Actuating device for a camshaft timing apparatus

Abstract

An actuating device for a camshaft timing apparatus, having a movable actuating member being supported displaceable along a translational axis, and a force generator for generating a force driving the actuating member along the translational axis, wherein the actuating member is supported rotatable about a rotational axis and wherein the actuating device comprises a torque generator for subjecting the actuating member to a torque about the rotational axis.

Claims

1. An actuating device for a camshaft timing apparatus, the actuating device comprising: a movable actuating member being supported displaceable along a translational axis, the actuating member being supported rotatable about a rotational axis; a force generator to generating a force driving the actuating member along the translational axis; and a torque generator to subject the actuating member to a torque about the rotational axis, wherein the actuating member comprises a shaft extending along the translational axis and a protrusion extending transverse to the shaft and being tension-proof and thrust-proof connected to the shaft, wherein the actuating device comprises two end stops being arranged at a distance from each other with the protrusion in between thus defining a first axial position and a second axial position of the protrusion, and wherein each of the two end stops has a central bore, the shaft of the actuating member extending through the central bore of each of the two end stops.

2. The actuating device according to claim 1, wherein the actuating device comprises a restorer for restoring an axial position of the protrusion between the two end stops, thus defining a third axial position of the protrusion between the first axial position and the second axial position.

3. The actuating device according to claim 1, wherein the torque generator is axially fixed and the protrusion is torque-proof connected to the shaft, wherein the torque generator and the protrusion each comprise an axial face, the axial faces facing each other providing a rotational resistance to the protrusion abutting the torque generator if forced against each other.

4. The actuating device according to claim 1, wherein the protrusion comprises a magnetizable material and the force generator comprises a magnetic field generator for generating a magnetic field subjecting the protrusion to a driving force.

5. The actuating device according to claim 4, wherein the force generator comprises two solenoids being arranged at a distance from each other with the protrusion in between, wherein each of the two solenoids has at least one pole piece providing or supporting one of the two end stops.

6. The actuating device according to claim 1, wherein the rotational axis extends parallel or collinear to the translational axis.

7. A method for operating an actuating device for a camshaft timing apparatus, the method comprising: providing the actuating device with a movable actuating member defining a translational axis and being supported displaceable along the translational axis; and defining a rotational axis and supporting the movable actuating member rotatable about the rotational axis; generating a force via a force generator to drive the actuating member along the translational axis; and subjecting the actuating member to a torque, via a torque generator, about the rotational axis, and varying the torque generated by the torque generator by varying the driving force generated by the force generator, wherein the actuating member comprises a shaft extending along the translational axis and a protrusion extending transverse to the shaft and being tension-proof and thrust-proof connected to the shaft, wherein the actuating device comprises two end stops being arranged at a distance from each other with the protrusion in between thus defining a first axial position and a second axial position of the protrusion, and wherein each of the two end stops has a central bore, the shaft of the actuating member extending through the central bore of each of the two end stops.

8. The method according to claim 7, wherein the force generator generates a magnetic field via a magnetic field generator comprising at least one solenoid for subjecting the actuating member comprising a magnetizable material to a magnetic force wherein an average strength of the magnetic force is varied by varying a strength of a continuous directed electric current and/or a width-ratio of a pulse modulated directed electric current flowing through the at least one solenoid.

9. A system comprising: a camshaft timing apparatus having a valve actuator defining a translational axis and being axially displaceable along the translational axis and a torque transmitter defining a rotational axis and being rotatable about the rotational axis; an actuating device having a movable actuating member, the actuating member defining the translational axis and being supported displaceable along the translational axis, and a force generator to generate a force driving the actuating member along the translational axis, wherein the actuating member of the actuating device is thrust-proof and tension-proof connectable or connected to the valve actuator of the camshaft timing apparatus in the mounted state of the system, wherein the actuating member defines the rotational axis and is supported rotatable about the rotational axis, wherein the actuating device comprises a torque generator for subjecting the actuating member to a torque about the rotational axis, and wherein the actuating member of the actuating device is torque-proof connected to the torque transmitter of the camshaft timing apparatus in the mounted state of the system.

10. The system according to claim 9, wherein the actuating member comprises a shaft extending along the translational axis.

11. A method for operating a system comprising a camshaft timing apparatus and an actuating device for a camshaft timing apparatus according to claim 9, the method comprising: actuating a valve of the camshaft timing apparatus by the actuating device, the actuating device displacing the valve actuator of the valve along a translational axis, the valve controlling a connection between a hydraulic pump of the camshaft timing apparatus and a hydraulic motor of the camshaft timing apparatus, the hydraulic motor being coupled to a crankshaft and a camshaft and being configured for adjusting an angular position of the camshaft relative to the crankshaft; actuating the hydraulic pump by providing a rotation of a rotor of the hydraulic pump about the rotational axis relative to the camshaft; and controlling the rotational speed of the rotor relative to the camshaft by the actuating device, the actuating device subjecting the rotor to a variable torque about the rotational axis.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

(2) FIG. 1 shows a perspective explosion view of an actuating device according to the invention.

(3) FIG. 2 shows a perspective view of the actuating member of the actuating device shown in FIG. 1.

(4) FIG. 3 shows a perspective view of a first end stop of the actuating device shown in FIG. 1.

(5) FIG. 4 shows a perspective view of a second end stop of the actuating device shown in FIG. 1.

(6) FIG. 5 shows a perspective explosion view of a camshaft timing apparatus of a system according to the invention.

DETAILED DESCRIPTION

(7) In FIGS. 1 to 4 an exemplary embodiment of an actuating device 10 for a camshaft timing apparatus 50 according to the invention is shown. The actuating device 10 comprises a movable actuating member 20 being supported displaceable along a translational axis 11 and rotatable about a rotational axis 21. In this example, the rotational axis 21 is identical with, i.e. extends collinear to the translational axis 11, however other relative orientations are not excluded.

(8) The actuating member 20 comprises a shaft 22 which may comprise an elongate cylindrical rod extending along the translational axis 11 and a protrusion 27 being tension-proof, thrust-proof and torque-proof connected to the shaft 22. The protrusion 27 may be integral with the shaft 20, as depicted, and may comprise a magnetizable material, i.e. a paramagnetic material. The protrusion 27 may be a circular disc extending perpendicular to the shaft 22 and may be arranged eccentric between opposite axial free ends 24, 26 of the shaft 22, thus dividing the shaft 22 into a shorter section 23 and a longer section 25. In other embodiments the protrusion may be centered, as well.

(9) The actuating device 10 further comprises a force generator 30 for generating a force driving the actuating member 20 along the translational axis 11. The force generator 30 may have a magnetic field generator for generating a magnetic field subjecting the protrusion 27 to a driving force. The magnetic field generator has two pot magnets. The pot magnets each may comprise a solenoid 31, 34 for generating a magnetic field and are arranged at a distance 37 from each other with the protrusion 27 in between, wherein each solenoid 31, 34 has a pole piece providing an axially fixed end stop 12, 13 to the protrusion 27.

(10) The end stops 12, 13, thus, are arranged at the distance 37 from each other and encompass and face the protrusion 27. Each end stop 12, 13 has a central bore 33, 36 which the shaft 22 of the actuating member 20 may extend through. The end stops 12, 13 define a first axial position and a second axial position of the protrusion 27 abutting the respective end stop 12, 13. The actuating device 10 has a restorer which may be a spring or the like for restoring a central axial position of the protrusion 27 between the end stops 12, 13 thus defining a third axial position of the protrusion 27 between the first axial position and the second axial position.

(11) Furthermore, the actuating device 10 comprises an axially fixed torque generator 40 for subjecting the actuating member 20 to a torque about the rotational axis 21. The torque generator 40 and the protrusion 27 may comprise axial faces 28, 29, 32, 35, respectively. The axial faces 28, 29, 32, 35 face each other providing a rotational resistance to the protrusion 27 abutting the torque generator 40 if forced against each other. The torque generator 40 may optionally comprise friction pads 38 which can be attached to or be integrated in the respective axial face 32, 35.

(12) In FIG. 5 a camshaft timing apparatus 50 of a preferred embodiment of a system according to the invention is shown. The camshaft timing apparatus is similar to the camshaft timing apparatuses described in PCT/EP2017/069942 and PCT/EP2017/069960 which are incorporated as fully disclosed herein. The camshaft timing apparatus 50 comprises a hydraulic motor 55 and a hydraulic pump 54 which both are integrated in the camshaft timing apparatus 50. The hydraulic motor 55 may be coupled to a crankshaft, e.g. via a belt drive or a gear, and a camshaft, e.g. via a flange or some other coupling and is configured for adjusting an angular position of the camshaft relative to the crankshaft. The hydraulic pump 54 has a rotor 53 and a torque transmitter 52 being torque-proof connected thereto.

(13) The rotor 53 has an integrated valve (not visible) fluidly connecting the hydraulic pump 54 to the hydraulic motor 55. The valve controls a connection between the hydraulic pump 54 of the camshaft timing apparatus 50 and the hydraulic motor 55 of the camshaft timing apparatus 50. The valve comprises a valve actuator 51 which may be configured as an elongate needle, as depicted. The valve actuator 51 extends through the torque transmitter 52 and the rotor 53 and is supported axially displaceable in corresponding cylindric bores of the torque transmitter 52 and the rotor 53, respectively. The needle has three axial positions: a first position in which the valve fluidly connects the hydraulic pump 54 with the hydraulic motor 55 to drive the hydraulic motor 55 in a first rotational direction. In a second position of the needle the valve fluidly connects the hydraulic pump 54 with the hydraulic motor 55 to drive the hydraulic motor 55 in a second rotational direction, being opposite to the first rotational direction. In the third, neutral position, the valve fluidly disconnects the hydraulic pump 54 and the hydraulic motor 55 and an inlet port of the hydraulic motor 55 and an outlet port of the hydraulic motor 55 are fluidly disconnected as well, to thereby block a rotor of the hydraulic motor 55 relative to a stator or the hydraulic motor 55.

(14) During operation of the system the valve of the camshaft timing apparatus 50 is actuated by means of the actuating device 10. The actuating device 10 displaces the valve actuator 51 of the valve along the translational axis 11 in order to realize axial positions of the valve actuator 51 depending on actual adjustment requirements. A first axial position of the valve actuator 51, e.t. the needle, corresponds to a first valve state which causes the hydraulic motor 55 to set ahead the camshaft relative to the crankshaft. A second axial position of the valve actuator 51, e.g. the needle, corresponds to a second valve state which causes the hydraulic motor 55 to set back the camshaft relative to the crankshaft. A third axial position of the valve actuator 51, e.g. the needle, causes a halt of the hydraulic motor 55 to keep the angular relation between the camshaft and the crankshaft constant.

(15) The hydraulic pump 54 of the camshaft timing apparatus 50 is actuated by providing a rotation of the rotor 53 of the hydraulic pump 54 about the rotational axis 21 relative to the camshaft. The rotational speed of the rotor 53 relative to the camshaft is controlled by the actuating device 10, the actuating device 10 subjecting the rotor 53 to a variable torque about the rotational axis 21.

(16) The variable torque is generated by the torque generator 40 as a frictional force and is varied by varying the magnetic force generated by the force generator 30. The magnetic force depends of the magnetic field generated by the solenoids 31, 34 and is varied by varying an average strength of a continuous directed electric current and/or a width-ratio of a pulse modulated directed electric current flowing through the solenoids 31, 34.

(17) In particular, no torque is applied to the torque transmitter 52 in the third valve state while in the first valve state and in the second valve state the torque applied to the torque transmitter 52 is adjusted to be adequate for driving the hydraulic motor 55.

(18) The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.