion engine and rotates at the speed of drive element 6, as long as shaft 5 rotates at the same speed. If, on the other hand, the speed of shaft 5 deviates from the rotational speed of drive element 6, then output element 8 is adjusted at a high speed reduction ratio. This adjustment process constitutes an adjustment of the phase angle of the camshaft in relation to the crankshaft of the same internal combustion engine, which is not shown in greater detail. Variator 4 is designed, for example, as a wobble plate mechanism or a harmonic drive.

[0030] The components of a signal generator, which is marked in its entirety with the reference numeral 9, are attached to housing 3 of electric motor 2. In FIG. 1 signal generator coil 10 is indicated, the inductance of which is L.sub.0 (see FIGS. 3 to 5). Signal generator coil 10 is located on the end face of electric motor 2 that faces adjustment module 4. Other components of signal generator 9 may be, for example, inside housing 3 or elsewhere in the internal combustion engine having fixed in position relative to camshaft adjuster 1.

[0031] An inductive coupling is provided between signal generator coil 10 and measurement circuit 11, which is integrated into adjustment module 4 and of which transmission coil 12 can be seen in FIG. 1. In the simplified representation according to FIG. 1, transmission coil 12 is radially inside signal generator coil 10. Signal generator coil 10 and transmission coil 12 could be just as well in adjacent planes. In any case the distance between said coils 10, 12 is at most a few millimeters.

[0032] Possible configurations of signal generator 9 and measurement circuit 11, both of which can be integrated, according to FIG. 1, into camshaft adjuster 1, are shown in FIGS. 3 to 5. These configurations make it possible to implement the resonant circuits, with a line-conducted power supply being provided exclusively to the stationary parts of camshaft adjuster 1 in all cases. Electric power is supplied by frequency generator 13, which is part of signal generator 9, and generates a variable electric signal in an order of magnitude of a few kHz to MHz. The coupling between signal generator 9 and measurement circuit 11 is shown by a double arrow labeled k.

[0033] In the exemplary embodiment according to FIG. 3, signal generator 9 comprises, in addition to signal generator coil 10, capacitor 14 having capacitance C, as a result of which a complete resonant circuit is already formed. The properties of this resonant circuit are affected at the same time by measurement circuit 11, which has, in addition to transmission coil 12, adjustment coil 15. The inductance of adjustment coil 15 is referred to as first inductance L.sub.1; the inductance of transmission coil 12, as second inductance L.sub.2. The amount of first inductance L.sub.1 depends on the angular position between drive element 6 and output element 8 of adjustment module 4, i.e., depends on the setting of camshaft adjuster 1, which will be discussed in still greater detail with reference to FIG. 2. Coupling k enables feedback between measurement circuit 11 and signal generator 9, with the feedback depending on the setting of camshaft adjuster 1. An attenuation, which is a function of the frequency, can be determined, in particular, in the resonant circuit, comprising signal generator coil 10, where in this case the frequency, at which the highest attenuation occurs, is a function of the electrical properties of measurement circuit 11, in particular, by the amount of first inductance L.sub.1.

[0034] The measurement setup, according to FIG. 4, differs from measurement setup 3 by the fact that the electric circuit, comprising frequency generator 13, does not have a capacitance as a separate component, whereas, instead, capacitor 16 is part of measurement circuit 11. Furthermore, as in the exemplary embodiment according to FIG. 3, transmission coil 12 and adjustment coil 15 are components of the setup for measuring the setting of camshaft adjuster 1, according to FIG. 4.

[0035] The exemplary embodiment, according to FIG. 5, combines the features of the exemplary embodiments, according to FIG. 3 and FIG. 4, and includes capacitors 17, 18 having capacitance C.sub.0 and C.sub.1 respectively, both of which are in the electric circuit comprising signal generator coil 10 and/or transmission coil 12.

[0036] In each of the designs according to FIGS. 3 to 5, adjustment coil 15 is provided as a resonant circuit component having electrical properties that are a function of the phase angle between the camshaft and the crankshaft. As an alternative, it is also possible, for example, that capacitance C, C.sub.1 or a resistance (not shown) inside measurement circuit 11 could have electrical properties that are a function of the torsion angle between drive element 6 and output element 8 of adjustment module 4. Similarly it is just as possible to implement embodiments, in which several components of measurement circuit 11 can be adjusted in such a way that a signal, which is a function of the setting of camshaft adjuster 1, is fed back to the stationary components of the measurement setup.

[0037] FIG. 2 shows three possible variants of adjustment coil 15, which can be built by choice into camshaft adjuster 1, according to FIG. 1, or can be integrated into each of the circuit arrangements according to FIGS. 3 to 5. Adjustment coil 15 comprises in all cases current-carrying component 19 (in the literal sense of the term the coil) as the first sub-component and non-current carrying component 20 as a second sub-component, which affects the properties of first sub-component 19.

[0038] According to the design of adjustment coil 15 shown at the top in FIG. 2, first current-carrying component 19 is a coil with three dimensional structure, into which pivotable iron core 21 dips as non-current carrying component 20. At the same time sub-components 19, 20 are securely connected to drive element 6 or output element 8 of camshaft adjuster 1, so that the angle between sub-components 19, 20 reflects the angle between said elements 6, 8 and, as a result, the setting of camshaft adjuster 1. In contrast to the simplified representation shown at the top in FIG. 2, current-carrying component 19 could also be implemented in the form of several individual coils, in each of which separate iron core 21 can dip. In this case the arrangement of all of the iron cores 21 forms second sub-component 20.

[0039] The design of adjustment coil 15, shown in the middle in FIG. 2, has a corresponding functionality. In this case current-carrying component 19 of adjustment coil 15, i.e., the coil in the literal sense of the term, is implemented as a printed circuit. First sub-component 19, which lies, thus, more or less in a plane, is arranged parallel to sheet metal ring 22, which acts, analogous to iron core 21, as a second non-current carrying component 20. Sheet metal ring 22 has four merging segments 23, each of which extends over 90 deg. and each of which has a width that varies in the circumferential direction of sheet metal ring 22. Segments 23 interact with four single coils 24, which together form current-carrying component 19 of adjustment coil 15, where in this case the current-carrying component is designed as a printed circuit. This design of adjustment coil 15 is distinguished by a particularly flat construction in the axial direction of camshaft adjuster 1 and, as a result, by an extremely small amount of space that is required on the end face of adjustment module 4 that faces actuator 2.

[0040] The design of adjustment coil 15, which is shown at the bottom in FIG. 2, has only single current-carrying component 19, which interacts with wedge 25 of non-current carrying component 20. In this case current-carrying component 19, i.e., single coil 24, is located radially outside of wedge 25 of the completely annular non-current carrying component 20. In contrast to the design that is shown, it is also possible to provide several, for example, four or six, single coils 24, opposite each of which there is wedge 25, which extends, for example, over an angle of at most 90 deg. or at most 60 deg.

[0041] It will be appreciated that various aspects of the disclosure above and other features and functions, or alternatives thereof, may be desirably combined into many other different systems or applications. Various presently unforeseen or unanticipated alternatives, modifications, variations, or improvements therein may be subsequently made by those skilled in the art which are also intended to be encompassed by the following claims.

REFERENCE LABELS

[0042] C capacitance [0043] C.sub.0 capacitance [0044] C.sub.1 capacitance [0045] k coupling [0046] L.sub.0 inductance [0047] L.sub.1 inductance [0048] L.sub.2 inductance [0049] 1 camshaft adjuster [0050] 2 actuator, electric motor [0051] 3 housing [0052] 4 adjustment module [0053] 5 shaft [0054] 6 drive element [0055] 7 transmission housing [0056] 8 output element [0057] 9 signal generator [0058] 10 signal generator coil [0059] 11 measurement circuit [0060] 12 transmission coil [0061] 13 frequency generator [0062] 14 capacitor [0063] 15 adjustment coil [0064] 16 capacitor [0065] 17 capacitor [0066] 18 capacitor [0067] 19 current-carrying component, first sub-component [0068] 20 non-current carrying component, second sub-component [0069] 21 iron core [0070] 22 sheet metal ring [0071] 23 segment [0072] 24 single coil [0073] 25 wedge